Pathfinder-Plus on a flight over Hawaiian island N'ihau

NASA Technical Reports Server (NTRS)

1998-01-01

Pathfinder-Plus on a flight over the Hawaiian island of N'ihau in 1998. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

Pathfinder-Plus on flight over Hawaiian island N'ihau

NASA Technical Reports Server (NTRS)

1998-01-01

Pathfinder-Plus on a flight over the Hawaiian island of N'ihau in 1998. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

Pathfinder-Plus on flight near Hawaiian island N'ihau

NASA Technical Reports Server (NTRS)

1998-01-01

Pathfinder-Plus on a flight with the Hawaiian island of N'ihau in the background. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

Pathfinder-Plus on flight over Hawaii

NASA Technical Reports Server (NTRS)

1998-01-01

Pathfinder-Plus flying over the Hawaiian Islands in 1998 with Ni'ihau Island in the background. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

Pathfinder-Plus on flight over Hawaii

NASA Technical Reports Server (NTRS)

1998-01-01

Pathfinder-Plus on flight over Hawaii. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

Pathfinder-Plus on a flight in Hawaii

NASA Technical Reports Server (NTRS)

1998-01-01

Pathfinder-Plus on a flight in 1998 over Hawaiian waters. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

Pathfinder-Plus on flight over Hawaiian Islands

NASA Technical Reports Server (NTRS)

1998-01-01

Pathfinder-Plus on flight over Hawaiian Islands in 1998. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

Pathfinder aircraft taking off - setting new solar powered altitude record

NASA Image and Video Library

1995-09-11

The Pathfinder solar-powered remotely piloted aircraft climbs to a record-setting altitude of 50,567 feet during a flight Sept. 11, 1995, at NASA's Dryden Flight Research Center, Edwards, California. The flight was part of the NASA ERAST (Environmental Research Aircraft and Sensor Technology) program. The Pathfinder was designed and built by AeroVironment Inc., Monrovia, California. Solar arrays cover nearly all of the upper wing surface and produce electricity to power the aircraft's six motors.

Identification of metabolic pathways using pathfinding approaches: a systematic review.

PubMed

Abd Algfoor, Zeyad; Shahrizal Sunar, Mohd; Abdullah, Afnizanfaizal; Kolivand, Hoshang

2017-03-01

Metabolic pathways have become increasingly available for various microorganisms. Such pathways have spurred the development of a wide array of computational tools, in particular, mathematical pathfinding approaches. This article can facilitate the understanding of computational analysis of metabolic pathways in genomics. Moreover, stoichiometric and pathfinding approaches in metabolic pathway analysis are discussed. Three major types of studies are elaborated: stoichiometric identification models, pathway-based graph analysis and pathfinding approaches in cellular metabolism. Furthermore, evaluation of the outcomes of the pathways with mathematical benchmarking metrics is provided. This review would lead to better comprehension of metabolism behaviors in living cells, in terms of computed pathfinding approaches. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Pathfinder-Plus on flight over Hawaiian Islands, with N'ihau and Lehua in the background

NASA Technical Reports Server (NTRS)

1998-01-01

Pathfinder-Plus on flight over Hawaiian Islands, with N'ihau and Lehua in the background. Pathfinder was a remotely controlled, solar-powered flying wing, designed and built as a proof-of-concept vehicle for a much larger aircraft capable of flying at extremely high altitudes for weeks at a time. It was built by AeroVironment, Inc., a California company that developed the human-powered Gossamer Condor and Gossamer Albatross lightweight aircraft during the 1970s, and later made the solar-electric powered Gossamer Penguin and Solar Challenger. The basic configuration and concepts for Pathfinder were first realized with the HALSOL (High Altitude Solar) aircraft, built in 1983 by AeroVironment and the Lawrence Livermore Laboratory. Pathfinder was constructed of advanced composites, plastics, and foam, and despite a wingspan of nearly 100 feet, it weighed only about 600 pounds. Pathfinder was one of several unpiloted prototypes under study by NASA's ERAST (Environmental Research Aircraft and Sensor Technology) program, a NASA-industry alliance which is helping develop advanced technologies that will enable aircraft to study the earth's environment during extremely long flights at altitudes in excess of 100,000 feet. (See project description below for Pathfinder's conversion to Pathfinder Plus.) In 1998, the Pathfinder solar-powered flying wing (see its photographs and project description) was modified into the longer-winged Pathfinder Plus configuration and on Aug. 6, 1998, Pathfinder Plus set an altitude record (for propeller-driven aircraft) of approximately 80,285 feet at the Pacific Missile Range Facility. The goal of the Pathfinder Plus flights was to validate new solar, aerodynamic, propulsion, and systems technology developed for its successor, the Centurion, which was designed to reach and sustain altitudes in the 100,000-foot range. The Centurion was succeeded by the Helios Prototype with a goal of reaching and sustaining flight at an altitude of 100,000 feet and flying non-stop for at least 4 days above 50,000 feet. Major activities of Pathfinder Plus' Hawaiian flights included detection of forest nutrient status, forest regrowth after damage caused by Hurricane Iniki in 1992, sediment/algal concentrations in coastal waters, and assessment of coral reef health. Pathfinder science activities were coordinated by NASA's Ames Research Center, Mountain View, California, and included researchers from the University of Hawaii and the University of California. Pathfinder is part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program managed by NASA's Dryden Flight Research Center, Edwards, California. Pathfinder and Pathfinder Plus were designed, built, and operated by AeroVironment, Inc., Monrovia, California. Pathfinder had a 98.4-foot wing span and weighed 560 pounds. Pathfinder Plus has a 121-foot wing span and weighs about 700 pounds. Pathfinder was powered by six electric motors while Pathfinder Plus has eight. Pathfinder's solar arrays produced approximately 8,000 watts of power while Pathfinder Plus' solar arrays produce about 12,500 watts of power. Both Pathfinder aircraft were built primarily of composites, plastic, and foam.

Prospects for discovering pulsars in future continuum surveys using variance imaging

NASA Astrophysics Data System (ADS)

Dai, S.; Johnston, S.; Hobbs, G.

2017-12-01

In our previous paper, we developed a formalism for computing variance images from standard, interferometric radio images containing time and frequency information. Variance imaging with future radio continuum surveys allows us to identify radio pulsars and serves as a complement to conventional pulsar searches that are most sensitive to strictly periodic signals. Here, we carry out simulations to predict the number of pulsars that we can uncover with variance imaging in future continuum surveys. We show that the Australian SKA Pathfinder (ASKAP) Evolutionary Map of the Universe (EMU) survey can find ∼30 normal pulsars and ∼40 millisecond pulsars (MSPs) over and above the number known today, and similarly an all-sky continuum survey with SKA-MID can discover ∼140 normal pulsars and ∼110 MSPs with this technique. Variance imaging with EMU and SKA-MID will detect pulsars with large duty cycles and is therefore a potential tool for finding MSPs and pulsars in relativistic binary systems. Compared with current pulsar surveys at high Galactic latitudes in the Southern hemisphere, variance imaging with EMU and SKA-MID will be more sensitive, and will enable detection of pulsars with dispersion measures between ∼10 and 100 cm-3 pc.

Pathfinder aircraft liftoff on altitude record setting flight of 71,500 feet

NASA Technical Reports Server (NTRS)

1997-01-01

The Pathfinder aircraft has set a new unofficial world record for high-altitude flight of over 71,500 feet for solar-powered aircraft at the U.S. Navy's Pacific Missile Range Facility, Kauai, Hawaii. Pathfinder was designed and manufactured by AeroVironment, Inc, of Simi Valley, California, and was operated by the firm under a jointly sponsored research agreement with NASA's Dryden Flight Research Center, Edwards, California. Pathfinder's record-breaking flight occurred July 7, 1997. The aircraft took off at 11:34 a.m. PDT, passed its previous record altitude of 67,350 feet at about 5:45 p.m. and then reached its new record altitude at 7 p.m. The mission ended with a perfect nighttime landing at 2:05 a.m. PDT July 8. The new record is the highest altitude ever attained by a propellor-driven aircraft. Before Pathfinder, the altitude record for propellor-driven aircraft was 67,028 feet, set by the experimental Boeing Condor remotely piloted aircraft. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus configuration. (See the Pathfinder Plus photos and project description.)

Pathfinder ground preparations prior to altitude record setting flight of 71,500 feet

NASA Technical Reports Server (NTRS)

1997-01-01

Technicians make final adjustments on the solar-powered Pathfinder remotely piloted research aircraft prior to the craft's taking off on a flight which established a new unofficial world's altitude record for both propellor-driven and solar-powered aircraft. The new record of more than 71,500 feet was set during a 14 1/2-hour flight July 7, 1997, from the U.S. Navy's Pacific Missile Range Facility (PMRF) at Barking Sands, Kauai, Hawaii. The new altitude record is subject to verification by the National Aeronautics Association. The Pathfinder took off at 8:34 a.m. HDT, passed its previous record altitude of 67,350 feet about 2:45 p.m., and then reached its new mark at about 4 p.m. Controllers on the ground then initiated a slow decent, and Pathfinder landed seven hours later at 11:05 p.m. HDT. The experimental Boeing Condor remotely-piloted aircraft had held the previous record for propellor-driven craft of 67,028 feet. The Pathfinder had exceeded that height on a previous flight on June 9, 1997, but not by a large enough margin to be considered a new record. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus configuration. (See the Pathfinder Plus photos and project description.)

Holographic beam mapping of the CHIME pathfinder array

NASA Astrophysics Data System (ADS)

Berger, Philippe; Newburgh, Laura B.; Amiri, Mandana; Bandura, Kevin; Cliche, Jean-François; Connor, Liam; Deng, Meiling; Denman, Nolan; Dobbs, Matt; Fandino, Mateus; Gilbert, Adam J.; Good, Deborah; Halpern, Mark; Hanna, David; Hincks, Adam D.; Hinshaw, Gary; Höfer, Carolin; Johnson, Andre M.; Landecker, Tom L.; Masui, Kiyoshi W.; Mena Parra, Juan; Oppermann, Niels; Pen, Ue-Li; Peterson, Jeffrey B.; Recnik, Andre; Robishaw, Timothy; Shaw, J. Richard; Siegel, Seth; Sigurdson, Kris; Smith, Kendrick; Storer, Emilie; Tretyakov, Ian; Van Gassen, Kwinten; Vanderlinde, Keith; Wiebe, Donald

2016-08-01

The Canadian Hydrogen Intensity Mapping Experiment (CHIME) Pathfinder radio telescope is currently surveying the northern hemisphere between 400 and 800 MHz. By mapping the large scale structure of neutral hydrogen through its redshifted 21 cm line emission between z 0.8-2.5 CHIME will contribute to our understanding of Dark Energy. Bright astrophysical foregrounds must be separated from the neutral hydrogen signal, a task which requires precise characterization of the polarized telescope beams. Using the DRAO John A. Galt 26 m telescope, we have developed a holography instrument and technique for mapping the CHIME Pathfinder beams. We report the status of the instrument and initial results of this effort.

(abstract) Scaling Nominal Solar Cell Impedances for Array Design

NASA Technical Reports Server (NTRS)

Mueller, Robert L; Wallace, Matthew T.; Iles, Peter

1994-01-01

This paper discusses a task the objective of which is to characterize solar cell array AC impedance and develop scaling rules for impedance characterization of large arrays by testing single solar cells and small arrays. This effort is aimed at formulating a methodology for estimating the AC impedance of the Mars Pathfinder (MPF) cruise and lander solar arrays based upon testing single cells and small solar cell arrays and to create a basis for design of a single shunt limiter for MPF power control of flight solar arrays having very different inpedances.

Estimating Noise in the Hydrogen Epoch of Reionization Array

NASA Astrophysics Data System (ADS)

Englund Mathieu, Philip; HERA Team

2017-01-01

The Hydrogen Epoch of Reionization Array (HERA) is a radio telescope dedicated to observing large scale structure during and prior to the epoch of reionization. Once completed, HERA will have unprecedented sensitivity to the 21-cm signal from hydrogen reionization. This poster will present time- and frequency-subtraction methods and results from a preliminary analysis of the noise characteristics of the nineteen-element pathfinder array.

PULSE@Parkes, Engaging Students through Hands-On Radio Astronomy

NASA Astrophysics Data System (ADS)

Hollow, Robert; Hobbs, George; Shannon, Ryan M.; Kerr, Matthew

2015-08-01

PULSE@Parkes is an innovative, free educational program run by CSIRO Astronomy and Space Science (CASS) in which high school students use the 64m Parkes radio telescope remotely in real time to observe pulsars then analyse their data. The program caters for a range of student ability and introduces students to hands-on observing and radio astronomy. Students are guided by professional astronomers, educators and PhD students during an observing session. They have ample time to interact with the scientists and discuss astronomy, careers and general scientific questions. Students use a web-based module to analyse pulsar properties. All data from the program are streamed via a web browser and are freely available from the online archive and may be used for open-ended student investigations. The data are also used by the team for ongoing pulsar studies with two scientific papers published to date.Over 100 sessions have been held so far. Most sessions are held at CASS headquarters in Sydney, Australia but other sessions are regularly held in other states with partner institutions. The flexibility of the program means that it is also possible to run sessions in other countries. This aspect of the program is useful for demonstrating capability, engaging students in diverse settings and fostering collaborations. The use of Twitter (@pulseatparkes) during allows followers worldwide to participate and ask questions.Two tours of Japan plus sessions in the UK, Netherlands and Canada have reached a wide audience. Plans for collaborations in China are well underway with the possibility of use with other countries also being explored. The program has also been successfully used in helping to train international graduate students via the International Pulsar Timing Array Schools. We have identified strong demand and need for programs such as this for training undergraduate students in Asia and the North America in observing and data analysis techniques so one area of planned development is teaching materials and a package for students at this level. The program has also been used to inform the development of educational programs for new telescopes such as the Australian SKA Pathfinder (ASKAP) and the SKA.http://pulseatparkes.atnf.csiro.au/

Pathfinder in flight over Hawaii

NASA Image and Video Library

1997-08-28

Pathfinder, NASA's solar-powered, remotely-piloted aircraft is shown while it was conducting a series of science flights to highlight the aircraft's science capabilities while collecting imagery of forest and coastal zone ecosystems on Kauai, Hawaii. The flights also tested two new scientific instruments, a high spectral resolution Digital Array Scanned Interferometer (DASI) and a high spatial resolution Airborne Real-Time Imaging System (ARTIS). The remote sensor payloads were designed by NASA's Ames Research Center, Moffett Field, California, to support NASA's Mission to Planet Earth science programs.

Pathfinder over runway in Hawaii

NASA Image and Video Library

1997-08-28

Pathfinder, NASA's solar-powered, remotely-piloted aircraft is shown while it was conducting a series of science flights to highlight the aircraft's science capabilities while collecting imagery of forest and coastal zone ecosystems on Kauai, Hawaii. The flights also tested two new scientific instruments, a high-spectral-resolution Digital Array Scanned Interferometer (DASI) and a high-spatial-resolution Airborne Real-Time Imaging System (ARTIS). The remote sensor payloads were designed by NASA's Ames Research Center, Moffett Field, California, to support NASA's Mission to Planet Earth science programs.

DART: Instrument Package Developed for Investigating Atmospheric Dust on Mars

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.

2001-01-01

Mars' dust-filled atmosphere could be a significant problem for photovoltaic array operation during long missions on the surface of Mars. Measurements made by Pathfinder showed a 0.3-percent loss of solar array performance per day due to dust obscuration. Thus, dust deposition is the limiting factor in the lifetime of solar arrays for Martian power systems, and developing design tools to mitigate this deposition is important for long missions.

Classification of ASKAP Vast Radio Light Curves

NASA Technical Reports Server (NTRS)

Rebbapragada, Umaa; Lo, Kitty; Wagstaff, Kiri L.; Reed, Colorado; Murphy, Tara; Thompson, David R.

2012-01-01

The VAST survey is a wide-field survey that observes with unprecedented instrument sensitivity (0.5 mJy or lower) and repeat cadence (a goal of 5 seconds) that will enable novel scientific discoveries related to known and unknown classes of radio transients and variables. Given the unprecedented observing characteristics of VAST, it is important to estimate source classification performance, and determine best practices prior to the launch of ASKAP's BETA in 2012. The goal of this study is to identify light curve characterization and classification algorithms that are best suited for archival VAST light curve classification. We perform our experiments on light curve simulations of eight source types and achieve best case performance of approximately 90% accuracy. We note that classification performance is most influenced by light curve characterization rather than classifier algorithm.

Solar Cell Angle of Incidence Corrections

NASA Technical Reports Server (NTRS)

Burger, Dale R.; Mueller, Robert L.

1995-01-01

The Mars Pathfinder mission has three different solar arrays each of which sees changes in incidence angle during normal operation. When solar array angle of incidence effects was researched little published data was found. The small amount of-published data created a need to obtain and evaluate such data. The donation of the needed data, which was taken in the fall of 1994, was a major factor in the preparation of this paper.

Powering the future - a new generation of high-performance solar arrays

NASA Astrophysics Data System (ADS)

Geyer, Freddy; Caswell, Doug; Signorini, Carla

2007-08-01

Funded by ESA's Advanced Research in Telecommunication (ARTES) programme, Thales Alenia Space has developed a new generation of high-power ultra-lightweight solar arrays for telecommunications satellites. Thanks to close cooperation with its industrial partners in Europe, the company has generically qualified a solar array io meet market needs. Indeed, three flight projects were already using the new design as qualification was completed. In addition, the excellent mechanical and thermal behaviour of the new panel structure are contributing to other missions such as Pleïades and LISA Pathfinder.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Yidong; Chen, Xuelei; Wang, Xin

The Tianlai experiment is dedicated to the observation of large-scale structures (LSS) by the 21 cm intensity mapping technique. In this paper, we make forecasts concerning its ability to observe or constrain the dark energy parameters and the primordial non-Gaussianity. From the LSS data, one can use the baryon acoustic oscillation (BAO) and growth rate derived from the redshift space distortion (RSD) to measure the dark energy density and equation of state. The primordial non-Gaussianity can be constrained either by looking for scale-dependent bias in the power spectrum, or by using the bispectrum. Here, we consider three cases: the Tianlaimore » cylinder array pathfinder that is currently being built, an upgrade of the Pathfinder Array with more receiver units, and the full-scale Tianlai cylinder array. Using the full-scale Tianlai experiment, we expect σ{sub w{sub 0}}∼0.082 and σ{sub w{sub a}}∼0.21 from the BAO and RSD measurements, σ{sub f{sub N{sub L}{sup local}}}∼14 from the power spectrum measurements with scale-dependent bias, and σ{sub f{sub N{sub L}{sup local}}}∼22 and σ{sub f{sub N{sub L}{sup equil}}}∼157 from the bispectrum measurements.« less

Results of the Imager for Mars Pathfinder windsock experiment

USGS Publications Warehouse

Sullivan, R.; Greeley, R.; Kraft, M.; Wilson, G.; Golombek, M.; Herkenhoff, K.; Murphy, J.; Smith, P.

2000-01-01

The Imager for Mars Pathfinder (IMP) windsock experiment measured wind speeds at three heights within 1.2 m of the Martian surface during Pathfinder landed operations. These wind data allowed direct measurement of near-surface wind profiles on Mars for the first time, including determination of aerodynamic roughness length and wind friction speeds. Winds were light during periods of windsock imaging, but data from the strongest breezes indicate aerodynamic roughness length of 3 cm at the landing site, with wind friction speeds reaching 1 m/s. Maximum wind friction speeds were about half of the threshold-of-motion friction speeds predicted for loose, fine-grained materials on smooth Martian terrain and about one third of the threshold-of-motion friction speeds predicted for the same size particles over terrain with aerodynamic roughness of 3 cm. Consistent with this, and suggesting that low wind speeds prevailed when the windsock array was not imaged and/or no particles were available for aeolian transport, no wind-related changes to the surface during mission operations have been recognized. The aerodynamic roughness length reported here implies that proposed deflation of fine particles around the landing site, or activation of duneforms seen by IMP and Sojourner, would require wind speeds >28 m/s at the Pathfinder top windsock height (or >31 m/s at the equivalent Viking wind sensor height of 1.6 m) and wind speeds >45 m/s above 10 m. These wind speeds would cause rock abrasion if a supply of durable particles were available for saltation. Previous analyses indicate that the Pathfinder landing site probably is rockier and rougher than many other plains units on Mars, so aerodynamic roughness length elsewhere probably is less than the 3-cm value reported for the Pathfinder site. Copyright 2000 by the American Geophysical Union.

Electrodynamic Dust Shield for Solar Panels on Mars

NASA Technical Reports Server (NTRS)

Calle, C. I.; Buhler, C. R.; Mantovani, J. G.; Clements S.; Chen, A.; Mazumder, M. K.; Biris, A. S.; Nowicki, A. W.

2004-01-01

The Materials Adherence Experiment on the Mars Pathfinder mission measured an obscuration of the solar arrays due to dust deposition at a rate of about 0.2 8% per day. It was estimated that settling dust may cause degradation in performance of a solar panel of between 22% and 89% over the course of two years [1, 2]. These results were obtained without the presence of a global dust storm. Several types of adherence forces keep dust particles attached to surfaces. The most widely discussed adherence force is the electrostatic force. Laboratory experiments [3] as well as indirect evidence from the Wheel Abrasion Experiment on Pathfinder [4] indicate that it is very likely that the particles suspended in the Martian atmosphere are electrostatically charged.

Extragalactic radio surveys in the pre-Square Kilometre Array era

PubMed Central

2017-01-01

The era of the Square Kilometre Array is almost upon us, and pathfinder telescopes are already in operation. This brief review summarizes our current knowledge of extragalactic radio sources, accumulated through six decades of continuum surveys at the low-frequency end of the electromagnetic spectrum and the extensive complementary observations at other wavelengths necessary to gain this understanding. The relationships between radio survey data and surveys at other wavelengths are discussed. Some of the outstanding questions are identified and prospects over the next few years are outlined. PMID:28791175

SERPent: Automated reduction and RFI-mitigation software for e-MERLIN

NASA Astrophysics Data System (ADS)

Peck, Luke W.; Fenech, Danielle M.

2013-08-01

The Scripted E-merlin Rfi-mitigation PipelinE for iNTerferometry (SERPent) is an automated reduction and RFI-mitigation procedure utilising the SumThreshold methodology (Offringa et al., 2010a), originally developed for the LOFAR pipeline. SERPent is written in the Parseltongue language enabling interaction with the Astronomical Image Processing Software (AIPS) program. Moreover, SERPent is a simple 'out of the box' Python script, which is easy to set up and is free of compilers. In addition to the flagging of RFI affected visibilities, the script also flags antenna zero-amplitude dropouts and Lovell telescope phase calibrator stationary scans inherent to the e-MERLIN system. Both the flagging and computational performances of SERPent are presented here, for e-MERLIN commissioning datasets for both L-band (1.3-1.8 GHz) and C-band (4-8 GHz) observations. RFI typically amounts to <20%-25% for the more problematic L-band observations and <5% for the generally RFI quieter C-band. The level of RFI detection and flagging is more accurate and delicate than visual manual flagging, with the output immediately ready for AIPS calibration. SERPent is fully parallelised and has been tested on a range of computing systems. The current flagging rate is at 110 GB day-1 on a 'high-end' computer (16 CPUs, 100 GB memory) which amounts to ˜6.9 GB CPU-1 day-1, with an expected increase in performance when e-MERLIN has completed its commissioning. The refining of automated reduction and calibration procedures is essential for the e-MERLIN legacy projects and future interferometers such as the SKA and the associated pathfinders (MeerKAT and ASKAP), where the vast data sizes (>TB) make traditional astronomer interactions unfeasible.

DETECTION OF FAST RADIO TRANSIENTS WITH MULTIPLE STATIONS: A CASE STUDY USING THE VERY LONG BASELINE ARRAY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, David R.; Wagstaff, Kiri L.; Majid, Walid A.

2011-07-10

Recent investigations reveal an important new class of transient radio phenomena that occur on submillisecond timescales. Often, transient surveys' data volumes are too large to archive exhaustively. Instead, an online automatic system must excise impulsive interference and detect candidate events in real time. This work presents a case study using data from multiple geographically distributed stations to perform simultaneous interference excision and transient detection. We present several algorithms that incorporate dedispersed data from multiple sites, and report experiments with a commensal real-time transient detection system on the Very Long Baseline Array. We test the system using observations of pulsar B0329+54.more » The multiple-station algorithms enhanced sensitivity for detection of individual pulses. These strategies could improve detection performance for a future generation of geographically distributed arrays such as the Australian Square Kilometre Array Pathfinder and the Square Kilometre Array.« less

Rationale for a Mars Pathfinder mission to Chryse Planitia and the Viking 1 lander

NASA Technical Reports Server (NTRS)

Craddock, Robert A.

1994-01-01

Presently the landing site for Mars Pathfinder will be constrained to latitudes between 0 deg and 30 deg N to facilitate communication with earth and to allow the lander and rover solar arrays to generate the maximum possible power. The reference elevation of the site must also be below 0 km so that the descent parachute, a Viking derivative, has sufficient time to open and slow the lander to the correct terminal velocity. Although Mars has as much land surface area as the continental crust of the earth, such engineering constraints immediately limit the number of possible landing sites to only three broad areas: Amazonis, Chryse, and Isidis Planitia. Of these, both Chryse and Isidis Planitia stand out as the sites offering the most information to address several broad scientific topics.

Progress of the Dust Accumulation and Removal Technology Experiment (DART) for the Mars 2001 Lander

NASA Technical Reports Server (NTRS)

Jenkins, Phillip; Landis, Geoffrey A.; Wilt, David; Krasowski, Michael; Greer, Lawrence; Baraona, Cosmo; Scheiman, David

2005-01-01

Dust deposition could be a significant problem for photovoltaic array operation for long duration missions on the surface of Mars. Measurements made by Pathfinder showed 0.3 percent loss of solar array performance per day due to dust obscuration. We have designed an experiment package, "DART", which is part of the Mars ISPP Precursor (MIP) package, to fly on the Mars-2001 Surveyor Lander. This mission, to launch in April 2001, will arrive on Mars in January 2002. The DART experiment is designed to quantify dust deposition from the Mars atmosphere, measure the properties of settled dust, measure the effect of dust deposition on array performance, and test several methods of clearing dust from solar cells.

A Fast Radio Burst Every Second?

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2017-09-01

How frequently do fast radio busts occur in the observable universe? Two researchers have now developed a new estimate.Extragalactic SignalsIn 2007, scientists looking through archival pulsar data discovered a transient radio pulse a flash that lasted only a few milliseconds. Since then, weve found another 22 such fast radio bursts (FRBs), yet we still dont know what causes these energetic signals.Artists illustration of the Very Large Array pinpointing the location of FRB 121102. [Bill Saxton/NRAO/AUI/NSF/Hubble Legacy Archive/ESA/NASA]Recently, some clues have finally come from FRB 121102, the only FRB ever observed to repeat. The multiple pulses detected from this source over the last five years have allowed us to confirm its extragalactic origin and pinpoint an origin for this FRB: a small, low-mass, metal-poor dwarf galaxy located about three billion light-years away.Is FRB 121102 typical? How frequently do such bursts occur, and how frequently can we hope to be able to detect them in the future? And what might these rates tell us about their origins? Two scientists from the Harvard-Smithsonian Center for Astrophysics, Anastasia Fialkov and Abraham Loeb, have now taken a phenomenological approach to answering these questions.Influencing FactorsFialkov and Loeb arguethat there are three main factors that influence the rate of observable FRBs in the universe:The spectral shape of the individual FRBsFRB 121102 had a Gaussian-like spectral profile, which means it peaks in a narrow range of frequencies and may not be detectable outside of that band. If this is typical for FRBs, then signals of distant FRBs may become redshifted to outside of the frequency band that we observe, making them undetectable.FRB detection rates in the 1.253.5GHz band predicted by the authors models (red and blue solid and dashed lines), as a function of the flux limit for detection (top) and as a function of the FRB hosts redshift (bottom). Grey circles mark our detections of FRBs thus far. [Fialkov Loeb 2017]The FRB luminosity functionFRBs may all have the same intrinsic brightness (like Type Ia supernovae, for instance). Alternatively, there may be many more faint and dim FRBs than bright ones (like the distribution of galaxy luminosities). Thisdifference affects the number of FRBs we could detect.The host galaxy populationAre FRBs most commonly hosted by low-mass galaxies like FRB 121102? Or do they occur in high-mass galaxies as well? This affects the number of FRBs we would expect to observe at different redshifts.Future HopeBy exploring a range of models that vary these three factors, Fialkov and Loeb find estimates for the rate of FRBs that would appear inthe 500 MHz3.5 GHz frequency band probed by observatories like Parkes, Arecibo, and the Australian Square Kilometre Array Pathfinder (ASKAP).Fialkov and Loeb find that, when we account for faint sources, one FRB may occur per second across the sky in this band. The authors show that future low-frequency radio telescopes with higher sensitivity, such as the Square Kilometre Array, should be able to detect many more of these sources, helping us to differentiate between the models and narrow down the properties of the bursts and their hosts. This, in turn, may finally reveal what causes these mysterious signals.CitationAnastasia Fialkov and Abraham Loeb 2017 ApJL 846 L27. doi:10.3847/2041-8213/aa8905

KSC-2014-2742

NASA Image and Video Library

2014-05-19

CAPE CANAVERAL, Fla. – Workers take an early morning walk along the Pathfinder Trail near the Operations and Support Building II at Kennedy Space Center in Florida, to officially kick off National Employee Health and Fitness Month with the NASA Moves! challenge. NASA Moves! challenged the workforce from each of the agency's field centers to engage in at least 20 minutes of activity, or 10,000 steps, each day from May 18-31. About 100 people participated in the kickoff event on the Pathfinder Trail in the heart of the center's Launch Complex 39. The one-third-mile-long gravel walkway traces the iconic shape of a space shuttle orbiter and features a set of exercise stations. The friendly contest is part of NASA's new Health4Life initiative, a Web-based health initiative designed to help employees track their health, fitness and nutrition. Health4Life also provides an array of resources geared toward increasing physical activity. Photo credit: NASA/Dimitri Gerondidakis

The Detection of an Extremely Bright Fast Radio Burst in a Phased Array Feed Survey

NASA Astrophysics Data System (ADS)

Bannister, K. W.; Shannon, R. M.; Macquart, J.-P.; Flynn, C.; Edwards, P. G.; O'Neill, M.; Osłowski, S.; Bailes, M.; Zackay, B.; Clarke, N.; D'Addario, L. R.; Dodson, R.; Hall, P. J.; Jameson, A.; Jones, D.; Navarro, R.; Trinh, J. T.; Allison, J.; Anderson, C. S.; Bell, M.; Chippendale, A. P.; Collier, J. D.; Heald, G.; Heywood, I.; Hotan, A. W.; Lee-Waddell, K.; Madrid, J. P.; Marvil, J.; McConnell, D.; Popping, A.; Voronkov, M. A.; Whiting, M. T.; Allen, G. R.; Bock, D. C.-J.; Brodrick, D. P.; Cooray, F.; DeBoer, D. R.; Diamond, P. J.; Ekers, R.; Gough, R. G.; Hampson, G. A.; Harvey-Smith, L.; Hay, S. G.; Hayman, D. B.; Jackson, C. A.; Johnston, S.; Koribalski, B. S.; McClure-Griffiths, N. M.; Mirtschin, P.; Ng, A.; Norris, R. P.; Pearce, S. E.; Phillips, C. J.; Roxby, D. N.; Troup, E. R.; Westmeier, T.

2017-05-01

We report the detection of an ultra-bright fast radio burst (FRB) from a modest, 3.4-day pilot survey with the Australian Square Kilometre Array Pathfinder. The survey was conducted in a wide-field fly’s-eye configuration using the phased-array-feed technology deployed on the array to instantaneously observe an effective area of 160 deg2, and achieve an exposure totaling 13200 deg2 hr . We constrain the position of FRB 170107 to a region 8\\prime × 8\\prime in size (90% containment) and its fluence to be 58 ± 6 Jy ms. The spectrum of the burst shows a sharp cutoff above 1400 MHz, which could be due to either scintillation or an intrinsic feature of the burst. This confirms the existence of an ultra-bright (> 20 Jy ms) population of FRBs.

Characterization of Settled Atmospheric Dust by the DART Experiment

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Jenkins, Phillip P.; Baraona, Cosmo

1999-01-01

The DART ("Dust Accumulation and Removal Test") package is an experiment which will fly as part of the MIP experiment on the Mars-2001 Surveyor Lander. Dust deposition could be a significant problem for photovoltaic array operation for long duration emissions on the surface of Mars. Measurements made by Pathfinder showed 0.3% loss of solar array performance per day due to dust obscuration. The DART experiment is designed to quantify dust deposition from the Mars atmosphere, measure the properties of settled dust, measure the effect of dust deposition on the array performance, and test several methods of mitigating the effect of settled dust on a solar array. Although the purpose of DART (along with its sister experiment, MATE) is to gather information critical to the design of future power systems on the surface of Mars, the dust characterization instrumentation on DART will also provide significant scientific data on the properties of settled atmospheric dust.

Data acquisition system and ground calibration of polarized gamma-ray observer (PoGOLite)

NASA Astrophysics Data System (ADS)

Takahashi, Hiromitsu; Chauvin, Maxime; Fukazawa, Yasushi; Jackson, Miranda; Kamae, Tuneyoshi; Kawano, Takafumi; Kiss, Mozsi; Kole, Merlin; Mikhalev, Victor; Mizuno, Tsunefumi; Moretti, Elena; Pearce, Mark; Rydström, Stefan

2014-07-01

The Polarized Gamma-ray Observer, PoGOLite, is a balloon experiment with the capability of detecting 10% polarization from a 200 mCrab celestial object between the energy-range 25-80 keV in one 6 hour flight. Polarization measurements in soft gamma-rays are expected to provide a powerful probe into high-energy emission mechanisms in/around neutron stars, black holes, supernova remnants, active-galactic nuclei etc. The "pathfinder" flight was performed in July 2013 for 14 days from Sweden to Russia. The polarization is measured using Compton scattering and photoelectric absorption in an array of 61 well-type phoswich detector cells (PDCs) for the pathfinder instrument. The PDCs are surrounded by 30 BGO crystals which form a side anti-coincidence shield (SAS) and passive polyethylene neutron shield. There is a neutron detector consisting of LiCaAlF6 (LiCAF) scintillator covered with BGOs to measure the background contribution of atmospheric neutrons. The data acquisition system treats 92 PMT signals from 61 PDCs + 30 SASs + 1 neutron detector, and it is developed based on SpaceWire spacecraft communication network. Most of the signal processing is done by digital circuits in Field Programmable Gate Arrays (FPGAs). This enables the reduction of the mass, the space and the power consumption. The performance was calibrated before the launch.

Source finding in linear polarization for LOFAR, and SKA predecessor surveys, using Faraday moments

NASA Astrophysics Data System (ADS)

Farnes, J. S.; Heald, G.; Junklewitz, H.; Mulcahy, D. D.; Haverkorn, M.; Van Eck, C. L.; Riseley, C. J.; Brentjens, M.; Horellou, C.; Vacca, V.; Jones, D. I.; Horneffer, A.; Paladino, R.

2018-03-01

The optimal source-finding strategy for linear polarization data is an unsolved problem, with many inhibitive factors imposed by the technically challenging nature of polarization observations. Such an algorithm is essential for Square Kilometre Array (SKA) pathfinder surveys, such as the Multifrequency Snapshot Sky Survey with the LOw Frequency ARray (LOFAR), as data volumes are significant enough to prohibit manual inspection. We present a new strategy of `Faraday Moments' for source-finding in linear polarization with LOFAR, using the moments of the frequency-dependent full-Stokes data (i.e. the mean, standard deviation, skewness, and excess kurtosis). Through simulations of the sky, we find that moments can identify polarized sources with a high completeness: 98.5 per cent at a signal to noise of 5. While the method has low reliability, rotation measure (RM) synthesis can be applied per candidate source to filter out instrumental and spurious detections. This combined strategy will result in a complete and reliable catalogue of polarized sources that includes the full sensitivity of the observational bandwidth. We find that the technique can reduce the number of pixels on which RM Synthesis needs to be performed by a factor of ≈1 × 105 for source distributions anticipated with modern radio telescopes. Through tests on LOFAR data, we find that the technique works effectively in the presence of diffuse emission. Extensions of this method are directly applicable to other upcoming radio surveys such as the POlarization Sky Survey of the Universe's Magnetism with the Australia Square Kilometre Array Pathfinder, and the SKA itself.

Status of the PAPPA experiment

NASA Technical Reports Server (NTRS)

Kogut, Alan

2006-01-01

The Primordial Anisotropy Polarization Pathfinder Array (PAPPA) is a balloonborne instrument to measure the polarization of the cosmic microwave background and search for the signature of primordial gravity waves. PAPPA uses a novel marriage of RF phase modulation and millimeter-wave bolometric detectors to produce a "polarimeter-on-a-chip" capable of simultaneously measuring the Stokes I, Q, and U parameters on the sky. I will discuss the current status and future plans for PAPPA.

Harnessing the Power of the Sun

NASA Technical Reports Server (NTRS)

2005-01-01

The Environmental Research Aircraft and Sensor Technology (ERAST) Alliance was created in 1994 and operated for 9 years as a NASA-sponsored coalition of 28 members from small companies, government, universities, and nonprofit organizations. ERAST s goal was to foster development of remotely piloted aircraft technology for scientific, humanitarian, and commercial purposes. Some of the aircraft in the ERAST Alliance were intended to fly unmanned at high altitudes for days at a time, and flying for such durations required alternative sources of power that did not add weight. The most successful solution for this type of sustained flight is the lightest solar energy. Photovoltaic cells convert sunlight directly into electricity. They are made of semi-conducting materials similar to those used in computer chips. When sunlight is absorbed, electrons are knocked loose from their atoms, allowing electricity to flow. Under the ERAST Alliance, two solar-powered technology demonstration aircraft, Pathfinder and Helios, were developed. Pathfinder is a lightweight, remotely piloted flying wing aircraft that demonstrated the technology of applying solar cells for long-duration, high-altitude flight. Solar arrays covering most of the upper wing surface provide power for the aircraft s electric motors, avionics, communications, and other electronic systems. Pathfinder also has a backup battery system that can provide power for between 2 and 5 hours to allow limited-duration flight after dark. It was designed, built, and operated by AeroVironment, Inc., of Monrovia, California. On September 11, 1995, Pathfinder reached an altitude of 50,500 feet, setting a new altitude record for solar-powered aircraft. The National Aeronautic Association presented the NASA-industry team with an award for 1 of the 10 Most Memorable Record Flights of 1995.

The Data Processor of the JEM-EUSO pathfinders

NASA Astrophysics Data System (ADS)

Scotti, V.; Osteria, G.

2014-06-01

JEM-EUSO is a wide-angle refractive UV telescope being proposed for attachment to the Japanese Experiment Module on ISS. The main goal of the mission is to study Extreme Energy Cosmic Rays. Two pathfinder mission are now in progress: EUSO-TA and EUSO-Balloon. The EUSO-TA project foresees the installation of a telescope prototype in the Telescope Array site. The aim of this project is to calibrate the telescope with the TA fluorescence detector. An initial run of one year starting from 2013 is foreseen. EUSO-Balloon is a pathfinder mission in which a prototype telescope will be mounted on a stratospheric balloon. The main aim of this mission is to perform a end-to-end test of all the key technologies and instrumentation of JEM-EUSO detectors and to prove the global detection chain. EUSO-Balloon will measure the UV background fundamental for the development of the simulations. EUSO-Balloon has the potential to detect Extensive Air Showers from above, paving the way for any future space-based EECR observatory. We will present the Data Processor of the pathfinders. The DP is the component of the Electronics System which performs data management and instrument control. The DP controls front-end electronics, performs 2nd level trigger filtering, tags events with arrival time and payload position through a GPS system, manages mass memory for data storage, measures live and dead time of the telescope, provides signals for time synchronization of the event, performs housekeeping monitor and handles interface to the telemetry system. We will describe the main components of the DP, the state-of-the-art and the results of the tests carried out.

Solar array model corrections from Mars Pathfinder lander data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ewell, R.C.; Burger, D.R.

1997-12-31

The MESUR solar array power model initially assumed values for input variables. After landing early surface variables such as array tilt and azimuth or early environmental variables such as array temperature can be corrected. Correction of later environmental variables such as tau versus time, spectral shift, dust deposition, and UV darkening is dependent upon time, on-board science instruments, and ability to separate effects of variables. Engineering estimates had to be made for additional shadow losses and Voc sensor temperature corrections. Some variations had not been expected such as tau versus time of day, and spectral shift versus time of day.more » Additions needed to the model are thermal mass of lander petal and correction between Voc sensor and temperature sensor. Conclusions are: the model works well; good battery predictions are difficult; inclusion of Isc and Voc sensors was valuable; and the IMP and MAE science experiments greatly assisted the data analysis and model correction.« less

Propulsion Technology Demonstrator. [Demonstrating Novel CubeSat Technologies in Low Earth Orbit

NASA Technical Reports Server (NTRS)

Marmie, John; Martinez, Andres; Petro, Andrew

2015-01-01

NASA's Pathfinder Technology Demonstrator (PTD) project will test the operation of a variety of novel CubeSat technologies in low- Earth orbit, providing significant enhancements to the performance of these small and effective spacecraft. Each Pathfinder Technology Demonstrator mission consists of a 6-unit (6U) CubeSat weighing approximately 26 pounds (12 kilograms) and measuring 12 inches x 10 inches x 4 inches (30 centimeters x 25 centimeters x 10 centimeters), comparable in size to a common shoebox. CubeSats are a class of nanosatellites that use a standard size and form factor. The standard Cube- Sat size uses a "one unit" or "1U" measuring 4 inches x 4 inches x 4 inches (10x10x10 centimeters) and is extendable to larger sizes by "stacking" a number of the 1U blocks to form a larger spacecraft. Each PTD spacecraft will also be equipped with deployable solar arrays that provide an average of 44 watts of power while in orbit.

KSC-2014-2737

NASA Image and Video Library

2014-05-19

CAPE CANAVERAL, Fla. – Kennedy Space Center Director Bob Cabana, right, Florida State Surgeon General John Armstrong and other guests prepare for an early morning run at the center's Pathfinder Trail near the Operations and Support Building II at Kennedy Space Center in Florida, to officially kick off National Employee Health and Fitness Month with the NASA Moves! challenge. NASA Moves! challenged the workforce from each of the agency's field centers to engage in at least 20 minutes of activity, or 10,000 steps, each day from May 18-31. About 100 people participated in the kickoff event on the Pathfinder Trail in the heart of the center's Launch Complex 39. The one-third-mile-long gravel walkway traces the iconic shape of a space shuttle orbiter and features a set of exercise stations. The friendly contest is part of NASA's new Health4Life initiative, a Web-based health initiative designed to help employees track their health, fitness and nutrition. Health4Life also provides an array of resources geared toward increasing physical activity. Photo credit: NASA/Dimitri Gerondidakis

KSC-2014-2740

NASA Image and Video Library

2014-05-19

CAPE CANAVERAL, Fla. – Kennedy Space Center Director Bob Cabana, right, and Florida State Surgeon General John Armstrong begin an early morning run along the center's Pathfinder Trail near the Operations and Support Building II at Kennedy Space Center in Florida, to officially kick off National Employee Health and Fitness Month with the NASA Moves! challenge. NASA Moves! challenged the workforce from each of the agency's field centers to engage in at least 20 minutes of activity, or 10,000 steps, each day from May 18-31. About 100 people participated in the kickoff event on the Pathfinder Trail in the heart of the center's Launch Complex 39. The one-third-mile-long gravel walkway traces the iconic shape of a space shuttle orbiter and features a set of exercise stations. The friendly contest is part of NASA's new Health4Life initiative, a Web-based health initiative designed to help employees track their health, fitness and nutrition. Health4Life also provides an array of resources geared toward increasing physical activity. Photo credit: NASA/Dimitri Gerondidakis

KSC-2014-2739

NASA Image and Video Library

2014-05-19

CAPE CANAVERAL, Fla. – Kennedy Space Center Director Bob Cabana, right, shakes hands with Florida State Surgeon General John Armstrong before an early morning run along the center's Pathfinder Trail near the Operations and Support Building II at Kennedy Space Center in Florida, to officially kick off National Employee Health and Fitness Month with the NASA Moves! challenge. NASA Moves! challenged the workforce from each of the agency's field centers to engage in at least 20 minutes of activity, or 10,000 steps, each day from May 18-31. About 100 people participated in the kickoff event on the Pathfinder Trail in the heart of the center's Launch Complex 39. The one-third-mile-long gravel walkway traces the iconic shape of a space shuttle orbiter and features a set of exercise stations. The friendly contest is part of NASA's new Health4Life initiative, a Web-based health initiative designed to help employees track their health, fitness and nutrition. Health4Life also provides an array of resources geared toward increasing physical activity. Photo credit: NASA/Dimitri Gerondidakis

KSC-2014-2745

NASA Image and Video Library

2014-05-19

CAPE CANAVERAL, Fla. – Kennedy Space Center Director Bob Cabana, left, and Florida State Surgeon General John Armstrong complete an early morning run along the center's Pathfinder Trail near the Operations and Support Building II at Kennedy Space Center in Florida, to officially kick off National Employee Health and Fitness Month with the NASA Moves! challenge. NASA Moves! challenged the workforce from each of the agency's field centers to engage in at least 20 minutes of activity, or 10,000 steps, each day from May 18-31. About 100 people participated in the kickoff event on the Pathfinder Trail in the heart of the center's Launch Complex 39. The one-third-mile-long gravel walkway traces the iconic shape of a space shuttle orbiter and features a set of exercise stations. The friendly contest is part of NASA's new Health4Life initiative, a Web-based health initiative designed to help employees track their health, fitness and nutrition. Health4Life also provides an array of resources geared toward increasing physical activity. Photo credit: NASA/Dimitri Gerondidakis

KSC-2014-2741

NASA Image and Video Library

2014-05-19

CAPE CANAVERAL, Fla. – Nancy Bray, right, Center Operations director at Kennedy Space Center, and Lori Hicks, Human Resources, take an early morning walk along the center's Pathfinder Trail near the Operations and Support Building II at Kennedy Space Center in Florida, to officially kick off National Employee Health and Fitness Month with the NASA Moves! challenge. NASA Moves! challenged the workforce from each of the agency's field centers to engage in at least 20 minutes of activity, or 10,000 steps, each day from May 18-31. About 100 people participated in the kickoff event on the Pathfinder Trail in the heart of the center's Launch Complex 39. The one-third-mile-long gravel walkway traces the iconic shape of a space shuttle orbiter and features a set of exercise stations. The friendly contest is part of NASA's new Health4Life initiative, a Web-based health initiative designed to help employees track their health, fitness and nutrition. Health4Life also provides an array of resources geared toward increasing physical activity. Photo credit: NASA/Dimitri Gerondidakis

KSC-2014-2743

NASA Image and Video Library

2014-05-19

CAPE CANAVERAL, Fla. – Kennedy Space Center Director Bob Cabana, right, and Florida State Surgeon General John Armstrong take an early morning run along the center's Pathfinder Trail near the Operations and Support Building II at Kennedy Space Center in Florida, to officially kick off National Employee Health and Fitness Month with the NASA Moves! challenge. NASA Moves! challenged the workforce from each of the agency's field centers to engage in at least 20 minutes of activity, or 10,000 steps, each day from May 18-31. About 100 people participated in the kickoff event on the Pathfinder Trail in the heart of the center's Launch Complex 39. The one-third-mile-long gravel walkway traces the iconic shape of a space shuttle orbiter and features a set of exercise stations. The friendly contest is part of NASA's new Health4Life initiative, a Web-based health initiative designed to help employees track their health, fitness and nutrition. Health4Life also provides an array of resources geared toward increasing physical activity. Photo credit: NASA/Dimitri Gerondidakis

Telescope Array Control System Based on Wireless Touch Screen Platform

NASA Astrophysics Data System (ADS)

Fu, X. N.; Huang, L.; Wei, J. Y.

2016-07-01

GWAC (Ground-based Wide Angle Cameras) are the ground-based observational instruments of the Sino-French cooperation SVOM (Space Variable Objects Monitor) astronomical satellite, and Mini-GWAC is a pathfinder and supplement of GWAC. In the context of the Mini-GWAC telescope array, this paper introduces the design and implementation of a kind of telescope array control system, which is based on wireless serial interface module to communicate. We describe the development and implementation of the system in detail in terms of control system principle, system hardware structure, software design, experiment, and test. The system uses the touch-control PC which is based on the Windows CE system as the upper-computer, the wireless transceiver module and PLC (Programmable Logic Controller) as the core. It has the advantages of low cost, reliable data transmission, and simple operation. So far, the control system has been applied to Mini-GWAC successfully.

H I debris in the IC 1459 galaxy group

NASA Astrophysics Data System (ADS)

Saponara, Juliana; Koribalski, Bärbel S.; Benaglia, Paula; Fernández López, Manuel

2018-01-01

We present H I synthesis imaging of the giant elliptical galaxy IC 1459 and its surroundings with the Australia Telescope Compact Array. Our search for extended H I emission revealed a large complex of H I clouds near IC 1459, likely to be the debris from tidal interactions with neighbouring galaxies. The total H I mass (∼109 M⊙) in the detected clouds spans 250 kpc from the north-east of the gas-rich spiral NGC 7418A to the south-east of IC 1459. The extent and mass of the H I debris, which shows rather irregular morphology and kinematics, are similar to those in other nearby groups. Together with H I clouds recently detected near two other IC 1459 group members, namely IC 5270 and NGC 7418, using phased-array feeds on the Australian Square Kilometre Array Pathfinder, the detected debris make up a significant fraction of the group's intergalactic medium.

Telescope Array Control System Based on Wireless Touch Screen Platform

NASA Astrophysics Data System (ADS)

Fu, Xia-nan; Huang, Lei; Wei, Jian-yan

2017-10-01

Ground-based Wide Angle Cameras (GMAC) are the ground-based observational facility for the SVOM (Space Variable Object Monitor) astronomical satellite of Sino-French cooperation, and Mini-GWAC is the pathfinder and supplement of GWAC. In the context of the Mini-GWAC telescope array, this paper introduces the design and implementation of a kind of telescope array control system based on the wireless touch screen platform. We describe the development and implementation of the system in detail in terms of control system principle, system hardware structure, software design, experiment, and test etc. The system uses a touch-control PC which is based on the Windows CE system as the upper computer, while the wireless transceiver module and PLC (Programmable Logic Controller) are taken as the system kernel. It has the advantages of low cost, reliable data transmission, and simple operation. And the control system has been applied to the Mini-GWAC successfully.

ALMA, APEX and beyond

NASA Astrophysics Data System (ADS)

Zwaan, M.; Testi, L.

The Atacama Large Millimeter/submillimeter Array (ALMA) is currently being constructed at the 5000m Chajnantor plateau in the Chilean Andes. ALMA has been designed and is being built to deliver transformational science in the millimeter and submillimeter regime for many years to come. We briefly describe the project status and timeline. The Atacama Pathfinder Experiment (APEX), built at the same site, is already operational and proves to be an effective survey instrument. We discuss which niches in millimeter/submillimeter astronomy will remain open for a possible facility in Antarctica.

JPL Big Data Technologies for Radio Astronomy

NASA Astrophysics Data System (ADS)

Jones, Dayton L.; D'Addario, L. R.; De Jong, E. M.; Mattmann, C. A.; Rebbapragada, U. D.; Thompson, D. R.; Wagstaff, K.

2014-04-01

During the past three years the Jet Propulsion Laboratory has been working on several technologies to deal with big data challenges facing next-generation radio arrays, among other applications. This program has focused on the following four areas: 1) We are investigating high-level ASIC architectures that reduce power consumption for cross-correlation of data from large interferometer arrays by one to two orders of magnitude. The cost of operations for the Square Kilometre Array (SKA), which may be dominated by the cost of power for data processing, is a serious concern. A large improvement in correlator power efficiency could have a major positive impact. 2) Data-adaptive algorithms (machine learning) for real-time detection and classification of fast transient signals in high volume data streams are being developed and demonstrated. Studies of the dynamic universe, particularly searches for fast (<< 1 second) transient events, require that data be analyzed rapidly and with robust RFI rejection. JPL, in collaboration with the International Center for Radio Astronomy Research in Australia, has developed a fast transient search system for eventual deployment on ASKAP. In addition, a real-time transient detection experiment is now running continuously and commensally on NRAO's Very Long Baseline Array. 3) Scalable frameworks for data archiving, mining, and distribution are being applied to radio astronomy. A set of powerful open-source Object Oriented Data Technology (OODT) tools is now available through Apache. OODT was developed at JPL for Earth science data archives, but it is proving to be useful for radio astronomy, planetary science, health care, Earth climate, and other large-scale archives. 4) We are creating automated, event-driven data visualization tools that can be used to extract information from a wide range of complex data sets. Visualization of complex data can be improved through algorithms that detect events or features of interest and autonomously generate images or video to display those features. This work has been carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

MIGHTEE: The MeerKAT International GHz Tiered Extragalactic Exploration

NASA Astrophysics Data System (ADS)

Taylor, A. Russ; Jarvis, Matt

2017-05-01

The MeerKAT telescope is the precursor of the Square Kilometre Array mid-frequency dish array to be deployed later this decade on the African continent. MIGHTEE is one of the MeerKAT large survey projects designed to pathfind SKA key science in cosmology and galaxy evolution. Through a tiered radio continuum deep imaging project including several fields totaling 20 square degrees to microJy sensitivities and an ultra-deep image of a single 1 square degree field of view, MIGHTEE will explore dark matter and large scale structure, the evolution of galaxies, including AGN activity and star formation as a function of cosmic time and environment, the emergence and evolution of magnetic fields in galaxies, and the magnetic counter part to large scale structure of the universe.

KSC-2014-2738

NASA Image and Video Library

2014-05-19

CAPE CANAVERAL, Fla. – Kennedy Space Center Director Bob Cabana, right, Florida State Surgeon General John Armstrong, other Kennedy managers and guests prepare for an early morning run at the center's Pathfinder Trail near the Operations and Support Building II at Kennedy Space Center in Florida, to officially kick off National Employee Health and Fitness Month with the NASA Moves! challenge. NASA Moves! challenged the workforce from each of the agency's field centers to engage in at least 20 minutes of activity, or 10,000 steps, each day from May 18-31. About 100 people participated in the kickoff event on the Pathfinder Trail in the heart of the center's Launch Complex 39. The one-third-mile-long gravel walkway traces the iconic shape of a space shuttle orbiter and features a set of exercise stations. The friendly contest is part of NASA's new Health4Life initiative, a Web-based health initiative designed to help employees track their health, fitness and nutrition. Health4Life also provides an array of resources geared toward increasing physical activity. Photo credit: NASA/Dimitri Gerondidakis

KSC-2014-2744

NASA Image and Video Library

2014-05-19

CAPE CANAVERAL, Fla. – From left, Florida State Surgeon General John Armstrong, Kennedy Space Center Director Bob Cabana, Center Operations Director Nancy Bray and Kennedy workers and guests prepare to take an early morning run along the center's Pathfinder Trail near the Operations and Support Building II at Kennedy Space Center in Florida, to officially kick off National Employee Health and Fitness Month with the NASA Moves! challenge. NASA Moves! challenged the workforce from each of the agency's field centers to engage in at least 20 minutes of activity, or 10,000 steps, each day from May 18-31. About 100 people participated in the kickoff event on the Pathfinder Trail in the heart of the center's Launch Complex 39. The one-third-mile-long gravel walkway traces the iconic shape of a space shuttle orbiter and features a set of exercise stations. The friendly contest is part of NASA's new Health4Life initiative, a Web-based health initiative designed to help employees track their health, fitness and nutrition. Health4Life also provides an array of resources geared toward increasing physical activity. Photo credit: NASA/Dimitri Gerondidakis

The Fourier-Kelvin Stellar Interferometer (FKSI): A Discovery Class TPF/DARWIN Pathfinder Mission Concept

NASA Technical Reports Server (NTRS)

Danchi, W. C.; Allen, R. J.; Benford, D. J.; Deming, D.; Gezan, D. Y.; Kuchner, M.; Leisawitz, D. T.; Linfield, R.; Millan-Gabet, R.; Monnier, J. D.

2003-01-01

The Fourier-Kelvin Stellar Interferometer (FKSI) is a mission concept for an imaging and nulling interferometer for the mid-infrared spectral region (5-30 microns). FKSI is conceived as a scientific and technological pathfinder to TPF/DARWIN as well as SPIRIT, SPECS, and SAFIR. It will also be a high angular resolution system complementary to NGST. The scientific emphasis of the mission is on the evolution of protostellar systems, from just after the collapse of the precursor molecular cloud core, through the formation of the disk surrounding the protostar, the formation of planets in the disk, and eventual dispersal of the disk material. FKSI will also search for brown dwarfs and Jupiter mass and smaller planets, and could also play a very powerful role in the investigation of the structure of active galactic nuclei and extra-galactic star formation. We have been studying alternative interferometer architectures and beam combination techniques, and evaluating the relevant science and technology tradeoffs. Some of the technical challenges include the development of the cryocooler systems necessary for the telescopes and focal plane array, light and stiff but well-damped truss systems to support the telescopes, and lightweight and coolable optical telescopes. We present results of detailed design studies of the FKSI starting with a design consisting of five one meter diameter telescopes arranged along a truss structure in a linear non-redundant array, cooled to 35 K. A maximum baseline of 20 meters gives a nominal resolution of 26 mas at 5 microns. Using a Fizeau beam combination technique, a simple focal plane camera could be used to obtain both Fourier and spectral data simultaneously for a given orientation of the array. The spacecraft will be rotated to give sufficient Fourier data to reconstruct complex images of a broad range of astrophysical sources. Alternative and simpler three and two telescope designs emphasizing nulling and spectroscopy also have been investigated and will be discussed.

Dynamic Pathfinders: Leveraging Your OPAC to Create Resource Guides

ERIC Educational Resources Information Center

Hunter, Ben

2008-01-01

Library pathfinders are a time-tested method of leading library users to important resources. However, paper-based pathfinders suffer from space limitations, and both paper-based and Web-based pathfinders require frequent updates to keep up with new library acquisitions. This article details a step-by-step method to create an online dynamic…

MARS PATHFINDER CAMERA TEST IN SAEF-2

NASA Technical Reports Server (NTRS)

1996-01-01

In the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2), workers from the Jet Propulsion Laboratory (JPL) are conducting a systems test of the imager for the Mars Pathfinder. Mounted on the Pathfinder lander, the imager (the white cylindrical element the worker is touching) is a specially designed camera featuring a stereo-imaging system with color capability provided by a set of selectable filters. It is mounted on an extendable mast that will pop up after the lander touches down on the Martian surface. The imager will transmit images of the terrain, allowing engineers back on Earth to survey the landing site before the Pathfinder rover is deployed to explore the area. The Mars Pathfinder is scheduled for launch aboard a Delta II expendable launch vehicle on Dec. 2. JPL manages the Pathfinder project for NASA.

Mars Pathfinder Status at Launch

NASA Technical Reports Server (NTRS)

Spear, A. J.; Freeman, Delma C., Jr.; Braun, Robert D.

1996-01-01

The Mars Pathfinder Flight System is in final test, assembly and launch preparations at the Kennedy Space Center in Florida. Launch is scheduled for 2 Dec. 1996. The Flight System development, in particular the Entry, Descent, and Landing (EDL) system, was a major team effort involving JPL, other NASA centers and industry. This paper provides a summary Mars Pathfinder description and status at launch. In addition, a section by NASA's Langley Research Center, a key EDL contributor, is provided on their support to Mars Pathfinder. This section is included as an example of the work performed by Pathfinder team members outside JPL.

Space Based Gravitational Wave Observatories (SGOs)

NASA Technical Reports Server (NTRS)

Livas, Jeff

2014-01-01

Space-based Gravitational-wave Observatories (SGOs) will enable the systematic study of the frequency band from 0.0001 - 1 Hz of gravitational waves, where a rich array of astrophysical sources is expected. ESA has selected The Gravitational Universe as the science theme for the L3 mission opportunity with a nominal launch date in 2034. This will be at a minimum 15 years after ground-based detectors and pulsar timing arrays announce their first detections and at least 18 years after the LISA Pathfinder Mission will have demonstrated key technologies in a dedicated space mission. It is therefore important to develop mission concepts that can take advantage of the momentum in the field and the investment in both technology development and a precision measurement community on a more near-term timescale than the L3 opportunity. This talk will discuss a mission concept based on the LISA baseline that resulted from a recent mission architecture study.

Rover imaging system for the Mars rover/sample return mission

NASA Technical Reports Server (NTRS)

1993-01-01

In the past year, the conceptual design of a panoramic imager for the Mars Environmental Survey (MESUR) Pathfinder was finished. A prototype camera was built and its performace in the laboratory was tested. The performance of this camera was excellent. Based on this work, we have recently proposed a small, lightweight, rugged, and highly capable Mars Surface Imager (MSI) instrument for the MESUR Pathfinder mission. A key aspect of our approach to optimization of the MSI design is that we treat image gathering, coding, and restoration as a whole, rather than as separate and independent tasks. Our approach leads to higher image quality, especially in the representation of fine detail with good contrast and clarity, without increasing either the complexity of the camera or the amount of data transmission. We have made significant progress over the past year in both the overall MSI system design and in the detailed design of the MSI optics. We have taken a simple panoramic camera and have upgraded it substantially to become a prototype of the MSI flight instrument. The most recent version of the camera utilizes miniature wide-angle optics that image directly onto a 3-color, 2096-element CCD line array. There are several data-taking modes, providing resolution as high as 0.3 mrad/pixel. Analysis tasks that were performed or that are underway with the test data from the prototype camera include the following: construction of 3-D models of imaged scenes from stereo data, first for controlled scenes and later for field scenes; and checks on geometric fidelity, including alignment errors, mast vibration, and oscillation in the drive system. We have outlined a number of tasks planned for Fiscal Year '93 in order to prepare us for submission of a flight instrument proposal for MESUR Pathfinder.

Pathfinder landing sites at candidate SNC impact ejection sites

NASA Technical Reports Server (NTRS)

Golombek, Matthew P.

1994-01-01

If Mars Pathfinder were able to land at a site on Mars from which the SNC meteorites were ejected by impact, the Pathfinder mission would essentially represent a very inexpensive sample return mission. Geologic units that contain four potential impact craters from which SNC meteorites could have been ejected from Mars are accessible to the Mars Pathfinder lander. Determining that SNC meteorites came from a particular spot on Mars raises the intriguing possibility of using Pathfinder as a sample return mission and providing a radiometric age for the considerably uncertain martian crater-age timescale. Pathfinder instruments are capable of determining if the rock type at the landing site is similar to that of one or more of the SNC meteorites, which would strengthen the hypothesis that the SNC meteorites did, in fact, come from Mars. Unfortunately, instrument observations from Pathfinder are probably not capable of determining if the geologic unit sampled by the lander is definitively the unit from which a SNC meteorite came from as opposed to Mars in general or perhaps a particular region on Mars. This abstract evaluates the possibility of landing at potential SNC ejection sites and the ability of Pathfinder to identify the landing site as the place from which an SNC meteorite came.

Spectraplakins: Master orchestrators of cytoskeletal dynamics

PubMed Central

Suozzi, Kathleen C.; Wu, Xiaoyang

2012-01-01

The dynamics of different cytoskeletal networks are coordinated to bring about many fundamental cellular processes, from neuronal pathfinding to cell division. Increasing evidence points to the importance of spectraplakins in integrating cytoskeletal networks. Spectraplakins are evolutionarily conserved giant cytoskeletal cross-linkers, which belong to the spectrin superfamily. Their genes consist of multiple promoters and many exons, yielding a vast array of differential splice forms with distinct functions. Spectraplakins are also unique in their ability to associate with all three elements of the cytoskeleton: F-actin, microtubules, and intermediate filaments. Recent studies have begun to unveil their role in a wide range of processes, from cell migration to tissue integrity. PMID:22584905

The semantic pathfinder: using an authoring metaphor for generic multimedia indexing.

PubMed

Snoek, Cees G M; Worring, Marcel; Geusebroek, Jan-Mark; Koelma, Dennis C; Seinstra, Frank J; Smeulders, Arnold W M

2006-10-01

This paper presents the semantic pathfinder architecture for generic indexing of multimedia archives. The semantic pathfinder extracts semantic concepts from video by exploring different paths through three consecutive analysis steps, which we derive from the observation that produced video is the result of an authoring-driven process. We exploit this authoring metaphor for machine-driven understanding. The pathfinder starts with the content analysis step. In this analysis step, we follow a data-driven approach of indexing semantics. The style analysis step is the second analysis step. Here, we tackle the indexing problem by viewing a video from the perspective of production. Finally, in the context analysis step, we view semantics in context. The virtue of the semantic pathfinder is its ability to learn the best path of analysis steps on a per-concept basis. To show the generality of this novel indexing approach, we develop detectors for a lexicon of 32 concepts and we evaluate the semantic pathfinder against the 2004 NIST TRECVID video retrieval benchmark, using a news archive of 64 hours. Top ranking performance in the semantic concept detection task indicates the merit of the semantic pathfinder for generic indexing of multimedia archives.

Navigation Flight Operations for Mars Pathfinder

NASA Technical Reports Server (NTRS)

Vaughan, Robin M.; Kallemeyn, Pieter H., Jr.; Spencer, David A.; Braun, Robert D.

2004-01-01

On July 4, 1997, Mars Pathfinder became the first spacecraft to land on the surface of Mars in 21 years. Pathfinder was launched on December 4, 1996 and spent seven months en route to the red planet. This report discusses the navigation flight experience for the Mars Pathfinder interplanetary cruise. In particular, orbit determination and maneuver design and execution results are presented. Special emphasis is given to the navigation role in the days and hours leading up to and including the Entry, Descent, and Landing (EDL) phase.

Validating the Usefulness of Combined Japanese GMS Data For Long-Term Global Change Studies

NASA Technical Reports Server (NTRS)

Simpson, James J.; Dodge, James C. (Technical Monitor)

2001-01-01

The primary objectives of the Geostationary Meteorological Satellite (GMS)-5 Pathfinder Project were the following: (1) to evaluate GMS-5 data for sources of error and develop methods for minimizing any such errors in GMS-5 data; (2) to prepare a GMS-5 Pathfinder data set for the GMS-5 Pathfinder Benchmark Period (1 July 95 - 30 June 96); and (3) show the usefulness of the improved Pathfinder data set in at least one geophysical application. All objectives were met.

Testing of the LISA pathfinder GRS

NASA Astrophysics Data System (ADS)

Antonucci, Federica; Cavalleri, Antonella; Ciani, Giacomo; Congedo, Giuseppe; Dolesi, Rita; de Marchi, Fabrizio; Ferraioli, Luigi; Hueller, Mauro; Nicolodi, Daniele; Tombolato, David; Vitale, Stefano; Wass, Peter J.; Weber, William J.

The ESA/NASA mission,LISA (Laser Interferometric Space Antenna), will measure gravita-tional waves emitted by astronomical sources, galactic and extra-galactic, at frequencies 10-4 to 10-1 Hz. LISA is a 5-million-km arm-length interferometer whose mirrors are test masses which must be nominally free-falling to a level which does not exceed 3 · 10-15 ms-2 Hz -1/2 in acceleration. LISA Pathfinder is a technology demonstration mission which will show that the relative parasitic acceleration between two masses on one spacecraft can be lower than 3 · 10-14 ms-2 Hz -1/2 , at frequencies around 1 mHz -one order of magnitude larger than LISA's goal. At the core of the LISA Pathfinder experiment is the GRS (gravitational reference sensor), a capacitive sensor with mm gaps used to measure the position of the test mass and actuate its position in 6-degrees-of-freedom. Testing the purity of free-fall for LISA Pathfinder on-ground is achieved using a torsion pendulum which allows us to measure force disturbances at a level relevant to LISA Pathfinder. We will present the latest campaign of tests of the LISA Pathfinder GRS using the 4-test-mass torsion pendulum facility aimed at measuring force-noise sources (responsible for the parasitic acceleration) for LISA Pathfinder in its frequency band. Our GRS , is the LISA Pathfinder flight-model replica, and its testing is crucial in verifying the design and performance of the flight instrument and measuring many of the unwanted disturbances which can limit the performance of LISA and LISA pathfinder. The measurements concern the dependence of the force on the test mass position in the sensor and their electrostatic coupling, electrostatic fields due to surface-potential variations and thermal gradients.

Airbag retraction

NASA Technical Reports Server (NTRS)

1997-01-01

This image shows that the Mars Pathfinder airbags have been successfully retracted, allowing safe deployment of the rover ramps. The Sojourner rover is at lower right, and rocks are visible in the background. Mars Pathfinder landed successfully on the surface of Mars today at 10:07 a.m. PDT.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Space Science

NASA Image and Video Library

1996-12-04

The Mars Pathfinder began the journey to Mars with liftoff atop a Delta II expendable launch vehicle from launch Complex 17B on Cape Canaveral Air Station. The Mars Pathfinder traveled on a direct trajectory to Mars, and arrived there in July 1997. Mars Pathfinder sent a lander and small robotic rover, Sojourner, to the surface of Mars. The primary objective of the mission was to demonstrate a low-cost way of delivering a science package to the surface of Mars using a direct entry, descent and landing with the aid of small rocket engines, a parachute, airbags and other techniques. In addition, landers and rovers of the future will share the heritage of Mars Pathfinder designs and technologies first tested in this mission. Pathfinder also collected invaluable data about the Martian surface.

Mars Pathfinder Atmospheric Entry Navigation Operations

NASA Technical Reports Server (NTRS)

Braun, R. D.; Spencer, D. A.; Kallemeyn, P. H.; Vaughan, R. M.

1997-01-01

On July 4, 1997, after traveling close to 500 million km, the Pathfinder spacecraft successfully completed entry, descent, and landing, coming to rest on the surface of Mars just 27 km from its target point. In the present paper, the atmospheric entry and approach navigation activities required in support of this mission are discussed. In particular, the flight software parameter update and landing site prediction analyses performed by the Pathfinder operations navigation team are described. A suite of simulation tools developed during Pathfinder's design cycle, but extendible to Pathfinder operations, are also presented. Data regarding the accuracy of the primary parachute deployment algorithm is extracted from the Pathfinder flight data, demonstrating that this algorithm performed as predicted. The increased probability of mission success through the software parameter update process is discussed. This paper also demonstrates the importance of modeling atmospheric flight uncertainties in the estimation of an accurate landing site. With these atmospheric effects included, the final landed ellipse prediction differs from the post-flight determined landing site by less then 0.5 km in downtrack.

Integrating Subject Pathfinders into Online Catalogs.

ERIC Educational Resources Information Center

Jarvis, William E.

1985-01-01

Discusses the integration of subject pathfinders into online public access catalogs (OPAC) through following features: within the OPAC, offline user guide manuals, remotely printed upon user request, or online as saved searches displayed in help screen format. Excerpts of a pathfinder display for biotechnology are presented. Four sources are…

Software Aids Visualization Of Mars Pathfinder Mission

NASA Technical Reports Server (NTRS)

Weidner, Richard J.

1996-01-01

Report describes Simulator for Imager for Mars Pathfinder (SIMP) computer program. SIMP generates "virtual reality" display of view through video camera on Mars lander spacecraft of Mars Pathfinder mission, along with display of pertinent textual and graphical data, for use by scientific investigators in planning sequences of activities for mission.

Pathfinder Rear Ramp

NASA Image and Video Library

1997-07-06

NASA's Mars Pathfinder's rear rover ramp can be seen successfully unfurled in this image, taken at the end of Sol 2 by the Imager for Mars Pathfinder (IMP). This ramp was later used for the deployment of the microrover Sojourner, which occurred at the end of Sol 2. Areas of a lander petal and deflated airbag are visible at left. The image helped Pathfinder scientists determine that the rear ramp was the one to use for rover deployment. At upper right is the rock dubbed "Barnacle Bill," which Sojourner will later study. http://photojournal.jpl.nasa.gov/catalog/PIA00627

JWST Pathfinder Telescope Risk Reduction Cryo Test Program

NASA Technical Reports Server (NTRS)

Matthews, Gary W.; Scorse, Thomas R.; Spina, John A.; Noel, Darin M.; Havey, Keith A., Jr.; Huguet, Jesse A.; Whitman, Tony L.; Wells, Conrad; Walker, Chanda B.; Lunt, Sharon;

Airbag retraction

NASA Technical Reports Server (NTRS)

1997-01-01

This image shows that the Mars Pathfinder airbags have been successfully retracted, allowing safe deployment of the rover ramps. The Sojourner rover, still in its deployed position, is at center image, and rocks are visible in the background. Mars Pathfinder landed successfully on the surface of Mars today at 10:07 a.m. PDT.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

MESUR Pathfinder Science Investigations

NASA Technical Reports Server (NTRS)

Golombek, M.

1993-01-01

The MESUR (Mars Environmental Survey) Pathfinder mission is the first Discovery mission planned for launch in 1996. MESUR Pathfinder is designed as an engineering demonstration of the entry, descent and landing approach to be employed by the follow-on MESUR Network mission, which will land of order 10 small stations on the surface of Mars to investigate interior, atmospheric and surface properties. Pathfinder is a small Mars lander, equipped with a microrover to deploy instruments and explore the local landing site. Instruments selected for Pathfinder include a surface imager on a 1 m pop-up mast (stereo with spectral filters), an atmospheric structure instrument/surface meteorology package, and an alpha proton x-ray spectrometer. The microrover will carry the alpha proton x-ray spectrometer to a number of different rocks and surface materials and provide close-up imaging...

Reduction and Analysis of Meteorology Data from the Mars Pathfinder Lander

NASA Technical Reports Server (NTRS)

Murphy, James R.; Bridger, Alison F. C.; Haberle, Robert M.

1998-01-01

Dr. James Murphy is a member of the Mars Pathfinder Atmospheric Structure Investigation Meteorology (ASI/MET) Science Team. The activities of Dr. Murphy, and his collaborators are summarized in this report, which reviews the activities in support of the analysis of the meteorology data from the Mars Pathfinder Lander.

Martian Surface & Pathfinder Airbags

NASA Technical Reports Server (NTRS)

1997-01-01

This image of the Martian surface was taken in the afternoon of Mars Pathfinder's first day on Mars. Taken by the Imager for Mars Pathfinder (IMP camera), the image shows a diversity of rocks strewn in the foreground. A hill is visible in the distance (the notch within the hill is an image artifact). Airbags are seen at the lower right.

The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.' It stands 1.8 meters above the Martian surface, and has a resolution of two millimeters at a range of two meters.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

AVHRR-Based Polar Pathfinder Products: Evaluation, Enhancement, and Transition to MODIS

NASA Technical Reports Server (NTRS)

Fowler, Charles; Maslanik, James; Stone, Robert; Stroeve, Julienne; Emery, William

2001-01-01

The AVHRR-Based Polar Pathfinder (APP) products include calibrated AVHRR channel data, surface temperatures, albedo, satellite scan and solar geometries, and a cloud mask composited into twice- per-day images, and daily averaged fields of sea ice motion, for regions poleward of 50 deg. latitude. Our goals under this grant, in general, are four-fold: 1. To quantify the APP accuracy and sources of error by comparing Pathfinder products with field measurements. 2. To determine the consistency of mean fields and trends in comparison with longer time series of available station data and forecast model output. 3. To investigate the consistency of the products between the different AVHRR instruments over the 1982-present period of the NOAA program. 4. To compare an annual cycle of the AVHRR Pathfinder products with MODIS to establish a baseline for extending Pathfinder-type products into the new ESE period. Year One tasks include intercomparisons of the Pathfinder products with field measurements, testing of algorithm assumptions, collection of field data, and further validation and possible improvement of the multi-sensor ice motion fields. Achievements for these tasks are summarized below.

Observing Solar Radio Bursts from the Lunar Surface

NASA Technical Reports Server (NTRS)

MacDowall, R. J.; Gopalswamy, N.; Kaiser, M. L.; Lazio, T. J.; Jones, D. L.; Bale, S. D.; Burns, J.; Kasper, J. C.; Weiler, K. W.

2011-01-01

Locating low frequency radio observatories on the lunar surface has a number of advantages, including fixes locations for the antennas and no terrestrial interference on the far side of the moon. Here, we describe the Radio Observatory for Lunar Sortie Science (ROLSS), a concept for a low frequency, radio imaging interferometric array designed to study particle acceleration in the corona and inner heliosphere. ROLSS would be deployed during an early lunar sortie or by a robotic rover as part of an unmanned landing. The prime science mission is to image type II and type III solar radio bursts with the aim of determining the sites at and mechanisms by which the radiating particles are accelerated. Secondary science goals include constraining the density of the lunar ionosphere by searching for a low radio frequency cutoff of the solar radio emissions and constraining the low energy electron population in astrophysical sources. Furthermore, ROLSS serves a pathfinder function for larger lunar radio arrays designed for faint sources.

MARS PATHFINDER PYRO SYSTEMS SWITCHING ACTIVITY

NASA Technical Reports Server (NTRS)

1996-01-01

The Mars Pathfinder lander is subjected to a electrical and functional tests of its pyrotechic petal deployer system by Jet Propulsion Laboratory (JPL) engineers and technicians in KSC's Spacecraft Assembly and Encapsulation Facility (SAEF-2). In the background is the Pathfinder cruise stage, which the lander will be mated to once its functional tests are complete. The lander will remain attached to this stage during its six-to-seven-month journey to Mars. When the lander touches down on the surface of Mars next year, the pyrotechnic system will deploy its three petals open like a flower and allow the Sojourner autonomous rover to explore the Martian surface. The Mars Pathfinder is scheduled for launch aboard a Delta II expendable launch vehicle on Dec. 2, the beginning of a 24-day launch period. JPL is managing the Mars Pathfinder project for NASA.

Terrain at Landing Site

NASA Image and Video Library

1997-07-05

Portions of Mars Pathfinder's deflated airbags (seen in the foreground), a large rock in mid-field, and a hill in the background were taken by the Imager for Mars Pathfinder (IMP) aboard Mars Pathfinder during the spacecraft's first day on the Red Planet. Pathfinder successfully landed on Mars at 10:07 a.m. PDT earlier today. The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per "eye." It stands 1.8 meters above the Martian surface, and has a resolution of two millimeters at a range of two meters. http://photojournal.jpl.nasa.gov/catalog/PIA00615

A review of parameters and heuristics for guiding metabolic pathfinding.

PubMed

Kim, Sarah M; Peña, Matthew I; Moll, Mark; Bennett, George N; Kavraki, Lydia E

2017-09-15

Recent developments in metabolic engineering have led to the successful biosynthesis of valuable products, such as the precursor of the antimalarial compound, artemisinin, and opioid precursor, thebaine. Synthesizing these traditionally plant-derived compounds in genetically modified yeast cells introduces the possibility of significantly reducing the total time and resources required for their production, and in turn, allows these valuable compounds to become cheaper and more readily available. Most biosynthesis pathways used in metabolic engineering applications have been discovered manually, requiring a tedious search of existing literature and metabolic databases. However, the recent rapid development of available metabolic information has enabled the development of automated approaches for identifying novel pathways. Computer-assisted pathfinding has the potential to save biochemists time in the initial discovery steps of metabolic engineering. In this paper, we review the parameters and heuristics used to guide the search in recent pathfinding algorithms. These parameters and heuristics capture information on the metabolic network structure, compound structures, reaction features, and organism-specificity of pathways. No one metabolic pathfinding algorithm or search parameter stands out as the best to use broadly for solving the pathfinding problem, as each method and parameter has its own strengths and shortcomings. As assisted pathfinding approaches continue to become more sophisticated, the development of better methods for visualizing pathway results and integrating these results into existing metabolic engineering practices is also important for encouraging wider use of these pathfinding methods.

Validation of the Version 1 NOAA/NASA Pathfinder Sea Surface Temperature Data Set

NASA Technical Reports Server (NTRS)

Smith, Elizabeth A.

1998-01-01

A high-resolution, global satellite-derived sea surface temperature (SST) data set called Pathfinder, from the Advanced Very High Resolution Radiometer (AVHRR) aboard the NOAA Polar Orbiters, is available from the Jet Propulsion Laboratory Physical Oceanography Distributed Active Archive Center (JPL PO.DAAC). Suitable for research as well as education, the Pathfinder SST data set is a result of a collaboration between the National Oceanographic and Atmospheric Administration (NOAA), the National Aeronautics and Space Administration (NASA) and investigators at several universities. NOAA and NASA are the sponsors of the Pathfinder Program, which takes advantage of currently archived Earth science data from satellites. Where necessary, satellite sensors have been intercalibrated, algorithms improved and processing procedures revised, in order to produce long time-series, global measurements of ocean, land and atmospheric properties necessary for climate research. Many Pathfinder data sets are available to researchers now, nearly a decade before the first launch of NASA's Earth Observing System (EOS). The lessons learned from the Pathfinder programs will facilitate the processing and management of terabytes of data from EOS. The Oceans component of Pathfinder has undertaken to reprocess all Global Area Coverage (GAC) data acquired by the 5-channel AVHRRs since 1981. The resultant data products are consistent and stably calibrated [Rao, 1993a, Rao, 1993b, Brown et al., 1993], Earth-gridded SST fields at a variety of spatial and temporal resolutions.

Big-Data Perspective to Operating an SKA-Type Synthesis Array Radio Telescope

NASA Astrophysics Data System (ADS)

Shanmugha Sundaram, GA

2015-08-01

Of the two forerunner sites, viz. Australia and South Africa, where pioneering advancements to state-of-the-art in synthesis array radio astronomy instrumentation are being attempted in the form of pathfinders to the Square Kilometer Array (SKA), for its eventual deployment, a diversity of site-dependent topology and design metrics exists. Towards addressing some of the fundamental mysteries in physics at the micro- and macro-cosm levels, that form the Key Science Projects (KSPs) for the SKA, and interfacing them to an optimally designed array conguration, a critical evaluation of their radio imaging capabilities and metrics becomes paramount. Here, the various KSPs and instrument design specifications are discussed, for relative merits and adaptability to either site, from invoking well-founded and established array-design and optimization principles designed into a customized software tool. Since the problem of array design is one that encompasses variables on several scales such as separation distances between the radio interferometric pair (termed the baseline), factors such as redundancy, flux and phase calibration, bandwidth, integration time, clock synchronization for the correlation process at the detector, and many other ambient-defined parameters, there is a significant component of big data involved in the complex visibilities that are to be Fourier transformed from the spatial to the radio-sky domain (to generate a radio sky map) using vast computational infrastructure, with robust data connectivity and data handling facilities to support this. A crucial requirement exists to make the general public aware of the implications of such a massive scale scientific and technological venture, which shall be the focus of this presentation.

Verification of Java Programs using Symbolic Execution and Invariant Generation

NASA Technical Reports Server (NTRS)

Pasareanu, Corina; Visser, Willem

2004-01-01

Software verification is recognized as an important and difficult problem. We present a norel framework, based on symbolic execution, for the automated verification of software. The framework uses annotations in the form of method specifications an3 loop invariants. We present a novel iterative technique that uses invariant strengthening and approximation for discovering these loop invariants automatically. The technique handles different types of data (e.g. boolean and numeric constraints, dynamically allocated structures and arrays) and it allows for checking universally quantified formulas. Our framework is built on top of the Java PathFinder model checking toolset and it was used for the verification of several non-trivial Java programs.

Pathfinder Instruments for Cloud and Aerosol Spaceborne Observations (PICASSO)

NASA Technical Reports Server (NTRS)

McCormick, M. Patrick; Winker, David M.

1998-01-01

This paper will describe the planned 3-year Pathfinder Instruments for Cloud and Aerosol Spaceborne Observations (PICASSO) mission, its instrumentation and implementation. It will use LITE and other data, plus analyses, to show the feasibility of such a mission. PICASSO is being proposed for NASA's Earth System Science Pathfinder (ESSP) program with launch predicted in 2003.

Pathfinder-Plus flight in Hawaii

NASA Technical Reports Server (NTRS)

2002-01-01

Pathfinder-Plus flight in Hawaii June 2002 AeroVironment's Pathfinder-Plus solar-powered flying wing recently flew a three-flight demonstration of its ability to relay third-generation cell phone and video signals as well as provide Internet linkage. The two pods underneath the center section of the wing carried the advanced two-way telecom package, developed by Japanese telecommunications interests.

Gambling on the Protestants: the Pathfinder Fund and birth control in Peru, 1958-1965.

PubMed

López, L Necochea

2014-01-01

Among the agencies involved in population control activities in the mid-twentieth century, none scored as many early victories in Latin America as did the Pathfinder Fund, founded by Procter & Gamble scion Clarence Gamble. This article analyzes a style in the delivery of family planning assistance in the developing world through the work of the Pathfinder Fund in Peru, the organization's hub in South America, and shows how Pathfinder personnel collaborated with local Protestant institutions. Its Protestant allies helped Pathfinder set up and manage rapid interventions such as the production of pamphlets, the smuggling of contraceptives, and the enrollment of physicians as advocates of the use of intrauterine devices. Although these rapid interventions helped quickly disseminate information and certain technologies among a fortunate few, they also weakened legitimate state agencies, neglected the monitoring of the safety of the drugs supplied, and alienated allies with their high-handed boldness.

LISA Pathfinder: An important first step towards a space-based gravitational wave observatory

NASA Astrophysics Data System (ADS)

Thorpe, James

2017-08-01

ESA's LISA Pathfinder mission was launched on Dec 3rd, 2015 and completed earlier this Summer. During this relatively short mission, Pathfinder at its two science payloads, Europe's LISA Technology Package and NASA's Disturbance Reduction System, demonstrated several techniques and technologies that enable development of a future space-based gravitational wave observatory. Most notably, Pathfinder demonstrated that the technique of drag-free flight could be utilized to place a test mass in near-perfect free-fall, with residual accelerations at the femto-g level in the milliHertz band. Additionally, technologies such as precision bonded optical structures for metrology, micropropulsion systems, and non-contact charge control, were successfully tested, retiring risk for LISA. In this talk, I will present an overview of Pathfinder's results to date and some perspective on how this success will be leveraged into realizing LISA.

Sojourner Sits Near Rock Garden

NASA Technical Reports Server (NTRS)

2003-01-01

The Mars Pathfinder Rover Sojourner is images by the Imager for Mars Pathfinder as it nears the rock 'Wedge.' Part of the Rock Garden is visible in the upper right of the image.

Pathfinder, a low-cost Discovery mission, is the first of a new fleet of spacecraft that are planned to explore Mars over the next ten years. Mars Global Surveyor, already en route, arrives at Mars on September 11 to begin a two year orbital reconnaissance of the planet's composition, topography, and climate. Additional orbiters and landers will follow every 26 months.

The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Readout of the UFFO Slewing Mirror Telescope to detect UV/optical photons from Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Kim, J. E.; Lim, H.; Nam, J. W.; Brandt, S.; Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chen, P.; Choi, H. S.; Grossan, B.; Huang, M. A.; Jeong, S.; Jung, A.; Kim, M. B.; Kim, S.-W.; Lee, J.; Linder, E. V.; Liu, T.-C.; Na, G. W.; Panasyuk, M. I.; Park, I. H.; Ripa, J.; Reglero, V.; Smoot, G. F.; Svertilov, S.; Vedenkin, N.; Yashin, I.

2013-07-01

The Slewing Mirror Telescope (SMT) was proposed for rapid response to prompt UV/optical photons from Gamma-Ray Bursts (GRBs). The SMT is a key component of the Ultra-Fast Flash Observatory (UFFO)-pathfinder, which will be launched aboard the Lomonosov spacecraft at the end of 2013. The SMT utilizes a motorized mirror that slews rapidly forward to its target within a second after triggering by an X-ray coded mask camera, which makes unnecessary a reorientation of the entire spacecraft. Subsequent measurement of the UV/optical is accomplished by a 10 cm aperture Ritchey-Chrètien telescope and the focal plane detector of Intensified Charge-Coupled Device (ICCD). The ICCD is sensitive to UV/optical photons of 200-650 nm in wavelength by using a UV-enhanced S20 photocathode and amplifies photoelectrons at a gain of 104-106 in double Micro-Channel Plates. These photons are read out by a Kodak KAI-0340 interline CCD sensor and a CCD Signal Processor with 10-bit Analog-to-Digital Converter. Various control clocks for CCD readout are implemented using a Field Programmable Gate Array (FPGA). The SMT readout is in charge of not only data acquisition, storage and transfer, but also control of the slewing mirror, the ICCD high voltage adjustments, power distribution, and system monitoring by interfacing to the UFFO-pathfinder. These functions are realized in the FPGA to minimize power consumption and to enhance processing time. The SMT readout electronics are designed and built to meet the spacecraft's constraints of power consumption, mass, and volume. The entire system is integrated with the SMT optics, as is the UFFO-pathfinder. The system has been tested and satisfies the conditions of launch and those of operation in space: those associated with shock and vibration and those associated with thermal and vacuum, respectively. In this paper, we present the SMT readout electronics: the design, construction, and performance, as well as the results of space environment test.

Efficient receiver tuning using differential evolution strategies

NASA Astrophysics Data System (ADS)

Wheeler, Caleb H.; Toland, Trevor G.

2016-08-01

Differential evolution (DE) is a powerful and computationally inexpensive optimization strategy that can be used to search an entire parameter space or to converge quickly on a solution. The Kilopixel Array Pathfinder Project (KAPPa) is a heterodyne receiver system delivering 5 GHz of instantaneous bandwidth in the tuning range of 645-695 GHz. The fully automated KAPPa receiver test system finds optimal receiver tuning using performance feedback and DE. We present an adaptation of DE for use in rapid receiver characterization. The KAPPa DE algorithm is written in Python 2.7 and is fully integrated with the KAPPa instrument control, data processing, and visualization code. KAPPa develops the technologies needed to realize heterodyne focal plane arrays containing 1000 pixels. Finding optimal receiver tuning by investigating large parameter spaces is one of many challenges facing the characterization phase of KAPPa. This is a difficult task via by-hand techniques. Characterizing or tuning in an automated fashion without need for human intervention is desirable for future large scale arrays. While many optimization strategies exist, DE is ideal for time and performance constraints because it can be set to converge to a solution rapidly with minimal computational overhead. We discuss how DE is utilized in the KAPPa system and discuss its performance and look toward the future of 1000 pixel array receivers and consider how the KAPPa DE system might be applied.

Mars Pathfinder Landing Site Workshop

NASA Technical Reports Server (NTRS)

Golombek, Matthew (Editor)

1994-01-01

The Mars Pathfinder Project is an approved Discovery-class mission that will place a lander and rover on the surface of the Red Planet in July 1997. The Mars Pathfinder Landing Site Workshop was designed to allow the Mars scientific community to provide input as to where to land Pathfinder on Mars. The workshop was attended by over 60 people from around the United States and from Europe. Over 20 landing sites were proposed at the workshop, and the scientific questions and problems concerning each were addressed. The workshop and the discussion that occured during and afterward have significantly improved the ability to select a scientifically exciting but safe landing site on Mars.

Pathfinder aircraft flight #1

NASA Image and Video Library

1996-11-19

The Pathfinder solar-powered research aircraft settles in for landing on the bed of Rogers Dry Lake at the Dryden Flight Research Center, Edwards, California, after a successful test flight Nov. 19, 1996. The ultra-light craft flew a racetrack pattern at low altitudes over the flight test area for two hours while project engineers checked out various systems and sensors on the uninhabited aircraft. The Pathfinder was controlled by two pilots, one in a mobile control unit which followed the craft, the other in a stationary control station. Pathfinder, developed by AeroVironment, Inc., is one of several designs being evaluated under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program.

Visible and Near-Infrared Properties of Optical Fibers Coupled to the Pathfinder High-Resolution NIR Spectrograph

NASA Astrophysics Data System (ADS)

McCoy, K.; Ramsey, L.

2011-09-01

The Penn State Astronomy and Astrophysics Department’s Pathfinder instrument is a fiber-fed, warm-bench echelle spectrograph designed to explore technical issues that must be resolved in order to measure precise radial velocities that will allow the detection of exoplanets in the near-infrared (NIR). In May 2010, Pathfinder demonstrated 10-20 m/s radial-velocity precision in the NIR at the 9 meter Hobby-Eberly Telescope. To attain even higher precision, we are investigating the NIR properties of the optical fibers that transmit light from the telescope to Pathfinder. We conducted a series of modal noise tests with visible and NIR laser diodes on a 200 micron diameter, fused-silica, multimode optical fiber as the preliminary step in analyzing the degrading effects of modal noise on radial-velocity precision. We report these test results and comment on our future tests to reduce the negative effects of modal noise and focal ratio degradation (FRD). The lessons learned from this research and the Pathfinder prototype will be used in Pathfinder II, which will aim to achieve better than 5 m/s in the NIR.

Martian Surface & Pathfinder Airbags

NASA Image and Video Library

1997-07-05

This image of the Martian surface was taken in the afternoon of Mars Pathfinder's first day on Mars. Taken by the Imager for Mars Pathfinder (IMP camera), the image shows a diversity of rocks strewn in the foreground. A hill is visible in the distance (the notch within the hill is an image artifact). Airbags are seen at the lower right. http://photojournal.jpl.nasa.gov/catalog/PIA00612

Motoneuron axon pathfinding errors in zebrafish: Differential effects related to concentration and timing of nicotine exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Menelaou, Evdokia; Paul, Latoya T.; Perera, Surangi N.

Nicotine exposure during embryonic stages of development can affect many neurodevelopmental processes. In the developing zebrafish, exposure to nicotine was reported to cause axonal pathfinding errors in the later born secondary motoneurons (SMNs). These alterations in SMN axon morphology coincided with muscle degeneration at high nicotine concentrations (15–30 μM). Previous work showed that the paralytic mutant zebrafish known as sofa potato exhibited nicotine-induced effects onto SMN axons at these high concentrations but in the absence of any muscle deficits, indicating that pathfinding errors could occur independent of muscle effects. In this study, we used varying concentrations of nicotine at differentmore » developmental windows of exposure to specifically isolate its effects onto subpopulations of motoneuron axons. We found that nicotine exposure can affect SMN axon morphology in a dose-dependent manner. At low concentrations of nicotine, SMN axons exhibited pathfinding errors, in the absence of any nicotine-induced muscle abnormalities. Moreover, the nicotine exposure paradigms used affected the 3 subpopulations of SMN axons differently, but the dorsal projecting SMN axons were primarily affected. We then identified morphologically distinct pathfinding errors that best described the nicotine-induced effects on dorsal projecting SMN axons. To test whether SMN pathfinding was potentially influenced by alterations in the early born primary motoneuron (PMN), we performed dual labeling studies, where both PMN and SMN axons were simultaneously labeled with antibodies. We show that only a subset of the SMN axon pathfinding errors coincided with abnormal PMN axonal targeting in nicotine-exposed zebrafish. We conclude that nicotine exposure can exert differential effects depending on the levels of nicotine and developmental exposure window. - Highlights: • Embryonic nicotine exposure can specifically affect secondary motoneuron axons in a dose-dependent manner. • The nicotine-induced secondary motoneuron axonal pathfinding errors can occur independent of any muscle fiber alterations. • Nicotine exposure primarily affects dorsal projecting secondary motoneurons axons. • Nicotine-induced primary motoneuron axon pathfinding errors can influence secondary motoneuron axon morphology.« less

JWST Pathfinder Telescope Integration

NASA Technical Reports Server (NTRS)

Matthews, Gary W.; Kennard, Scott H.; Broccolo, Ronald T.; Ellis, James M.; Daly, Elizabeth A.; Hahn, Walter G.; Amon, John N.; Mt. Pleasant, Stephen M.; Texter, Scott; Atkinson, Charles B.;

Sojourner, Wedge, & Shark

NASA Technical Reports Server (NTRS)

1997-01-01

This Imager for Mars Pathfinder (IMP) image taken near the end of daytime operations on Sol 50 shows the Sojourner rover between the rocks 'Wedge' (foreground) and 'Shark' (behind rover). The rover successfully deployed its Alpha Proton X-Ray Spectrometer on Shark on Sol 52.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Pathfinder aircraft liftoff on altitude record setting flight of 71,500 feet

NASA Image and Video Library

1997-07-07

The Pathfinder aircraft has set a new unofficial world record for high-altitude flight of over 71,500 feet for solar-powered aircraft at the U.S. Navy's Pacific Missile Range Facility, Kauai, Hawaii. Pathfinder was designed and manufactured by AeroVironment, Inc, of Simi Valley, California, and was operated by the firm under a jointly sponsored research agreement with NASA's Dryden Flight Research Center, Edwards, California. Pathfinder's record-breaking flight occurred July 7, 1997. The aircraft took off at 11:34 a.m. PDT, passed its previous record altitude of 67,350 feet at about 5:45 p.m. and then reached its new record altitude at 7 p.m. The mission ended with a perfect nighttime landing at 2:05 a.m. PDT July 8. The new record is the highest altitude ever attained by a propellor-driven aircraft. Before Pathfinder, the altitude record for propellor-driven aircraft was 67,028 feet, set by the experimental Boeing Condor remotely piloted aircraft.

Morning Martian Atmospheric Temperature Gradients and Fluctuations Observed by Mars Pathfinder

NASA Technical Reports Server (NTRS)

Mihalov, John D.; Haberle, R. M.; Murphy, J. R.; Seiff, A.; Wilson, G. R.

1999-01-01

We have studied the most prominent atmospheric temperature fluctuations observed during Martian mornings by Mars Pathfinder and have concluded, based on comparisons with wind directions, that they appear to be a result of atmospheric heating associated with the Lander spacecraft. Also, we have examined the morning surface layer temperature lapse rates, which are found to decrease as autumn approaches at the Pathfinder location, and which have mean (and median) values as large as 7.3 K/m in the earlier portions of the Pathfinder landed mission. It is plausible that brief isolated periods with gradients twice as steep are associated with atmospheric heating adjacent to Lander air bag material. In addition, we have calculated the gradient with height of the structure function obtained with Mars Pathfinder, for Mars' atmospheric temperatures measured within about 1.3 m from the surface, assuming a power law dependence, and have found that these gradients superficially resemble those reported for the upper region of the terrestrial stable boundary layer.

Mars Pathfinder Rover-Lewis Research Center Technology Experiments Program

NASA Technical Reports Server (NTRS)

Stevenson, Steven M.

1997-01-01

An overview of NASA's Mars Pathfinder Program is given and the development and role of three technology experiments from NASA's Lewis Research Center and carried on the Mars Pathfinder rover is described. Two recent missions to Mars were developed and managed by the Jet Propulsion Laboratory, and launched late last year: Mars Global Surveyor in November 1996 and Mars Pathfinder in December 1996. Mars Global Surveyor is an orbiter which will survey the planet with a number of different instruments, and will arrive in September 1997, and Mars Pathfinder which consists of a lander and a small rover, landing on Mars July 4, 1997. These are the first two missions of the Mars Exploration Program consisting of a ten year series of small robotic martian probes to be launched every 26 months. The Pathfinder rover will perform a number of technology and operational experiments which will provide the engineering information necessary to design and operate more complex, scientifically oriented surface missions involving roving vehicles and other machinery operating in the martian environment. Because of its expertise in space power systems and technologies, space mechanisms and tribology, Lewis Research Center was asked by the Jet Propulsion Laboratory, which is heading the Mars Pathfinder Program, to contribute three experiments concerning the effects of the martian environment on surface solar power systems and the abrasive qualities of the Mars surface material. In addition, rover static charging was investigated and a static discharge system of several fine Tungsten points was developed and fixed to the rover. These experiments and current findings are described herein.

Ventifacts at the Pathfinder landing site

USGS Publications Warehouse

Bridges, N.T.; Greeley, R.; Haldemann, A.F.C.; Herkenhoff, K. E.; Kraft, M.; Parker, T.J.; Ward, A.W.

1999-01-01

About half of the rocks at the Mars Pathfinder Ares Vallis landing site appear to be ventifacts, rocks abraded by windborne particles. Comparable resolution images taken by the Imager for Mars Pathfinder (IMP) camera and the Viking landers show that ventifacts are more abundant at the Pathfinder site. The ventifacts occur in several forms, including rocks with faceted edges, finger-like projections, elongated pits, flutes, grooves, and possible rills. The trends of elongated pits, flutes, grooves, and rills cluster at ???280-330?? clockwise from north and generally dip 10-30?? away from their trend direction. These orientations are indicative of southeast to northwest winds and differ from the trend of wind tails at the landing site, the direction of local wind streaks, and predictions of the Global Circulation Model, all of which indicate northeast to southwest winds. The disparity between these data sets strongly suggests that local circulation patterns have changed since the abrasion of the ventifacted rocks. The greater number of ventifacts at the Pathfinder site compared to either of the Viking sites is most easily explained as being due to a larger supply of abrading particles, composed of either sand-sized grains or indurated dust aggregates, and higher surface roughness, which should increase the momentum of saltating grains. The Pathfinder ventifacts may have formed shortly after the deposition of outflow channel sediments nearly 2 Gry ago, when a large local supply of abrading particles should have been abundant and atmospheric conditions may have been more conducive to rock abrasion from saltating grains. Based on how ventifacts form on Earth, the several ventifact forms seen at the Pathfinder site and their presence on some rocks but not on others are probably due to local airflow conditions, original rock shape, exposure duration, rock movement, and to a lesser extent, rock lithology. The abundance of ventifacts at the Pathfinder site, together with other evidence of weathering, indicates that unaltered rock surfaces are rare on Mars. Copyright 1999 by the American Geophysical Union.

Using low-frequency pulsar observations to study the 3-D structure of the Galactic magnetic field

NASA Astrophysics Data System (ADS)

Sobey, C.; LOFAR Collaboration; MWA Collaboration

2018-05-01

The Galactic magnetic field (GMF) plays a role in many astrophysical processes and is a significant foreground to cosmological signals, such as the Epoch of Reionization (EoR), but is not yet well understood. Dispersion and Faraday rotation measurements (DMs and RMs, respectively) towards a large number of pulsars provide an efficient method to probe the three-dimensional structure of the GMF. Low-frequency polarisation observations with large fractional bandwidth can be used to measure precise DMs and RMs. This is demonstrated by a catalogue of RMs (corrected for ionospheric Faraday rotation) from the Low Frequency Array (LOFAR), with a growing complementary catalogue in the southern hemisphere from the Murchison Widefield Array (MWA). These data further our knowledge of the three-dimensional GMF, particularly towards the Galactic halo. Recently constructed or upgraded pathfinder and precursor telescopes, such as LOFAR and the MWA, have reinvigorated low-frequency science and represent progress towards the construction of the Square Kilometre Array (SKA), which will make significant advancements in studies of astrophysical magnetic fields in the future. A key science driver for the SKA-Low is to study the EoR, for which pulsar and polarisation data can provide valuable insights in terms of Galactic foreground conditions.

Rocky terrain & airbags

NASA Technical Reports Server (NTRS)

1997-01-01

An area of very rocky terrain at the Ares Vallis landing site, along with the lander's deflated airbags, were imaged by the Imager for Mars Pathfinder (IMP) before its deployment on Sol 2. The metallic object at the bottom is a bracket for the IMP's release mechanism.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Sojourner's APXS at Shark

NASA Technical Reports Server (NTRS)

1997-01-01

The Sojourner rover is seen next to the rock 'Shark', in this image taken by the Imager for Mars Pathfinder (IMP) near the end of daytime operations on Sol 52. The rover's Alpha Proton X-Ray Spectrometer is deployed against the rock. The rock 'Wedge' is in the foreground.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Motoneuron axon pathfinding errors in zebrafish: Differential effects related to concentration and timing of nicotine exposure

PubMed Central

Menelaou, Evdokia; Paul, Latoya T.; Perera, Surangi N.; Svoboda, Kurt R.

2015-01-01

Nicotine exposure during embryonic stages of development can affect many neurodevelopmental processes. In the developing zebrafish, exposure to nicotine was reported to cause axonal pathfinding errors in the later born secondary motoneurons (SMN). These alterations in SMN axon morphology coincided with muscle degeneration at high nicotine concentrations (15–30µM). Previous work showed that the paralytic mutant zebrafish known as sofa potato, exhibited nicotine-induced effects onto SMN axons at these high concentrations but in the absence of any muscle deficits, indicating that pathfinding errors could occur independent of muscle effects. In this study, we used varying concentrations of nicotine at different developmental windows of exposure to specifically isolate its effects onto subpopulations of motoneuron axons. We found that nicotine exposure can affect SMN axon morphology in a dose-dependent manner. At low concentrations of nicotine, SMN axons exhibited pathfinding errors, in the absence of any nicotine-induced muscle abnormalities. Moreover, the nicotine exposure paradigms used affected the 3 subpopulations of SMN axons differently, but the dorsal projecting SMN axons were primarily affected. We then identified morphologically distinct pathfinding errors that best described the nicotine-induced effects on dorsal projecting SMN axons. To test whether SMN pathfinding was potentially influenced by alterations in the early born primary motoneuron (PMN), we performed dual labeling studies, where both PMN and SMN axons were simultaneously labeled with antibodies. We show that only a subset of the SMN axon pathfinding errors coincided with abnormal PMN axonal targeting in nicotine-exposed zebrafish. We conclude that nicotine exposure can exert differential effects depending on the levels of nicotine and developmental exposure window. PMID:25668718

MOC's Highest Resolution View of Mars Pathfinder Landing Site

NASA Technical Reports Server (NTRS)

2000-01-01

[figure removed for brevity, see original site] (A) Mars Pathfinder site, left: April 1998; right: January 2000.

[figure removed for brevity, see original site] (B) top: April 1998; bottom: January 2000.

Can Mars Global Surveyor's 1.5 meter (5 ft) per pixel camera be used to find any evidence as to the fate of the Mars Polar Lander that was lost on December 3, 1999? One way to find out is to look for one of the other Mars landers and determine what, if anything, can be seen. There have been three successful Mars lander missions: Viking 1 (July 1976), Viking 2 (September 1976), and Mars Pathfinder (July 1997). Of these, the location of Mars Pathfinder is known the best because there are several distinct landmarks visible in the lander's images that help in locating the spacecraft. The MGS MOC Operations Team at Malin Space Science Systems has been tasked since mid-December 1999 with looking for the lost Polar Lander. Part of this effort has been to test the capabilities of MOC by taking a picture of the landing site of Mars Pathfinder.

An attempt to photograph the Pathfinder site was made once before, in April 1998, by turning the entire MGS spacecraft so that the camera could point at the known location of the Mars Pathfinder lander. Turning the MGS spacecraft like this is not a normal operation--it takes considerable planning, and disrupts the on-going, normal acquisition of science data. It took 3 attempts to succeed, but on April 22, 1998, MOC acquired the picture seen on the left side of Figure A, above. The three near-by major landmarks that were visible to the Pathfinder's cameras are labeled here (North Peak, Big Crater, Twin Peaks). It was known at the time that this image was not adequate to see the Pathfinder lander because the camera was not in focus and had a resolution of only 3.3 meters (11 ft) per pixel. In this and all other images shown here, north is up. All views of the 1998 MOC image are illuminated from the lower right, all views of the 2000 MOC image are illuminated from the lower left.

As part of the Polar Lander search effort, the Mars Pathfinder site was targeted again in December 1999 and January 2000. Like the 1998 attempt, the spacecraft had to be pointed off of its normal, nadir (straight-down) view. Like history repeating itself, it once again took 3 tries before the Pathfinder landing site was hit. The picture on the right side of Figure A, above, shows the new image that was acquired on January 16, 2000. The white box indicates the location shown in Figure B (above, right). The 1000 m scale bar equals 0.62 miles.

Figure B (above) shows a subsection of both the 1998 image (top, labeled SPO-1-25603) and the 2000 image (bottom, labeled m11-2414) projected at a scale of 3 meters (10 ft) per pixel. At this scale, the differences in camera focus and sunlight illumination angle are apparent, with the January 2000 image being both in focus and having better lighting conditions. In addition, the MGS spacecraft took the 2000 image from a lower altitude than in 1998, thus the image has better spatial resolution overall. The 500 m scale bar is equal to about 547 yards. The white box shows the location of images in Figure C, below.

[figure removed for brevity, see original site] (C) higher-resolution view; left: April 1998; right: January 2000.

[figure removed for brevity, see original site] D) Erroneous, preliminary identification of Mars Pathfinder location in January 2000 image. Subsequent analysis (Figures E & F, below) identified the correct spot.

The third figure (C, above) again shows portions of the April 1998 image (C, left) and January 2000 image (C, right), only this time they have been enlarged to a resolution of 0.75 meters (2.5 ft) per pixel. The intrinsic resolution of the January 2000 image is 1.5 meters (5 ft), so this is a 200% expanded view of the actual M11-02414 image. The circular features in this and the previous images are impact craters in various states of erosion. Some boulders (dark dots) can be seen near the crater in the lower left corner. The texture that runs diagonally across the scene from upper left toward lower right consists of ridges created by the giant floods that washed through the Pathfinder site from Ares and/or Tiu Vallis many hundreds of millions of years ago. These ridges and the troughs between them were also seen by the Pathfinder lander; their crests often covered with boulders and cobbles (which cannot be seen at the resolution of the MOC image). The 100 m scale bar is equal to 109 yards (which can be compared with a 100 yard U.S. football field). The Mars Pathfinder landing site is located near the center of this view.

The fourth picture, Figure D (above), shows a feature that was initially thought to be the Mars Pathfinder lander by MOC investigators. This and the following figures point out just how difficult it is to find a lander on the martian surface using the MGS MOC. Figure D was prepared early in the week following receipt of the new MOC image on January 17, 2000, and for several days it was believed that the lander had been found. As the subsequent two figures will show (E, and F, below), this location appears to be in error. How the features were misidentified is discussed below. Both Figure D and Figure F, showing possible locations of the Pathfinder lander in the MOC image, are enlarged by a factor of three over the intrinsic resolution of that image (that is, to a scale of 0.5 meters or about 1 ft, 7 inch per pixel). The right picture in Figure D shows sight-lines to the large horizon features--Big Crater, Twin Peaks, and North Peak--that were derived by the MOC team by looking at the images taken by the lander in 1997. After placing these lines on the overall image, there appeared to be two features close to the intersection of the sight-lines. Based upon the consistency of the size and shape of the lander as illuminated by sunlight in this image, the northern of the two candidate features (the small 'hump' at the center of both left and right pictures) was considered, at the time, to be the most likely. HOWEVER...

[figure removed for brevity, see original site] (E) Photoclinometry, Topography, and Revised Landing Site Location.

[figure removed for brevity, see original site] (F) Mars Pathfinder Landing Site; lander not resolved by MOC.

Later in the week following acquisition of the January 16, 2000, image (and over the following weekend), there was time for additional analysis to determine whether the rounded hump identified earlier in the week (Figure D, above) was, in fact, the Mars Pathfinder lander. A computer program that estimates relative topography in a MOC image from knowledge of the illumination (called 'shape-from-shading' or photoclinometry) was run to determine which parts of the landing site image are depressions, which are hills, and which are flat surfaces. The picture at the left in Figure E (above) shows the photoclinometry results for the area around the Pathfinder lander. The picture at the center of Figure E shows the same photoclinometry results overlain by an inset of a topographic map of the Pathfinder landing site derived by the U.S. Geological Survey Astrogeology Branch (Flagstaff, Arizona) from photogrammetry (parallax measurements) using images from Pathfinder's own stereo camera. By matching the features seen by MOC with those seen by the Pathfinder (the large arrows are examples of the matching), the location of the lander was refined and is now indicated in the picture on the right side of Figure E. The large, rounded hump previously identified as Pathfinder in Figure D (above), is more likely a large boulder that was seen in Pathfinder's images and named 'Couch' by the Pathfinder science team in 1997.

Figure F is summary of the results of this effort to find Mars Pathfinder: it shows that while the landing site of Mars Pathfinder can be identified, the lander itself cannot be seen. It is too small to be resolved in an image where each pixel acquired by the MOC covers a square of 1.5 meters (5 feet) to a side, given the contrast conditions on Mars and the MOC's ability to discriminate contrast. At this scale, Pathfinder is not much larger than two pixels, and the same is true of the lost Polar Lander.

No evidence has been found in the January 2000 MOC image of the aft portion of Mars Pathfinder's aeroshell or its parachute, either. If the aeroshell is laying on its side, as interpreted from Mars Pathfinder's images, then it would be very difficult to see this from orbit. Because Pathfinder did not image the parachute, it is not known how it may be configured on the surface--it could be wrapped around the aeroshell or a boulder, for example.

This effort to photograph the Mars Pathfinder lander demonstrates that it is extremely difficult to find a lander on the surface of Mars using the Mars Orbiter Camera aboard the MGS spacecraft. This analysis suggests that it is not very likely that the December 1999 Polar Lander will be found by MOC.

MARS PATHFINDER INSPECTED BY ENGINEER LINDA ROBECK IN SAEF-2

NASA Technical Reports Server (NTRS)

1996-01-01

In the SAEF-2 spacecraft checkout facility, engineer Linda Robeck of the Jet Propulsion Laboratory inspects the Mars Pathfinder lander. The spacecraft arrived at Kennedy Space Center from Pasadena, CA on Aug. 13, 1996. The petals of the lander will be opened for checkout of the spacecraft and the installation of the small rover. Launch of Mars Pathfinder aboard a McDonnell Douglas Delta II rocket will occur from Pad B at Complex 17 on Dec. 2.

Enabling a high throughput real time data pipeline for a large radio telescope array with GPUs

NASA Astrophysics Data System (ADS)

Edgar, R. G.; Clark, M. A.; Dale, K.; Mitchell, D. A.; Ord, S. M.; Wayth, R. B.; Pfister, H.; Greenhill, L. J.

2010-10-01

The Murchison Widefield Array (MWA) is a next-generation radio telescope currently under construction in the remote Western Australia Outback. Raw data will be generated continuously at 5 GiB s-1, grouped into 8 s cadences. This high throughput motivates the development of on-site, real time processing and reduction in preference to archiving, transport and off-line processing. Each batch of 8 s data must be completely reduced before the next batch arrives. Maintaining real time operation will require a sustained performance of around 2.5 TFLOP s-1 (including convolutions, FFTs, interpolations and matrix multiplications). We describe a scalable heterogeneous computing pipeline implementation, exploiting both the high computing density and FLOP-per-Watt ratio of modern GPUs. The architecture is highly parallel within and across nodes, with all major processing elements performed by GPUs. Necessary scatter-gather operations along the pipeline are loosely synchronized between the nodes hosting the GPUs. The MWA will be a frontier scientific instrument and a pathfinder for planned peta- and exa-scale facilities.

A simple algorithm to compute the peak power output of GaAs/Ge solar cells on the Martian surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glueck, P.R.; Bahrami, K.A.

1995-12-31

The Jet Propulsion Laboratory`s (JPL`s) Mars Pathfinder Project will deploy a robotic ``microrover`` on the surface of Mars in the summer of 1997. This vehicle will derive primary power from a GaAs/Ge solar array during the day and will ``sleep`` at night. This strategy requires that the rover be able to (1) determine when it is necessary to save the contents of volatile memory late in the afternoon and (2) determine when sufficient power is available to resume operations in the morning. An algorithm was developed that estimates the peak power point of the solar array from the solar arraymore » short-circuit current and temperature telemetry, and provides functional redundancy for both measurements using the open-circuit voltage telemetry. The algorithm minimizes vehicle processing and memory utilization by using linear equations instead of look-up tables to estimate peak power with very little loss in accuracy. This paper describes the method used to obtain the algorithm and presents the detailed algorithm design.« less

Pathfinder aircraft flight #1

NASA Image and Video Library

1996-11-19

The Pathfinder solar-powered research aircraft is silhouetted against a clear blue sky as it soars aloft during a checkout flight from the Dryden Flight Research Center, Edwards, California, November, 1996.

Constraints and Approach for Selecting the Mars Surveyor '01 Landing Site

NASA Technical Reports Server (NTRS)

Golombek, M.; Bridges, N.; Gilmore, M.; Haldemann, A.; Parker, T.; Saunders, R.; Spencer, D.; Smith, J.; Weitz, C.

1999-01-01

There are many similarities between the Mars Surveyor '01 (MS '01) landing site selection process and that of Mars Pathfinder. The selection process includes two parallel activities in which engineers define and refine the capabilities of the spacecraft through design, testing and modeling and scientists define a set of landing site constraints based on the spacecraft design and landing scenario. As for Pathfinder, the safety of the site is without question the single most important factor, for the simple reason that failure to land safely yields no science and exposes the mission and program to considerable risk. The selection process must be thorough and defensible and capable of surviving multiple withering reviews similar to the Pathfinder decision. On Pathfinder, this was accomplished by attempting to understand the surface properties of sites using available remote sensing data sets and models based on them. Science objectives are factored into the selection process only after the safety of the site is validated. Finally, as for Pathfinder, the selection process is being done in an open environment with multiple opportunities for community involvement including open workshops, with education and outreach opportunities.

Constraints, Approach and Present Status for Selecting the Mars Surveyor 2001 Landing Site

NASA Technical Reports Server (NTRS)

Golombek, M.; Anderson, F.; Bridges, N.; Briggs, G.; Gilmore, M.; Gulick, V.; Haldemann, A.; Parker, T.; Saunders, R.; Spencer, D.;

MARS PATHFINDER CAMERA TEST IN SAEF-2

NASA Technical Reports Server (NTRS)

1996-01-01

In the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2), workers from the Jet Propulsion Laboratory (JPL) are conducting a systems test of the imager for the Mars Pathfinder. The imager (white and metallic cylindrical element close to hand of worker at left) is a specially designed camera featuring a stereo- imaging system with color capability provided by a set of selectable filters. It is mounted atop an extendable mast on the Pathfinder lander. Visible to the far left is the small rover which will be deployed from the lander to explore the Martian surface. Transmitting back to Earth images of the trail left by the rover will be one of the mission objectives for the imager. To the left of the worker standing near the imager is the mast for the low-gain antenna; the round high-gain antenna is to the right. Visible in the background is the cruise stage that will carry the Pathfinder on a direct trajectory to Mars. The Mars Pathfinder is one of two Mars-bound spacecraft slated for launch aboard Delta II expendable launch vehicles this year.

NASA's Chemical Transfer Propulsion Program for Pathfinder

NASA Technical Reports Server (NTRS)

Hannum, Ned P.; Berkopec, Frank D.; Zurawski, Robert L.

1989-01-01

Pathfinder is a research and technology project, with specific deliverables, initiated by the National Aeronautics and Space Administration (NASA) which will strengthen the technology base of the United States civil space program in preparation for future space exploration missions. Pathfinder begins in Fiscal Year 1989, and is to advance a collection of critical technologies for these missions and ensure technology readiness for future national decisions regarding exploration of the solar system. The four major thrusts of Pathfinder are: surface exploration, in-space operations, humans-in-space, and space transfer. The space transfer thrust will provide the critical technologies needed for transportation to, and return from, the Moon, Mars, and other planets in the solar system, as well as for reliable and cost-effective Earth-orbit operations. A key element of this thrust is the Chemical Transfer Propulsion program which will provide the propulsion technology for high performance, liquid oxygen/liquid hydrogen expander cycle engines which may be operated and maintained in space. Described here are the program overview including the goals and objectives, management, technical plan, and technology transfer for the Chemical Transfer Propulsion element of Pathfinder.

Free-Flight Experiments in LISA Pathfinder

NASA Technical Reports Server (NTRS)

Thorpe, J. I.; Cutler, C. J.; Hewitson, M.; Jennrich, O.; Maghami, P.; Paczkowski, S.; Russano, G.; Vitale, S.; Weber, W. J.

2014-01-01

The LISA Pathfinder mission will demonstrate the technology of drag-free test masses for use as inertial references in future space-based gravitational wave detectors. To accomplish this, the Pathfinder spacecraft will perform drag-free flight about a test mass while measuring the acceleration of this primary test mass relative to a second reference test mass. Because the reference test mass is contained within the same spacecraft, it is necessary to apply forces on it to maintain its position and attitude relative to the spacecraft. These forces are a potential source of acceleration noise in the LISA Pathfinder system that are not present in the full LISA configuration. While LISA Pathfinder has been designed to meet it's primary mission requirements in the presence of this noise, recent estimates suggest that the on-orbit performance may be limited by this 'suspension noise'. The drift-mode or free-flight experiments provide an opportunity to mitigate this noise source and further characterize the underlying disturbances that are of interest to the designers of LISA-like instruments. This article provides a high-level overview of these experiments and the methods under development to analyze the resulting data.

Preliminary Findings of the Photovoltaic Cell Calibration Experiment on Pathfinder Flight 95-3

NASA Technical Reports Server (NTRS)

Vargas-Aburto, Carlos

1997-01-01

The objective of the photovoltaic (PV) cell calibration experiment for Pathfinder was to develop an experiment compatible with an ultralight UAV to predict the performance of PV cells at AM0, the solar spectrum in space, using the Langley plot technique. The Langley plot is a valuable technique for this purpose and requires accurate measurements of air mass (pressure), cell temperature, solar irradiance, and current-voltage(IV) characteristics with the cells directed normal to the direct ray of the sun. Pathfinder's mission objective (95-3) of 65,000 ft. maximum altitude, is ideal for performing the Langley plot measurements. Miniaturization of electronic data acquisition equipment enabled the design and construction of an accurate and light weight measurement system that meets Pathfinder's low payload weight requirements.

Rover Soil Experiments Near Yogi

NASA Technical Reports Server (NTRS)

1997-01-01

Sojourner, while on its way to the rock Yogi, performed several soil mechanics experiments. Piles of loose material churned up from the experiment are seen in front of and behind the Rover. The rock Pop-Tart is visible near the front right rover wheel. Yogi is at upper right. The image was taken by the Imager for Mars Pathfinder.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Mars Pathfinder Landing Site and Surroundings

NASA Technical Reports Server (NTRS)

2007-01-01

NASA's Mars Pathfinder landed on Mars on July 4, 1997, and continued operating until Sept. 27 of that year. The landing site is on an ancient flood plain of the Ares and Tiu outflow channels. The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter took an image on Dec. 21, 2006, that provides unprecedented detail of the geology of the region and hardware on the surface.

[figure removed for brevity, see original site] HiRISE Image This is the entire image. The crater at center bottom was unofficially named 'Big Crater' by the Pathfinder team. Its wall was visible from Pathfinder, located 3 kilometers (2 miles) to the north. The two bright features to the upper left of Big Crater are the 'Twin Peaks,' also observed by Pathfinder. The bright mound to the upper right of the Twin Peaks is 'North Knob,' seen in Pathfinder images as peaking over the horizon.

At this scale there is no obvious geologic evidence of an ancient flood. Rather, impact craters dominate the scene, attesting to an old surface. The age is probably on the order of 1.8 billion to 3.5 billion years, when the Ares and Tiu floods are estimated to have occurred. Wind-formed linear ripples and dunes are seen throughout and are concentrated within craters. Sets of polygonal ridges of enigmatic origin are seen east of the Pathfinder lander. Rocks are visible over the entire image, with heavy concentrations near fresh-looking craters. Most of them are probably blocks tossed outward by crater-forming impacts.

The complete image is centered at 19.1 degrees north latitude, 326.8 degrees east longitude. The range to the target site was 284.7 kilometers (177.9 miles). At this distance the image scale is 28.5 centimeters (11 inches) per pixel, so objects about 85 centimeters (33 inches) across are resolved. The image shown here has been map-projected to 25 centimeters (10 inches) per pixel. North is up. The image was taken at a local Mars time of 3:35 p.m., and the scene is illuminated from the west with a solar incidence angle of 52 degrees, thus the sun was about 38 degrees above the horizon. At a solar longitude of 154.0 degrees, the season on Mars is northern summer.

[figure removed for brevity, see original site] Landing Site Region This is a close-up of the area in the vicinity of the Pathfinder landing site. Major features are named. The white box outlines the area of the image, discussed next, where hardware is seen.

[figure removed for brevity, see original site] Hardware on the Surface This image shows the Pathfinder lander on the surface. Zooming in, one can discern the ramps, science deck, and portions of the airbags on the Pathfinder lander. (See next image for closer view.) The back shell and parachute are to the south, and four features that may be portions of the heat shield are identified. Two of these were visible from Pathfinder. At the time of that mission, the nearest object was provisionally identified as the back shell. However, analysis of the HiRISE image and reinterpretation of Pathfinder images, plus an improved understanding of how hardware looks on the Martian surface based on ground-level and orbital images of the Mars Exploration Rover landing sites, indicate that the glint is bright enough that it may be insulating material from inside the heat shield. The back shell and parachute were out of sight behind a ridge from Pathfinder's ground view. One of the three bright features, identified as heat shield debris, was also identified during the Pathfinder mission.

[figure removed for brevity, see original site] [figure removed for brevity, see original site] Annotated Version Unannotated Version Topographic Map of Landing Site Region Portions of the HiRISE image are overlaid onto color-coded topographic maps constructed by the U.S. Geological Survey from stereo images acquired by the Imager for Mars Pathfinder on the lander. The white feature at the center is Pathfinder lander. The scales on the x and y axes are in meters, with the lander as the zero point. The color code for elevation relative to the lander is different in the left and right images, and shown in meters underneath each image. The correspondence between the overhead view revealed by HiRISE and the positions of topographic features inferred almost a decade ago from Pathfinder's horizontal view of the landscape is striking. The close-up on the right complements panoramas taken by the lander's camera, including the accompanying composite version showing the Sojourner rover at various locations it reached during the mission.

[figure removed for brevity, see original site] Mars Pathfinder Gallery Panorama This version of the Gallery Panorama taken with the lander's Imager for Mars Pathfinder camera shows many of the locations where the mission's Sojourner rover ended a Martian day during the 12-week mission. (There was only one Sojourner. The image is a composite.) One annotation indicates the last known position of Sojourner, near the rock 'Chimp,' at the time of the final data transmission from the lander. The location labeled 'Sojourner?' has been tentatively identified as the current position of the rover based on comparison of the ground-level view with the Dec. 21, 2006, image from NASA's Mars Reconnaissance Orbiter. At the proposed current location of the rover, a feature can be discerned in the 2006 orbital image that is about the right size for Sojourner and wasn't present when the Gallery Panorama was taken. Some rocks and other features that can be identified in the orbiter's high-resolution view are labeled in this ground-level view.

[figure removed for brevity, see original site] Topographic Perspective of Landing Site Region) This is a perspective view based on the topographic map and artificial color derived from Pathfinder and other data. The vertical scale is exaggerated by a factor of three, compared with horizontal dimensions. The white feature at center is the Pathfinder lander. It appears flat because the topographic map derived from the Imager for Mars Pathfinder data did not include the spacecraft itself.

MARS PATHFINDER LANDER REMOVED FROM SHIPPING CONTAINER IN SAEF-2

NASA Technical Reports Server (NTRS)

1996-01-01

In the SAEF-2 spacecraft checkout facility at Kennedy Space Center, engineers and technicians from Jet Propulsion Laboratory remove the Mars Pathfinder lander from its shipping container, still covered in protective wrapping. Pictured from L-R, Linda Robeck, Jerry Gutierrez, Lorraine Garcia, Chuck Foehlinger of JPL. The arrival of the spacecraft at KSC from Pasadena, CA occurred on Aug. 13, 1996. Launch of Mars Pathfinder aboard a McDonnell Douglas Delta II rocket will occur from Pad B at Complex 17 on Dec. 2.

Pathfinder aircraft in flight

NASA Image and Video Library

1995-07-27

The Pathfinder research aircraft's wing structure was clearly defined as it soared under a clear blue sky during a test flight July 27, 1995, from Dryden Flight Research Center, Edwards, California. The center section and outer wing panels of the aircraft had ribs constructed of thin plastic foam, while the ribs in the inner wing panels are fabricated from lightweight composite material. Developed by AeroVironment, Inc., the Pathfinder was one of several unmanned aircraft being evaluated under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program.

Mars Pathfinder Microrover- Implementing a Low Cost Planetary Mission Experiment

NASA Technical Reports Server (NTRS)

Matijevic, J.

1996-01-01

The Mars Pathfinder Microrover Flight Experiment (MFEX) is a NASA Office of Space Access and Technology (OSAT) flight experiment which has been delivered and integrated with the Mars Pathfinder (MPF) lander and spacecraft system. The total cost of the MFEX mission, including all subsystem design and development, test, integration with the MPF lander and operations on Mars has been capped at $25 M??is paper discusses the process and the implementation scheme which has resulted in the development of this first Mars rover.

MARS PATHFINDER AIR BAG INSTALLATION IN SAEF-2

NASA Technical Reports Server (NTRS)

1996-01-01

In the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2), the Jet Propulsion Laboratory (JPL) team installs air bags on the Mars Pathfinder lander. The four airbags will cushion the lander as it touches down on the Martian surface, protecting the delicate instruments and Surveyor small rover inside the tetrahedral-shaped lander. The Mars Pathfinder is one of two Mars-bound spacecraft being prepared for launch this fall. Liftoff is set for Dec. 2 at the beginning of a 24-day launch period.

Pathfinder Innovation Projects

EPA Pesticide Factsheets

The Pathfinder program supports high-risk, high-reward research ideas with funding and staff time. The goal is to feed a culture of innovation in the Agency and integrate innovative ideas in EPA research programs.

Dust Accumulation and Solar Panel Array Performance on the Mars Exploration Rover (MER) Project

NASA Technical Reports Server (NTRS)

Turgay, Eren H.

2004-01-01

One of the most fundamental design considerations for any space vehicle is its power supply system. Many options exist, including batteries, fuel cells, nuclear reactors, radioisotopic thermal generators (RTGs), and solar panel arrays. Solar arrays have many advantages over other types of power generation. They are lightweight and relatively inexpensive, allowing more mass and funding to be allocated for other important devices, such as scientific instruments. For Mars applications, solar power is an excellent option, especially for long missions. One might think that dust storms would be a problem; however, while dust blocks some solar energy, it also scatters it, making it diffuse rather than beamed. Solar cells are still able to capture this diffuse energy and convert it into substantial electrical power. For these reasons, solar power was chosen to be used on the 1997 Mars Pathfinder mission. The success of this mission set a precedent, as NASA engineers have selected solar power as the energy system of choice for all future Mars missions, including the Mars Exploration Rover (MER) Project. Solar sells have their drawbacks, however. They are difficult to manufacture and are relatively fragile. In addition, solar cells are highly sensitive to different parts of the solar spectrum, and finding the correct balance is crucial to the success of space missions. Another drawback is that the power generated is not a constant with respect to time, but rather changes with the relative angle to the sun. On Mars, dust accumulation also becomes a factor. Over time, dust settles out of the atmosphere and onto solar panels. This dust blocks and shifts the frequency of the incoming light, degrading solar cell performance. My goal is to analyze solar panel telemetry data from the two MERs (Spirit and Opportunity) in an effort to accurately model the effect of dust accumulation on solar panels. This is no easy process due to the large number of factors involved. Changing solar flux (the amount of solar energy reaching the planet), solar spectrum, solar angle, rover tilt, and optical depth (the opacity of the atmosphere due to dust) were the most significant. Microsoft Excel and Visual Basic are used for data analysis. The results of this work will be used to improve the dust accumulation and atmosphere effects model that was first created after the Mars Pathfinder mission. This model will be utilized and applied when considering the design of solar panel array systems on future Mars projects. Based on this data, and depending upon the tenure and application of the mission, designers may also elect to employ special tools to abate dust accumulation, or decide that the expected level of accumulation is acceptable.

Immersive Environments for Mission Operations: Beyond Mars Pathfinder

NASA Technical Reports Server (NTRS)

Wright, J.; Hartman, F.; Cooper, B.

1998-01-01

Immersive environments are just beginning to be used to support mission operations at the Jet Propulsion Laboratory. This technology contributed to the Mars Pathfinder Mission in planning sorties for the Sojourner rover.

Pathfinder Innovation Projects: Awardees 2015

EPA Pesticide Factsheets

The Pathfinder program supports high-risk, high-reward research ideas with funding and staff time. The goal is to feed a culture of innovation in the Agency and integrate innovative ideas in EPA research programs.

Pathfinder Innovation Projects: Awardees 2016

EPA Pesticide Factsheets

The Pathfinder program supports high-risk, high-reward research ideas with funding and staff time. The goal is to feed a culture of innovation in the Agency and integrate innovative ideas in EPA research programs.

Photogrammetric analysis of horizon panoramas: The Pathfinder landing site in Viking orbiter images

USGS Publications Warehouse

Oberst, J.; Jaumann, R.; Zeitler, W.; Hauber, E.; Kuschel, M.; Parker, T.; Golombek, M.; Malin, M.; Soderblom, L.

1999-01-01

Tiepoint measurements, block adjustment techniques, and sunrise/sunset pictures were used to obtain precise pointing data with respect to north for a set of 33 IMP horizon images. Azimuth angles for five prominent topographic features seen at the horizon were measured and correlated with locations of these features in Viking orbiter images. Based on this analysis, the Pathfinder line/sample coordinates in two raw Viking images were determined with approximate errors of 1 pixel, or 40 m. Identification of the Pathfinder location in orbit imagery yields geological context for surface studies of the landing site. Furthermore, the precise determination of coordinates in images together with the known planet-fixed coordinates of the lander make the Pathfinder landing site the most important anchor point in current control point networks of Mars. Copyright 1999 by the American Geophysical Union.

Yogi the rock

NASA Technical Reports Server (NTRS)

1997-01-01

Yogi, a rock taller than rover Sojourner, is the subject of this image, taken by the deployed Imager for Mars Pathfinder (IMP) on Sol 3. The soil in the foreground will be the location of multiple soil mechanics experiments performed by Sojourner's cleated wheels. Pathfinder scientists will be able to control the force inflicted on the soil beneath the rover's wheels, giving them insight into the soil's mechanical properties.

The image was taken by the Imager for Mars Pathfinder (IMP) after its deployment on Sol 3. Mars Pathfinder was developed and managed by the Jet Propulsion Laboratory (JPL) for the National Aeronautics and Space Administration. JPL is an operating division of the California Institute of Technology (Caltech). The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Mineralogic and compositional properties of Martian soil and dust: results from Mars Pathfinder

USGS Publications Warehouse

Bell, J.F.; McSween, H.Y.; Crisp, J.A.; Morris, R.V.; Murchie, S.L.; Bridges, N.T.; Johnson, J. R.; Britt, D.T.; Golombek, M.P.; Moore, H.J.; Ghosh, A.; Bishop, J.L.; Anderson, R.C.; Brückner, J.; Economou, T.; Greenwood, J.P.; Gunnlaugsson, H.P.; Hargraves, R.M.; Hviid, S.; Knudsen, J.M.; Madsen, M.B.; Reid, R.; Rieder, R.; Soderblom, L.

2000-01-01

Mars Pathfinder obtained multispectral, elemental, magnetic, and physical measurements of soil and dust at the Sagan Memorial Station during the course of its 83 sol mission. We describe initial results from these measurements, concentrating on multispectral and elemental data, and use these data, along with previous Viking, SNC meteorite, and telescopic results, to help constrain the origin and evolution of Martian soil and dust. We find that soils and dust can be divided into at least eight distinct spectral units, based on parameterization of Imager for Mars Pathfinder (IMP) 400 to 1000 nm multispectral images. The most distinctive spectral parameters for soils and dust are the reflectivity in the red, the red/blue reflectivity ratio, the near-IR spectral slope, and the strength of the 800 to 1000 nm absorption feature. Most of the Pathfinder spectra are consistent with the presence of poorly crystalline or nanophase ferric oxide(s), sometimes mixed with small but varying degrees of well-crystalline ferric and ferrous phases. Darker soil units appear to be coarser-grained, compacted, and/or mixed with a larger amount of dark ferrous materials relative to bright soils. Nanophase goethite, akaganeite, schwertmannite, and maghemite are leading candidates for the origin of the absorption centered near 900 nm in IMP spectra. The ferrous component in the soil cannot be well-constrained based on IMP data. Alpha proton X-ray spectrometer (APXS) measurements of six soil units show little variability within the landing site and show remarkable overall similarity to the average Viking-derived soil elemental composition. Differences exist between Viking and Pathfinder soils, however, including significantly higher S and Cl abundances and lower Si abundances in Viking soils and the lack of a correlation between Ti and Fe in Pathfinder soils. No significant linear correlations were observed between IMP spectral properties and APXS elemental chemistry. Attempts at constraining the mineralogy of soils and dust using normative calculations involving mixtures of smectites and silicate and oxide minerals did not yield physically acceptable solutions. We attempted to use the Pathfinder results to constrain a number of putative soil and dust formation scenarios, including palagonitization and acid-fog weathering. While the Pathfinder soils cannot be chemically linked to the Pathfinder rocks by palagonitization, this study and McSween et al. [1999] suggest that palagonitic alteration of a Martian basaltic rock, plus mixture with a minor component of locally derived andesitic rock fragments, could be consistent with the observed soil APXS and IMP properties.

Constraints, Approach, and Status of Mars Surveyor 2001 Landing Site Selection

NASA Technical Reports Server (NTRS)

Golombek, M.; Bridges, N.; Briggs, G.; Gilmore, M.; Haldemann, A.; Parker, T.; Saunders, R.; Spencer, D.; Smith, J.; Soderblom, L.

1999-01-01

There are many similarities between the Mars Surveyor '01 (MS '01) landing site selection process and that of Mars Pathfinder. The selection process includes two parallel activities in which engineers define and refine the capabilities of the spacecraft through design, testing and modeling and scientists define a set of landing site constraints based on the spacecraft design and landing scenario. As for Pathfinder, the safety of the site is without question the single most important factor, for the simple reason that failure to land safely yields no science and exposes the mission and program to considerable risk. The selection process must be thorough and defensible and capable of surviving multiple withering reviews similar to the Pathfinder decision. On Pathfinder, this was accomplished by attempting to understand the surface properties of sites using available remote sensing data sets and models based on them. Science objectives are factored into the selection process only after the safety of the site is validated. Finally, as for Pathfinder, the selection process is being done in an open environment with multiple opportunities for community involvement including open workshops, with education and outreach opportunities. Additional information is contained in the original extended abstract.

Yogi the rock - 3D

NASA Technical Reports Server (NTRS)

1997-01-01

Yogi, a rock taller than rover Sojourner, is the subject of this image, taken in stereo by the deployed Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. The soil in the foreground has been the location of multiple soil mechanics experiments performed by Sojourner's cleated wheels. Pathfinder scientists were able to control the force inflicted on the soil beneath the rover's wheels, giving them insight into the soil's mechanical properties. The soil mechanics experiments were conducted after this image was taken.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

Advanced photovoltaic power system technology for lunar base applications

NASA Astrophysics Data System (ADS)

Brinker, David J.; Flood, Dennis J.

1992-09-01

The development of an advanced photovoltaic power system that would have application for a manned lunar base is currently planned under the Surface Power element of Pathfinder. Significant mass savings over state-of-the-art photovoltaic/battery systems are possible with the use of advanced lightweight solar arrays coupled with regenerative fuel cell storage. The solar blanket, using either ultrathin GaAs or amorphous silicon solar cells, would be integrated with a reduced-g structure. Regenerative fuel cells with high-pressure gas storage in filament-wound tanks are planned for energy storage. An advanced PV/RFC power system is a leading candidate for a manned lunar base as it offers a tremendous weight advantage over state-of-the-art photovoltaic/battery systems and is comparable in mass to other advanced power generation technologies.

Operations and Autonomy of the Mars Pathfinder Microrover

NASA Technical Reports Server (NTRS)

Mishkin, A. H.; Morrison, J. C.; Nguyen, T. T.; Stone, H. W.; Cooper, B. K.

1998-01-01

The Microrover Flight Experiment (MFEX) is a NSAS OACT (Office of Advanced Concepts and Technology) flight experiment which, integrated with the Mars Pathfinder (MPF) lander and spacecraft system, landed on Mars on July 4, 1997.

Lithium-Thionyl Chloride Batteries for the Mars Pathfinder Microrover

NASA Technical Reports Server (NTRS)

Deligiannis, Frank; Frank, Harvey; Staniewicz, R. J.; Willson, John

1996-01-01

A discussion of the power requirements for the Mars Pathfinder Mission is given. Topics include: battery requirements; cell design; battery design; test descriptions and results. A summary of the results is also included.

Pathfinder on lakebed rolling out for test flight

NASA Image and Video Library

1995-12-10

The Pathfinder research aircraft's wing structure is clearly defined in this photo as personnel from AeroVironment rolled it out onto the lakebed at NASA's Dryden Flight Research Center, Edwards, California, for another test flight.

Constellations Solar Array Design, Industrialization And In-Flight Results

NASA Astrophysics Data System (ADS)

Combet, Yannick; Clapper, Paul

2011-10-01

Constellations has become a recurring opportunities in Thales Alenia Space since 3 majors programs had been awarded: Globalstar was the pathfinder with 48 flight sets followed by O3b with 8 an the latest is Iridium Next with 81 models. For these 3 programs, the Solar Array is fully developed, validated and produced by Thales Alenia Space with major subcontractors. This new segment of the activity leads to new development, design and industrialization approaches. This paper describes the Solar Array design and the alternative to current approach build and applied with the following drivers: - the low recurring cost and mass of the flight hardware, with particular attention on the Solar Array, - high robustness for system integration and in-orbit operations, - a long mission duration (typically 15 years in LEO) leading to take into account high number of thermal cycles (60 to 72.000 cycles), - new production concept with strict schedule management, - design segmented in subassemblies to reduce the integration time as well as a improved trouble shooting management, - delivery rate up to 1 wing per week and after learning curve effect, a integration duration divided by 3 compared to current production, - a delivery of a qualified PFM solar array in 22 months including the design to producibility constrains, This demanding requirement for delivery scheme and cost target did not jeopardize the requirements and standards for space application. After a brief description of the way the main drivers have been considered, the paper presents the main features and performances of the subsystem and shows the main validation test results. The first launch was successful in October 2010 and the first in-orbit results are presented.

Processing and Analysis of Mars Pathfinder Science Data at JPL's Science Data Processing Section

NASA Technical Reports Server (NTRS)

LaVoie, S.; Green, W.; Runkle, A.; Alexander, D.; Andres, P.; DeJong, E.; Duxbury, E.; Freda, D.; Gorjian, Z.; Hall, J.;

Sojourner Sits Near "Rock Garden"

NASA Image and Video Library

2003-02-01

The Mars Pathfinder Rover Sojourner images by the Imager for Mars Pathfinder as it nears the rock "Wedge." Part of the Rock Garden is visible in the upper right of the image. http://photojournal.jpl.nasa.gov/catalog/PIA04318

Analysis of Mars Pathfinder Entry Data, Aerothermal Heating, and Heat Shield Material Response

NASA Technical Reports Server (NTRS)

Milos, Frank; Chen, Y. K.; Tran, H. K.; Rasky, Daniel J. (Technical Monitor)

1997-01-01

The Mars Pathfinder heatshield contained several thermocouples and resistance thermometers. A description of the experiment, the entry data, and analysis of the entry environment and material response is presented. In particular, the analysis addresses uncertainties of the data and the fluid dynamics and material response models. The calculations use the latest trajectory and atmosphere reconstructions for the Pathfinder entry. A modified version of the GIANTS code is used for CFD (computational fluid dynamics) analyses, and FIAT is used for material response. The material response and flowfield are coupled appropriately. Three different material response models are considered. The analysis of Pathfinder entry data for validation of aerothermal heating and material response models is complicated by model uncertainties and unanticipated data-acquisition and processing problems. We will discuss these issues as well as ramifications of the data and analysis for future Mars missions.

Pathfinder technologies for bold new missions. [U.S. research and development program for space exploration

NASA Technical Reports Server (NTRS)

Sadin, Stanley R.; Rosen, Robert

1987-01-01

Project Pathfinder is a proposed U.S. Space Research and Technology program intended to enable bold new missions of space exploration. Pathfinder continues the advancement of technological capabilities and extends the foundation established under the Civil Space Technology Initiative, CSTI. By filling critical technological gaps, CSTI enhances access to Earth orbit and supports effective operations and science missions therein. Pathfinder, with a longer-term horizon, looks to a future that builds on Shuttle and Space Station and addresses technologies that support a range of exploration missions including: a return to the Moon to build an outpost; piloted missions to Mars; and continued scientific exploration of Earth and the other planets. The program's objective is to develop, within reasonable time frames, those emerging and innovative technologies that will make possible both new and enhanced missions and system concepts.

Shark

NASA Technical Reports Server (NTRS)

1997-01-01

This false color composite image from the Pathfinder lander shows the rock 'Shark' at upper right (Shark is about 0.69 m wide, 0.40 m high, and 6.4 m from the lander). The rock looks like a conglomerate in Sojourner rover images, but only the large elements of its surface textures can be seen here. This demonstrates the usefulness of having a robot rover geologist able to examine rocks up close.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

AVHRR-Based Polar Pathfinder Products: Evaluation, Enhancement and Transition to MODIS

NASA Technical Reports Server (NTRS)

Fowler, Charles; Masalanik, James; Stone, Robert; Stroeve, Julienne; Emery, William

2001-01-01

The Advanced Very High Resolution Radiometer (AVHRR)-Based Polar Pathfinder (APP) products include calibrated AVHRR channel data, surface temperatures, albedo, satellite scan and solar geometries, and cloud mask, all composited into twice-per-day images, and daily averaged fields of sea ice motion, for regions poleward of 50 latitude. Our general goals under this grant: (1) Quantify the APP accuracy and sources of error by comparing Pathfinder products with field measurements; (2) Determine the consistency of mean fields and trends in comparison with longer time series of available station data and forecast model output; (3) Investigate the consistency of the products between the different AVHRR instruments over the 1982-present period of the NOAA program; and (4) Compare and annual cycle of the APP products with MODIS to establish a baseline for extending Pathfinder-type products into the new ESE period.

Modeling to Mars: a NASA Model Based Systems Engineering Pathfinder Effort

NASA Technical Reports Server (NTRS)

Phojanamongkolkij, Nipa; Lee, Kristopher A.; Miller, Scott T.; Vorndran, Kenneth A.; Vaden, Karl R.; Ross, Eric P.; Powell, Bobby C.; Moses, Robert W.

2017-01-01

The NASA Engineering Safety Center (NESC) Systems Engineering (SE) Technical Discipline Team (TDT) initiated the Model Based Systems Engineering (MBSE) Pathfinder effort in FY16. The goals and objectives of the MBSE Pathfinder include developing and advancing MBSE capability across NASA, applying MBSE to real NASA issues, and capturing issues and opportunities surrounding MBSE. The Pathfinder effort consisted of four teams, with each team addressing a particular focus area. This paper focuses on Pathfinder team 1 with the focus area of architectures and mission campaigns. These efforts covered the timeframe of February 2016 through September 2016. The team was comprised of eight team members from seven NASA Centers (Glenn Research Center, Langley Research Center, Ames Research Center, Goddard Space Flight Center IV&V Facility, Johnson Space Center, Marshall Space Flight Center, and Stennis Space Center). Collectively, the team had varying levels of knowledge, skills and expertise in systems engineering and MBSE. The team applied their existing and newly acquired system modeling knowledge and expertise to develop modeling products for a campaign (Program) of crew and cargo missions (Projects) to establish a human presence on Mars utilizing In-Situ Resource Utilization (ISRU). Pathfinder team 1 developed a subset of modeling products that are required for a Program System Requirement Review (SRR)/System Design Review (SDR) and Project Mission Concept Review (MCR)/SRR as defined in NASA Procedural Requirements. Additionally, Team 1 was able to perform and demonstrate some trades and constraint analyses. At the end of these efforts, over twenty lessons learned and recommended next steps have been identified.

Interactions of UNC-34 Enabled With Rac GTPases and the NIK Kinase MIG-15 in Caenorhabditis elegans Axon Pathfinding and Neuronal Migration

PubMed Central

Shakir, M. Afaq; Gill, Jason S.; Lundquist, Erik A.

2006-01-01

Many genes that affect axon pathfinding and cell migration have been identified. Mechanisms by which these genes and the molecules they encode interact with one another in pathways and networks to control developmental events are unclear. Rac GTPases, the cytoskeletal signaling molecule Enabled, and NIK kinase have all been implicated in regulating axon pathfinding and cell migration. Here we present evidence that, in Caenorhabditis elegans, three Rac GTPases, CED-10, RAC-2, and MIG-2, define three redundant pathways that each control axon pathfinding, and that the NIK kinase MIG-15 acts in each Rac pathway. Furthermore, we show that the Enabled molecule UNC-34 defines a fourth partially redundant pathway that acts in parallel to Rac/MIG-15 signaling in axon pathfinding. Enabled and the three Racs also act redundantly to mediate AQR and PQR neuronal cell migration. The Racs and UNC-34 Ena might all control the formation of actin-based protrusive structures (lamellipodia and filopodia) that mediate growth cone outgrowth and cell migration. MIG-15 does not act with the three Racs in execution of cell migration. Rather, MIG-15 affects direction of PQR neuronal migration, similar to UNC-40 and DPY-19, which control initial Q cell polarity, and Wnt signaling, which acts later to control Q cell-directed migration. MIG-2 Rac, which acts with CED-10 Rac, RAC-2 Rac, and UNC-34 Ena in axon pathfinding and cell migration, also acts with MIG-15 in PQR directional migration. PMID:16204220

Disturbance Reduction System Thrusters Stabilize LISA Pathfinder

NASA Image and Video Library

2015-12-03

The LISA Pathfinder spacecraft is on its way to space, having successfully launched from Kourou, French Guiana Dec. 3, 2015. On board is the state-of-the-art Disturbance Reduction System DRS, a thruster technology developed at NASA JPL.

Dark Energy and Gravity Experiment Explorer and Pathfinder

NASA Astrophysics Data System (ADS)

Chiow, S.-w.; Yu, N.

2018-02-01

We propose to utilize the unique gravity and vacuum environment in the orbits of the Deep Space Gateway for direct detections of dark energy using atom interferometers, and for pathfinder experiments for future gravitational wave and dark matter detections.

Modis, SeaWIFS, and Pathfinder funded activities

NASA Technical Reports Server (NTRS)

Evans, Robert H.

1995-01-01

MODIS (Moderate Resolution Imaging Spectrometer), SeaWIFS (Sea-viewing Wide Field Sensor), Pathfinder, and DSP (Digital Signal Processor) objectives are summarized. An overview of current progress is given for the automatic processing database, client/server status, matchup database, and DSP support.

Design Overview of the DM Radio Pathfinder Experiment

NASA Technical Reports Server (NTRS)

Silva-Feaver, Maximiliano; Chaudhuri, Saptarshi; Cho, Hsaio-Mei; Dawson, Carl; Graham, Peter; Irwin, Kent; Kuenstner, Stephen; Li, Dale; Mardon, Jeremy; Moseley, Harvey;

"Roadrunner Flats"

NASA Image and Video Library

1997-10-14

This enhanced color image of the Pathfinder landing site shows the eastern horizon. The elongated, reddish, low contrast region in the distance is "Roadrunner Flats." This image was taken by the Imager for Mars Pathfinder (IMP). Sojourner spent 83 days of a planned seven-day mission exploring the Martian terrain, acquiring images, and taking chemical, atmospheric and other measurements. The final data transmission received from Pathfinder was at 10:23 UTC on September 27, 1997. Although mission managers tried to restore full communications during the following five months, the successful mission was terminated on March 10, 1998. http://photojournal.jpl.nasa.gov/catalog/PIA00979

Strategy for selecting Mars Pathfinder landing sites

NASA Technical Reports Server (NTRS)

Greeley, Ronald; Kuzmin, Ruslin O.

1994-01-01

A strategy for Pathfinder site selection must be developed that is fundamentally different from most previous considerations. At least two approaches can be identified. In one approach, the objective is to select a site representing a key geologic unit on Mars, i.e., a unit that is widespread, easily recognized, and used frequently as a datum in various investigations. The second approach is to select a site that potentially affords access to a wide variety of rock types. Because rover range is limited, rocks from a variety of sources must be assembled in a small area for sampling. Regardless of the approach taken in site selection, the Pathfinder site should include eolian deposits and provisions should be made to obtain measurements on soils. A recommended approach for selecting the Mars Pathfinder landing site is to identify a deltaic deposit, composed of sediments derived from sources of various ages and geologic units that shows evidence of eolian activity. The site should be located as close as possible to the part of the outwash where rapid deposition occurred because the likelihood of 'sorting' by size and composition increases with distance, decreasing the probability of heterogeneity. In addition, it is recommended that field operation tests be conducted to gain experience and insight into conducting science with Pathfinder.

Rock Abrasion on Mars: Clues from the Pathfinder and Viking Landing Sites

NASA Technical Reports Server (NTRS)

Bridges, N. T.; Parker, T. J.; Kramer, G. M.

2000-01-01

A significant discovery of the Mars Pathfinder (MPF) mission was that many rocks exhibit characteristics of ventifacts, rocks that have been sculpted by saltating particles. Diagnostic features identifying the rocks as ventifacts am elongated pits, flutes, and grooves (collectively referred to as "flutes" unless noted otherwise). Faceted rocks or rock portions, circular pits, rills, and possibly polished rock surfaces are also seen and could be due, to aeolian abrasion. Many of these features were initially identified in rover images, where spatial resolution generally exceeded that of the IMP (Imager for Mars Pathfinder) camera. These images had two major limitations: 1) Only a limited number of rocks were viewed by the rover, biasing flute statistics; and 2) The higher resolution obtained by the rover images and the lack of such pictures at the Viking landing sites hampered comparisons of rock morphologies between the Pathfinder and Viking sites. To avoid this problem, rock morphology and ventifact statistics have been examined using new "super-resolution" IMP and Viking Lander images. Analyses of these images show that: 1) Flutes are seen on about 50% or more of the rocks in the near field at the MPF site; 2) The orientation of these flutes is similar to that for flutes identified in rover images; and 3) Ventifacts are significantly more abundant at the Pathfinder landing site than at the two Viking Landing sites, where rocks have undergone only a limited amount of aeolian abrasion. This is most likely due to the ruggedness of the Pathfinder site and a greater supply of abrading particles available shortly after the Arcs and Tiu Valles outflow channel floods.

Curricular/Instructional Technology Resources.

ERIC Educational Resources Information Center

Roy, Loriene, Comp.

Part of a larger report on the Four Directions Project, an American Indian technology innovation project, this section includes 10 "pathfinders" to locating information on learning and instructional technology resources. The pathfinders were designed by students in the Graduate School of Library and Information Science at the University…

Internet Technology Resources.

ERIC Educational Resources Information Center

Roy, Loriene, Comp.

Part of a larger report on the Four Directions Project, an American Indian technology innovation project, this section includes six "pathfinders" to locating information on Internet resources. The pathfinders were designed by students in the Graduate School of Library and Information Science at the University of Texas at Austin in…

Cultural Themes.

ERIC Educational Resources Information Center

Roy, Loriene, Comp.

Part of a larger report on the Four Directions Project, an American Indian technology innovation project, this section includes 10 "pathfinders" to locating information on Native American cultural themes. The pathfinders were designed by students in the Graduate School of Library and Information Science at the University of Texas at…

Correspondence and Least Squares Analyses of Soil and Rock Compositions for the Viking Lander 1 and Pathfinder Sites

NASA Technical Reports Server (NTRS)

Larsen, K. W.; Arvidson, R. E.; Jolliff, B. L.; Clark, B. C.

2000-01-01

Correspondence and Least Squares Mixing Analysis techniques are applied to the chemical composition of Viking 1 soils and Pathfinder rocks and soils. Implications for the parent composition of local and global materials are discussed.

Sunset over Twin Peaks

NASA Technical Reports Server (NTRS)

1997-01-01

This image was taken by the Imager for Mars Pathfinder (IMP) about one minute after sunset on Mars on Sol 21. The prominent hills dubbed 'Twin Peaks' form a dark silhouette at the horizon, while the setting sun casts a pink glow over the darkening sky. The image was taken as part of a twilight study which indicates how the brightness of the sky fades with time after sunset. Scientists found that the sky stays bright for up to two hours after sunset, indicating that Martian dust extends very high into the atmosphere.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Pre-Dawn Martian Sky

NASA Technical Reports Server (NTRS)

1997-01-01

On Sol 39 there were wispy blue clouds in the pre-dawn sky of Mars, as seen by the Imager for Mars Pathfinder (IMP). The color image was made by taking blue, green, and red images and then combining them into a single color image. The clouds appear to have a bluish side and a greenish side because they moved (in the wind from the northeast) between images. This picture was made an hour and twenty minutes before sunrise -- the sun is not shining directly on the water ice clouds, but they are illuminated by the dawn twilight.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Wind effects on Martian soil

NASA Technical Reports Server (NTRS)

1997-01-01

This false-color combination image highlights details of wind effects on the Martian soil at the Pathfinder landing site. Red and blue filter images have been combined to enhance brightness contrasts among several soil units. Martian winds have distributed these lighter and darker fine materials in complex patterns around the rocks in the scene (blue). For scale, the rock at right center is 16 centimeters (6.3 inches) long. This scene is one of several that will be monitored weekly for changes caused by wind activity.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages and Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Soil disturbance by airbags

NASA Technical Reports Server (NTRS)

1997-01-01

Disturbance of the drift at the Pathfinder landing site reveals a shallow subsurface that is slightly darker but has similar spectral properties. The top set of images, in true color, shows the soils disturbed by the last bounce of the lander on its airbags before coming to rest and the marks created by retraction of the airbags. In the bottom set of images color differences have been enhanced. The mast at center is the Atmospheric Structure Instrument/Meteorology Package (ASI/MET). The ASI/MET is an engineering subsytem that acquired atmospheric data during Pathfinder's descent, and will continue to get more data through the entire landed mission. A shadow of the ASI/MET appears on a rock at left.

Mars Pathfinder was developed and managed by the Jet Propulsion Laboratory (JPL) for the National Aeronautics and Space Administration. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Atmosphere Processing Module Automation and Catalyst Durability Analysis for Mars ISRU Pathfinder

NASA Technical Reports Server (NTRS)

Petersen, Elspeth M.

2016-01-01

The Mars In-Situ Resource Utilization Pathfinder was designed to create fuel using components found in the planet’s atmosphere and regolith for an ascension vehicle to return a potential sample return or crew return vehicle from Mars. The Atmosphere Processing Module (APM), a subunit of the pathfinder, uses cryocoolers to isolate and collect carbon dioxide from Mars simulant gas. The carbon dioxide is fed with hydrogen into a Sabatier reactor where methane is produced. The APM is currently undergoing the final stages of testing at Kennedy Space Center prior to process integration testing with the other subunits of the pathfinder. The automation software for the APM cryocoolers was tested and found to perform nominally. The catalyst used for the Sabatier reactor was investigated to determine the factors contributing to catalyst failure. The results from the catalyst testing require further analysis, but it appears that the rapid change in temperature during reactor start up or the elevated operating temperature is responsible for the changes observed in the catalyst.

Distributed Active Archive Center

NASA Technical Reports Server (NTRS)

Bodden, Lee; Pease, Phil; Bedet, Jean-Jacques; Rosen, Wayne

1993-01-01

The Goddard Space Flight Center Version 0 Distributed Active Archive Center (GSFC V0 DAAC) is being developed to enhance and improve scientific research and productivity by consolidating access to remote sensor earth science data in the pre-EOS time frame. In cooperation with scientists from the science labs at GSFC, other NASA facilities, universities, and other government agencies, the DAAC will support data acquisition, validation, archive and distribution. The DAAC is being developed in response to EOSDIS Project Functional Requirements as well as from requirements originating from individual science projects such as SeaWiFS, Meteor3/TOMS2, AVHRR Pathfinder, TOVS Pathfinder, and UARS. The GSFC V0 DAAC has begun operational support for the AVHRR Pathfinder (as of April, 1993), TOVS Pathfinder (as of July, 1993) and the UARS (September, 1993) Projects, and is preparing to provide operational support for SeaWiFS (August, 1994) data. The GSFC V0 DAAC has also incorporated the existing data, services, and functionality of the DAAC/Climate, DAAC/Land, and the Coastal Zone Color Scanner (CZCS) Systems.

Assessing risk from a stakeholder perspective

NASA Technical Reports Server (NTRS)

Cooper, L. P.

2003-01-01

Planetary exploration missions are subject to a vast array of interpretations of 'success' based on the concerns of multiple stakeholder groups. While project risk management generally focuses on issues of cost/schedule constraints or reliability issues, a broader interpretation of 'risk' as it applies to stakeholders such as sponsors (e.g., NASA), the public at large, the scientific community, the home organization, and the project team itself can provide important insights into the full spectrum of risk that needs to be managed. This paper presents a stakeholder view of risk which is divided into failure, not-a-failure, success, and stunning-success zones. Using the Mars Pathfinder mission as an example, an alternative interpretation of the risks to that mission is presented from the view of key stakeholders. The implications of the stakeholder perspective to project risk management are addressed.

The Fizeau Interferometer Testbed

NASA Technical Reports Server (NTRS)

Zhang, Xiaolei; Carpenter, Kenneth G.; Lyon, Richard G,; Huet, Hubert; Marzouk, Joe; Solyar, Gregory

2003-01-01

The Fizeau Interferometer Testbed (FIT) is a collaborative effort between NASA's Goddard Space Flight Center, the Naval Research Laboratory, Sigma Space Corporation, and the University of Maryland. The testbed will be used to explore the principles of and the requirements for the full, as well as the pathfinder, Stellar Imager mission concept. It has a long term goal of demonstrating closed-loop control of a sparse array of numerous articulated mirrors to keep optical beams in phase and optimize interferometric synthesis imaging. In this paper we present the optical and data acquisition system design of the testbed, and discuss the wavefront sensing and control algorithms to be used. Currently we have completed the initial design and hardware procurement for the FIT. The assembly and testing of the Testbed will be underway at Goddard's Instrument Development Lab in the coming months.

PATHFINDER: Probing Atmospheric Flows in an Integrated and Distributed Environment

NASA Technical Reports Server (NTRS)

Wilhelmson, R. B.; Wojtowicz, D. P.; Shaw, C.; Hagedorn, J.; Koch, S.

1995-01-01

PATHFINDER is a software effort to create a flexible, modular, collaborative, and distributed environment for studying atmospheric, astrophysical, and other fluid flows in the evolving networked metacomputer environment of the 1990s. It uses existing software, such as HDF (Hierarchical Data Format), DTM (Data Transfer Mechanism), GEMPAK (General Meteorological Package), AVS, SGI Explorer, and Inventor to provide the researcher with the ability to harness the latest in desktop to teraflop computing. Software modules developed during the project are available in the public domain via anonymous FTP from the National Center for Supercomputing Applications (NCSA). The address is ftp.ncsa.uiuc.edu, and the directory is /SGI/PATHFINDER.

Disturbing Pop-Tart

NASA Technical Reports Server (NTRS)

1997-01-01

The Sojourner rover's front right camera imaged Pop-tart, a small rock or indurated soil material which was pushed out of the surrounding drift material by Sojourner's front left wheel during a soil mechanics experiment.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Pathfinder: A Retrospective

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Lyons, Valerie (Technical Monitor)

2002-01-01

Mars is one of the most interesting planets in the solar system, featuring enormous canyons, giant volcanoes, and indications that, early in its history, it might have had rivers and perhaps even oceans. Five years ago, in July of 1997, the Pathfinder mission landed on Mars, bringing with it the microwave-oven sized Sojourner rover to wander around on the surface and analyse rocks. Among the experiments on the mission was one designed to analyse dust deposition. Pathfinder is only the first of an armada of spacecraft which will examine Mars from the pole to the equator in the next decade, culminating with a mission to bring humans to Mars.

Pathfinder, v6 n6, Nov/Dec 2008. Foundation Data and Technology

DTIC Science & Technology

2008-12-01

Geospatial-Intelligence Agency,Office of Corporate Communications,4600 Sangamore Road ,Bethesda,MD, 20816 -5003 8. PERFORMING ORGANIZATION REPORT...Communications 4600 Sangamore Road, Mail Stop D-54 Bethesda, MD 20816 -5003 Telephone: (301) 227-7388, DSN 287-7388 E-mail: pathfinder@nga.mil

A Pathfinder for Animal Research and Animal Rights.

ERIC Educational Resources Information Center

Anderson, David C.

1992-01-01

This pathfinder was originally prepared for "Biomedical Research and Animal Rights," a session sponsored by the Veterinary Medical Libraries and Research Libraries Sections of the Medical Library Association. Current resources are described, from bibliographies to electronic bulletin boards, which relate to the issue of laboratory animal…

Is it feasible to pool funds for local children's services in England? Evidence from the national evaluation of children's trust pathfinders.

PubMed

Lorgelly, Paula; Bachmann, Max; Shreeve, Ann; Reading, Richard; Thorburn, June; Mugford, Miranda; O'Brien, Margaret; Husbands, Chris

2009-01-01

To describe how funds were pooled or otherwise jointly managed by National Health Service (NHS) primary care trusts and local authorities in England. To compare expenditure on local children's services by health, education and social services. We conducted a questionnaire survey of all 35 children's trust pathfinders, six months after they were launched, with a follow-up at 2.5 years. We also undertook an in-depth analysis of local authorities and primary care trusts, within eight pathfinder areas and three non-pathfinder areas, whereby we compared expenditure on children's services, interviewed managers and professionals and examined financial documents. Local authorities and NHS trusts coordinated expenditure in various ways, most commonly through informal agreements and aligning budgets but also by formally pooling budgets. The latter were usually for selected services such as child and adolescent mental health services, though four children's trusts pathfinders pooled (or aligned) their budgets for all children's services. Total expenditure per child was greatest for education, lowest for social services and intermediate for health. However, it was difficult to quantify education expenditure on children with health and social care needs, and health care expenditure on children. Sharing money for local children's services requires shared objectives, trust, and legal and accounting expertise. Several different mechanisms are permitted and many are feasible but programme budgeting for children's services could make them more effective.

Uncoupling nicotine mediated motoneuron axonal pathfinding errors and muscle degeneration in zebrafish

DOE Office of Scientific and Technical Information (OSTI.GOV)

Welsh, Lillian; Tanguay, Robert L.; Svoboda, Kurt R.

Zebrafish embryos offer a unique opportunity to investigate the mechanisms by which nicotine exposure impacts early vertebrate development. Embryos exposed to nicotine become functionally paralyzed by 42 hpf suggesting that the neuromuscular system is compromised in exposed embryos. We previously demonstrated that secondary spinal motoneurons in nicotine-exposed embryos were delayed in development and that their axons made pathfinding errors (Svoboda, K.R., Vijayaraghaven, S., Tanguay, R.L., 2002. Nicotinic receptors mediate changes in spinal motoneuron development and axonal pathfinding in embryonic zebrafish exposed to nicotine. J. Neurosci. 22, 10731-10741). In that study, we did not consider the potential role that altered skeletalmore » muscle development caused by nicotine exposure could play in contributing to the errors in spinal motoneuron axon pathfinding. In this study, we show that an alteration in skeletal muscle development occurs in tandem with alterations in spinal motoneuron development upon exposure to nicotine. The alteration in the muscle involves the binding of nicotine to the muscle-specific AChRs. The nicotine-induced alteration in muscle development does not occur in the zebrafish mutant (sofa potato, [sop]), which lacks muscle-specific AChRs. Even though muscle development is unaffected by nicotine exposure in sop mutants, motoneuron axonal pathfinding errors still occur in these mutants, indicating a direct effect of nicotine exposure on nervous system development.« less

The Pathfinder Microrover

NASA Technical Reports Server (NTRS)

Matijevic, J. R.; Bickler, D. B.; Braun, D. F.; Eisen, H. J.; Matthies, L. H.; Mishkin, A. H.; Stone, H. W.; van Nieuwstadt, L. M.; Wen, L. C.; Wilcox, B. H.;

Pathfinders: An Intellectual Guide to Libraries.

ERIC Educational Resources Information Center

Jung, Claudia Ruediger; And Others

Intended as an example for other college libraries, this collection of 38 pathfinders and bibliographies was developed by the reference staff of the Calvin Coolidge Library at Castleton State College, Vermont. Designed to present the types of literature available in particular subject fields and those works readily available in the Coolidge…

Pathfinder Teaching and Learning Units.

ERIC Educational Resources Information Center

Hawaii Univ., Honolulu. Sea Grant Program.

This collection of teaching units were selected from materials developed during the Operation Pathfinder Institutes (OPI) which took place in the Pacific region between 1994 and 1999. The institutes were intended to provide upper elementary and middle school science teachers with an opportunity to develop a deeper understanding of the marine…

Sedimentary geomorphology of the Mars Pathfinder Landing Site

NASA Technical Reports Server (NTRS)

Rice, James W., Jr.; Parker, Timothy Jay

1997-01-01

The first landing on Mars in over 20 years will take place July 4, 1997, near te mouth of the Ares Vallis outflow channel located in southeastern Chryse Planitia. Mars Pathfinder, unlike Viking 1, is expected to land on a surface that has a distinct and unambiguous fluvial signature.

Teacher Job Satisfaction: Lessons from the TSW Pathfinder Project

ERIC Educational Resources Information Center

Butt, Graham; Lance, Ann; Fielding, Antony; Gunter, Helen; Rayner, Steve; Thomas, Hywel

2005-01-01

Government policy assumes that modernization and remodelling will be effective as external intervention mechanisms to improve job satisfaction. Based on data collected as part of the evaluation of the "Transforming the School Workforce Pathfinder Project", an argument is presented here which suggests that internal management models may…

Airbag Retraction

NASA Image and Video Library

1997-07-05

This image shows that the Mars Pathfinder airbags have been successfully retracted, allowing safe deployment of the rover ramps. The Sojourner rover is at lower right, and rocks are visible in the background. Mars Pathfinder landed successfully on the surface of Mars today at 10:07 a.m. PDT. http://photojournal.jpl.nasa.gov/catalog/PIA00618

Pathfinders on Black Dance in America.

ERIC Educational Resources Information Center

Roy, Loriene, Ed.

This is a compilation of 18 pathfinders (i.e., a bibliographic instruction aid) on black dance in America, prepared by graduate students in the "Information Resources in the Humanities" and the "Information Resources in the Social Sciences" classes in the Graduate School of Library and Information Science at the University of…

Mechanical design of the Mars Pathfinder mission

NASA Technical Reports Server (NTRS)

Eisen, Howard Jay; Buck, Carl W.; Gillis-Smith, Greg R.; Umland, Jeffrey W.

1997-01-01

The Mars Pathfinder mission and the Sojourner rover is reported on, with emphasis on the various mission steps and the performance of the technologies involved. The mechanical design of mission hardware was critical to the success of the entry sequence and the landing operations. The various mechanisms employed are considered.

Pathfinder, Volume 7. Number 4, Jul/Aug 2009. GEOINT in Action

DTIC Science & Technology

2009-08-01

Rd,Bethesda,MD, 20816 -5003 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S...Communications 4600 Sangamore Road, Mail Stop D-39 Bethesda, MD 20816 -5003 Telephone: (301) 227-7388, DSN 287-7388 E-mail: pathfinder@nga.mil

Pathfinder, v6 n3, May/Jun 2008. Unifying the Intelligence Profession

DTIC Science & Technology

2008-06-01

ADDRESS(ES) National Geospatial-Intelligence Agency,Office of Corporate Communications,4600 Sangamore Road ,Bethesda,MD, 20816 -5003 8. PERFORMING...Sangamore Road, Mail Stop D-54 Bethesda, MD 20816 -5003 Telephone: (301) 227-7388, DSN 287-7388 E-mail: pathfinder@nga.mil Director Vice Adm. Robert

Pathfinder, v6 n5, Sep/Oct 2008. Shielding Our Home and Nation

DTIC Science & Technology

2008-10-01

Agency,Office of Corporate Communications,4600 Sangamore Road ,Bethesda,MD, 20816 -5003 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING... 20816 -5003 Telephone: (301) 227-7388, DSN 287-7388 E-mail: pathfinder@nga.mil Director Vice Adm. Robert B. Murrett, U.S. Navy Deputy Director

The Twin Peaks in 3-D, as Viewed by the Mars Pathfinder IMP Camera

NASA Image and Video Library

1997-11-04

Twin Peaks are modest-size hills to the southwest of NASA Mars Pathfinder landing site. They were discovered on the first panoramas taken by the IMP camera on the 4th of July, 1997. 3D glasses are necessary to identify surface detail.

Observing Solar Radio Bursts from the Lunar Surface

NASA Technical Reports Server (NTRS)

MacDowall, R. J.; Lazio, T. J.; Bale, S. D.; Burns, J.; Gopalswamy, N.; Jones, D. L.; Kaiser, M. L.; Kasper, J.; Weiler, K. W.

2010-01-01

Locating low frequency radio observatories on the lunar surface has a number of advantages. Here, we describe the Radio Observatory for Lunar Sortie Science (ROLSS), a concept for a low frequency, radio imaging interferometric array designed to study particle acceleration in the corona and inner heliosphere. ROLSS would be deployed during an early lunar sortie or by a robotic rover as part of an unmanned landing. The prime science mission is to image type II and type III solar radio bursts with the aim of determining the sites at and mechanisms by which the radiating particles are accelerated. Secondary science goals include constraining the density of the lunar ionosphere by searching for a low radio frequency cutoff of the solar radio emissions and constraining the low energy electron population in astrophysical sources. Furthermore, ROLSS serves a pathfinder function for larger lunar radio arrays. Key design requirements on ROLES include the operational frequency and angular resolution. The electron densities in the solar corona and inner heliosphere are such that the relevant emission occurs below 10 MHz, essentially unobservable from Earth's surface due to the terrestrial ionospheric cutoff. Resolving the potential sites of particle acceleration requires an instrument with an angular resolution of at least 2 deg, equivalent to a linear array size of approximately 500 meters. Operations would consist of data acquisition during the lunar day, with regular data downlinks. The major components of the ROLSS array are 3 antenna arms arranged in a Y shape, with a central electronics package (CEP). Each antenna arm is a linear strip of polyimide film (e.g., Kapton (TM)) on which 16 single polarization dipole antennas are located by depositing a conductor (e.g., silver). The arms also contain transmission lines for carrying the radio signals from the science antennas to the CEP.

Interface Generation and Compositional Verification in JavaPathfinder

NASA Technical Reports Server (NTRS)

Giannakopoulou, Dimitra; Pasareanu, Corina

2009-01-01

We present a novel algorithm for interface generation of software components. Given a component, our algorithm uses learning techniques to compute a permissive interface representing legal usage of the component. Unlike our previous work, this algorithm does not require knowledge about the component s environment. Furthermore, in contrast to other related approaches, our algorithm computes permissive interfaces even in the presence of non-determinism in the component. Our algorithm is implemented in the JavaPathfinder model checking framework for UML statechart components. We have also added support for automated assume-guarantee style compositional verification in JavaPathfinder, using component interfaces. We report on the application of the presented approach to the generation of interfaces for flight software components.

Dust Wind Tails Around Rocks

NASA Technical Reports Server (NTRS)

1997-01-01

This image was taken by the Sojourner rover's left front camera on Sol 32. The Pathfinder lander is at right and is about 9 meters away. Wind tails of dust are clearly seen extending from the left side of many of the small rocks in the foreground. The large rocks on the horizon at left center are the next goal of Sojourner as it continues our exploration of Mars.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and managed the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

Review of the trajectory and atmospheric structure reconstruction for Mars Pathfinder

NASA Astrophysics Data System (ADS)

Withers, Paul; Towner, Martin; Hathi, Brijen; Zarnecki, John

2004-02-01

Mars Pathfinder landed on Mars on July 4, 1997. It used a novel deceleration procedure, consisting of a hypersonic aeroshell, a transonic parachute, retro-rockets, and airbags, to reach the surface safely. Its aerodynamic properties passively maintained a near-zero angle of attack throughout its entry. There were no gyroscopes to monitor attitude. Several different trajectory reconstructions have been based on the assumptions that accelerations along its symmetry axis are directed along its flight path and that accelerations in other directions are insignificant. The aerodynamics of Pathfinder once its parachute opened are still not well-understood and the available observations are probably not sufficient to improve matters significantly in the future.

James Webb Space Telescope Optical Telescope Element Integrated Science Instrument Module (OTIS) Status

NASA Technical Reports Server (NTRS)

Feinberg, Lee; Voyton, Mark; Lander, Julie; Keski-Kuha, Ritva; Matthews, Gary

2016-01-01

The James Webb Space Telescope Optical Telescope Element (OTE) and Integrated ScienceInstrument Module (ISIM)are integrated together to form the OTIS. Once integrated, the OTIS undergoes primary mirrorcenter of curvatureoptical tests, electrical and operational tests, acoustics and vibration testing at the Goddard SpaceFlight Center beforebeing shipped to the Johnson Space Center for cryogenic optical testing of the OTIS. In preparationfor the cryogenicoptical testing, the JWST project has built a Pathfinder telescope and has completed two OpticalGround SystemEquipment (OGSE) cryogenic optical tests with the Pathfinder. In this paper, we will summarize opticaltest results todate and status the final Pathfinder test and the OTIS integration and environmental test preparations

HOWARD EISEN, JPL'S LEAD MECHANICAL TECHNICIAN, HOLDS MARS PATHFINDER 'SOJOURNER' ROVER 1:1 SCALE DU

NASA Technical Reports Server (NTRS)

1996-01-01

The Mars Pathfinder 'Sojourner' rover l:l scale duplicate test vehicle is held by Howard Eisen, its lead mechanical technician from the Jet Propulsion Laboratory, with Kennedy Space Center's Vehicle Assembly Building looming in the background. The launch of NASA's Mars Pathfinder spacecraft aboard a McDonnell Douglas Delta II rocket is scheduled for Monday, Dec. 2, at 2:09:11 a.m. EST. This is a single instantaneous target launch time without a second opportunity on that day. Liftoff will occur from Pad B at Launch Complex 17 on Cape Canaveral Air Station, Fla. There is a 24-day launch opportunity which extends through Dec. 31.

LISA Pathfinder: A Mission Status

NASA Astrophysics Data System (ADS)

Hewitson, Martin; LISA Pathfinder Team Team

2016-03-01

On December 3rd at 04:04 UTC, The European Space Agency launched the LISA Pathfinder satellite on board a VEGA rocket from Kourou in French Guiana. After a series of orbit raising manoeuvres and a 2 month long transfer orbit, LISA Pathfinder arrived at L1. Following a period of commissioning, the science operations commenced at the start of March, beginning the demonstration of technologies and methodologies which pave the way for a future large-scale gravitational wave observatory in space. This talk will present the scientific goals of the mission, discuss the technologies being tested, elucidate the link to a future space-based observatory, such as LISA, and present preliminary results from the in-orbit operations and experiments.

Pathfinders: Making a Way from Segregation to Community Life.

ERIC Educational Resources Information Center

O'Brien, Connie Lyle; Mount, Beth; O'Brien, John; Rosen, Fredda

This paper describes the Pathfinders program in New York (New York), which works to facilitate the full integration of adults with developmental disabilities into workplaces and neighborhoods. The paper is organized around the question of whether students graduating from special education can find paid and volunteer work in community settings,…

AeroVironment's Jim Daley, Rik Meininger, Derek Lisoski and Wyatt Sadler (clockwise from bottom left) closely monitor systems testing of the Pathfinder-Plus.

NASA Image and Video Library

2004-09-17

AeroVironment's test director Jim Daley, backup pilot Rik Meininger, stability and controls engineer Derek Lisoski and pilot Wyatt Sadler (clockwise from bottom left) closely monitor systems testing of the Pathfinder-Plus solar aircraft from the control station.

Do Integrated Children's Services Improve Children's Outcomes?: Evidence from England's Children's Trust Pathfinders

ERIC Educational Resources Information Center

O'Brien, Margaret; Bachmann, Max O.; Jones, Natalia R.; Reading, Richard; Thoburn, June; Husbands, Chris; Shreeve, Ann; Watson, Jacqueline

2009-01-01

Thirty-five children's trust pathfinders, local cross-sector partnerships, were introduced across England in 2003 to promote greater integration in children's services. Using administrative performance data, this paper tracks yearly trends in child service outputs and child well-being outcomes from 1997 to 2004 in these local areas, including the…

Global Climate Change Pathfinder: A Guide to Information Resources. Second Edition.

ERIC Educational Resources Information Center

Pintozzi, Chestalene; Jones, Douglas E.

This pathfinder is a guide to scientific and technical aspects of global climate change including meteorological and climatological aspects; biological, agricultural, and public policy implications; and the chemical processes involved. Sources are arranged by type of publication and include: (1) 10 reference sources; (2) 12 bibliographies; (3) 44…

Pathfinder. Volume 8, Number 3, May/June 2010. Technology - Rendering an Ever-Clearer Picture

DTIC Science & Technology

2010-06-01

Agency,Office of Corporate Communications,4600 Sangamore Road, Mail Stop D-54,Bethesda,MD, 20816 -5003 8. PERFORMING ORGANIZATION REPORT NUMBER 9...Bethesda, MD 20816 -5003 Telephone: (301) 227-7388, DSN 287-7388 E-mail: pathfinder@nga.mil Director Vice Adm. Robert B. Murrett, U.S. Navy Deputy

Wind Drifts at Viking 1 Landing Site

NASA Technical Reports Server (NTRS)

1997-01-01

This image is of so-called wind drifts seen at the Viking 1 landing site. These are somewhat different from the features seen at the Pathfinder site in two important ways. 1) These landforms have no apparent slip-or avalanche-face as do both terrestrial dunes and the Pathfinder features, and may represent deposits of sediment falling from the air, as opposed to dune sand, which 'hops' or saltates along the ground; 2) these features may indicate erosion on one side, because of the layering and apparent scouring on their right sides. They may, therefore have been deposited by a wind moving left to right, partly or weakly cemented or solidified by surface processes at some later time, then eroded by a second wind (right to left), exposing their internal structure.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

Statistical analysis of soil geochemical data to identify pathfinders associated with mineral deposits: An example from the Coles Hill uranium deposit, Virginia, USA

USGS Publications Warehouse

Levitan, Denise M.; Zipper, Carl E.; Donovan, Patricia; Schreiber, Madeline E.; Seal, Robert; Engle, Mark A.; Chermak, John A.; Bodnar, Robert J.; Johnson, Daniel K.; Aylor, Joseph G.

2015-01-01

Soil geochemical anomalies can be used to identify pathfinders in exploration for ore deposits. In this study, compositional data analysis is used with multivariate statistical methods to analyse soil geochemical data collected from the Coles Hill uranium deposit, Virginia, USA, to identify pathfinders associated with this deposit. Elemental compositions and relationships were compared between the collected Coles Hill soil and reference soil samples extracted from a regional subset of a national-scale geochemical survey. Results show that pathfinders for the Coles Hill deposit include light rare earth elements (La and Ce), which, when normalised by their Al content, are correlated with U/Al, and elevated Th/Al values, which are not correlated with U/Al, supporting decoupling of U from Th during soil generation. These results can be used in genetic and weathering models of the Coles Hill deposit, and can also be applied to future prospecting for similar U deposits in the eastern United States, and in regions with similar geological/climatic conditions.

MARS PATHFINDER CAMERA TEST IN SAEF-2

NASA Technical Reports Server (NTRS)

1996-01-01

Jet Propulsion Laboratory (JPL) workers conduct a systems test of the Mars Pathfinder imager, installed atop the Pathfinder lander (with JPL insignia). The imager is the white cyclindrical structure close to the worker's gloved hand. At left is the small rover that will be deployed from the lander to explore the Martian surface. The rover is mounted on one of three petals that will be attached to the lander. The two-pronged mast extending upward from the lander is for the low-gain antenna. The imager is mounted on a mast that will be extended after the lander touches down on Mars, affording a better view of the area. The imager is a camera that will transmit images of the Martian surface as well as the trail left by the rover, helping researchers to better understand the composition of the soil. It also is equipped with selectable filters for gathering data about the atmosphere of the Red Planet. JPL manages the Mars Pathfinder project for NASA. The journey to Mars is scheduled to begin with liftoff Dec. 2 aboard a Delta II expendable launch vehicle.

Actuation crosstalk in free-falling systems: Torsion pendulum results for the engineering model of the LISA pathfinder gravitational reference sensor

NASA Astrophysics Data System (ADS)

Bassan, M.; Cavalleri, A.; De Laurentis, M.; De Marchi, F.; De Rosa, R.; Di Fiore, L.; Dolesi, R.; Finetti, N.; Garufi, F.; Grado, A.; Hueller, M.; Marconi, L.; Milano, L.; Minenkov, Y.; Pucacco, G.; Stanga, R.; Vetrugno, D.; Visco, M.; Vitale, S.; Weber, W. J.

2018-01-01

In this paper we report on measurements on actuation crosstalk, relevant to the gravitational reference sensors for LISA Pathfinder and LISA. In these sensors, a Test Mass (TM) falls freely within a system of electrodes used for readout and control. These measurements were carried out on ground with a double torsion pendulum that allowed us to estimate both the torque injected into the sensor when a control force is applied and, conversely, the force leaking into the translational degree of freedom due to the applied torque.The values measured on our apparatus (the engineering model of the LISA Pathfinder sensor) agree to within 0.2% (over a maximum measured crosstalk of 1%) with predictions of a mathematical model when measuring force to torque crosstalk, while it is somewhat larger than expected (up to 3.5%) when measuring torque to force crosstalk. However, the values in the relevant range, i.e. when the TM is well centered ( ± 10 μm) in the sensor, remain smaller than 0.2%, satisfying the LISA Pathfinder requirements.

Relating MBSE to Spacecraft Development: A NASA Pathfinder

NASA Technical Reports Server (NTRS)

Othon, Bill

2016-01-01

The NASA Engineering and Safety Center (NESC) has sponsored a Pathfinder Study to investigate how Model Based Systems Engineering (MBSE) and Model Based Engineering (MBE) techniques can be applied by NASA spacecraft development projects. The objectives of this Pathfinder Study included analyzing both the products of the modeling activity, as well as the process and tool chain through which the spacecraft design activities are executed. Several aspects of MBSE methodology and process were explored. Adoption and consistent use of the MBSE methodology within an existing development environment can be difficult. The Pathfinder Team evaluated the possibility that an "MBSE Template" could be developed as both a teaching tool as well as a baseline from which future NASA projects could leverage. Elements of this template include spacecraft system component libraries, data dictionaries and ontology specifications, as well as software services that do work on the models themselves. The Pathfinder Study also evaluated the tool chain aspects of development. Two chains were considered: 1. The Development tool chain, through which SysML model development was performed and controlled, and 2. The Analysis tool chain, through which both static and dynamic system analysis is performed. Of particular interest was the ability to exchange data between SysML and other engineering tools such as CAD and Dynamic Simulation tools. For this study, the team selected a Mars Lander vehicle as the element to be designed. The paper will discuss what system models were developed, how data was captured and exchanged, and what analyses were conducted.

NASA's Webb "Pathfinder Telescope" Successfully Completes First Super-Cold Optical Test

NASA Image and Video Library

2017-12-08

Testing is crucial part of NASA's success on Earth and in space. So, as the actual flight components of NASA's James Webb Space Telescope come together, engineers are testing the non-flight equipment to ensure that tests on the real Webb telescope later goes safely and according to plan. Recently, the "pathfinder telescope," or just “Pathfinder,” completed its first super-cold optical test that resulted in many first-of-a-kind demonstrations. "This test is the first dry-run of the equipment and procedures we will use to conduct an end-to-end optical test of the flight telescope and instruments," said Mark Clampin, Webb telescope Observatory Project Scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "It provides confidence that once the flight telescope is ready, we are fully prepared for a successful test of the flight hardware." The Pathfinder is a non-flight replica of the Webb telescope’s center section backplane, or “backbone,” that includes mirrors. The flight backplane comes in three segments, a center section and two wing-like parts, all of which will support large hexagonal mirrors on the Webb telescope. The pathfinder only consists of the center part of the backplane. However, during the test, it held two full size spare primary mirror segments and a full size spare secondary mirror to demonstrate the ability to optically test and align the telescope at the planned operating temperatures of -400 degrees Fahrenheit (-240 Celsius). Read more: www.nasa.gov/feature/goddard/nasas-webb-pathfinder-telesc... Credit: NASA/Goddard/Chris Gunn NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Coexpression of high-voltage-activated ion channels Kv3.4 and Cav1.2 in pioneer axons during pathfinding in the developing rat forebrain.

PubMed

Huang, Chia-Yi; Chu, Dachen; Hwang, Wei-Chao; Tsaur, Meei-Ling

2012-11-01

Precise axon pathfinding is crucial for establishment of the initial neuronal network during development. Pioneer axons navigate without the help of preexisting axons and pave the way for follower axons that project later. Voltage-gated ion channels make up the intrinsic electrical activity of pioneer axons and regulate axon pathfinding. To elucidate which channel molecules are present in pioneer axons, immunohistochemical analysis was performed to examine 14 voltage-gated ion channels (Kv1.1-Kv1.3, Kv3.1-Kv3.4, Kv4.3, Cav1.2, Cav1.3, Cav2.2, Nav1.2, Nav1.6, and Nav1.9) in nine axonal tracts in the developing rat forebrain, including the optic nerve, corpus callosum, corticofugal fibers, thalamocortical axons, lateral olfactory tract, hippocamposeptal projection, anterior commissure, hippocampal commissure, and medial longitudinal fasciculus. We found A-type K⁺ channel Kv3.4 in both pioneer axons and early follower axons and L-type Ca²⁺ channel Cav1.2 in pioneer axons and early and late follower axons. Spatially, Kv3.4 and Cav1.2 were colocalized with markers of pioneer neurons and pioneer axons, such as deleted in colorectal cancer (DCC), in most fiber tracts examined. Temporally, Kv3.4 and Cav1.2 were expressed abundantly in most fiber tracts during axon pathfinding but were downregulated beginning in synaptogenesis. By contrast, delayed rectifier Kv channels (e.g., Kv1.1) and Nav channels (e.g., Nav1.2) were absent from these fiber tracts (except for the corpus callosum) during pathfinding of pioneer axons. These data suggest that Kv3.4 and Cav1.2, two high-voltage-activated ion channels, may act together to control Ca²⁺ -dependent electrical activity of pioneer axons and play important roles during axon pathfinding. Copyright © 2012 Wiley Periodicals, Inc.

Assessment of Mars Pathfinder landing site predictions

USGS Publications Warehouse

Golombek, M.P.; Moore, H.J.; Haldemann, A.F.C.; Parker, T.J.; Schofield, J.T.

1999-01-01

Remote sensing data at scales of kilometers and an Earth analog were used to accurately predict the characteristics of the Mars Pathfinder landing site at a scale of meters. The surface surrounding the Mars Pathfinder lander in Ares Vallis appears consistent with orbital interpretations, namely, that it would be a rocky plain composed of materials deposited by catastrophic floods. The surface and observed maximum clast size appears similar to predictions based on an analogous surface of the Ephrata Fan in the Channeled Scabland of Washington state. The elevation of the site measured by relatively small footprint delay-Doppler radar is within 100 m of that determined by two-way ranging and Doppler tracking of the spacecraft. The nearly equal elevations of the Mars Pathfinder and Viking Lander 1 sites allowed a prediction of the atmospheric conditions with altitude (pressure, temperature, and winds) that were well within the entry, descent, and landing design margins. High-resolution (~38 m/pixel) Viking Orbiter 1 images showed a sparsely cratered surface with small knobs with relatively low slopes, consistent with observations of these features from the lander. Measured rock abundance is within 10% of that expected from Viking orbiter thermal observations and models. The fractional area covered by large, potentially hazardous rocks observed is similar to that estimated from model rock distributions based on data from the Viking landing sites, Earth analog sites, and total rock abundance. The bulk and fine-component thermal inertias measured from orbit are similar to those calculated from the observed rock size-frequency distribution. A simple radar echo model based on the reflectivity of the soil (estimated from its bulk density), and the measured fraction of area covered by rocks was used to approximate the quasi-specular and diffuse components of the Earth-based radar echos. Color and albedo orbiter data were used to predict the relatively dust free or unweathered surface around the Pathfinder lander compared to the Viking landing sites. Comparisons with the experiences of selecting the Viking landing sites demonstrate the enormous benefit the Viking data and its analyses and models had on the successful predictions of the Pathfinder site. The Pathfinder experience demonstrates that, in certain locations, geologic processes observed in orbiter data can be used to infer surface characteristics where those processes dominate over other processes affecting the Martian surface layer. Copyright 1999 by the American Geophysical Union.

VAMOS: A pathfinder for the HAWC gamma-ray observatory

NASA Astrophysics Data System (ADS)

Abeysekara, A. U.; Alfaro, R.; Alvarez, C.; Álvarez, J. D.; Ángeles, F.; Arceo, R.; Arteaga-Velázquez, J. C.; Avila-Aroche, A.; Ayala Solares, H. A.; Badillo, C.; Barber, A. S.; Baughman, B. M.; Bautista-Elivar, N.; Becerra Gonzalez, J.; Belmont, E.; Benítez, E.; BenZvi, S. Y.; Berley, D.; Bernal, A.; Bonilla Rosales, M.; Braun, J.; Caballero-Lopez, R. A.; Caballero-Mora, K. S.; Cabrera, I.; Carramiñana, A.; Castañeda-Martínez, L.; Castillo, M.; Cotti, U.; Cotzomi, J.; de la Fuente, E.; De León, C.; DeYoung, T.; Diaz-Azuara, A.; Diaz-Cruz, L.; Diaz Hernandez, R.; Díaz-Vélez, J. C.; Dingus, B. L.; Dultzin, D.; DuVernois, M. A.; Ellsworth, R. W.; Fernandez, A.; Fiorino, D. W.; Fraija, N.; Galindo, A.; García-Torales, G.; Garfias, F.; González, A.; González, L. X.; González, M. M.; Goodman, J. A.; Grabski, V.; Gussert, M.; Guzmán-Cerón, C.; Hampel-Arias, Z.; Harding, J. P.; Hernández-Cervantes, L.; Hui, C. M.; Hüntemeyer, P.; Imran, A.; Iriarte, A.; Karn, P.; Kieda, D.; Kunde, G. J.; Langarica, R.; Lara, A.; Lara, G.; Lauer, R. J.; Lee, W. H.; Lennarz, D.; León Vargas, H.; Linares, E. C.; Linnemann, J. T.; Longo, M.; Luna-Garcia, R.; Marinelli, A.; Martínez, L. A.; Martínez, H.; Martínez, O.; Martínez-Castro, J.; Martos, M.; Matthews, J. A. J.; McEnery, J.; Mendoza Torres, E.; Miranda-Romagnoli, P.; Moreno, E.; Mostafá, M.; Nava, J.; Nellen, L.; Newbold, M.; Noriega-Papaqui, R.; Oceguera-Becerra, T.; Page, D. P.; Patricelli, B.; Pelayo, R.; Pérez-Pérez, E. G.; Pretz, J.; Ramírez, I.; Rentería, A.; Rivière, C.; Rosa-González, D.; Ruiz-Sala, F.; Ruiz-Velasco, E. L.; Ryan, J.; Sacahui, J. R.; Salazar, H.; Salesa, F.; Sandoval, A.; Santos, E.; Schneider, M.; Silich, S.; Sinnis, G.; Smith, A. J.; Sparks Woodle, K.; Springer, R. W.; Suarez, F.; Taboada, I.; Tepe, A.; Toale, P. A.; Tollefson, K.; Torres, I.; Tinoco, S.; Ukwatta, T. N.; Valdés Galicia, J. F.; Vanegas, P.; Vázquez, A.; Villaseñor, L.; Wall, W.; Weisgarber, T.; Westerhoff, S.; Wisher, I. G.; Wood, J.; Yodh, G. B.; Younk, P. W.; Zaborov, D.; Zepeda, A.; Zhou, H.

2015-03-01

VAMOS was a prototype detector built in 2011 at an altitude of 4100 m a.s.l. in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design, construction techniques and data acquisition system of the HAWC observatory. HAWC is an air-shower array currently under construction at the same site of VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water Cherenkov detectors and two different data acquisition systems. It was in operation between October 2011 and May 2012 with an average live time of 30%. Besides the scientific verification purposes, the eight months of data were used to obtain the results presented in this paper: the detector response to the Forbush decrease of March 2012, and the analysis of possible emission, at energies above 30 GeV, for long gamma-ray bursts GRB111016B and GRB120328B.

Precise and Scalable Static Program Analysis of NASA Flight Software

NASA Technical Reports Server (NTRS)

Brat, G.; Venet, A.

2005-01-01

Recent NASA mission failures (e.g., Mars Polar Lander and Mars Orbiter) illustrate the importance of having an efficient verification and validation process for such systems. One software error, as simple as it may be, can cause the loss of an expensive mission, or lead to budget overruns and crunched schedules. Unfortunately, traditional verification methods cannot guarantee the absence of errors in software systems. Therefore, we have developed the CGS static program analysis tool, which can exhaustively analyze large C programs. CGS analyzes the source code and identifies statements in which arrays are accessed out of bounds, or, pointers are used outside the memory region they should address. This paper gives a high-level description of CGS and its theoretical foundations. It also reports on the use of CGS on real NASA software systems used in Mars missions (from Mars PathFinder to Mars Exploration Rover) and on the International Space Station.

Transient Phenomena: Opportunities for New Discoveries

NASA Technical Reports Server (NTRS)

Lazio, T. Joseph W.

2010-01-01

Known classes of radio wavelength transients range from the nearby (stellar flares and radio pulsars) to the distant Universe (gamma-ray burst afterglows). Hypothesized classes of radio transients include analogs of known objects, such as extrasolar planets emitting Jovian-like radio bursts and giant-pulse emitting pulsars in other galaxies, to the exotic, such as prompt emission from gamma-ray bursts, evaporating black holes and transmitters from other civilizations. Time domain astronomy has been recognized internationally as a means of addressing key scientific questions in astronomy and physics, and pathfinders and Precursors to the Square Kilometre Array (SKA) are beginning to offer a combination of wider fields of view and more wavelength agility than has been possible in the past. These improvements will continue when the SKA itself becomes operational. I illustrate the range of transient phenomena and discuss how the detection and study of radio transients will improve immensely.

Stray light suppression in the Goddard IRAM 2-Millimeter Observer (GISMO)

NASA Astrophysics Data System (ADS)

Sharp, E. H.; Benford, D. J.; Fixsen, D. J.; Moseley, S. H.; Staguhn, J. G.; Wollack, E. J.

2012-09-01

The Goddard-IRAM Superconducting 2 Millimeter Observer (GISMO) is an 8x16 Transition Edge Sensor (TES) array of bolometers built as a pathfinder for TES detector development efforts at NASA Goddard Space Flight Center. GISMO has been used annually at the Institut de Radioastronomie Millimétrique (IRAM) 30 meter telescope since 2007 under engineering time and was opened in the spring of 2012 to the general astronomical community. The spring deployment provided an opportunity to modify elements of the room temperature optics before moving the instrument to its new permanent position in the telescope receiver cabin. This allowed for the possibility to extend the cryostat, introduce improved cold baffling and thus further optimize the stray light performance for final astronomical use of the instrument, which has been completed and validated. We will demonstrate and discuss several of the methods used to quantify and limit the influence of stray light in the GISMO camera.

Measurement of Cosmic-Ray TeV Electrons

NASA Astrophysics Data System (ADS)

Schubnell, Michael; Anderson, T.; Bower, C.; Coutu, S.; Gennaro, J.; Geske, M.; Mueller, D.; Musser, J.; Nutter, S.; Park, N.; Tarle, G.; Wakely, S.

2011-09-01

The Cosmic Ray Electron Synchrotron Telescope (CREST) high-altitude balloon experiment is a pathfinding effort to detect for the first time multi-TeV cosmic-ray electrons. At these energies distant sources will not contribute to the local electron spectrum due to the strong energy losses of the electrons and thus TeV observations will reflect the distribution and abundance of nearby acceleration sites. CREST will detect electrons indirectly by measuring the characteristic synchrotron photons generated in the Earth's magnetic field. The instrument consist of an array of 1024 BaF2 crystals viewed by photomultiplier tubes surrounded by a hermetic scintillator shield. Since the primary electron itself need not traverse the payload, an effective detection area is achieved that is several times the nominal 6.4 m2 instrument. CREST is scheduled to fly in a long duration circumpolar orbit over Antarctica during the 2011-12 season.

Searching for TeV cosmic electrons with the CREST experiment

NASA Astrophysics Data System (ADS)

Coutu, S.; Anderson, T.; Bower, C.; Gennaro, J.; Geske, M.; Müller, D.; Musser, J.; Nutter, S.; Park, N. H.; Schubnell, M.; Tarlé, G.; Wakely, S.; Yagi, A.

2011-06-01

The Cosmic Ray Electron Synchrotron Telescope (CREST) high-altitude balloon experiment is a pathfinding effort to detect for the first time multi-TeV cosmic-ray electrons. Such would be the markers of nearby cosmic accelerators, as energetic electrons from distant Galactic sources are expected to be depleted by radiative losses during interstellar transport. Electrons will be detected indirectly by the characteristic signature of their geomagnetic synchrotron losses, in the form of a burst of coaligned x-ray photons intersecting the plane of the instrument. Since the primary electron itself need not traverse the payload, an effective detection area is achieved that is several times the nominal 6.4 m2 instrument. The payload is composed of an array of 1024 BaF2 crystals surrounded by a set of veto scintillator detectors. A long-duration balloon flight in Antarctica is planned for the 2011-12 season.

Stray Light Suppression in the Goddard IRAM 2-Millimeter Observer (GISMO)

NASA Technical Reports Server (NTRS)

Sharp, E. H.; Benford, D. J.; Fixsen, D. J.; Moseley, S. H.; Staguhn, J. G.; Wollack, E. J.

2012-01-01

The Goddard-IRAM Superconducting 2 Millimeter Observer (GISMO) is an 8xl6 Transition Edge Sensor (TES) array of bolometers built as a pathfinder for TES detector development efforts at NASA Goddard Space Flight Center. GISMO has been used annually at the Institut de Radioastronomie Millimetrique (IRAM) 30 meter telescope since 2007 under engineering time and was opened in the spring of 2012 to the general astronomical community. The spring deployment provided an opportunity to modify elements of the room temperature optics before moving the instrument to its new permanent position in the telescope receiver cabin. This allowed for the possibility to extend the cryostat, introduce improved cold baffling and thus further optimize the stray light performance for final astronomical use of the instrument, which has been completed and validated. We will demonstrate and discuss several of the methods used to quantify and limit the influence of stray light in the GISMO camera.

Airbag Retraction

NASA Image and Video Library

1997-07-05

This image shows that the Mars Pathfinder airbags have been successfully retracted, allowing safe deployment of the rover ramps. The Sojourner rover, still in its deployed position, is at center image, and rocks are visible in the background. Mars Pathfinder landed successfully on the surface of Mars today at 10:07 a.m. PDT. http://photojournal.jpl.nasa.gov/catalog/PIA00617

Pathfinder: The Geospatial Intelligence Magazine Serving the Front Line, March/April 2009. Volume 7, Number 2

DTIC Science & Technology

2009-04-01

ADDRESS(ES) National Geospatial-Intelligence Agency,4600 Sangamore Rd Mail Stop D-54,Bethesda,MD, 20816 -5003 8. PERFORMING ORGANIZATION REPORT NUMBER 9...Bethesda, MD 20816 -5003 Telephone: (301) 227-7388, DSN 287-7388 E-mail: pathfinder@nga.mil Director Vice Adm. Robert B. Murrett, U.S. Navy Deputy

Global comparisons between the modified Pathfinder derived sea surface temperature and skin temperatures from the along-track scanning radiometer on board ERS-2: how close are we getting?

NASA Technical Reports Server (NTRS)

Vazquez, J.

2001-01-01

Sea Surface Temperatures (SST) as derived from the Pathfinder Sea Surface Temperature Data Set and the Along-Track Scanning Radiometer on-board the European Remote Sensing Satellite provide a unique opportunity for comparing two independent SST data sets.

SLS Pathfinder Segments Car Train Departure

NASA Image and Video Library

2016-03-02

An Iowa Northern locomotive, contracted by Goodloe Transportation of Chicago, departs from NASA’s Kennedy Space Center in Florida, with two containers on railcars for transport to the Jay Jay railroad yard. The containers held two pathfinders, or test versions, of solid rocket booster segments for NASA’s Space Launch System rocket that were delivered to the Rotation, Processing and Surge Facility (RPSF). Inside the RPSF, the Ground Systems Development and Operations Program and Jacobs Engineering, on the Test and Operations Support Contract, will conduct a series of lifts, moves and stacking operations using the booster segments, which are inert, to prepare for Exploration Mission-1, deep-space missions and the journey to Mars. The pathfinder booster segments are from Orbital ATK in Utah.

James Webb Space Telescope Optical Telescope Element/Integrated Science Instrument Module (OTIS) Status

NASA Technical Reports Server (NTRS)

Feinberg, Lee; Voyton, Mark; Lander, Juli; Keski-Kuha, Ritva; Matthews, Gary

2016-01-01

The James Webb Space Telescope Optical Telescope Element (OTE) and Integrated Science Instrument Module (ISIM) are integrated together to form the OTIS. Once integrated, the OTIS undergoes primary mirror center of curvature optical tests, electrical and operational tests, acoustics and vibration testing at the Goddard Space Flight Center before being shipped to the Johnson Space Center for cryogenic optical testing of the OTIS. In preparation for the cryogenic optical testing, the JWST project has built a Pathfinder telescope and has completed two Optical Ground System Equipment (OGSE) cryogenic optical tests with the Pathfinder. In this paper, we will summarize optical test results to date and status the final Pathfinder test and the OTIS integration and environmental test preparations

New Insights into the Geology of the Mars Pathfinder Landing Site from Spectral and Morphologic Analysis of the 12-Color Superpan Panorama

NASA Technical Reports Server (NTRS)

Murchie, S.; Barnouin-Jha, O.; Barnouin-Jha, K.; Bishop, J.; Johnson, J.; McSween, H.; Morris, R.

2003-01-01

New analyses of rocks and soils at the Mars Pathfinder landing site have been completed using the full Imager for Mars Pathfinder (IMP) 12- color SuperPan panorama. These revise early conclusions that rocks at the landing site are a single lithology coated only by windblown dust. We conclude instead that there is also a second lithology in addition to the dominant gray rock, and that it is consistent with highlands material excavated from beneath a thin veneer of northern plains; that many rocks have cemented coatings that formed during an early, probably wetter climate; and that young rocks excavated after coating formation ceased are mainly breccias or conglomerates.

LISA Pathfinder Spacecraft Artist Concept

NASA Image and Video Library

2015-12-03

This artist's concept shows ESA's LISA Pathfinder spacecraft, which launched on Dec. 3, 2015, from Kourou, French Guiana, will help pave the way for a mission to detect gravitational waves. LISA Pathfinder, led by the European Space Agency (ESA), is designed to test technologies that could one day detect gravitational waves. Gravitational waves, predicted by Einstein's theory of general relativity, are ripples in spacetime produced by any accelerating body. But the waves are so weak that Earth- or space-based observatories would likely only be able to directly detect such signals coming from massive astronomical systems, such as binary black holes or exploding stars. Detecting gravitational waves would be an important piece in the puzzle of how our universe began. http://photojournal.jpl.nasa.gov/catalog/PIA20196

SLS Pathfinder Segments Car Train Departure

NASA Image and Video Library

2016-03-02

An Iowa Northern locomotive, contracted by Goodloe Transportation of Chicago, departs from the Rotation, Processing and Surge Facility (RPSF) at NASA’s Kennedy Space Center in Florida, with two containers on railcars for transport to the NASA Jay Jay railroad yard. The containers held two pathfinders, or test versions, of solid rocket booster segments for NASA’s Space Launch System rocket that were delivered to the RPSF. Inside the RPSF, the Ground Systems Development and Operations Program and Jacobs Engineering, on the Test and Operations Support Contract, will conduct a series of lifts, moves and stacking operations using the booster segments, which are inert, to prepare for Exploration Mission-1, deep-space missions and the journey to Mars. The pathfinder booster segments are from Orbital ATK in Utah.

Fabrication of FORTIS

NASA Astrophysics Data System (ADS)

McCandliss, Stephan R.; Fleming, Brian; Kaiser, Mary Elizabeth; Kruk, Jeffrey; Feldman, Paul D.; Kutyrev, Alexander S.; Li, Mary J.; Goodwin, Phillip A.; Rapchun, David; Lyness, Eric; Brown, Ari D.; Moseley, Harvey; Siegmund, Oswald; Vallerga, John

2010-07-01

The Johns Hopkins University sounding rocket group is building the Far-ultraviolet Off Rowland-circle Telescope for Imaging and Spectroscopy (FORTIS), which is a Gregorian telescope with rulings on the secondary mirror. FORTIS will be launched on a sounding rocket from White Sand Missile Range to study the relationship between Lyman alpha escape and the local gas-to-dust ratio in star forming galaxies with non-zero redshifts. It is designed to acquire images of a 30' x 30' field and provide fully redundant "on-the-fly" spectral acquisition of 43 separate targets in the field with a bandpass of 900 - 1800 Angstroms. FORTIS is an enabling scientific and technical activity for future cutting edge far- and near-uv survey missions seeking to: search for Lyman continuum radiation leaking from star forming galaxies, determine the epoch of He II reionization and characterize baryon acoustic oscillations using the Lyman forest. In addition to the high efficiency "two bounce" dual-order spectro-telescope design, FORTIS incorporates a number of innovative technologies including: an image dissecting microshutter array developed by GSFC; a large area (~ 45 mm x 170 mm) microchannel plate detector with central imaging and "outrigger" spectral channels provided by Sensor Sciences; and an autonomous targeting microprocessor incorporating commercially available field programable gate arrays. We discuss progress to date in developing our pathfinder instrument.

Technology Advances at the NRAO Green Bank Telescope

NASA Astrophysics Data System (ADS)

Lockman, Felix James

2015-08-01

The 100 meter diameter Green Bank Telescope, with its large frequency coverage, great sensitivity, all-sky tracking, and location at a protected, radio-quiet site, offers a unique platform for technological advances in astronomical instrumentation that can yield an immediate scientific payoff.MUSTANG-1.5 is a feedhorn-coupled bolometer array for 3mm that has recently been installed on the telescope. It has 64 pixels (expandable to 223) and offers sensitivity to angular scales from 9" to more than 3' over a band from 75 GHz to 105 GHz. Its capabilities for science at 3mm are complimentary to, and in some cases superior to, those offered by ALMA. MUSTANG-1.5 is a collaboration between UPenn., NIST, NRAO, and other institutions.ARGUS is a 16-pixel focal plane array for millimeter spectroscopy that will be in use on the GBT in 2015. The array architecture is designed as a scalable technology pathfinder for larger arrays, but by itself it will provide major capabilities for spectroscopy from 75-107 GHz with 8" angular resolution over a wide field-of-view. It is a collaboration between Stanford Univ., Caltech, JPL, Univ. Maryland, Univ. Miami, and NRAO.FLAG is a prototype phased array receiver operating at 21cm wavelength that is under development for the GBT. It will produce multiple beams over a wide field of view with a sensitivity competitive with that of single-pixel receivers, allowing rapid astronomical surveys. FLAG is a collaboration between BYU, WVU, and NRAO.Also under development is a mm-wave phased array receiver for the GBT, designed to operate near 90 GHz as a prototype for very large format phased array receivers in the 3mm band. It is a collaboration between UMass and BYU.VEGAS is the new spectrometer for the GBT, offering multiple configurations well matched to GBT receivers from 1 to 100 GHz and suitable for use with focal plane arrays. It is a collaboration between UCal (Berkeley) and NRAO.The new receivers and spectrometers create extremely big data sets during both observation and later processing. Studies are under way at the GBT of data-streaming methodologies and pipeline processing techniques to meet the challenges posed by this new generation of instrumentation.

Feasibility of solar power for Mars

NASA Technical Reports Server (NTRS)

Appelbaum, Joseph; Landis, Geoffrey A.

1991-01-01

NASA, through Project Pathfinder, has put in place an advanced technology program to address future needs of manned space exploration. Included in the missions under study is the establishment of outposts on the surface of Mars. The Surface Power program in Pathfinder is aimed at providing photovoltaic array technology for such an application (as well as for the lunar surface). Another important application is for unmanned precursor missions, such as the photovoltaic-power aircraft, which will scout landing sites and investigate Mars geology for a 1 to 2 year mission without landing on the surface. Effective design and utilization of solar energy depend to a large extent on adequate knowledge of solar radiation characteristics in the region of solar energy system operation. The two major climatic components needed for photovoltaic system designs are the distributions of solar insolation and ambient temperature. These distributions for the Martian climate are given at the two Viking lander locations but can also be used, to the first approximation, for other latitudes. One of the most important results is that there is a large diffuse component of the insolation, even at high optical depth, so that solar energy system operation is still possible. If the power system is to continue to generate power even on high optical opacity days, it is thus important that the photovoltaic system be designed to collect diffuse irradiance as well as direct. In absence of long term insolation and temperature data for Mars, the data presented can be used until updated data are available. The ambient temperature data are given as measured directly by the temperature sensor; the insolation data are calculated from optical depth measurements of the atmosphere.

Indoor A* Pathfinding Through an Octree Representation of a Point Cloud

NASA Astrophysics Data System (ADS)

Rodenberg, O. B. P. M.; Verbree, E.; Zlatanova, S.

2016-10-01

There is a growing demand of 3D indoor pathfinding applications. Researched in the field of robotics during the last decades of the 20th century, these methods focussed on 2D navigation. Nowadays we would like to have the ability to help people navigate inside buildings or send a drone inside a building when this is too dangerous for people. What these examples have in common is that an object with a certain geometry needs to find an optimal collision free path between a start and goal point. This paper presents a new workflow for pathfinding through an octree representation of a point cloud. We applied the following steps: 1) the point cloud is processed so it fits best in an octree; 2) during the octree generation the interior empty nodes are filtered and further processed; 3) for each interior empty node the distance to the closest occupied node directly under it is computed; 4) a network graph is computed for all empty nodes; 5) the A* pathfinding algorithm is conducted. This workflow takes into account the connectivity for each node to all possible neighbours (face, edge and vertex and all sizes). Besides, a collision avoidance system is pre-processed in two steps: first, the clearance of each empty node is computed, and then the maximal crossing value between two empty neighbouring nodes is computed. The clearance is used to select interior empty nodes of appropriate size and the maximal crossing value is used to filter the network graph. Finally, both these datasets are used in A* pathfinding.

Pathfinder-Plus aircraft in flight

NASA Technical Reports Server (NTRS)

1998-01-01

The Pathfinder-Plus solar-powered aircraft is shown taking off from a runway, then flying at low altitude over the ocean. The vehicle, which looks like a flying ruler, operates at low airspeed. Among the missions proposed for a solar-powered aircraft are communications relay, atmospheric studies, pipeline monitoring and gas leak detection, environmental monitoring using thermal and radar images, and disaster relief and monitoring.

Predictive Validity of Measures of the Pathfinder Scaling Algorithm on Programming Performance: Alternative Assessment Strategy for Programming Education

ERIC Educational Resources Information Center

Lau, Wilfred W. F.; Yuen, Allan H. K.

2009-01-01

Recent years have seen a shift in focus from assessment of learning to assessment for learning and the emergence of alternative assessment methods. However, the reliability and validity of these methods as assessment tools are still questionable. In this article, we investigated the predictive validity of measures of the Pathfinder Scaling…

Pathfinders and Problem Solving: Comparative Effects of Two Cognitive-Behavioral Programs among Men and Women Offenders in Community and Prison

ERIC Educational Resources Information Center

Spiropoulos, Georgia V.; Spruance, Lisa; Van Voorhis, Patricia; Schmitt, Michelle M.

2005-01-01

The effects of "Problem Solving" (Taymans & Parese, 1998) are compared across small diversion and prison samples for men and women. A second program, "Pathfinders" (Hansen, 1993), was compared to the Problem Solving program among incarcerated women offenders to determine whether its focus upon empowerment and relationships enhanced the effects of…

Sojourner Rover View of Pathfinder Lander

NASA Technical Reports Server (NTRS)

1997-01-01

Image of Pathfinder Lander on Mars taken from Sojourner Rover left front camera on sol 33. The IMP (on the lattice mast) is looking at the rover. Airbags are prominent, and the meteorology mast is shown to the right. Lowermost rock is Ender, with Hassock behind it and Yogi on the other side of the lander.

NOTE: original caption as published in Science Magazine

A Review of Solar-Powered Aircraft Flight Activity at the Pacific Missile Range Test Facility, Kauai, Hawaii

NASA Technical Reports Server (NTRS)

Ehernberger, L. J.; Donohue, Casey; Teets, Edward H., Jr.

2004-01-01

A series of solar-powered aircraft have been designed and operated by AeroVironment, Inc. (Monrovia, CA) as a part of National Aeronautics and Space Administration (NASA) objectives to develop energy-efficient high-altitude long-endurance platforms for earth observations and communications applications. Flight operations have been conducted at NASA's Dryden Flight Research Center, Edwards CA and at the U.S. Navy Pacific Missile Range Facility (PMRF) at Barking Sands, Kauai, HI. These aircraft flown at PMRF are named Pathfinder , Pathfinder Plus and Helios . Sizes of these three aircraft range from 560 lb with a 99-ft wingspan to 2300 lb with a 247-ft wingspan. Available payload capacity reaches approximately 200 lb. Pathfinder uses six engines and propellers: Pathfinder Plus 8; and Helios 14. The 2003 Helios fuel cell configurations used 10 engines and propellers. The PMRF was selected as a base of operations because if offers optimal summertime solar exposure, low prevailing wind-speeds on the runway, modest upper-air wind-speeds and the availability of suitable airspace. Between 1997 and 2001, successive altitude records of 71,530 ft, 80,200 ft, and 96,863 ft were established. Flight durations extended to 18 hours.

A Study to Compare the Failure Rates of Current Space Shuttle Ground Support Equipment with the New Pathfinder Equipment and Investigate the Effect that the Proposed GSE Infrastructure Upgrade Might Have to Reduce GSE Infrastructure Failures

NASA Technical Reports Server (NTRS)

Kennedy, Barbara J.

2004-01-01

The purposes of this study are to compare the current Space Shuttle Ground Support Equipment (GSE) infrastructure with the proposed GSE infrastructure upgrade modification. The methodology will include analyzing the first prototype installation equipment at Launch PAD B called the "Pathfinder". This study will begin by comparing the failure rate of the current components associated with the "Hardware interface module (HIM)" at the Kennedy Space Center to the failure rate of the neW Pathfinder components. Quantitative data will be gathered specifically on HIM components and the PAD B Hypergolic Fuel facility and Hypergolic Oxidizer facility areas which has the upgraded pathfinder equipment installed. The proposed upgrades include utilizing industrial controlled modules, software, and a fiber optic network. The results of this study provide evidence that there is a significant difference in the failure rates of the two studied infrastructure equipment components. There is also evidence that the support staff for each infrastructure system is not equal. A recommendation to continue with future upgrades is based on a significant reduction of failures in the new' installed ground system components.

Extreme Rock Distributions on Mars and Implications for Landing Safety

NASA Technical Reports Server (NTRS)

Golombek, M. P.

2001-01-01

Prior to the landing of Mars Pathfinder, the size-frequency distribution of rocks from the two Viking landing sites and Earth analog surfaces was used to derive a size-frequency model, for nomimal rock distributions on Mars. This work, coupled with extensive testing of the Pathfinder airbag landing system, allowed an estimate of what total rock abundances derived from thermal differencing techniques could be considered safe for landing. Predictions based on this model proved largely correct at predicting the size-frequency distribution of rocks at the Mars Pathfinder site and the fraction of potentially hazardous rocks. In this abstract, extreme rock distributions observed in Mars Orbiter Camera (MOC) images are compared with those observed at the three landing sites and model distributions as an additional constraint on potentially hazardous surfaces on Mars.

Rock Garden

NASA Technical Reports Server (NTRS)

1997-01-01

This false color composite image of the Rock Garden shows the rocks 'Shark' and 'Half Dome' at upper left and middle, respectively. Between these two large rocks is a smaller rock (about 0.20 m wide, 0.10 m high, and 6.33 m from the Lander) that was observed close-up with the Sojourner rover (see PIA00989).

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Diversity of soils near rover deploy region

NASA Technical Reports Server (NTRS)

1997-01-01

The surface near the rover's egress from the lander contains mainly bright red drift (#1), dark gray rocks such as Cradle (# 3), soil intermediate in color to the rocks and drift (#2), and dark red soil on and around the rock Lamb (#4). Globally, Mars is characterized by similar color variations. The spectra, measured using the full 13-color capability of the Imager for Mars Pathfinder (IMP), provide evidence for the mineralogy of the unweathered rocks and highly weathered red soils.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech).

SLS Pathfinder Segments Car Train Departure

NASA Image and Video Library

2016-03-02

An Iowa Northern locomotive, contracted by Goodloe Transportation of Chicago, travels along the NASA railroad bridge over the Indian River north of Kennedy Space Center, carrying one of two containers on a railcar for transport to the NASA Jay Jay railroad yard. The containers held two pathfinders, or test versions, of solid rocket booster segments for NASA’s Space Launch System rocket that were delivered to the Rotation, Processing and Surge Facility (RPSF). Inside the RPSF, the Ground Systems Development and Operations Program and Jacobs Engineering, on the Test and Operations Support Contract, will conduct a series of lifts, moves and stacking operations using the booster segments, which are inert, to prepare for Exploration Mission-1, deep-space missions and the journey to Mars. The pathfinder booster segments are from Orbital ATK in Utah.

SLS Pathfinder Segments Car Train Departure

NASA Image and Video Library

2016-03-02

An Iowa Northern locomotive, conracted by Goodloe Transportation of Chicago, travels along the NASA railroad bridge over the Indian River north of Kennedy Space Center, with two containers on railcars for transport to the NASA Jay Jay railroad yard. The containers held two pathfinders, or test versions, of solid rocket booster segments for NASA’s Space Launch System rocket that were delivered to the Rotation, Processing and Surge Facility (RPSF). Inside the RPSF, the Ground Systems Development and Operations Program and Jacobs Engineering, on the Test and Operations Support Contract, will conduct a series of lifts, moves and stacking operations using the booster segments, which are inert, to prepare for Exploration Mission-1, deep-space missions and the journey to Mars. The pathfinder booster segments are from Orbital ATK in Utah.

SLS Pathfinder Segments Car Train Departure

NASA Image and Video Library

2016-03-02

An Iowa Northern locomotive, contracted by Goodloe Transportation of Chicago, approaches the raised span of the NASA railroad bridge to continue over the Indian River north of Kennedy Space Center with two containers on railcars for storage at the NASA Jay Jay railroad yard. The containers held two pathfinders, or test versions, of solid rocket booster segments for NASA’s Space Launch System rocket that were delivered to the Rotation, Processing and Surge Facility (RPSF). Inside the RPSF, the Ground Systems Development and Operations Program and Jacobs Engineering, on the Test and Operations Support Contract, will conduct a series of lifts, moves and stacking operations using the booster segments, which are inert, to prepare for Exploration Mission-1, deep-space missions and the journey to Mars. The pathfinder booster segments are from Orbital ATK in Utah.

SLS Pathfinder Segments Car Train Departure

NASA Image and Video Library

2016-03-02

An Iowa Northern locomotive, contracted by Goodloe Transportation of Chicago, travels along the NASA railroad bridge over the Indian River north of Kennedy Space Center, carrying one of two containers on a railcar for transport to the NASA Jay Jay railroad yard near the center. The containers held two pathfinders, or test versions, of solid rocket booster segments for NASA’s Space Launch System rocket that were delivered to the Rotation, Processing and Surge Facility (RPSF). Inside the RPSF, the Ground Systems Development and Operations Program and Jacobs Engineering, on the Test and Operations Support Contract, will conduct a series of lifts, moves and stacking operations using the booster segments, which are inert, to prepare for Exploration Mission-1, deep-space missions and the journey to Mars. The pathfinder booster segments are from Orbital ATK in Utah.

SLS Pathfinder Segments Car Train Departure

NASA Image and Video Library

2016-03-02

An Iowa Northern locomotive, contracted by Goodloe Transportation of Chicago, continues along the NASA railroad bridge over the Indian River north of Kennedy Space Center, carrying one of two containers on a railcar for transport to the NASA Jay Jay railroad yard. The containers held two pathfinders, or test versions, of solid rocket booster segments for NASA’s Space Launch System rocket that were delivered to the Rotation, Processing and Surge Facility (RPSF). Inside the RPSF, the Ground Systems Development and Operations Program and Jacobs Engineering, on the Test and Operations Support Contract, will conduct a series of lifts, moves and stacking operations using the booster segments, which are inert, to prepare for Exploration Mission-1, deep-space missions and the journey to Mars. The pathfinder booster segments are from Orbital ATK in Utah.

Marie Curie during ORT4

NASA Technical Reports Server (NTRS)

2003-01-01

Marie Curie rover drives down the rear ramp during Operational Readiness Test (ORT) 4.

Pathfinder, a low-cost Discovery mission, is the first of a new fleet of spacecraft that are planned to explore Mars over thenext ten years. Mars Global Surveyor, already en route, arrives at Mars on September 11 to begin a two year orbital reconnaissance of the planet's composition, topography, and climate. Additional orbiters and landers will follow every 26 months.

The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

LISA Pathfinder

NASA Technical Reports Server (NTRS)

Stebbins, Robin

2008-01-01

USA Pathfinder is a space mission dedicated to demonstrating technology for the Laser Interferometer Space Antenna (LISA). LISA is a joint ESA/NASA mission to detect low-frequency gravitational waves on the 0.0001 to 0.1 Hz frequency band. LISA is expected to observe 100's of merging massive black hole binaries out z-15, tens of thousands of close compact binary systems in the Milky Way, merging intermediate-mass black hole binaries, tens of stellar-mass black holes falling into supermassive black holes in galactic centers, and possibly other exotic sources. Several critical LISA technologies have not been demonstrated at the requisite level of performance. In spaceflight, and some fight hardware cannot be tested in a 1-g environment. Hence, the LISA Pathfinder mission is being implemented to demonstrate these critical LISA technologies in a relevant flight environment. LISA Pathfinder mimics one arm of the LISA constellation by shrinking the 5-million-kilometer armlength down to a few tens of centimeters. The experimental concept is to measure the relative separation between two test masses nominally following their own geodesics, and thereby determine the relative residual acceleration between them near 1 mHz, about a decade above the lowest frequency required by LISA. To implement such a concept, disturbances on the test masses must be kept very small by many design features, but chiefly by "drag-free" flight. A drag-free spacecraft follows a free-falling test mass which it encloses, but has no mechanical connection to. The spacecraft senses it's orientation and separation with respect to the proof mass, and its propulsion system is commanded to keep the spacecraft centered about the test mass. Thus, the spacecraft shields the test mass from most external influences, and minimizes the effect of force gradients arising from the spacecraft, and acting on the test mass. LISA Pathfinder will compare the geodesic of one test mass against that of the other. Only a metrology system based on interferometry can achieve the displacement sensitivity. Interferometers monitor the separation of both test masses with a sensitivity comparable to that required by LISA, and using the same technologies. LISA Pathfinder is scheduled to be launched in the first half of 1020 to a Lissajous orbit around the first Sun-Earth Lagrange point, L1. In addition to a complete European technology package (the LISA Technology Package, or LTP), LISA Pathfinder will also carry thrusters and software, known as ST-7, a part of NASA's New Millennium Program.

Cryogenic Test Technology 1984.

DTIC Science & Technology

1985-04-01

requirements. The material selection for the Pathfinder I was further restricted by long delivery times before Nitronic 40 was chosen. The alloys under...severe requirements of cryogenic model building. A detailed study of the characteristics of Nitronic 40 is reported in reference 36. This paper, and...remarks elsewhere about experience with Pathfinder I (made from Nitronic 40 ), suggest that quality control problems were encountered with at least one batch

JPL Experience with the Mars Pathfinder, Mission Simulation Battery

NASA Technical Reports Server (NTRS)

Perrone, Dave; Ewell, Richard

1997-01-01

A summary of the Mars Pathfinder Battery is given. The battery survived 47 days at 25 deg. C; it survived a 7 month stand at 10 to -5 deg. C; it met and exceeded 40 ampere-hour capacity for EDL; it met the 30 cycle minimum for Mars surface operation; and the project power profile for MArs surface operation does not yield energy balance.

Mars Pathfinder Landing Site Workshop 2: Characteristics of the Ares Vallis Region and Field Trips in the Channeled Scabland, Washington

NASA Technical Reports Server (NTRS)

Golombek, M. P. (Editor); Edgett, K. S. (Editor); Rice, J. W. , Jr. (Editor)

1995-01-01

Mars Pathfinder will place a single lander on the surface of Mars on July 4, 1997, following a December 1996 launch. As a result of the very successful first Mars Pathfinder Landing Site Workshop, the project has selected the Ares Vallis outflow channel in Chryse Planitia as the landing site. This location is where a large catastrophic outflow channel debouches into the northern lowlands. A second workshop and series of field trips, entitled Mars Pathfinder Landing Site Workshop 2: Characteristics of the Ares Vallis Region and Field Trips in the Channeled Scabland, Washington, were held in Spokane and Moses Lake, Washington. The purpose of the workshop was to provide a focus for learning as much as possible about the Ares Vallis region on Mars before landing there. The rationale is that the more that can be learned about the general area prior to landing, the better scientists will be able interpret the observations made by the lander and rover and place them in the proper geologic context. The field trip included overflights and surface investigations of the Channeled Scabland (an Earth analog for the martian catastrophic outflow channels), focusing on areas particularly analogous to Ares Vallis and the landing site. The overflights were essential for placing the enormous erosional and depositional features of the Channeled Scabland into proper three-dimensional context. The field trips were a joint educational outreach activity involving K-12 science educators, Mars Pathfinder scientists and engineers, and interested scientists from the Mars scientific community. Part 1 of the technical report on this workshop includes a description of the Mars Pathfinder mission, abstracts accepted for presentation at the workshop, an introduction to the Channeled Scabland, and field trip guides for the overflight and two field trips. This part, Part 2, includes the program for the workshop, summaries of the workshop technical sessions, a summary of the field trips and ensuing discussions, late abstracts of workshop presentations, reports on the education and public outreach activities carried out by the educators, and a list of the workshop and field trip participants.

Future X Pathfinder: Quick, Low Cost Flight Testing for Tomorrow's Launch Vehicles

NASA Technical Reports Server (NTRS)

London, John, III; Sumrall, Phil

1999-01-01

The DC-X and DC-XA Single Stage Technology flight program demonstrated the value of low cost rapid prototyping and flight testing of launch vehicle technology testbeds. NASA is continuing this important legacy through a program referred to as Future-X Pathfinder. This program is designed to field flight vehicle projects that cost around $100M each, with a new vehicle flying about every two years. Each vehicle project will develop and extensively flight test a launch vehicle technology testbed that will advance the state of the art in technologies directly relevant to future space transportation systems. There are currently two experimental, or "X" vehicle projects in the Pathfinder program, with additional projects expected to follow in the near future. The first Pathfinder project is X-34. X-34 is a suborbital rocket plane capable of flights to Mach 8 and 75 kilometers altitude. There are a number of reusable launch vehicle technologies embedded in the X-34 vehicle design, such as composite structures and propellant tanks, and advanced reusable thermal protection systems. In addition, X-34 is designed to carry experiments applicable to both the launch vehicle and hypersonic aeronautics community. X-34 is scheduled to fly later this year. The second Pathfinder project is the X-37. X-37 is an orbital space plane that is carried into orbit either by the Space Shuttle or by an expendable launch vehicle. X-37 provides NASA access to the orbital and orbital reentry flight regimes with an experimental testbed vehicle. The vehicle will expose embedded and carry-on advanced space transportation technologies to the extreme environments of orbit and reentry. Early atmospheric approach and landing tests of an unpowered version of the X-37 will begin next year, with orbital flights beginning in late 2001. Future-X Pathfinder is charting a course for the future with its growing fleet of low-cost X- vehicles. X-34 and X-37 are leading the assault on high launch costs and enabling the flight testing of technologies that will lead to affordable access to space.

Mars Pathfinder Landing Site Workshop 2: Characteristics of the Ares Vallis Region and Field Trips in the Channeled Scabland, Washington

NASA Technical Reports Server (NTRS)

Golombek, M. P. (Editor); Edgett, K. S. (Editor); Rice, J. W., Jr. (Editor)

1995-01-01

This volume, the first of two comprising the technical report for this workshop, contains papers that have been accepted for presentation at the Mars Pathfinder Landing Site Workshop 2: Characteristics of the Ares Vallis Region, September 24-30, 1995, in Spokane, Washington. The Mars Pathfinder Project received a new start in October 1993 as one of the next missions in NASA's long-term Mars exploration program. The mission involves landing a single vehicle on the surface of Mars in 1997. The project is one of the first Discovery-class missions and is required to be a quick, low-cost mission and achieve a set of significant but focused engineering, science, and technology objectives. The primary objective is to demonstrate a low-cost cruise, entry, descent, and landing system required to place a payload on the martian surface in a safe, operational configuration. Additional objectives include the deployment and operation of various science instruments and a microrover. Pathfinder paves the way for a cost-effective implementation of future Mars lander missions. Also included in this volume is the field trip guide to the Channeled Scabland and Missoula Lake Break-out. On July 4, 1997, Mars Pathfinder is scheduled to land near 19.5 deg N, 32.8 deg W, in a portion of Ares Vallis. The landing ellipse covers a huge (100 x 200 km) area that appears to include both depositional and erosional landforms created by one or more giant, catastrophic floods. One of the best known terrestrial analogs to martian outflow channels (such as Ares Vallis) is the region known as the Channeled Scabland. The field trip guide describes some of the geomorphological features of the Channeled Scabland and adjacent Lake Missoula break-out area near Lake Pend Oreille, Idaho.

Overhead View of Area Surrounding Pathfinder

NASA Technical Reports Server (NTRS)

1997-01-01

Overhead view of the area surrounding the Pathfinder lander illustrating the Sojourner traverse. Red rectangles are rover positions at the end of sols 1-30. Locations of soil mechanics experiments, wheel abrasion experiments, and APXS measurements are shown. The A numbers refer to APXS measurements as discussed in the paper by Rieder et al. (p. 1770, Science Magazine, see image note). Coordinates are given in the LL frame.

The photorealistic, interactive, three-dimensional virtual reality (VR) terrain models were created from IMP images using a software package developed for Pathfinder by C. Stoker et al. as a participating science project. By matching features in the left and right camera, an automated machine vision algorithm produced dense range maps of the nearfield, which were projected into a three-dimensional model as a connected polygonal mesh. Distance and angle measurements can be made on features viewed in the model using a mouse-driven three-dimensional cursor and a point-and-click interface. The VR model also incorporates graphical representations of the lander and rover and the sequence and spatial locations at which rover data were taken. As the rover moved, graphical models of the rover were added for each position that could be uniquely determined using stereo images of the rover taken by the IMP. Images taken by the rover were projected into the model as two-dimensional 'billboards' to show the proper perspective of these images.

NOTE: original caption as published in Science Magazine

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

First image of clouds over Mars

NASA Technical Reports Server (NTRS)

1997-01-01

This is the first image ever taken from the surface of Mars of an overcast sky. Featured are stratus clouds coming from the northeast at about 15 miles per hour (6.7 meters/second) at an approximate height of ten miles (16 kilometers) above the surface. The 'you are here' notation marks where Earth was situated in the sky at the time the image was taken. Scientists had hoped to see Earth in this image, but the cloudy conditions prevented a clear viewing. Similar images will be taken in the future with the hope of capturing a view of Earth. From Mars, Earth would appear as a tiny blue dot as a star would appear to an Earthbound observer. Pathfinder's imaging system will not be able to resolve Earth's moon. The clouds consist of water ice condensed on reddish dust particles suspended in the atmosphere. Clouds on Mars are sometimes localized and can sometimes cover entire regions, but have not yet been observed to cover the entire planet. The image was taken about an hour and forty minutes before sunrise by the Imager for Mars Pathfinder (IMP) on Sol 16 at about ten degrees up from the eastern Martian horizon.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages and Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Canadian Hydrogen Intensity Mapping Experiment (CHIME) pathfinder

NASA Astrophysics Data System (ADS)

Bandura, Kevin; Addison, Graeme E.; Amiri, Mandana; Bond, J. Richard; Campbell-Wilson, Duncan; Connor, Liam; Cliche, Jean-François; Davis, Greg; Deng, Meiling; Denman, Nolan; Dobbs, Matt; Fandino, Mateus; Gibbs, Kenneth; Gilbert, Adam; Halpern, Mark; Hanna, David; Hincks, Adam D.; Hinshaw, Gary; Höfer, Carolin; Klages, Peter; Landecker, Tom L.; Masui, Kiyoshi; Mena Parra, Juan; Newburgh, Laura B.; Pen, Ue-li; Peterson, Jeffrey B.; Recnik, Andre; Shaw, J. Richard; Sigurdson, Kris; Sitwell, Mike; Smecher, Graeme; Smegal, Rick; Vanderlinde, Keith; Wiebe, Don

2014-07-01

A pathfinder version of CHIME (the Canadian Hydrogen Intensity Mapping Experiment) is currently being commissioned at the Dominion Radio Astrophysical Observatory (DRAO) in Penticton, BC. The instrument is a hybrid cylindrical interferometer designed to measure the large scale neutral hydrogen power spectrum across the redshift range 0.8 to 2.5. The power spectrum will be used to measure the baryon acoustic oscillation (BAO) scale across this poorly probed redshift range where dark energy becomes a significant contributor to the evolution of the Universe. The instrument revives the cylinder design in radio astronomy with a wide field survey as a primary goal. Modern low-noise amplifiers and digital processing remove the necessity for the analog beam forming that characterized previous designs. The Pathfinder consists of two cylinders 37m long by 20m wide oriented north-south for a total collecting area of 1,500 square meters. The cylinders are stationary with no moving parts, and form a transit instrument with an instantaneous field of view of ~100 degrees by 1-2 degrees. Each CHIME Pathfinder cylinder has a feedline with 64 dual polarization feeds placed every ~30 cm which Nyquist sample the north-south sky over much of the frequency band. The signals from each dual-polarization feed are independently amplified, filtered to 400-800 MHz, and directly sampled at 800 MSps using 8 bits. The correlator is an FX design, where the Fourier transform channelization is performed in FPGAs, which are interfaced to a set of GPUs that compute the correlation matrix. The CHIME Pathfinder is a 1/10th scale prototype version of CHIME and is designed to detect the BAO feature and constrain the distance-redshift relation. The lessons learned from its implementation will be used to inform and improve the final CHIME design.

Color Mosaic of Rover & Terrain

NASA Image and Video Library

1997-07-05

NASA's Sojourner rover and undeployed ramps onboard the Mars Pathfinder spacecraft can be seen in this image, by the Imager for Mars Pathfinder (IMP) on July 4 (Sol 1). This image has been corrected for the curvature created by parallax. The microrover Sojourner is latched to the petal, and has not yet been deployed. The ramps are a pair of deployable metal reels which will provide a track for the rover as it slowly rolls off the lander, over the spacecraft's deflated airbags, and onto the surface of Mars. Pathfinder scientists will use this image to determine whether it is safe to deploy the ramps. One or both of the ramps will be unfurled, and then scientists will decide whether the rover will use either the forward or backward ramp for its descent. http://photojournal.jpl.nasa.gov/catalog/PIA00621

Sojourner near the Rock Garden

NASA Technical Reports Server (NTRS)

1997-01-01

This image of the Sojourner rover was taken near the end of daytime operations on Sol 42. The rover is between the rocks 'Wedge' (left) and 'Flute Top' (right). Other rocks visible include 'Flat Top' (behind Flute Top) and those in the Rock Garden, at the top of the frame. The cylindrical object extending from the back end of Sojourner is the Alpha Proton X-Ray Spectrometer.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Marie Curie during ORT6

NASA Technical Reports Server (NTRS)

2003-01-01

Marie Curie sits on the lander petal prior to deployment during the pre launch Operations Readiness Test (ORT) 6.

Pathfinder, a low-cost Discovery mission, is the first of a new fleet of spacecraft that are planned to explore Mars over thenext ten years. Mars Global Surveyor, already en route, arrives at Mars on September 11 to begin a two year orbital reconnaissance of the planet's composition, topography, and climate. Additional orbiters and landers will follow every 26 months.

The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

DSMC Simulations of Blunt Body Flows for Mars Entries: Mars Pathfinder and Mars Microprobe Capsules

NASA Technical Reports Server (NTRS)

Moss, James N.; Wilmoth, Richard G.; Price, Joseph M.

1997-01-01

The hypersonic transitional flow aerodynamics of the Mars Pathfinder and Mars Microprobe capsules are simulated with the direct simulation Monte Carlo method. Calculations of axial, normal, and static pitching coefficients were obtained over an angle of attack range comparable to actual flight requirements. Comparisons are made with modified Newtonian and free-molecular-flow calculations. Aerothermal results were also obtained for zero incidence entry conditions.

Measuring Pilot Knowledge in Training: The Pathfinder Network Scaling Technique

DTIC Science & Technology

2007-01-01

Network Scaling Technique Leah J. Rowe Roger W. Schvaneveldt L -3 Communications Arizona State University Mesa, AZ Mesa, AZ leah.rowe...7293 Page 2 of 8 Measuring Pilot Knowledge in Training: The Pathfinder Network Scaling Technique Leah J. Rowe Roger W. Schvaneveldt L -3...training. ABOUT THE AUTHORS Leah J. Rowe is a Training Research Specialist with L -3 Communications at the Air Force Research Laboratory

Reconsidering the Theological and Ethical Implications of Extraterrestrial Life

NASA Technical Reports Server (NTRS)

Randolph, Richard O. (Editor); Race, Margaret S.; McKay, Christopher P. (Editor)

1997-01-01

As we stand on the threshold of a new millennium, we also find ourselves at the brink of a new and exciting era in space exploration. In fact, this new era has already begun, with the successful landing and exploration of Mars by the Pathfinder mission in July 1997. Pathfinder represents an important scientific accomplishment for NASA because it demonstrated the agency's ability to successfully explore space at a relatively modest price. At the same time, Pathfinder revealed once again the genuine interest and fascination that people all over planet Earth have for space exploration. The Pathfinder mission is just one of several recent events-both scientific and cultural-that reveal this deep and almost unquenchable curiosity about space-and the possibility that there is life "out there." In August 1996, the public was captivated with NASA's announcement that a meteorite from Mars may contain evidence of early microscopic life. Shortly after the NASA announcement, media coverage of the discovery-and public discourse concerning the discovery-turned to an examination of the theological implications of evidence for extraterrestrial, albeit unintelligent, life. To a lesser extent, public reaction to the Hale-Bopp comet in the Spring of 1996 is also suggestive of many persons' deep passion to know more about space.

North Twin Peak in super resolution

NASA Technical Reports Server (NTRS)

1997-01-01

This pair of images shows the result of taking a sequence of 25 identical exposures from the Imager for Mars Pathfinder (IMP) of the northern Twin Peak, with small camera motions, and processing them with the Super-Resolution algorithm developed at NASA's Ames Research Center.

The upper image is a representative input image, scaled up by a factor of five, with the pixel edges smoothed out for a fair comparison. The lower image allows significantly finer detail to be resolved.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

The super-resolution research was conducted by Peter Cheeseman, Bob Kanefsky, Robin Hanson, and John Stutz of NASA's Ames Research Center, Mountain View, CA. More information on this technology is available on the Ames Super Resolution home page at

http://ic-www.arc.nasa.gov/ic/projects/bayes-group/ group/super-res/

Mars Pathfinder [foldout].

PubMed

1997-12-05

The following foldout present images and analysis from the Mars Pathfinder Mission that are discussed in seven subsequent Reports. The center is a four-page panorama of the surface of Mars around the lander (Plate 1). The back of the foldout contains surface images (Plate 7), a different perspective of the landing site (Plate 2), rover targets (Plate 3), locations of rocks and other features (Plate 6) and data analysis (Plates 4, 4, 8, 9, and 10).

Mars Pathfinder Project: Planetary Constants and Models

NASA Technical Reports Server (NTRS)

Vaughan, Robin

1995-01-01

This document provides a common set of astrodynamic constants and planetary models for use by the Mars Pathfinder Project. It attempts to collect in a single reference all the quantities and models in use across the project during development and for mission operations. These models are central to the navigation and mission design functions, but they are also used in other aspects of the project such as science observation planning and data reduction.

LISA Pathfinder first results

NASA Astrophysics Data System (ADS)

Vetrugno, D.

LISA Pathfinder (LPF) is an in-flight technological demonstrator designed and launched to prove the feasibility of sub-femto-g free fall of kilo-sized test masses (TM), an essential ingredient for the future gravitational wave observatory from space. Half a year after launch, the first results are available and show an incredibly well-performing instrument. The results represent a first and important step towards the long awaited construction and launch of LISA, the Laser Interferometer Space Antenna.

Mechanosensing is critical for axon growth in the developing brain

PubMed Central

Pillai, Eva K.; Sheridan, Graham K.; Svoboda, Hanno; Viana, Matheus; da F. Costa, Luciano; Guck, Jochen; Holt, Christine E.; Franze, Kristian

2016-01-01

During nervous system development, neurons extend axons along well-defined pathways. The current understanding of axon pathfinding is based mainly on chemical signalling. However, growing neurons interact not only chemically but also mechanically with their environment. Here we identify mechanical signals as important regulators of axon pathfinding. In vitro, substrate stiffness determined growth patterns of Xenopus retinal ganglion cell (RGC) axons. In vivo atomic force microscopy revealed striking stiffness gradient patterns in the embryonic brain. RGC axons grew towards the tissue’s softer side, which was reproduced in vitro in the absence of chemical gradients. To test the importance of mechanical signals for axon growth in vivo, we altered brain stiffness, blocked mechanotransduction pharmacologically, and knocked down the mechanosensitive ion channel Piezo1. All treatments resulted in aberrant axonal growth and pathfinding errors, suggesting that local tissue stiffness–read out by mechanosensitive ion channels–is critically involved in instructing neuronal growth in vivo. PMID:27643431

VR for Mars Pathfinder

NASA Technical Reports Server (NTRS)

Blackmon, Theodore

1998-01-01

Virtual reality (VR) technology has played an integral role for Mars Pathfinder mission, operations Using an automated machine vision algorithm, the 3d topography of the Martian surface was rapidly recovered fro -a the stereo images captured. by the Tender camera to produce photo-realistic 3d models, An advanced, interface was developed for visualization and interaction with. the virtual environment of the Pathfinder landing site for mission scientists at the Space Flight Operations Facility of the Jet Propulsion Laboratory. The VR aspect of the display allowed mission scientists to navigate on Mars in Bud while remaining here on Earth, thus improving their spatial awareness of the rock field that surrounds the lenders Measurements of positions, distances and angles could be easily extracted from the topographic models, providing valuable information for science analysis and mission. planning. Moreover, the VR map of Mars has also been used to assist with the archiving and planning of activities for the Sojourner rover.

The Development of a Novel High Throughput Computational Tool for Studying Individual and Collective Cellular Migration

PubMed Central

Chapnick, Douglas A.; Jacobsen, Jeremy; Liu, Xuedong

2013-01-01

Understanding how cells migrate individually and collectively during development and cancer metastasis can be significantly aided by a computation tool to accurately measure not only cellular migration speed, but also migration direction and changes in migration direction in a temporal and spatial manner. We have developed such a tool for cell migration researchers, named Pathfinder, which is capable of simultaneously measuring the migration speed, migration direction, and changes in migration directions of thousands of cells both instantaneously and over long periods of time from fluorescence microscopy data. Additionally, we demonstrate how the Pathfinder software can be used to quantify collective cell migration. The novel capability of the Pathfinder software to measure the changes in migration direction of large populations of cells in a spatiotemporal manner will aid cellular migration research by providing a robust method for determining the mechanisms of cellular guidance during individual and collective cell migration. PMID:24386097

The LISA Pathfinder Mission: Sub-picometer Interferometry in Space

NASA Astrophysics Data System (ADS)

Slutsky, Jacob; LISA Pathfinder Collaboration

2018-01-01

The European Space Agency’s LISA Pathfinder was a mission built to demonstrate the technologies essential to implement a space-based gravitational wave observatory sensitive in the milli-Hertz frequency band. ESA recently selected the LISA mission as such a future observatory, scheduled to launch in the early 2030s. LISA Pathfinder launched in late 2015 and concluded its final extended mission in July 2017, during which time it placed the two test masses into free fall and successfully measured the relative acceleration between them to a sensitivity that validates a number of critical technologies for LISA. These include drag-free control of the test masses, low noise microNewton thrusters to control the spacecraft, and sub-picometer-level laser metrology in space. The mission also served as a sensitive probe of the environmenal conditions in which LISA will operate. This poster summarizes the recent analysis results, with an eye towards the implications for the LISA mission.

Rover Touchdown on Martian Surface

NASA Image and Video Library

1997-07-06

This picture taken by the IMP (Imager for Mars Pathfinder) aboard the Mars Pathfinder spacecraft depicts the rover Sojourner's position after driving onto the Martian surface. Sojourner has become the first autonomous robot ever to traverse the surface of Mars. This image reflects the success of Pathfinder's principle objective -- to place a payload on Mars in a safe, operational configuration. The primary mission of Sojourner, scheduled to last seven days, will be to use its Alpha Proton X-ray Spectrometer (APXS) instrument to determine the elements that make up the rocks and soil on Mars. A full study using the APXS takes approximately ten hours, and can measure all elements except hydrogen at any time of the Martian day or night. The APXS will conduct its studies by bombarding rocks and soil samples with alpha particle radiation -- charged particles equivalent to the nucleus of a helium atom, consisting of two protons and two neutrons. http://photojournal.jpl.nasa.gov/catalog/PIA00623

Pooh Bear rock and Mermaid Dune

NASA Technical Reports Server (NTRS)

1997-01-01

One of the two forward cameras aboard Sojourner imaged this area of Martian terrain on Sol 26. The large rock dubbed 'Pooh Bear' is at far left, and stands between four and five inches high. Mermaid Dune is the smooth area stretching horizontally across the top quarter of the image. The Alpha Proton X-Ray Spectrometer (APXS) instrument aboard Sojourner will be deployed on Mermaid Dune, and the rover will later use its cleated wheels to dig into it.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages and Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wass, P. J.; Araujo, H.; Sumner, T.

We present the concept, design and testing of the radiation monitor for LISA Pathfinder. Galactic cosmic rays (GCRs) and solar energetic particles (SEPs) will cause charging of the LISA Pathfinder test masses producing unwanted disturbances which could be significant during a large solar eruption. A radiation monitor on board LISA Pathfinder, using silicon PIN diodes as particle detectors, will measure the particle flux responsible for charging. It will also be able to record spectral information to identify solar energetic particle events. The design of the monitor was supported by Monte Carlo simulations which allow detailed predictions of the radiation monitormore » performance. We present these predictions as well as the results of high-energy proton tests carried out at the Paul Scherrer Institute, Switzerland. The tests show good agreement with our simulations and confirm the capability of the radiation monitor to perform well in the space environment, meeting all science requirements.« less

Trio combines with dock to regulate Pak activity during photoreceptor axon pathfinding in Drosophila.

PubMed

Newsome, T P; Schmidt, S; Dietzl, G; Keleman, K; Asling, B; Debant, A; Dickson, B J

2000-04-28

Correct pathfinding by Drosophila photoreceptor axons requires recruitment of p21-activated kinase (Pak) to the membrane by the SH2-SH3 adaptor Dock. Here, we identify the guanine nucleotide exchange factor (GEF) Trio as another essential component in photoreceptor axon guidance. Regulated exchange activity of one of the two Trio GEF domains is critical for accurate pathfinding. This GEF domain activates Rac, which in turn activates Pak. Mutations in trio result in projection defects similar to those observed in both Pak and dock mutants, and trio interacts genetically with Rac, Pak, and dock. These data define a signaling pathway from Trio to Rac to Pak that links guidance receptors to the growth cone cytoskeleton. We propose that distinct signals transduced via Trio and Dock act combinatorially to activate Pak in spatially restricted domains within the growth cone, thereby controlling the direction of axon extension.

Occurrence of nonspecific reactions among stool specimens tested by the Abbott TestPack rotavirus enzyme immunoassay.

PubMed Central

Lipson, S M; Leonardi, G P; Salo, R J; Schutzbank, T E; Kaplan, M H

1990-01-01

Sixty-five stool specimens obtained from children suffering from gastroenteritis were tested for the presence of antigen to rotavirus by the Abbott TestPack Rotavirus (TestPack) enzyme immunoassay kit. The Kallestad Pathfinder enzyme immunoassay, polyacrylamide gel electrophoresis, immune electron microscopy, and virus isolation were utilized as reference assays. Fifty-four specimens were in accord by TestPack and Kallestad Pathfinder. Among 11 discordant specimens positive with TestPack but negative by Kallestad Pathfinder, rotavirus was not identified by polyacrylamide gel electrophoresis, immune electron microscopy, or isolation in primary African green monkey kidney cell cultures. TestPack displayed a performance specificity of 83%. The inordinately high number of stool specimens reported as false-positive by TestPack precludes the incorporation of this antigen detection kit into our routine regimen of diagnostic virologic testing. Images PMID:2166074

Validation of Interannual Differences of AIRS Monthly Mean Parameters

NASA Technical Reports Server (NTRS)

Susskind, Joel; Iredell, Lena; Keita, Fricky; Molnar, Gyula

2005-01-01

Monthly mean fields of select geophysical parameters derived from analysis of AIRS/AMSU data, and their interannual differences, are shown and compared with analogous fields derived from other sources. All AIRS fields are derived using the AIRS Science Team Version 4 algorithm. Monthly mean results are shown for January 2004, as are interannual differences between January 2004 and January 2003. AIRS temperature and water vapor profile fields are compared with monthly mean collocated ECMWF 3 hour forecast and monthly mean TOVS Pathfinder Path A data. AIRS Tropospheric and Stratospheric coarse climate indicators are compared with analogous MSU products derived by Spencer and christy and found in the TOVS Pathfinder Path A data set. Total ozone is compared with results produced by TOMS. OLR is compared with OLR derived using CERES data and found in the TOVS Pathfinder Path A data set. AIRS results agree well in all cases, especially in the interannual difference sense.

Exploring the Last Electromagnetic Frontier with the Long Wavelength Array (LWA)

NASA Astrophysics Data System (ADS)

Kassim, Namir E.; Cohen, A. S.; Crane, P. C.; Gross, C. A.; Hicks, B. C.; Lane, W. M.; Lazio, J.; Polisensky, E. J.; Ray, P. S.; Weiler, K. W.; Clarke, T. E.; Schmitt, H. R.; Hartman, J. M.; Helmboldt, J. F.; Craig, J.; Gerstle, W.; Pihlstrom, Y.; Rickard, L. J.; Taylor, G. B.; Ellingson, S. W.; D'Addario, L. R.; Navarro, R.

2009-05-01

Several decades ago, instruments like the Very Large Array (VLA) first opened the GHz frequency sky to high dynamic range imaging. Today, a path-finding VLA 74 MHz system is providing the first sub-arcminute resolution view of the radio universe below 100 MHz, a technical innovation inspiring an emerging suite of large (> 100 km), much more powerful long-wavelength instruments including the Long Wavelength Array (LWA). Similar in philosophy to the VLA and also located in New Mexico, the LWA will be a versatile, user-oriented electronic array designed to open the 20--80 MHz frequency range to detailed exploration for the first time. The LWA's mJy sensitivity and near-arcsecond resolution will surpass, by 2--3 orders of magnitude, the imaging power of previous interferometers in its frequency range. LWA scientific frontiers include: (1) the high-z universe, including distant radio galaxies and clusters - tools for understanding the earliest black holes and the cosmological evolution of Dark Matter and Dark Energy, respectively; (2) acceleration, propagation, and turbulence in the ISM, including the space-distribution and spectrum of Galactic cosmic rays and supernova remnants; (3) planetary, solar, and space science, including space-weather prediction and extra-solar planet searches; and (4) the radio transient universe including GRBs, ultra-high energy cosmic rays, and new sources of unknown origin. Because the LWA will explore one of the most poorly investigated spectral regions the potential for new discoveries is high, and there is a strong synergy with exciting new X-ray and Gamma-ray measurements. The LWA will also provide an unparalleled measure of small-scale ionospheric structure, a pre-requisite for accurate calibration and imaging. This presentation focuses on LWA science, while a companion paper reviews the technical design subjected to Preliminary Design Review in March 2009. Basic research in radio astronomy at the Naval Research Laboratory is supported by 6.1 base funding.

2D Bayesian automated tilted-ring fitting of disc galaxies in large H I galaxy surveys: 2DBAT

NASA Astrophysics Data System (ADS)

Oh, Se-Heon; Staveley-Smith, Lister; Spekkens, Kristine; Kamphuis, Peter; Koribalski, Bärbel S.

2018-01-01

We present a novel algorithm based on a Bayesian method for 2D tilted-ring analysis of disc galaxy velocity fields. Compared to the conventional algorithms based on a chi-squared minimization procedure, this new Bayesian-based algorithm suffers less from local minima of the model parameters even with highly multimodal posterior distributions. Moreover, the Bayesian analysis, implemented via Markov Chain Monte Carlo sampling, only requires broad ranges of posterior distributions of the parameters, which makes the fitting procedure fully automated. This feature will be essential when performing kinematic analysis on the large number of resolved galaxies expected to be detected in neutral hydrogen (H I) surveys with the Square Kilometre Array and its pathfinders. The so-called 2D Bayesian Automated Tilted-ring fitter (2DBAT) implements Bayesian fits of 2D tilted-ring models in order to derive rotation curves of galaxies. We explore 2DBAT performance on (a) artificial H I data cubes built based on representative rotation curves of intermediate-mass and massive spiral galaxies, and (b) Australia Telescope Compact Array H I data from the Local Volume H I Survey. We find that 2DBAT works best for well-resolved galaxies with intermediate inclinations (20° < i < 70°), complementing 3D techniques better suited to modelling inclined galaxies.

Mars Array Technology Experiment Developed to Test Solar Arrays on Mars

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.

2001-01-01

Solar arrays will be the power supply for future missions to the planet Mars, including landers, rovers, and eventually human missions to explore the Martian surface. Until Mars Pathfinder landed in July 1997, no solar array had been used on the surface. The MATE package is intended to measure the solar energy reaching the surface, characterize the Martian environment to gather the baseline information required for designing power systems for long-duration missions, and to quantify the performance and degradation of advanced solar cells on the Martian surface. To measure the properties of sunlight reaching the Martian surface, MATE incorporates two radiometers and a visible/NIR spectrometer. The radiometers consist of multiple thermocouple junctions using thin-film technology. These devices generate a voltage proportional to the solar intensity. One radiometer measures the global broadband solar intensity, including both the direct and scattered sunlight, with a field of view of approximately 130. The second radiometer incorporates a slit to measure the direct (unscattered) intensity radiation. The direct radiometer can only be read once per day, with the Sun passing over the slit. The spectrometer measures the global solar spectrum with two 256-element photodiode arrays, one Si sensitive in the visible range (300 to 1100 nm), and a second InGaAs sensitive to the near infrared (900 to 1700 nm). This range covers 86 percent of the total energy from the Sun, with approximately 5-nm resolution. Each photodiode array has its own fiber-optic feed and grating. Although the purpose of the MATE is to gather data useful in designing solar arrays for Mars surface power systems, the radiometer and spectrometer measurements are expected to also provide important scientific data for characterizing the properties of suspended atmospheric dust. In addition to measuring the solar environment of Mars, MATE will measure the performance of five different individual solar cell types and two different solar cell strings, to qualify advanced solar cell types for future Mars missions. The MATE instrument, designed for the Mars-2001 Surveyor Lander mission, contains a capable suite of sensors that will provide both scientific information as well as important engineering data on the operation of solar power systems on Mars. MATE will characterize the intensity and spectrum of the solar radiation on Mars and measure the performance of solar arrays in the Mars environment. MATE flight hardware was built and tested at the NASA Glenn Research Center and is ready for flight.

Preliminary analysis of EUSO—TA data

NASA Astrophysics Data System (ADS)

Fenu, F.; Piotrowski, L. W.; Shin, H.; Jung, A.; Bacholle, S.; Bisconti, F.; Capel, F.; Eser, J.; Kawasaki, Y.; Kuznetsov, E.; Larsson, O.; Mackovjak, S.; Miyamoto, H.; Plebaniak, Z.; Prevot, G.; Putis, M.; Shinozaki, K.; Adams, J.; Bertaina, M.; Bobik, P.; Casolino, M.; Matthews, J. N.; Ricci, M.; Wiencke, L.; EUSO-TA Collaboration

2016-05-01

The EUSO-TA detector is a pathfinder for the JEM-EUSO project and is currently installed in Black Rock Mesa (Utah) on the site of the Telescope Array fluorescence detectors. Aim of this experiment is to validate the observation principle of JEM-EUSO on air showers measured from ground. The experiment gets data in coincidence with the TA triggers to increase the likelihood of cosmic ray detection. In this framework the collaboration is also testing the detector response with respect to several test events from lasers and LED flashers. Moreover, another aim of the project is the validation of the stability of the data acquisition chain in real sky condition and the optimization of the trigger scheme for the rejection of background. Data analysis is ongoing to identify cosmic ray events in coincidence with the TA detector. In this contribution we will show the response of the EUSO-TA detector to all the different typologies of events and we will show some preliminary results on the trigger optimization performed on such data.

AUTONOMOUS GAUSSIAN DECOMPOSITION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lindner, Robert R.; Vera-Ciro, Carlos; Murray, Claire E.

2015-04-15

We present a new algorithm, named Autonomous Gaussian Decomposition (AGD), for automatically decomposing spectra into Gaussian components. AGD uses derivative spectroscopy and machine learning to provide optimized guesses for the number of Gaussian components in the data, and also their locations, widths, and amplitudes. We test AGD and find that it produces results comparable to human-derived solutions on 21 cm absorption spectra from the 21 cm SPectral line Observations of Neutral Gas with the EVLA (21-SPONGE) survey. We use AGD with Monte Carlo methods to derive the H i line completeness as a function of peak optical depth and velocitymore » width for the 21-SPONGE data, and also show that the results of AGD are stable against varying observational noise intensity. The autonomy and computational efficiency of the method over traditional manual Gaussian fits allow for truly unbiased comparisons between observations and simulations, and for the ability to scale up and interpret the very large data volumes from the upcoming Square Kilometer Array and pathfinder telescopes.« less

Characterization of the Martian surface deposits by the Mars Pathfinder rover, Sojourner.

NASA Astrophysics Data System (ADS)

Matijevic, J. R.; Crisp, J.; Bickler, D. B.; Banes, R. S.; Cooper, B. K.; Eisen, H. J.; Gensler, J.; Haldemann, A.; Hartman, F.; Jewett, K. A.; Matthies, L. H.; Laubach, S. L.; Mishkin, A. H.; Morrison, J. C.; Nguyen, T. T.; Sirota, A. R.; Stone, H. W.; Stride, S.; Sword, L. F.; Tarsala, J. A.; Thompson, A. D.; Wallace, M. T.; Welch, R.; Wellman, E.; Wilcox, B. H.; Ferguson, D.; Jenkins, P.; Kolecki, J.; Landis, G. A.; Wilt, D.; Rover Team

1997-12-01

The Mars Pathfinder rover discovered pebbles on the surface and in rocks that may be sedimentary - not volcanic - in origin. Surface pebbles may have been rounded by Ares flood waters or liberated by weathering of sedimentary rocks called conglomerates. Conglomerates imply that water existed elsewhere and earlier than the Ares flood. Most soil-like deposits are similar to moderately dense soils on Earth. Small amounts of dust are currently settling from the atmosphere.

Pathfinder

NASA Image and Video Library

2004-04-15

This artist's concept depicts the X-34 Demonstrator in flight. Part of the Pathfinder Program, the X-34 was a reusable technology testbed vehicle that was designed and built by the Marshall Space Flight Center to demonstrate technologies that were essential to lowering the cost of access to space. Powered by a LOX and RP-1 liquid Fastrac engine, the X-34 would be capable of speeds up to Mach 8 and altitudes of 250,000-feet. The X-34 program was cancelled in 2001.

Pathfinder

NASA Image and Video Library

2004-04-15

Pictured is the X-34 Demonstrator parked on the runway. Part of the Pathfinder Program, the X-34 was a reusable technology testbed vehicle that was designed and built by the Marshall Space Flight Center to demonstrate technologies that are essential to lowering the cost of access to space. Powered by a LOX and RP-1 liquid Fastrac engine, the X-34 would be capable of speeds up to Mach 8 and altitudes of 250,000-feet. The X-34 program was cancelled in 2001.

Generation of Level 3 SMMR and SSM/I Brightness Temperatures for the Period 1978-1999

NASA Technical Reports Server (NTRS)

Partington, Kim

1999-01-01

The NOAA/NASA Pathfinder Program was initially designed to assure that certain key remote sensing data sets of particular significance to global change research were scientifically validated, consistently processed and made readily available to the research community at minimal cost. Through this Program the National Snow and Ice Data Center (NSIDC), University of Colorado has successfully processed, archived and distributed the Scanning Multichannel Microwave Radiometer (SMMR) and Special Sensor Microwave/Imager (SSM/I) Level 3 (EASE-Grid format) Pathfinder data sets for the period 1978 to 1999. These data are routinely distributed to approximately 150 researchers through various media including CD-ROM, 8 mm tape, ftp and the EOS Information Management System (IMS). At NSIDC these data are currently being applied in the development and validation of algorithms to derive snow water equivalent (NASA NAG5-6636), the mapping of frozen ground and the detection of the onset of melt over ice sheets, sea ice and snow cover. The EASE-Grid format, developed at NSIDC in conjunction with the SMMR-SSM/I Pathfinder project has also been applied to Advanced Very High Resolution Radiometer (AVHRR) and TOVS Pathfinder data, as well as ancillary data such as digital elevation, land cover classification and several in situ data sets. EASE-Grid will also be used for all land products derived from the NASA EOS AMSR-E instrument.

The Second-generation z (Redshift) and Early Universe Spectrometer. I. First-light Observation of a Highly Lensed Local-ulirg Analog at High-z

NASA Astrophysics Data System (ADS)

Ferkinhoff, Carl; Brisbin, Drew; Parshley, Stephen; Nikola, Thomas; Stacey, Gordon J.; Schoenwald, Justin; Higdon, James L.; Higdon, Sarah J. U.; Verma, Aprajita; Riechers, Dominik; Hailey-Dunsheath, Steven; Menten, Karl M.; Güsten, Rolf; Weiß, Axel; Irwin, Kent; Cho, Hsiao M.; Niemack, Michael; Halpern, Mark; Amiri, Mandana; Hasselfield, Matthew; Wiebe, D. V.; Ade, Peter A. R.; Tucker, Carol E.

2014-01-01

We recently commissioned our new spectrometer, the second-generation z(Redshift) and Early Universe Spectrometer (ZEUS-2) on the Atacama Pathfinder Experiment telescope. ZEUS-2 is a submillimeter grating spectrometer optimized for detecting the faint and broad lines from distant galaxies that are redshifted into the telluric windows from 200 to 850 μm. It uses a focal plane array of transition-edge sensed bolometers, the first use of these arrays for astrophysical spectroscopy. ZEUS-2 promises to be an important tool for studying galaxies in the years to come because of its synergy with Atacama Large Millimeter Array and its capabilities in the short submillimeter windows that are unique in the post-Herschel era. Here, we report on our first detection of the [C II] 158 μm line with ZEUS-2. We detect the line at z ~ 1.8 from H-ATLAS J091043.1-000322 with a line flux of (6.44 ± 0.42) × 10-18 W m-2. Combined with its far-IR luminosity and a new Herschel-PACS detection of the [O I] 63 μm line, we model the line emission as coming from a photo-dissociation region with far-ultraviolet radiation field, G ~ 2 × 104 G 0, gas density, n ~ 1 × 103 cm-3 and size between ~0.4 and 1 kpc. On the basis of this model, we conclude that H-ATLAS J091043.1-000322 is a high-redshift analog of a local ultra-luminous IR galaxy; i.e., it is likely the site of a compact starburst caused by a major merger. Further identification of these merging systems is important for constraining galaxy formation and evolution models.

The Breakthrough Listen Initiative and the Future of the Search for Intelligent Life

NASA Astrophysics Data System (ADS)

Enriquez, J. Emilio; Siemion, Andrew; Falcke, Heino; Croft, Steve; DeBoer, David R.; Gajjar, Vishal; Hickish, Jack; Isaacson, Howard T.; Lebofsky, Matt; MacMahon, David; Price, Danny C.; Tellis, Nate; Werthimer, Dan; ter Veen, Sander; Garrett, Michael A.; Hellbourg, Greg

2017-01-01

Unprecedented recent results in the fields of exoplanets and astrobiology have dramatically increased the interest in the potential existence of intelligent life elsewhere in the galaxy. Additionally, the capabilities of modern Searches for Extraterrestrial Intelligence (SETI) have increased tremendously. Much of this improvement is due to the ongoing development of wide bandwidth radio instruments and the Moore’s Law increase in computational power over the previous decades. Together, these instrumentation improvements allow for narrow band signal searches of billions of frequency channels at once.The Breakthrough Listen Initiative (BL) was launched on July 20, 2015 at the Royal Society in London, UK with a charge to conduct the most comprehensive and sensitive search for advanced life in humanity’s history. Here we detail important milestones achieved during the first year of the program, describe the key BL SETI surveys and briefly describe current facilities, including the Green Bank Telescope, the Automated Planet Finder and the Parkes Observatory.Complementary to the BL initiative (at a smaller scale), pioneering SETI work at low radio frequencies (20-250 MHz) is being undertaken with the LOw Frequency ARray (LOFAR). This program uses simple fixed-stationary antennas and multiple phased-array beams formed in a supercomputer to search many targets at once and will lay the groundwork for future searches with SKA1-low and mid frequency aperture array pathfinders. We will present the results of a volume complete sample of nearby stars (< 5pc) observed with LOFAR, searching for drifting narrow band signals with expected Doppler drifts covering a wide range of potential transmitter host planets.We conclude with a brief view towards future SETI searches with upcoming next-generation radio facilities such as SKA and ngVLA.

H I observations of the nearest starburst galaxy NGC 253 with the SKA precursor KAT-7

NASA Astrophysics Data System (ADS)

Lucero, D. M.; Carignan, C.; Elson, E. C.; Randriamampandry, T. H.; Jarrett, T. H.; Oosterloo, T. A.; Heald, G. H.

2015-07-01

We present H I observations of the Sculptor group starburst spiral galaxy NGC 253, obtained with the Karoo Array Telescope (KAT-7). KAT-7 is a pathfinder for the Square Kilometre Array precursor MeerKAT, under construction. The short baselines and low system temperature of the telescope make it very sensitive to large-scale, low-surface-brightness emission. The KAT-7 observations detected 33 per cent more flux than previous Very Large Array observations, mainly in the outer parts and in the halo for a total H I mass of 2.1 ± 0.1 × 109 M⊙. H I can be found at large distances perpendicular to the plane out to projected distances of ˜9-10 kpc away from the nucleus and ˜13-14 kpc at the edge of the disc. A novel technique, based on interactive profile fitting, was used to separate the main disc gas from the anomalous (halo) gas. The rotation curve (RC) derived for the H I disc confirms that it is declining in the outer parts, as seen in previous optical Fabry-Perot measurements. As for the anomalous component, its RC has a very shallow gradient in the inner parts and turns over at the same radius as the disc, kinematically lagging by 100 km s-1. The kinematics of the observed extra-planar gas is compatible with an outflow due to the central starburst and galactic fountains in the outer parts. However, the gas kinematics shows no evidence for inflow. Analysis of the near-IR WISE data, shows clearly that the star formation rate is compatible with the starburst nature of NGC 253.

Pathfinder Sea Surface Temperature Climate Data Record

NASA Astrophysics Data System (ADS)

Baker-Yeboah, S.; Saha, K.; Zhang, D.; Casey, K. S.

2016-02-01

Global sea surface temperature (SST) fields are important in understanding ocean and climate variability. The NOAA National Centers for Environmental Information (NCEI) develops and maintains a high resolution, long-term, climate data record (CDR) of global satellite SST. These SST values are generated at approximately 4 km resolution using Advanced Very High Resolution Radiometer (AVHRR) instruments aboard NOAA polar-orbiting satellites going back to 1981. The Pathfinder SST algorithm is based on the Non-Linear SST algorithm using the modernized NASA SeaWiFS Data Analysis System (SeaDAS). Coefficients for this SST product were generated using regression analyses with co-located in situ and satellite measurements. Previous versions of Pathfinder included level 3 collated (L3C) products. Pathfinder Version 5.3 includes level 2 pre-processed (L2P), level 3 Uncollated (L3C), and L3C products. Notably, the data were processed in the cloud using Amazon Web Services and are made available through all of the modern web visualization and subset services provided by the THREDDS Data Server, the Live Access Server, and the OPeNDAP Hyrax Server.In this version of Pathfinder SST, anomalous hot-spots at land-water boundaries are better identified and the dataset includes updated land masks and sea ice data over the Antarctic ice shelves. All quality levels of SST values are generated, giving the user greater flexibility and the option to apply their own cloud-masking procedures. Additional improvements include consistent cloud tree tests for NOAA-07 and NOAA-19 with respect to the other sensors, improved SSTs in sun glint areas, and netCDF file format improvements to ensure consistency with the latest Group for High Resolution SST (GHRSST) requirements. This quality controlled satellite SST field is a reference environmental data record utilized as a primary resource of SST for numerous regional and global marine efforts.

A design pathfinder with material correlation points for inflatable systems

NASA Astrophysics Data System (ADS)

Fulcher, Jared Terrell

The incorporation of inflatable structures into aerospace systems can produce significant advantages in stowed volume to mechanical effectiveness and overall weight. Many applications of these ultra-lightweight systems are designed to precisely control internal or external surfaces, or both, to achieve desired performance. The modeling of these structures becomes complex due to the material nonlinearities inherent to the majority of construction materials used in inflatable structures. Furthermore, accurately modeling the response and behavior of the interfacing boundaries that are common to many inflatable systems will lead to better understanding of the entire class of structures. The research presented involved using nonlinear finite element simulations correlated with photogrammetry testing to develop a procedure for defining material properties for commercially available polyurethane-coated woven nylon fabric, which is representative of coated materials that have been proven materials for use in many inflatable systems. Further, the new material model was used to design and develop an inflatable pathfinder system which employs only internal pressure to control an assembly of internal membranes. This canonical inflatable system will be used for exploration and development of general understanding of efficient design methodology and analysis of future systems. Canonical structures are incorporated into the design of the phased pathfinder system to allow for more universal insight. Nonlinear finite element simulations were performed to evaluate the effect of various boundary conditions, loading configurations, and material orientations on the geometric precision of geometries representing typical internal/external surfaces commonly incorporated into inflatable pathfinder system. The response of the inflatable system to possible damage was also studied using nonlinear finite element simulations. Development of a correlated material model for analysis of the inflatable pathfinder system has improved the efficiency of design and analysis techniques of future inflatable structures. KEYWORDS: Nonlinear Finite Element, Inflatable Structures, Gossamer Space Systems, Photogrammetry Measurements, Coated Woven Fabric.

Pathfinder. Volume 9, Number 3, May/June 2011

DTIC Science & Technology

2011-05-01

Pathfinder magazine .” Any reproduction of graphics, photographs and imagery is subject to the original copyright. 2 On My Mind 5 NGA in the News ›› F E A...team analyst stationed in Baghdad to search for and identify advertising billboards in Baghdad, a large and mundane task. To a CA commander, however...unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 On My Mind Putting the Power of GEOINT in the Warfighter’s Hands As a

Pathfinder

NASA Image and Video Library

2004-04-15

Pictured is NASA's poster art for the X-34 technology Demonstrator. The X-34 was part of NASA's Pathfinder Program which demonstrated advanced space transportation technologies through the use of flight experiments and experimental vehicles. These technology demonstrators and flight experiments would support the Agency's goal of dramatically reducing the cost of access to space and would define the future of space transportation pushing technology into a new era of space development and exploration at the dawn of the new century. The X-34 program was cancelled in 2001.

Pathfinder

NASA Image and Video Library

2004-04-15

This artist's concept depicts the X-34 Demonstrator sitting on a runway. Part of the Pathfinder Program, the X-34 was a reusable technology testbed vehicle that was designed and built by the Marshall Space Flight Center to demonstrate technologies that were essential to lowering the cost of access to space. Powered by a LOX and RP-1 liquid Fastrac engine, the X-34 would be capable of speeds up to Mach 8 and altitudes of 250,000-feet. The X-34 program was cancelled in 2001.

Pathfinder

NASA Image and Video Library

2004-04-15

This artist's concept depicts the X-34 Demonstrator landing in a dessert. Part of the Pathfinder Program, the X-34 was a reusable technology testbed vehicle that was designed and built by the Marshall Space Flight Center to demonstrate technologies that were essential to lowering the cost of access to space. Powered by a LOX and RP-1 liquid Fastrac engine, the X-34 would be capable of speeds up to Mach 8 and altitudes of 250,000-feet. The X-34 program was cancelled in 2001.

Grid resolution and solution convergence for Mars Pathfinder forebody

NASA Technical Reports Server (NTRS)

Nettelhorst, Heather L.; Mitcheltree, Robert A.

1994-01-01

As part of the Discovery Program, NASA Plans to launch a series of probes to Mars. The Mars Pathfinder project is the first of this series with a scheduled Mars arrival in July 1997. The entry vehicle will perform a direct entry into the atmosphere and deliver a lander to the surface. Predicting the entry vehicle's flight performance and designing the forebody heatshield requires knowledge of the expected aerothermodynamic environment. Much of this knowledge can be obtained through computational fluid dynamic (CFD) analysis.

Hillary Clinton visits Pathfinder projects in Brazil.

PubMed

1996-01-01

In October 1995, US First Lady Hillary Clinton visited a maternity hospital in Salvador, Brazil, in which a family planning (FP)/reproductive health program has been administered by Pathfinder International since 1981 with funding from USAID. During her tour of the facility, Clinton learned about the high degree of unmet need for FP in the region which results from a lack of sufficient resources to meet demand. Clinton, in turn, praised the state of Bahia for its emphasis on FP in low-income areas.

Symbolic PathFinder: Symbolic Execution of Java Bytecode

NASA Technical Reports Server (NTRS)

Pasareanu, Corina S.; Rungta, Neha

2010-01-01

Symbolic Pathfinder (SPF) combines symbolic execution with model checking and constraint solving for automated test case generation and error detection in Java programs with unspecified inputs. In this tool, programs are executed on symbolic inputs representing multiple concrete inputs. Values of variables are represented as constraints generated from the analysis of Java bytecode. The constraints are solved using off-the shelf solvers to generate test inputs guaranteed to achieve complex coverage criteria. SPF has been used successfully at NASA, in academia, and in industry.

Mars pathfinder Rover egress deployable ramp assembly

NASA Technical Reports Server (NTRS)

Spence, Brian R.; Sword, Lee F.

1996-01-01

The Mars Pathfinder Program is a NASA Discovery Mission, led by the Jet Propulsion Laboratory, to launch and place a small planetary Rover for exploration on the Martian surface. To enable safe and successful egress of the Rover vehicle from the spacecraft, a pair of flight-qualified, deployable ramp assemblies have been developed. This paper focuses on the unique, lightweight deployable ramp assemblies. A brief mission overview and key design requirements are discussed. Design and development activities leading to qualification and flight systems are presented.

Verification Tools Secure Online Shopping, Banking

NASA Technical Reports Server (NTRS)

2010-01-01

Just like rover or rocket technology sent into space, the software that controls these technologies must be extensively tested to ensure reliability and effectiveness. Ames Research Center invented the open-source Java Pathfinder (JPF) toolset for the deep testing of Java-based programs. Fujitsu Labs of America Inc., based in Sunnyvale, California, improved the capabilities of the JPF Symbolic Pathfinder tool, establishing the tool as a means of thoroughly testing the functionality and security of Web-based Java applications such as those used for Internet shopping and banking.

Pathfinder

NASA Image and Video Library

2004-04-15

Pictured in the high bay, is the X-34 Technology Demonstrator in the process of completion. The X-34 wass part of NASA's Pathfinder Program which demonstrated advanced space transportation technologies through the use of flight experiments and experimental vehicles. These technology demonstrators and flight experiments supported the Agency's goal of dramatically reducing the cost of access to space and defined the future of space transportation pushing technology into a new era of space development and exploration at the dawn of the new century. The X-34 program was cancelled in 2001.

Java PathFinder: A Translator From Java to Promela

NASA Technical Reports Server (NTRS)

Havelund, Klaus

1999-01-01

JAVA PATHFINDER, JPF, is a prototype translator from JAVA to PROMELA, the modeling language of the SPIN model checker. JPF is a product of a major effort by the Automated Software Engineering group at NASA Ames to make model checking technology part of the software process. Experience has shown that severe bugs can be found in final code using this technique, and that automated translation from a programming language to a modeling language like PROMELA can help reducing the effort required.

Demonstration of a Large-Scale Tank Assembly Via Circumferential Friction Stir Welds

NASA Technical Reports Server (NTRS)

Jones, Chip; Adams, Glynn; Colligan, Kevin; McCool, A. (Technical Monitor)

2000-01-01

Five (5) each 14-foot diameter circumferential FSWelds were conducted on the modified CWT, two (2) each pathfinder and three (3) each assembly welds Tapered circumferential welds were successfully demonstrated The use of a closeout anvil was successfully demonstrated during one of the pathfinder welds Considerable difficulty maintaining joint f it-up during the weld process Anvil deflections Hardware dimensional tolerances Inadequate clamping Variations in the heat sink characteristics of the circumferential anvil as compared to the test panel anvil

Acidalia and Chryse Plains, Mars

NASA Image and Video Library

2000-06-14

Somewhere down there sits the Mars Pathfinder lander and Sojourner rover. This Mars Global Surveyor Mars Orbiter Camera view of the red planet shows the region that includes Ares Vallis and the Chryse Plains upon which both Mars Pathfinder and the Viking 1 landed in 1997 and 1976, respectively. Acidalia Planitia is the dark surface that dominates the center left. The Pathfinder site is immediately south of Acidalia, just left of center in this view. Also shown--the north polar cap is at the top, and Arabia Terra and Sinus Meridiani are to the right. The bluish-white features are clouds. This is a color composite of 9 red and 9 blue image strips taken by the Mars Global Surveyor Mars Orbiter Camera on 9 successive orbits from pole-to-pole during the calibration phase of the mission in March 1999. The color is computer-enhanced and is not shown as it would actually appear to the human eye. http://photojournal.jpl.nasa.gov/catalog/PIA02000

Measuring fN force variations in the presence of constant nN forces: a torsion pendulum ground test of the LISA Pathfinder free-fall mode

NASA Astrophysics Data System (ADS)

Russano, G.; Cavalleri, A.; Cesarini, A.; Dolesi, R.; Ferroni, V.; Gibert, F.; Giusteri, R.; Hueller, M.; Liu, L.; Pivato, P.; Tu, H. B.; Vetrugno, D.; Vitale, S.; Weber, W. J.

2018-02-01

LISA Pathfinder is a differential accelerometer with the main goal being to demonstrate the near perfect free-fall of reference test masses, as is needed for an orbiting gravitational wave observatory, with a target sensitivity of 30 fm s‑2 Hz-1/2 at 1 mHz. Any lasting background differential acceleration between the two test masses must be actively compensated, and noise associated with the applied actuation force can be a dominant source of noise. To remove this actuation, and the associated force noise, a ‘free-fall’ actuation control scheme has been designed; actuation is limited to brief impulses, with both test masses in free-fall in the time between the impulses, allowing measurement of the remaining acceleration noise sources. In this work, we present an on-ground torsion pendulum testing campaign of this technique and associated data analysis algorithms at a level nearing the sub-femto-g/\\sqrtHz performance required for LISA Pathfinder.

New perspective of undeployed rover

NASA Technical Reports Server (NTRS)

1997-01-01

This image features a different perspective of one of the first pictures taken by the Imager for Mars Pathfinder (IMP) lander shortly after its touchdown at 10:07 AM Pacific Daylight Time on July 4. The image has been transformed to a perspective that would match that of an observer standing at the point the image was taken. Sojourner is seen in the foreground in its stowed position on a solar panel of the lander. Both ramps, the rear of which Sojourner would use on July 5 to safely descend to the Martian surface, were still undeployed when this image was taken. The double hills called 'Twin Peaks' are clearly visible in the background.

The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

PathFinder: reconstruction and dynamic visualization of metabolic pathways.

PubMed

Goesmann, Alexander; Haubrock, Martin; Meyer, Folker; Kalinowski, Jörn; Giegerich, Robert

2002-01-01

Beyond methods for a gene-wise annotation and analysis of sequenced genomes new automated methods for functional analysis on a higher level are needed. The identification of realized metabolic pathways provides valuable information on gene expression and regulation. Detection of incomplete pathways helps to improve a constantly evolving genome annotation or discover alternative biochemical pathways. To utilize automated genome analysis on the level of metabolic pathways new methods for the dynamic representation and visualization of pathways are needed. PathFinder is a tool for the dynamic visualization of metabolic pathways based on annotation data. Pathways are represented as directed acyclic graphs, graph layout algorithms accomplish the dynamic drawing and visualization of the metabolic maps. A more detailed analysis of the input data on the level of biochemical pathways helps to identify genes and detect improper parts of annotations. As an Relational Database Management System (RDBMS) based internet application PathFinder reads a list of EC-numbers or a given annotation in EMBL- or Genbank-format and dynamically generates pathway graphs.

Detection of Micrometeoroids with LISA Pathfinder

NASA Astrophysics Data System (ADS)

Thorpe, Ira; Littenberg, Tyson; Janchez, Diego; Baker, John; The LISA Pathfinder Team Team

2017-01-01

The LISA Pathfinder mission (LPF), a joint ESA/NASA technology demonstration mission currently operating at the Sun-Earth L1 point, contains the most precise accelerometry system ever flown. Analysis suggests that LPF should have sufficient sensitivity to detect impacts of small micrometeoroids and dust through their transfer of momentum to the spacecraft. Moreover, LPF's ability to fully resolve both the linear and angular momentum transfer in three dimensions allows a magnitude, direction, and location to be estimated for each impact. We present preliminary results from a systematic search of the LISA Pathfinder data for such impacts and discuss the prospects for using these and future results to inform models of the formation and evolution of dust populations in the inner solar system. These models have wide applicability to both pure and applied space science, ranging from the physics of planet formation and dynamics of minor Solar System bodies to estimates of the micrometeorite hazard for future spacecraft. 2017 NASA Science Innovation Fund.

A torsion pendulum test of the Lisa Pathfinder free-fall mode

NASA Astrophysics Data System (ADS)

Russano, Giuliana; Dolesi, Rita; Cavalleri, Antonella; Hueller, Mauro; Vitale, Stefano; Weber, William Joseph; Tu, HaiBo

The LISA Pathfinder geodesic explorer mission for gravitational wave astronomy aims to demonstrate the proof of a low acceleration noise level. The relative acceleration between two test masses free falling in orbit is perturbed by the presence of a larger constant relative acceleration that must be actively compensated in order to keep the test particles centered inside an orbiting apparatus. The actuation force applied to compensate this effect introduces a dominant source of force noise. To suppress this noise source, a “free-fall” actuation control scheme has been designed: actuation is limited to brief impulses, with test masses in free fall in between two “kicks”, with this actuation-free motion then analyzed for the remaining sources of acceleration ultra noise. In this work, we will discuss and present preliminary data for an on-ground torsion pendulum experiment to test this technique, and the associated analysis algorithms, at a level nearing the sub-femto-g/sqrt(Hz) performance required for LISA Pathfinder.

Classification and Distribution of Mars Pathfinder Rocks Using Quantitative Morphologic Indices

NASA Technical Reports Server (NTRS)

Yingst, R. A.; Biederman, K. L.; Monhead, A. M.; Haldemann, A. F. C.; Kowalczyk, M. R.

2004-01-01

The Mars Pathfinder (MPF) landing site was predicted to contain a broad sampling of rock types varying in mineralogical, physical, mechanical and geochemical characteristics. Although rocks have been divided into several spectral categories based on Imager for Mars Pathfinder visible/near-infrared spectra, it has not been fully determined which of these stem from intrinsic mineralogical differences between rocks or rock surfaces, and which result from factors such as physical or chemical weathering. This has made isolation of unique mineralogy's difficult. Efforts in isolating and classifying spectral units among MPF rocks and soils have met with varying degrees of success, and the current understanding is such that many factors influencing spectral signatures cannot be quantified to a sufficient level so they may be removed. The result is that fundamental questions regarding information needed to reveal the present and past interactions between the rocks and rock surfaces and the Martian environment remain unanswered. But it is possible to approach the issue of identifying distinct rock and rock surface types from a different angle.

The Role of APEX as a Pathfinder for AtLAST

NASA Astrophysics Data System (ADS)

Wyrowski, Friedrich

2018-01-01

Now more than 12 years in operation, the Atacama Pathfinder Experiment (APEX) 12 m submillimeter telescope has significantly contributed to a wide variety of submillimeter astronomy science areas, ranging from the discoveries of new molecules to large and deep imaging of the submillimeter sky. While ALMA operation is in full swing, APEX is strengthening its role not only as pathfinder for studying large source samples and spatial scales to prepare detailed high angular resolution ALMA follow ups, but also as fast response instruments to complement new results from ALMA. Furthermore, APEX ensures southern hemisphere access for submillimeter projects complementing archival Herschel research as well as new SOFIA science. With new broadband and multipixel receivers as well as large cameras for wide-field continuum imaging, APEX will pave the way towards the science envisioned with ATLAST. In this contribution, the current status and ongoing upgrades of APEX will be discussed, with an emphasis on the importance of continuous cutting edge science and state-of-the-art instrumentation that will bridge the gap towards ATLAST.

Hydrogeochemical prospecting for porphyry copper deposits in the tropical-marine climate of Puerto Rico

USGS Publications Warehouse

Miller, W.R.; Ficklin, W.H.; Learned, R.E.

1982-01-01

A hydrogeochemical survey utilizing waters from streams and springs was conducted in the area of two known porphyry copper deposits in the tropical-marine climate of westcentral Puerto Rico. The most important pathfinder for regional hydrogeochemical surveys is sulfate which reflects the associated pyrite mineralization. Because of increased mobility due to intense chemical weathering and the low pH environment, dissolved copper can also be used as a pathfinder for regional surveys and has the advantage of distinguishing barren pyrite from pyrite associated with copper mineralization. For follow-up surveys, the most important pathfinders are copper, sulfate, pH, zinc, and fluoride. High concentrations of dissolved copper and moderate concentrations of sulfate is a diagnostic indication of nearby sources of copper minerals. An understanding of the geochemical processes taking place in the streambeds and the weathering environment, such as the precipitation of secondary copper minerals, contributes to the interpretation of the geochemical data and the selection of the most favorable areas for further exploration. ?? 1982.

NASA Ocean Altimeter Pathfinder Project. Report 2; Data Set Validation

NASA Technical Reports Server (NTRS)

Koblinsky, C. J.; Ray, Richard D.; Beckley, Brian D.; Bremmer, Anita; Tsaoussi, Lucia S.; Wang, Yan-Ming

1999-01-01

The NOAA/NASA Pathfinder program was created by the Earth Observing System (EOS) Program Office to determine how existing satellite-based data sets can be processed and used to study global change. The data sets are designed to be long time-series data processed with stable calibration and community consensus algorithms to better assist the research community. The Ocean Altimeter Pathfinder Project involves the reprocessing of all altimeter observations with a consistent set of improved algorithms, based on the results from TOPEX/POSEIDON (T/P), into easy-to-use data sets for the oceanographic community for climate research. Details are currently presented in two technical reports: Report# 1: Data Processing Handbook Report #2: Data Set Validation This report describes the validation of the data sets against a global network of high quality tide gauge measurements and provides an estimate of the error budget. The first report describes the processing schemes used to produce the geodetic consistent data set comprised of SEASAT, GEOSAT, ERS-1, TOPEX/ POSEIDON, and ERS-2 satellite observations.

Career pathfinders: a qualitative study of career development.

PubMed

Beutell, Icholas J; O'Hare, Marianne M

2006-04-01

This paper examined the perceptions of career path and issues of MBA students in response to Lore's The Pathfinder, a comprehensive career-planning model. Using internet discussion boards, an interactive dialogue was mentioned by participants in response to the components of Lore's model. The sample consisted of 50 fully employed MBA students enrolled in a course on self-assessment and career planning. A total of 1,781 separate postings were made and analyzed, using inductive analysis derived from discussion threads based on Lore's categories: comments on Lore's Pathfinder model, living a life you love (what's the holdup, career fantasies, work and family issues, and career selection), how to get there from here (commitment and future from the present), and designing your future career. Findings indicated several interesting trends in the career planning of current MBA students, particularly the importance of self or self-reflective observations in real time as students who are also fully employed formulate career plans. Implications for psychologists and career counselors, career development models, and suggestions for research are presented.

An Analysis of Coupling between the x1 and x12 Interferometers for LISA Pathfinder

NASA Astrophysics Data System (ADS)

Howard, Brittany

2017-01-01

Due to tolerances in the manufacturing process, noise from the jittering of the spacecraft housing LISA Pathfinder (LPF) is appearing in the differential measurement between its two test masses (TM's). This phenomenon manifests as a small but measurable coupling between the readouts of LPF's two heterodyne interferometers, x1 and x12. In this study, two LISA Pathfinder experiments are analyzed using three methods in an effort to characterize and quantify the coupling as well as to potentially identify its source. The main question considered is this: does the coupling change with the absolute displacement between the TM's? As a result of this work, reliable values for coupling between LPF's x1 and x12 interferometers are found, and they are seen to depend on the absolute displacement between the test masses to some degree. Completed at the Albert Einstein Institute for Gravitational Physics under the International REU program from the University of Florida.

Experiments and Spectral Studies of Martian Volcanic Rocks: Implications for the Origin of Pathfinder Rocks and Soils

NASA Technical Reports Server (NTRS)

Rutherford, Malcolm J.; Mustard, Jack; Weitz, Catherine

2002-01-01

The composition and spectral properties of the Mars Pathfinder rocks and soils together with the identification of basaltic and andesitic Mars terrains based on Thermal Emission Spectrometer (TES) data raised interesting questions regarding the nature and origin of Mars surface rocks. We have investigated the following questions: (1) are the Pathfinder rocks igneous and is it possible these rocks could have formed by known igneous processes, such as equilibrium or fractional crystallization, operating within SNC magmas known to exist on Mars? If it is possible, what P (depth) and PH2O conditions are required? (2) whether TES-based interpretations of plagioclase-rich basalt and andesitic terrains in the south and north regions of Mars respectively are unique. Are the surface compositions of these regions plagioclase-rich, possibly indicating the presence of old AI-rich crust of Mars, or are the spectra being affected by something like surface weathering processes that might determine the spectral pyroxene to plagioclase ratio?

LISA Pathfinder: First steps to observing gravitational waves from space

NASA Astrophysics Data System (ADS)

McNamara, Paul; LISA Pathfinder Collaboration

2017-01-01

With the first direct detection of gravitational waves a little over a year ago, the gravitational window to the Universe has been opened. The gravitational wave spectrum spans many orders of magnitude in frequency, with several of the most interesting astronomical sources emitting gravitational waves at frequencies only observable from space The European Space Agency (ESA) has been active in the field of space-borne gravitational wave detection for many years, and in 2013 selected the Gravitational Universe as the science theme for the third large class mission in the Cosmic Vision science programme. In addition, ESA took the step of developing the LISA Pathfinder mission to demonstrate the critical technologies required for a future mission. The goal of the LISA Pathfinder mission is to place a test body in free fall such that any external forces (acceleration) are reduced to levels lower than those expected from the passage of a gravitational wave LISA Pathfinder was launched on the 3rd December 2015 from the European Spaceport in Kourou, French Guiana. After a series of 6 apogee raising manoeuvres, the satellite left earth orbit, and travelled to its final science orbit around the first Sun-Earth Lagrange point (L1). Following a relatively short commissioning phase, science operations began on 1st March 2016. In the following 3 months over 100 experiments and over 1500hours of noise measurements have been performed, demonstrating that the observation of gravitational waves from space can be realised.

Zebrafish foxP2 Zinc Finger Nuclease Mutant Has Normal Axon Pathfinding

PubMed Central

Xing, Lingyan; Hoshijima, Kazuyuki; Grunwald, David J.; Fujimoto, Esther; Quist, Tyler S.; Sneddon, Jacob; Chien, Chi-Bin; Stevenson, Tamara J.; Bonkowsky, Joshua L.

2012-01-01

foxP2, a forkhead-domain transcription factor, is critical for speech and language development in humans, but its role in the establishment of CNS connectivity is unclear. While in vitro studies have identified axon guidance molecules as targets of foxP2 regulation, and cell culture assays suggest a role for foxP2 in neurite outgrowth, in vivo studies have been lacking regarding a role for foxP2 in axon pathfinding. We used a modified zinc finger nuclease methodology to generate mutations in the zebrafish foxP2 gene. Using PCR-based high resolution melt curve analysis (HRMA) of G0 founder animals, we screened and identified three mutants carrying nonsense mutations in the 2nd coding exon: a 17 base-pair (bp) deletion, an 8bp deletion, and a 4bp insertion. Sequence analysis of cDNA confirmed that these were frameshift mutations with predicted early protein truncations. Homozygous mutant fish were viable and fertile, with unchanged body morphology, and no apparent differences in CNS apoptosis, proliferation, or patterning at embryonic stages. There was a reduction in expression of the known foxP2 target gene cntnap2 that was rescued by injection of wild-type foxP2 transcript. When we examined axon pathfinding using a pan-axonal marker or transgenic lines, including a foxP2-neuron-specific enhancer, we did not observe any axon guidance errors. Our findings suggest that foxP2 is not necessary for axon pathfinding during development. PMID:22937139

Zebrafish foxP2 zinc finger nuclease mutant has normal axon pathfinding.

PubMed

Xing, Lingyan; Hoshijima, Kazuyuki; Grunwald, David J; Fujimoto, Esther; Quist, Tyler S; Sneddon, Jacob; Chien, Chi-Bin; Stevenson, Tamara J; Bonkowsky, Joshua L

2012-01-01

foxP2, a forkhead-domain transcription factor, is critical for speech and language development in humans, but its role in the establishment of CNS connectivity is unclear. While in vitro studies have identified axon guidance molecules as targets of foxP2 regulation, and cell culture assays suggest a role for foxP2 in neurite outgrowth, in vivo studies have been lacking regarding a role for foxP2 in axon pathfinding. We used a modified zinc finger nuclease methodology to generate mutations in the zebrafish foxP2 gene. Using PCR-based high resolution melt curve analysis (HRMA) of G0 founder animals, we screened and identified three mutants carrying nonsense mutations in the 2(nd) coding exon: a 17 base-pair (bp) deletion, an 8bp deletion, and a 4bp insertion. Sequence analysis of cDNA confirmed that these were frameshift mutations with predicted early protein truncations. Homozygous mutant fish were viable and fertile, with unchanged body morphology, and no apparent differences in CNS apoptosis, proliferation, or patterning at embryonic stages. There was a reduction in expression of the known foxP2 target gene cntnap2 that was rescued by injection of wild-type foxP2 transcript. When we examined axon pathfinding using a pan-axonal marker or transgenic lines, including a foxP2-neuron-specific enhancer, we did not observe any axon guidance errors. Our findings suggest that foxP2 is not necessary for axon pathfinding during development.

Multispectral Imaging from Mars PATHFINDER

NASA Technical Reports Server (NTRS)

Ferrand, William H.; Bell, James F., III; Johnson, Jeffrey R.; Bishop, Janice L.; Morris, Richard V.

2007-01-01

The Imager for Mars Pathfinder (IMP) was a mast-mounted instrument on the Mars Pathfinder lander which landed on Mars Ares Vallis floodplain on July 4, 1997. During the 83 sols of Mars Pathfinders landed operations, the IMP collected over 16,600 images. Multispectral images were collected using twelve narrowband filters at wavelengths between 400 and 1000 nm in the visible and near infrared (VNIR) range. The IMP provided VNIR spectra of the materials surrounding the lander including rocks, bright soils, dark soils, and atmospheric observations. During the primary mission, only a single primary rock spectral class, Gray Rock, was recognized; since then, Black Rock, has been identified. The Black Rock spectra have a stronger absorption at longer wavelengths than do Gray Rock spectra. A number of coated rocks have also been described, the Red and Maroon Rock classes, and perhaps indurated soils in the form of the Pink Rock class. A number of different soil types were also recognized with the primary ones being Bright Red Drift, Dark Soil, Brown Soil, and Disturbed Soil. Examination of spectral parameter plots indicated two trends which were interpreted as representing alteration products formed in at least two different environmental epochs of the Ares Vallis area. Subsequent analysis of the data and comparison with terrestrial analogs have supported the interpretation that the rock coatings provide evidence of earlier martian environments. However, the presence of relatively uncoated examples of the Gray and Black rock classes indicate that relatively unweathered materials can persist on the martian surface.

Reconsidering the Theological and Ethical Implications of Extraterrestrial Life

NASA Technical Reports Server (NTRS)

Randolph, Richard O. (Editor); Race, Margaret S.; McKay, Christopher P.

1997-01-01

As we stand on the threshold of a new millennium, we also find ourselves at the brink of a new and exciting era in space exploration. In fact, this new era has already begun, with the successful landing and exploration of Mars by the Pathfinder mission in July 1997. Pathfinder represents an important scientific accomplishment for NASA because it demonstrated the agency's ability to successfully explore space at a relatively modest price. At the same time, Pathfinder revealed once again the genuine interest and fascination that people all over planet Earth have for space exploration. The recent Pathfinder mission to Mars was only the first in an ambitious series of NASA missions planned for exploration of Mars, Earth's nearest planetary neighbor where extraterrestrial life is a real possibility. In March 1998, the next step in this exploration takes place, when the Mars Global Surveyor--which is already in orbit around Mars--begins photographing and mapping the Martian surface. NASA plans to continue its exploration with additional landers and orbiters taking off for Mars every 26 months, when the paths of Mars and Earth bring them in closer proximity. By the year 2005, NASA hopes to launch a mission that will return martian samples to Earth. And, as early as 2011, astronauts could be rocketing from Earth for the first human landing on the Red Planet. In the distant future, there may be even more grandiose plans, including the possibility of engineering an atmosphere on Mars that could support biological life.

Laser Interferometry for Gravitational Wave Observation: LISA and LISA Pathfinder

NASA Technical Reports Server (NTRS)

Guzman, Felipe

2010-01-01

The Laser Interferometer Space Antenna (LISA) is a planned NASA-ESA gravitational wave observatory in the frequency range of 0.1mHz-100mHz. This observation band is inaccessible to ground-based detectors due to the large ground motions of the Earth. Gravitational wave sources for LISA include galactic binaries, mergers of supermasive black-hole binaries, extreme-mass-ratio inspirals, and possibly from as yet unimagined sources. LISA is a constellation of three spacecraft separated by 5 million km in an equilateral triangle, whose center follows the Earth in a heliocentric orbit with an orbital phase offset oF 20 degrees. Challenging technology is required to ensure pure geodetic trajectories of the six onboard test masses, whose distance fluctuations will be measured by interspacecraft laser interferometers with picometer accuracy. LISA Pathfinder is an ESA-launched technology demonstration mission of key LISA subsystems such us spacecraft control with micro-newton thrusters, test mass drag-free control, and precision laser interferometry between free-flying test masses. Ground testing of flight hardware of the Gravitational Reference Sensor and Optical Metrology subsystems of LISA Pathfinder is currently ongoing. An introduction to laser interferometric gravitational wave detection, ground-based observatories, and a detailed description of the two missions together with an overview of current investigations conducted by the community will bc discussed. The current status in development and implementation of LISA Pathfinder pre-flight systems and latest results of the ongoing ground testing efforts will also be presented

NASA Ocean Altimeter Pathfinder Project. Report 1; Data Processing Handbook

NASA Technical Reports Server (NTRS)

Koblinsky, C. J.; Beckley, Brian D.; Ray, Richard D.; Wang, Yan-Ming; Tsaoussi, Lucia; Brenner, Anita; Williamson, Ron

1998-01-01

The NOAA/NASA Pathfinder program was created by the Earth Observing System (EOS) Program Office to determine how satellite-based data sets can be processed and used to study global change. The data sets are designed to be long time-sedes data processed with stable calibration and community consensus algorithms to better assist the research community. The Ocean Altimeter Pathfinder Project involves the reprocessing of all altimeter observations with a consistent set of improved algorithms, based on the results from TOPEX/POSEIDON (T/P), into easy-to-use data sets for the oceanographic community for climate research. This report describes the processing schemes used to produce a consistent data set and two of the products derived f rom these data. Other reports have been produced that: a) describe the validation of these data sets against tide gauge measurements and b) evaluate the statistical properties of the data that are relevant to climate change. The use of satellite altimetry for earth observations was proposed in the early 1960s. The first successful space based radar altimeter experiment was flown on SkyLab in 1974. The first successful satellite radar altimeter was flown aboard the Geos-3 spacecraft between 1975 and 1978. While a useful data set was collected from this mission for geophysical studies, the noise in the radar measured and incomplete global coverage precluded ft from inclusion in the Ocean Altimeter Pathfinder program. This program initiated its analysis with the Seasat mission, which was the first satellite radar altimeter flown for oceanography.

Genesis Sample Return Capsule Overview

NASA Technical Reports Server (NTRS)

Willcockson, Bill

2005-01-01

I. Simple Entry Capsule Concept: a) Spin-Stabilized/No Active Control Systems; b) Ballistic Entry for 11.04 km/sec Velocity; c) No Heatshield Separation During Entry; d) Parachute Deploy via g-Switch + Timer. II. Stardust Design Inheritance a) Forebody Shape; b) Seal Concepts; c) Parachute Deploy Control; d) Utah Landing Site (UTTR). III. TPS Systems a) Heatshield - Carbon-Carbon - First Planetary Entry; b) Backshell - SLA-561V - Flight Heritage from Pathfinder, MER; d) Forebody Structural Penetrations Aerothermal and TPS Design Process has the Same Methodology as Used for Pathfinder, MER Flight Vehicles.

Cloud-Aerosol LIDAR and Infrared Pathfinder Satellite Observation (CALIPSO) Spacecraft: Independent Technical Assessment

NASA Technical Reports Server (NTRS)

Gilbrech, Richard J.; McManamen, John P.; Wilson, Timmy R.; Robinson, Frank; Schoren, William R.

2004-01-01

CALIPSO is a joint science mission between the CNES, LaRC and GSFC. It was selected as an Earth System Science Pathfinder satellite mission in December 1998 to address the role of clouds and aerosols in the Earth's radiation budget. The spacecraft includes a NASA light detecting and ranging (LIDAR) instrument, a NASA wide-field camera and a CNES imaging infrared radiometer. The scope of this effort was a review of the Proteus propulsion bus design and an assessment of the potential for personnel exposure to hydrazine propellant.

Towards a Framework for Generating Tests to Satisfy Complex Code Coverage in Java Pathfinder

NASA Technical Reports Server (NTRS)

Staats, Matt

2009-01-01

We present work on a prototype tool based on the JavaPathfinder (JPF) model checker for automatically generating tests satisfying the MC/DC code coverage criterion. Using the Eclipse IDE, developers and testers can quickly instrument Java source code with JPF annotations covering all MC/DC coverage obligations, and JPF can then be used to automatically generate tests that satisfy these obligations. The prototype extension to JPF enables various tasks useful in automatic test generation to be performed, such as test suite reduction and execution of generated tests.

Optical Bench Interferometer - From LISA Pathfinder to NGO/eLISA

NASA Astrophysics Data System (ADS)

Taylor, A.; d'Arcio, L.; Bogenstahl, J.; Danzmann, K.; Diekmann, C.; Fitzsimons, E. D.; Gerberding, O.; Heinzel, G.; Hennig, J.-S.; Hogenhuis, H.; Killow, C. J.; Lieser, M.; Lucarelli, S.; Nikolov, S.; Perreur-Lloyd, M.; Pijnenburg, J.; Robertson, D. I.; Sohmer, A.; Tröbs, M.; Ward, H.; Weise, D.

2013-01-01

We present a short summary of some optical bench construction and alignment developments that build on experience gained during the LISA Pathfinder optical bench assembly. These include evolved fibre injectors, a new beam vector measurement system, and thermally stable mounting hardware. The beam vector measurement techniques allow the alignment of beams to targets with absolute accuracy of a few microns and 20 microradians. We also describe a newly designed ultra-low-return beam dump that is expected to be a crucial element in the control of ghost beams on the optical benches.

Sojourner APXS at Shark

NASA Image and Video Library

1997-08-28

NASA's Sojourner rover is seen next to the rock "Shark," in this image taken by the Imager for Mars Pathfinder (IMP) near the end of daytime operations on Sol 52. The rover's Alpha Proton X-Ray Spectrometer is deployed against the rock. The rock "Wedge" is in the foreground. The Sojourner rover is seen next to the rock "Shark," in this image taken by the Imager for Mars Pathfinder (IMP) near the end of daytime operations on Sol 52. The rover's Alpha Proton X-Ray Spectrometer is deployed against the rock. The rock "Wedge" is in the foreground.

Physarum solver: A biologically inspired method of road-network navigation

NASA Astrophysics Data System (ADS)

Tero, Atsushi; Kobayashi, Ryo; Nakagaki, Toshiyuki

2006-04-01

We have proposed a mathematical model for the adaptive dynamics of the transport network in an amoeba-like organism, the true slime mold Physarum polycephalum. The model is based on physiological observations of this species, but can also be used for path-finding in the complicated networks of mazes and road maps. In this paper, we describe the physiological basis and the formulation of the model, as well as the results of simulations of some complicated networks. The path-finding method used by Physarum is a good example of cellular computation.

Cloud-Aerosol LIDAR and Infrared Pathfinder Satellite Observation (CALIPSO) Spacecraft: Independent Technical Assessment

NASA Technical Reports Server (NTRS)

Gilbrech, Richard J.; McManamen, John P.; Wilson, Timmy R.; Robinson, Frank; Schoren, William R.

2005-01-01

CALIPSO is a joint science mission between the CNES, LaRC and GSFC. It was selected as an Earth System Science Pathfinder satellite mission in December 1998 to address the role of clouds and aerosols in the Earth's radiation budget. The spacecraft includes a NASA light detecting and ranging (LIDAR) instrument, a NASA wide-field camera and a CNES imaging infrared radiometer. The scope of this effort was a review of the Proteus propulsion bus design and an assessment of the potential for personnel exposure to hydrazine propellant.

Selection of radio sources for Venus balloon-Pathfinder Delta-DOR navigation at 1.7 GHz

NASA Technical Reports Server (NTRS)

Liewer, K. M

1986-01-01

In order to increase the success rate of the Delta-DOR (Delta-Differential One-way Range) VLBI navigational support for the French-Soviet Venus Balloon and Halley Pathfinder projects, forty-four extragalactic radio sources were observed in advance of these projects to determine which were suitable for use as reference sources. Of these forty-four radio sources taken from the existing JPL radio source catalogue, thirty-six were determined to be of sufficient strength for use in Delta-DOR VLBI navigation.

Cryogenic Characterization and Testing of Magnetically-Actuated Microshutter Arrays for the James Webb Space Telescope

NASA Technical Reports Server (NTRS)

King, T. T.; Kletetschka, G.; Jah, M. A.; Li, M. J.; Jhabvala, M. D.; Wang, L. L.; Beamesderfer, M. A.; Kutyrev, A. S.; Silverberg, R. F.; Rapchun, D.;

Calibration of radio-astronomical data on the cloud. LOFAR, the pathway to SKA

NASA Astrophysics Data System (ADS)

Sabater, J.; Sánchez-Expósito, S.; Garrido, J.; Ruiz, J. E.; Best, P. N.; Verdes-Montenegro, L.

2015-05-01

The radio interferometer LOFAR (LOw Frequency ARray) is fully operational now. This Square Kilometre Array (SKA) pathfinder allows the observation of the sky at frequencies between 10 and 240 MHz, a relatively unexplored region of the spectrum. LOFAR is a software defined telescope: the data is mainly processed using specialized software running in common computing facilities. That means that the capabilities of the telescope are virtually defined by software and mainly limited by the available computing power. However, the quantity of data produced can quickly reach huge volumes (several Petabytes per day). After the correlation and pre-processing of the data in a dedicated cluster, the final dataset is handled to the user (typically several Terabytes). The calibration of these data requires a powerful computing facility in which the specific state of the art software under heavy continuous development can be easily installed and updated. That makes this case a perfect candidate for a cloud infrastructure which adds the advantages of an on demand, flexible solution. We present our approach to the calibration of LOFAR data using Ibercloud, the cloud infrastructure provided by Ibergrid. With the calibration work-flow adapted to the cloud, we can explore calibration strategies for the SKA and show how private or commercial cloud infrastructures (Ibercloud, Amazon EC2, Google Compute Engine, etc.) can help to solve the problems with big datasets that will be prevalent in the future of astronomy.

Free-Suspension Residual Flexibility Testing of Space Station Pathfinder: Comparison to Fixed-Base Results

NASA Technical Reports Server (NTRS)

Tinker, Michael L.

1998-01-01

Application of the free-suspension residual flexibility modal test method to the International Space Station Pathfinder structure is described. The Pathfinder, a large structure of the general size and weight of Space Station module elements, was also tested in a large fixed-base fixture to simulate Shuttle Orbiter payload constraints. After correlation of the Pathfinder finite element model to residual flexibility test data, the model was coupled to a fixture model, and constrained modes and frequencies were compared to fixed-base test. modes. The residual flexibility model compared very favorably to results of the fixed-base test. This is the first known direct comparison of free-suspension residual flexibility and fixed-base test results for a large structure. The model correlation approach used by the author for residual flexibility data is presented. Frequency response functions (FRF) for the regions of the structure that interface with the environment (a test fixture or another structure) are shown to be the primary tools for model correlation that distinguish or characterize the residual flexibility approach. A number of critical issues related to use of the structure interface FRF for correlating the model are then identified and discussed, including (1) the requirement of prominent stiffness lines, (2) overcoming problems with measurement noise which makes the antiresonances or minima in the functions difficult to identify, and (3) the use of interface stiffness and lumped mass perturbations to bring the analytical responses into agreement with test data. It is shown that good comparison of analytical-to-experimental FRF is the key to obtaining good agreement of the residual flexibility values.

Navigating Without Road Maps: The Early Business of Automobile Route Guide Publishing in the United States

NASA Astrophysics Data System (ADS)

Bauer, John T.

2018-05-01

In the United States, automobile route guides were important precursors to the road maps that Americans are familiar with today. Listing turn-by-turn directions between cities, they helped drivers navigate unmarked, local roads. This paper examines the early business of route guide publishing through the Official Automobile Blue Book series of guides. It focuses specifically on the expansion, contraction, and eventual decline of the Blue Book publishing empire and also the work of professional "pathfinders" that formed the company's data-gathering infrastructure. Be- ginning in 1901 with only one volume, the series steadily grew until 1920, when thirteen volumes were required to record thousands of routes throughout the country. Bankruptcy and corporate restructuring in 1921 forced the publishers to condense the guide into a four-volume set in 1922. Competition from emerging sheet maps, along with the nationwide standardization of highway numbers, pushed a switch to an atlas format in 1926. Blue Books, however, could not remain competitive and disappeared after 1937. "Pathfinders" were employed by the publishers and equipped with reliable automobiles. Soon they developed a shorthand notation system for recording field notes and efficiently incorporating them into the development workflow. Although pathfinders did not call themselves cartographers, they were geographical data field collectors and considered their work to be an "art and a science," much the same as modern-day cartographers. The paper concludes with some comments about the place of route guides in the history of American commercial cartography and draws some parallels between "pathfinders" and the digital road mappers of today.

Notochord alters the permissiveness of myotome for pathfinding by an identified motoneuron in embryonic zebrafish.

PubMed

Beattie, C E; Eisen, J S

1997-02-01

During zebrafish development, identified motoneurons innervate cell-specific regions of each trunk myotome. One motoneuron, CaP, extends an axon along the medial surface of the ventral myotome. To learn how this pathway is established during development, the CaP axon was used as an assay to ask whether other regions of the myotome were permissive for normal CaP pathfinding. Native myotomes were replaced with donor myotomes in normal or reversed dorsoventral orientations and CaP pathfinding was assayed. Ventral myotomes were permissive for CaP axons, even when they were taken from older embryos, suggesting that the CaP pathway remained present on ventral myotome throughout development. Dorsal myotomes from young embryos were also permissive for CaP axons, however, older dorsal myotomes were non-permissive, showing that permissiveness of dorsal myotome for normal CaP pathfinding diminished over time. This process appears to depend on signals from the embryo, since dorsal myotomes matured in vitro remained permissive for CaP axons. Genetic mosaics between wild-type and floating head mutant embryos revealed notochord involvement in dorsal myotome change of permissiveness. Dorsal and ventral myotomes from both younger and older floating head mutant embryos were permissive for CaP axons. These data suggest that initially both dorsal and ventral myotomes are permissive for CaP axons but as development proceeds, there is a notochord-dependent decrease in permissiveness of dorsal myotome for CaP axonal outgrowth. This change participates in restricting the CaP pathway to the ventral myotome and thus to neuromuscular specificity.

Charge-Induced Force Noise on Free-Falling Test Masses: Results from LISA Pathfinder

NASA Astrophysics Data System (ADS)

Armano, M.; Audley, H.; Auger, G.; Baird, J. T.; Binetruy, P.; Born, M.; Bortoluzzi, D.; Brandt, N.; Bursi, A.; Caleno, M.; Cavalleri, A.; Cesarini, A.; Cruise, M.; Danzmann, K.; de Deus Silva, M.; Diepholz, I.; Dolesi, R.; Dunbar, N.; Ferraioli, L.; Ferroni, V.; Fitzsimons, E. D.; Flatscher, R.; Freschi, M.; Gallegos, J.; García Marirrodriga, C.; Gerndt, R.; Gesa, L.; Gibert, F.; Giardini, D.; Giusteri, R.; Grimani, C.; Grzymisch, J.; Harrison, I.; Heinzel, G.; Hewitson, M.; Hollington, D.; Hueller, M.; Huesler, J.; Inchauspé, H.; Jennrich, O.; Jetzer, P.; Johlander, B.; Karnesis, N.; Kaune, B.; Killow, C. J.; Korsakova, N.; Lloro, I.; Liu, L.; López-Zaragoza, J. P.; Maarschalkerweerd, R.; Madden, S.; Mance, D.; Martín, V.; Martin-Polo, L.; Martino, J.; Martin-Porqueras, F.; Mateos, I.; McNamara, P. W.; Mendes, J.; Mendes, L.; Moroni, A.; Nofrarias, M.; Paczkowski, S.; Perreur-Lloyd, M.; Petiteau, A.; Pivato, P.; Plagnol, E.; Prat, P.; Ragnit, U.; Ramos-Castro, J.; Reiche, J.; Romera Perez, J. A.; Robertson, D. I.; Rozemeijer, H.; Rivas, F.; Russano, G.; Sarra, P.; Schleicher, A.; Slutsky, J.; Sopuerta, C.; Sumner, T. J.; Texier, D.; Thorpe, J. I.; Trenkel, C.; Vetrugno, D.; Vitale, S.; Wanner, G.; Ward, H.; Wass, P. J.; Wealthy, D.; Weber, W. J.; Wittchen, A.; Zanoni, C.; Ziegler, T.; Zweifel, P.; LISA Pathfinder Collaboration

2017-04-01

We report on electrostatic measurements made on board the European Space Agency mission LISA Pathfinder. Detailed measurements of the charge-induced electrostatic forces exerted on free-falling test masses (TMs) inside the capacitive gravitational reference sensor are the first made in a relevant environment for a space-based gravitational wave detector. Employing a combination of charge control and electric-field compensation, we show that the level of charge-induced acceleration noise on a single TM can be maintained at a level close to 1.0 fm s-2 Hz-1 /2 across the 0.1-100 mHz frequency band that is crucial to an observatory such as the Laser Interferometer Space Antenna (LISA). Using dedicated measurements that detect these effects in the differential acceleration between the two test masses, we resolve the stochastic nature of the TM charge buildup due to interplanetary cosmic rays and the TM charge-to-force coupling through stray electric fields in the sensor. All our measurements are in good agreement with predictions based on a relatively simple electrostatic model of the LISA Pathfinder instrument.

Mars Pathfinder and Mars Global Surveyor Outreach Compilation

NASA Astrophysics Data System (ADS)

1999-09-01

This videotape is a compilation of the best NASA JPL (Jet Propulsion Laboratory) videos of the Mars Pathfinder and Mars Global Surveyor missions. The mission is described using animation and narration as well as some actual footage of the entire sequence of mission events. Included within these animations are the spacecraft orbit insertion; descent to the Mars surface; deployment of the airbags and instruments; and exploration by Sojourner, the Mars rover. JPL activities at spacecraft control during significant mission events are also included at the end. The spacecraft cameras pan the surrounding Mars terrain and film Sojourner traversing the surface and inspecting rocks. A single, brief, processed image of the Cydonia region (Mars face) at an oblique angle from the Mars Global Surveyor is presented. A description of the Mars Pathfinder mission, instruments, landing and deployment process, Mars approach, spacecraft orbit insertion, rover operation are all described using computer animation. Actual color footage of Sojourner as well as a 360 deg pan of the Mars terrain surrounding the spacecraft is provided. Lower quality black and white photography depicting Sojourner traversing the Mars surface and inspecting Martian rocks also is included.

jFuzz: A Concolic Whitebox Fuzzer for Java

NASA Technical Reports Server (NTRS)

Jayaraman, Karthick; Harvison, David; Ganesh, Vijay; Kiezun, Adam

2009-01-01

We present jFuzz, a automatic testing tool for Java programs. jFuzz is a concolic whitebox fuzzer, built on the NASA Java PathFinder, an explicit-state Java model checker, and a framework for developing reliability and analysis tools for Java. Starting from a seed input, jFuzz automatically and systematically generates inputs that exercise new program paths. jFuzz uses a combination of concrete and symbolic execution, and constraint solving. Time spent on solving constraints can be significant. We implemented several well-known optimizations and name-independent caching, which aggressively normalizes the constraints to reduce the number of calls to the constraint solver. We present preliminary results due to the optimizations, and demonstrate the effectiveness of jFuzz in creating good test inputs. The source code of jFuzz is available as part of the NASA Java PathFinder. jFuzz is intended to be a research testbed for investigating new testing and analysis techniques based on concrete and symbolic execution. The source code of jFuzz is available as part of the NASA Java PathFinder.

Charge-Induced Force Noise on Free-Falling Test Masses: Results from LISA Pathfinder.

PubMed

Armano, M; Audley, H; Auger, G; Baird, J T; Binetruy, P; Born, M; Bortoluzzi, D; Brandt, N; Bursi, A; Caleno, M; Cavalleri, A; Cesarini, A; Cruise, M; Danzmann, K; de Deus Silva, M; Diepholz, I; Dolesi, R; Dunbar, N; Ferraioli, L; Ferroni, V; Fitzsimons, E D; Flatscher, R; Freschi, M; Gallegos, J; García Marirrodriga, C; Gerndt, R; Gesa, L; Gibert, F; Giardini, D; Giusteri, R; Grimani, C; Grzymisch, J; Harrison, I; Heinzel, G; Hewitson, M; Hollington, D; Hueller, M; Huesler, J; Inchauspé, H; Jennrich, O; Jetzer, P; Johlander, B; Karnesis, N; Kaune, B; Killow, C J; Korsakova, N; Lloro, I; Liu, L; López-Zaragoza, J P; Maarschalkerweerd, R; Madden, S; Mance, D; Martín, V; Martin-Polo, L; Martino, J; Martin-Porqueras, F; Mateos, I; McNamara, P W; Mendes, J; Mendes, L; Moroni, A; Nofrarias, M; Paczkowski, S; Perreur-Lloyd, M; Petiteau, A; Pivato, P; Plagnol, E; Prat, P; Ragnit, U; Ramos-Castro, J; Reiche, J; Romera Perez, J A; Robertson, D I; Rozemeijer, H; Rivas, F; Russano, G; Sarra, P; Schleicher, A; Slutsky, J; Sopuerta, C; Sumner, T J; Texier, D; Thorpe, J I; Trenkel, C; Vetrugno, D; Vitale, S; Wanner, G; Ward, H; Wass, P J; Wealthy, D; Weber, W J; Wittchen, A; Zanoni, C; Ziegler, T; Zweifel, P

2017-04-28

We report on electrostatic measurements made on board the European Space Agency mission LISA Pathfinder. Detailed measurements of the charge-induced electrostatic forces exerted on free-falling test masses (TMs) inside the capacitive gravitational reference sensor are the first made in a relevant environment for a space-based gravitational wave detector. Employing a combination of charge control and electric-field compensation, we show that the level of charge-induced acceleration noise on a single TM can be maintained at a level close to 1.0  fm s^{-2} Hz^{-1/2} across the 0.1-100 mHz frequency band that is crucial to an observatory such as the Laser Interferometer Space Antenna (LISA). Using dedicated measurements that detect these effects in the differential acceleration between the two test masses, we resolve the stochastic nature of the TM charge buildup due to interplanetary cosmic rays and the TM charge-to-force coupling through stray electric fields in the sensor. All our measurements are in good agreement with predictions based on a relatively simple electrostatic model of the LISA Pathfinder instrument.

Mars Pathfinder and Mars Global Surveyor Outreach Compilation

NASA Technical Reports Server (NTRS)

1999-01-01

This videotape is a compilation of the best NASA JPL (Jet Propulsion Laboratory) videos of the Mars Pathfinder and Mars Global Surveyor missions. The mission is described using animation and narration as well as some actual footage of the entire sequence of mission events. Included within these animations are the spacecraft orbit insertion; descent to the Mars surface; deployment of the airbags and instruments; and exploration by Sojourner, the Mars rover. JPL activities at spacecraft control during significant mission events are also included at the end. The spacecraft cameras pan the surrounding Mars terrain and film Sojourner traversing the surface and inspecting rocks. A single, brief, processed image of the Cydonia region (Mars face) at an oblique angle from the Mars Global Surveyor is presented. A description of the Mars Pathfinder mission, instruments, landing and deployment process, Mars approach, spacecraft orbit insertion, rover operation are all described using computer animation. Actual color footage of Sojourner as well as a 360 deg pan of the Mars terrain surrounding the spacecraft is provided. Lower quality black and white photography depicting Sojourner traversing the Mars surface and inspecting Martian rocks also is included.

adrift, a novel bnl-induced Drosophila gene, required for tracheal pathfinding into the CNS.

PubMed

Englund, C; Uv, A E; Cantera, R; Mathies, L D; Krasnow, M A; Samakovlis, C

1999-04-01

Neurons and glial cells provide guidance cues for migrating neurons. We show here that migrating epithelial cells also contact specific neurons and glia during their pathfinding, and we describe the first gene required in the process. In wild-type Drosophila embryos, the ganglionic tracheal branch navigates a remarkably complex path along specific neural and glial substrata, switching substrata five times before reaching its ultimate target in the CNS. In adrift mutants, ganglionic branches migrate normally along the intersegmental nerve, but sporadically fail to switch to the segmental nerve and enter the CNS; they wind up meandering along the ventral epidermis instead. adrift encodes a novel nuclear protein with an evolutionarily conserved motif. The gene is required in the trachea and is expressed in the leading cells of migrating ganglionic branches where it is induced by the branchless FGF pathway. We propose that Adrift regulates expression of tracheal genes required for pathfinding on the segmental nerve, and FGF induction of adrift expression in migrating tracheal cells promotes the switch from the intersegmental to the segmental nerve.

Sedimentary Geochemistry of Martian Samples from the Pathfinder Mission

NASA Technical Reports Server (NTRS)

McLennan, Scott M.

2001-01-01

The purpose of this research project was to evaluate the APXS data collected on soils and rocks at the Pathfinder site in terms of sedimentary geochemistry. Below are described the major findings of this research: (1) An influential model to explain the chemical variation among Pathfinder soils and rocks is a two component mixing model where rocks of fairly uniform composition mix with soil of uniform composition; (2) The very strong positive correlation between MgO and SO, points to a control by a MgSO4 mineral however, spectroscopic data continue to suggest that Fe-sulfates, notably schwertmannite and jarosite, may be important components; (3) In an attempt to better understand the causes of complexities in mixing relationships, the possible influence of sedimentary transport has been evaluated; (4) Another aspect of this research has been to examine the possibility of sedimentary silica being a significant phase on Mars; and (5) On Earth, the geochemistry of sedimentary rocks has been used to constrain the chemical composition of the continental crust and an important part of this research was to evaluate this approach for Mars.

OCAPI: a multidirectional multichannel polarizing imager

NASA Astrophysics Data System (ADS)

Le Naour, C.; Eichen, G.; Léon, J. F.

2017-11-01

OCAPI (Optical Carbonaceous and anthropogenic Aerosols Pathfinder Instrument) is an imager dedicated to the observation of the spectral, directional and polarized signatures of the solar radiance reflected by the Earth-Atmosphere system. The measurements are used to study air quality and pollution by tracking aerosol quantity, types and circulation at various scales in the visible range. The main characteristics of OCAPI are a 110° along track and cross track field of view, eight polarized channels distributed between 320 and 2130 nm. The resolution is 4 x 4 km2 in the visible and the shortwave infrared (SWIR) range, and 10 x 10 km2 in the UV. The instrumental concept is derived from POLDER and PARASOL with additional channels in the UV and SWIR to better determine aerosol properties and constrain Earth surface and cloud contributions in the detected signal. It is based on three wide field-ofview telecentric optics (UV, Visible and SWIR), a rotating wheel bearing spectral and polarized filters and two dimensional detector arrays at the focal plane of the optics. The instrument requirements, concept and budgets are presented.

Delta II Mars Pathfinder

NASA Technical Reports Server (NTRS)

1998-01-01

Final preparations for lift off of the DELTA II Mars Pathfinder Rocket are shown. Activities include loading the liquid oxygen, completing the construction of the Rover, and placing the Rover into the Lander. After the countdown, important visual events include the launch of the Delta Rocket, burnout and separation of the three Solid Rocket Boosters, and the main engine cutoff. The cutoff of the main engine marks the beginning of the second stage engine. After the completion of the second stage, the third stage engine ignites and then cuts off. Once the third stage engine cuts off spacecraft separation occurs.

Interior structure and seasonal mass redistribution of Mars from radio tracking of Mars Pathfinder

NASA Technical Reports Server (NTRS)

Folkner, W. M.; Yoder, C. F.; Yuan, D. N.; Standish, E. M.; Preston, R. A.

1997-01-01

Doppler and range measurements to the Mars Pathfinder lander made using its radio communications system have been combined with similar measurements from the Viking landers to estimate improved values of the precession of Mars' pole of rotation and the variation in Mars' rotation rate. The observed precession of -7576 +/- 35 milliarc seconds of angle per year implies a dense core and constrains possible models of interior composition. The estimated annual variation in rotation is in good agreement with a model of seasonal mass exchange of carbon dioxide between the atmosphere and ice caps.

Shark as viewed by Sojourner Rover

NASA Technical Reports Server (NTRS)

1998-01-01

This close-up image of Shark, in the Bookshelf at the back of the Rock Garden, was taken by Sojourner Rover on Sol 75. Also in the image are Half Dome (right) and Desert Princess (lower right). At the bottom left, a thin 'crusty' soil layer has been disturbed by the rover wheels.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

AGU Pathfinder: Career and Professional Development Resources for Earth and Space Scientists

NASA Astrophysics Data System (ADS)

Harwell, D. E.; Asher, P. M.; Hankin, E. R.; Janick, N. G.; Marasco, L.

2017-12-01

The American Geophysical Union (AGU) is committed to inspiring and educating present and future generations of diverse, innovative, and creative Earth and space scientists. To meet our commitment, AGU provides career and educational resources, webinars, mentoring, and support for students and professionals at each level of development to reduce barriers to achievement and to promote professional advancement. AGU is also working with other organizations and educational institutions to collaborate on projects benefiting the greater geoscience community. The presentation will include an overview of current Pathfinder efforts, collaborative efforts, and an appeal for additional partnerships.

Rock Garden Mosaic

NASA Technical Reports Server (NTRS)

1997-01-01

This image mosaic of part of the 'Rock Garden' was taken by the Sojourner rover's left front camera on Sol 71 (September 14). The rock 'Shark' is at left center and 'Half Dome' is at right. Fine-scale textures on the rocks are clearly seen. Broken crust-like material is visible at bottom center.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

Interior structure and seasonal mass redistribution of Mars from radio tracking of Mars Pathfinder.

PubMed

Folkner, W M; Yoder, C F; Yuan, D N; Standish, E M; Preston, R A

1997-12-05

Doppler and range measurements to the Mars Pathfinder lander made using its radio communications system have been combined with similar measurements from the Viking landers to estimate improved values of the precession of Mars' pole of rotation and the variation in Mars' rotation rate. The observed precession of -7576 +/- 35 milliarc seconds of angle per year implies a dense core and constrains possible models of interior composition. The estimated annual variation in rotation is in good agreement with a model of seasonal mass exchange of carbon dioxide between the atmosphere and ice caps.

Charge Management in LISA Pathfinder: The Continuous Discharging Experiment

NASA Astrophysics Data System (ADS)

Ewing, Becca Elizabeth

2018-01-01

Test mass charging is a significant source of excess force and force noise in LISA Pathfinder (LPF). The planned design scheme for mitigation of charge induced force noise in LISA is a continuous discharge by UV light illumination. We report on analysis of a charge management experiment on-board LPF conducted during December 2016. We discuss the measurement of test mass charging noise with and without continuous UV illumination, in addition to the dynamic response in the continuous discharge scheme. Results of the continuous discharge system will be discussed for their application to operating LISA with lower test mass charge.

Results from the Mars Pathfinder camera.

PubMed

Smith, P H; Bell, J F; Bridges, N T; Britt, D T; Gaddis, L; Greeley, R; Keller, H U; Herkenhoff, K E; Jaumann, R; Johnson, J R; Kirk, R L; Lemmon, M; Maki, J N; Malin, M C; Murchie, S L; Oberst, J; Parker, T J; Reid, R J; Sablotny, R; Soderblom, L A; Stoker, C; Sullivan, R; Thomas, N; Tomasko, M G; Wegryn, E

1997-12-05

Images of the martian surface returned by the Imager for Mars Pathfinder (IMP) show a complex surface of ridges and troughs covered by rocks that have been transported and modified by fluvial, aeolian, and impact processes. Analysis of the spectral signatures in the scene (at 440- to 1000-nanometer wavelength) reveal three types of rock and four classes of soil. Upward-looking IMP images of the predawn sky show thin, bluish clouds that probably represent water ice forming on local atmospheric haze (opacity approximately 0.5). Haze particles are about 1 micrometer in radius and the water vapor column abundance is about 10 precipitable micrometers.

Mars PathFinder Rover Traverse Image

NASA Technical Reports Server (NTRS)

1998-01-01

This figure contains an azimuth-elevation projection of the 'Gallery Panorama.' The original Simple Cylindrical mosaic has been reprojected to the inside of a sphere so that lines of constant azimuth radiate from the center and lines of constant elevation are concentric circles. This projection preserves the resolution of the original panorama. Overlaid onto the projected Martian surface is a delineation of the Sojourner rover traverse path during the 83 Sols (Martian days) of Pathfinder surface operations. The rover path was reproduced using IMP camera 'end of day' and 'Rover movie' image sequences and rover vehicle telemetry data as references.

The effect of environmental initiatives on NASA specifications and standards activities

NASA Technical Reports Server (NTRS)

Griffin, Dennis; Webb, David; Cook, Beth

1995-01-01

The NASA Operational Environment Team (NOET) has conducted a survey of NASA centers specifications and standards that require the use of Ozone Depleting Substances (ODS's) (Chlorofluorocarbons (CFCs), Halons, and chlorinated solvents). The results of this survey are presented here, along with a pathfinder approach utilized at Marshall Space Flight Center (MSFC) to eliminate the use of ODS's in targeted specifications and standards. Presented here are the lessons learned from a pathfinder effort to replace CFC-113 in a significant MSFC specification for cleaning and cleanliness verification methods for oxygen, fuel and pneumatic service, including Shuttle propulsion elements.

Mars Pathfinder Wheel Abrasion Experiment Ground Test

NASA Technical Reports Server (NTRS)

Keith, Theo G., Jr.; Siebert, Mark W.

1998-01-01

The National Aeronautics and Space Administration (NASA) sent a mission to the martian surface, called Mars Pathfinder. The mission payload consisted of a lander and a rover. The primary purpose of the mission was demonstrating a novel entry, descent, and landing method that included a heat shield, a parachute, rockets, and a cocoon of giant air bags. Once on the surface, the spacecraft returned temperature measurements near the Martian surface, atmosphere pressure, wind speed measurements, and images from the lander and rover. The rover obtained 16 elemental measurements of rocks and soils, performed soil-mechanics, atmospheric sedimentation measurements, and soil abrasiveness measurements.

Mars Pathfinder: The Wheel Abrasion Experiment

NASA Technical Reports Server (NTRS)

1996-01-01

NASA Lewis Research Center's Wheel Abrasion Experiment (WAE) will measure the amount of wear on wheel surfaces of the Mars Pathfinder rover. WAE uses thin films of Al, Ni, and Pt (ranging in thickness from 200 to 1000 angstroms) deposited on black, anodized Al strips attached to the rover wheel. As the wheel moves across the martian surface, changes in film reflectivity will be monitored by reflected sunlight. These changes, measured as output from a special photodetector mounted on the rover chassis, will be due to abrasion of the metal films by martian surface sand, dust, and clay.

Pathfinder Atomic Power Plant Nozzle Galling Test, Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

None, None

1961-12-29

Galling tests of 304, 17-4PH, and chrome-plated 304 stainless-steel nozzles with 304 stainless-steel sleeves were conducted at Pathflnder reactor conditions of 480 deg F, 600 psig. A horizontal force was imposed on the sleeve with the nozzle inserted; and the nozzle was moved axially to determine galling tendencies. Galling was produced on both the 304 and 17-4PH stainless-steel nozzles. The chrome-plated 304-stainless-steel nozzles were cycled numerous times without galling. On the basis of these tests, chrome-plated 304-stainless- steel is the material selected for the Pathfinder boiler fuel-element nozzle.

Tracking Solar Type II Bursts with Space Based Radio Interferometers

NASA Astrophysics Data System (ADS)

Hegedus, Alexander M.; Kasper, Justin C.; Manchester, Ward B.

2018-06-01

The Earth’s Ionosphere limits radio measurements on its surface, blocking out any radiation below 10 MHz. Valuable insight into many astrophysical processes could be gained by having a radio interferometer in space to image the low frequency window for the first time. One application is observing type II bursts tracking solar energetic particle acceleration in Coronal Mass Ejections (CMEs). In this work we create a simulated data processing pipeline for several space based radio interferometer (SBRI) concepts and evaluate their performance in the task of localizing these type II bursts.Traditional radio astronomy software is hard coded to assume an Earth based array. To circumvent this, we manually calculate the antenna separations and insert them along with the simulated visibilities into a CASA MS file for analysis. To create the realest possible virtual input data, we take a 2-temperature MHD simulation of a CME event, superimpose realistic radio emission models from the CME-driven shock front, and propagate the signal through simulated SBRIs. We consider both probabilistic emission models derived from plasma parameters correlated with type II bursts, and analytical emission models using plasma emission wave interaction theory.One proposed SBRI is the pathfinder mission SunRISE, a 6 CubeSat interferometer to circle the Earth in a GEO graveyard orbit. We test simulated trajectories of SunRISE and image what the array recovers, comparing it to the virtual input. An interferometer on the lunar surface would be a stable alternative that avoids noise sources that affect orbiting arrays, namely the phase noise from positional uncertainty and atmospheric 10s-100s kHz noise. Using Digital Elevation Models from laser altimeter data, we test different sets of locations on the lunar surface to find near optimal configurations for tracking type II bursts far from the sun. Custom software is used to model the response of different array configurations over the lunar year, combining ephemerides of the sun and moon to correlate the virtual data. We analyze the pros and cons of all approaches and offer recommendations for SRBIs that track type II bursts.

Automatic remote sensing detection of the convective boundary layer structure over flat and complex terrain using the novel PathfinderTURB algorithm

NASA Astrophysics Data System (ADS)

Poltera, Yann; Martucci, Giovanni; Hervo, Maxime; Haefele, Alexander; Emmenegger, Lukas; Brunner, Dominik; Henne, stephan

2016-04-01

We have developed, applied and validated a novel algorithm called PathfinderTURB for the automatic and real-time detection of the vertical structure of the planetary boundary layer. The algorithm has been applied to a year of data measured by the automatic LIDAR CHM15K at two sites in Switzerland: the rural site of Payerne (MeteoSwiss station, 491 m, asl), and the alpine site of Kleine Scheidegg (KSE, 2061 m, asl). PathfinderTURB is a gradient-based layer detection algorithm, which in addition makes use of the atmospheric variability to detect the turbulent transition zone that separates two low-turbulence regions, one characterized by homogeneous mixing (convective layer) and one above characterized by free tropospheric conditions. The PathfinderTURB retrieval of the vertical structure of the Local (5-10 km, horizontal scale) Convective Boundary Layer (LCBL) has been validated at Payerne using two established reference methods. The first reference consists of four independent human-expert manual detections of the LCBL height over the year 2014. The second reference consists of the values of LCBL height calculated using the bulk Richardson number method based on co-located radio sounding data for the same year 2014. Based on the excellent agreement with the two reference methods at Payerne, we decided to apply PathfinderTURB to the complex-terrain conditions at KSE during 2014. The LCBL height retrievals are obtained by tilting the CHM15K at an angle of 19 degrees with respect to the horizontal and aiming directly at the Sphinx Observatory (3580 m, asl) on the Jungfraujoch. This setup of the CHM15K and the processing of the data done by the PathfinderTURB allows to disentangle the long-transport from the local origin of gases and particles measured by the in-situ instrumentation at the Sphinx Observatory. The KSE measurements showed that the relation amongst the LCBL height, the aerosol layers above the LCBL top and the gas + particle concentration is all but trivial. Retrieving the structure of the LCBL along the line of sight connecting KSE to the Sphinx Observatory allows to monitor when the LCBL top reaches the altitude of the in-situ instrumentation at the Sphinx and to relate the measured gas + particle concentration with the locally-produced aerosols. On the other hand, when the LCBL top is lower than the Sphinx altitude, the measured concentration of gas + particle at the Sphinx is either due to long transport of aerosols (>100 km) or to the residual aerosol layer reaching the Sphinx's height or to non-local (> 5 km and <100 km) CBL aerosols advected at the Sphinx's height. Except when the aerosol layer is decoupled from the LCBL underneath, for all the other cases the CHM15K sees the probed layer as a continuous (not necessarily well-mixed) aerosol layer starting at the KSE surface. The depth of this continuous layer has been retrieved by the PathfinderTURB and related with the black carbon absorption coefficient measured at Sphinx. The result of the comparison shows clearly that the depth of the layer is well correlated with the absorption coefficient measured at the Sphinx. This is an important result that allows not only to retrieve real-time CBL heights in an automatic and trustworthy way, but also to adapt the retrievals to complex-terrain and complex-atmospheric conditions with customized tilted instrument settings.

Apical root canal transportation of different pathfinding systems and their effects on shaping ability of ProTaper Next

PubMed Central

Türker, Sevinç-Aktemur

2015-01-01

Background This study aimed to compare glide path preparation of different pathfinding systems and their effects on the apical transportation of ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland) in mesial root canals of extracted human mandibular molars, using digital subtraction radiography. Material and Methods The mesial canals of 40 mandibular first molars (with curvature angles between 25° and 35°) were selected for this study. The specimens were divided randomly into 4 groups with 10 canals each. Glide paths were created in group 1 with #10, #15 and #20 K-type (Dentsply Maillefer, Ballaigues, Switzerland) stainless steel manual files; in group 2 with Path-File (Dentsply Maillefer) #1, #2, and #3 and in group 3 with #16 ProGlider (Dentsply Maillefer) rotary instruments; in group 4 no glide paths were created. All canals were instrumented up to ProTaper Next X2 to the working length. A double digital radiograph technique was used, pre and post-instrumentation, to assess whether apical transportation and/or aberration in root canal morphology occurred. Instrument failures were also recorded. The data were analyzed statistically using ANOVA and Tukey tests (p<0.05). Results No significant differences were found among groups regarding apical transportation (p>0.05). Two ProTaper Next instruments failed in-group 4. Conclusions Within the parameters of this study, there was no difference between the performance of path-finding files and ProTaper Next system maintained root canal curvature well and was safe to use either with path-finding files or alone. Key words:Glide path, PathFile, ProGlider, ProTaper Next, transportation. PMID:26330936

Periodontal status among adolescents in Georgia. A pathfinder study.

PubMed

Levin, Liran; Margvelashvili, Vladimer; Bilder, Leon; Kalandadze, Manana; Tsintsadze, Nino; Machtei, Eli E

2013-01-01

Objectives. The aim of the present pathfinder study was to screen and map the periodontal status of Georgian population in accordance with the guidelines of the World Health Organization for population based surveys. Methods. During 2012, a pathfinder study was conducted to collect this data. For the periodontal portion of the study, 15-year-old school children were examined in the capital city of Tbilisi as well as in two other large cities and 4 smaller villages. All participants were examined by a trained dental team in a classroom using a dental mirror and a periodontal probe. Periodontal examination included plaque scores, calculus scores, probing depth measurements and bleeding on probing. These measurements were recorded for the Ramfjord index teeth. Results. A total of 397 15-year-old participants were examined in this pathfinder study. There were 240 females (60.45%) and 157 males (39.55%). Of the total participants 196 (49.37%) were urban adolescents while 201 (50.63%) were from rural communities. Mean probing depth was 3.34 ± 0.57 mm with a range of 1 to 10 mm; a relatively high proportion (34.26%) of these subjects presented with at least one site with pockets of 5 mm or deeper. Males presented with greater plaque, calculus and probing depths than females. When urban and rural populations were compared, urban participants presented with more plaque, probing depths and bleeding on probing. Greater pocket depths were found to be related to the presence of plaque calculus and bleeding on probing. Conclusions. Overall, rather high incidences of periodontal pockets ≥ 5 mm were detected in this population. This data should serve to prepare further more detailed epidemiological studies that will serve to plan and implement prevent and treat strategies for periodontal diseases in Georgia and also help make manpower decisions.

Filopodial adhesion does not predict growth cone steering events in vivo.

PubMed

Isbister, C M; O'Connor, T P

1999-04-01

Migration of growth cones is in part mediated by adhesive interactions between filopodia and the extracellular environment, transmitting forces and signals necessary for pathfinding. To elucidate the role of substrate adhesivity in growth cone pathfinding, we developed an in vivo assay for measuring filopodial-substrate adhesivity using the well-characterized Ti pioneer neuron pathway of the embryonic grasshopper limb. Using time-lapse imaging and a combination of rhodamine-phalloidin injections and DiI labeling, we demonstrate that the filopodial retraction rate after treatment with cytochalasin D or elastase reflects the degree of filopodial-substrate adhesivity. Measurements of filopodial retraction rates along regions of known differing substrate adhesivities confirmed the use of this assay to examine filopodial-substrate adhesion during in vivo pathfinding events. We analyzed 359 filopodia from 22 Ti growth cones and found that there is no difference between the retraction rates of filopodia extending toward the correct target (on-axis) and filopodia extending away from the correct target (off-axis). These results indicate on-axis and off-axis filopodia have similar substrate adherence. Interestingly, we observed a 300% increase in the extension rates of on-axis filopodia during Ti growth cone turning events. Therefore, in addition to providing filopodia with important guidance information, regional cues are capable of modulating the filopodial extension rate. The homogeneity in filopodial retraction rates, even among these turning growth cones in which differential adhesivity might be expected to be greatest, strongly establishes that differential adhesion does not govern Ti pioneer neuron migration rate or pathfinding. We propose that the presence of local differences in receptor-mediated second messenger cascades and the resulting assembly of force-generating machinery may underlie the ability of filopodial contacts to regulate growth cone steering in vivo.

Observations and Analyses of Heliospheric Faraday Rotation of a Coronal Mass Ejection (CME) Using the LOw Frequency ARray (LOFAR) and Space-Based Imaging Techniques

NASA Astrophysics Data System (ADS)

Bisi, Mario Mark; Jensen, Elizabeth; Sobey, Charlotte; Fallows, Richard; Jackson, Bernard; Barnes, David; Giunta, Alessandra; Hick, Paul; Eftekhari, Tarraneh; Yu, Hsiu-Shan; Odstrcil, Dusan; Tokumaru, Munetoshi; Wood, Brian

2017-04-01

Geomagnetic storms of the highest intensity are general driven by coronal mass ejections (CMEs) impacting the Earth's space environment. Their intensity is driven by the speed, density, and, most-importantly, their magnetic-field orientation and magnitude of the incoming solar plasma. The most-significant magnetic-field factor is the North-South component (Bz in Geocentric Solar Magnetic - GSM - coordinates). At present, there are no reliable prediction methods available for this magnetic-field component ahead of the in-situ monitors around the Sun-Earth L1 point. Observations of Faraday rotation (FR) can be used to attempt to determine average magnetic-field orientations in the inner heliosphere. Such a technique has already been well demonstrated through the corona, ionosphere, and also the interstellar medium. Measurements of the polarisation of astronomical (or spacecraft in superior conjunction) radio sources (beacons/radio frequency carriers) through the inner corona of the Sun to obtain the FR have been demonstrated but mostly at relatively-high radio frequencies. Here we show some initial results of true heliospheric FR using the Low Frequency Array (LOFAR) below 200 MHz to investigate the passage of a coronal mass ejection (CME) across the line of sight. LOFAR is a next-generation low-frequency radio interferometer, and a pathfinder to the Square Kilometre Array (SKA) - LOW telescope. We demonstrate preliminary heliospheric FR results through the analysis of observations of pulsar J1022+1001, which commenced on 13 August 2014 at 13:00UT and spanned over 150 minutes in duration. We also show initial comparisons to the FR results via various modelling techniques and additional context information to understand the structure of the inner heliosphere being detected. This observation could indeed pave the way to an experiment which might be implemented for space-weather purposes that will eventually lead to a near-global method for determining the magnetic field throughout the inner heliosphere.

Pebbles, Cobbles, and Sockets

NASA Technical Reports Server (NTRS)

1997-01-01

This Rover image of 'Shark' (upper left center), 'Half Dome' (upper right), and a small rock (right foreground) reveal textures and structures not visible in lander camera images. These rocks are interpreted as conglomerates because their surfaces have rounded protrusions up to several centimeters in size. It is suggested that the protrusions are pebbles and granules.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

Sojourner Rover View of Sockets and Pebbles

NASA Technical Reports Server (NTRS)

1997-01-01

Well-rounded objects, like the ones in this image, were not seen at the Viking sites. These are thought to be pebbles liberated from sedimentary rocks composed of cemented silts, sands and rounded fragments; such rocks are called conglomerates. The 'sockets' could be the former sites of such pebbles.

NOTE: original caption as published in Science Magazine

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

Wind Tails Near Chimp

NASA Technical Reports Server (NTRS)

1997-01-01

This image of the rock 'Chimp' was taken by the Sojourner rover's right front camera on Sol 72 (September 15). Fine-scale texture on Chimp and other rocks is clearly visible. Wind tails, oriented from lower right to upper left, are seen next to small pebbles in the foreground. These were most likely produced by wind action.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

Stereo Images of Wind Tails Near Chimp

NASA Technical Reports Server (NTRS)

1997-01-01

This stereo image pair of the rock 'Chimp' was taken by the Sojourner rover's front cameras on Sol 72 (September 15). Fine-scale texture on Chimp and other rocks is clearly visible. Wind tails, oriented from lower right to upper left, are seen next to small pebbles in the foreground. These were most likely produced by wind action.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

Pathfinder Rover, Airbags, & Martian Terrain

NASA Image and Video Library

1997-07-05

This is one of the first pictures taken by the camera on the Mars Pathfinder lander shortly after its touchdown at 10:07 AM Pacific Daylight Time on July 4, 1997. The small rover, named Sojourner, is seen in the foreground in its position on a solar panel of the lander. The white material on either side of the rover is part of the deflated airbag system used to absorb the shock of the landing. Between the rover and the horizon is the rock-strewn martian surface. Two hills are seen in the right distance, profiled against the light brown sky. http://photojournal.jpl.nasa.gov/catalog/PIA00611

Airbags and Sojourner Rover

NASA Image and Video Library

1997-07-05

This image from the Imager for Mars Pathfinder (IMP) camera shows the rear part of the Sojourner rover, the rolled-up rear ramp, and portions of the partially deflated airbags. The Alpha Proton X-ray Spectrometer instrument is protruding from the rear (right side) of the rover. The airbags behind the rover are presently blocking the ramp from being safely unfurled. The ramps are a pair of deployable metal reels that will provide a track for the rover as it slowly rolls off the lander, and onto the surface of Mars, once Pathfinder scientists determine it is safe to do so. http://photojournal.jpl.nasa.gov/catalog/PIA00614

Cars on Mars

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.

2002-01-01

Mars is one of the most fascinating planets in the solar system, featuring an atmosphere, water, and enormous volcanoes and canyons. The Mars Pathfinder, Global Surveyor, and Odyssey missions mark the first wave of the Planet Earth's coming invasion of the red planet, changing our views of the past and future of the planet and the possibilities of life. Scientist and science-fiction writer Geoffrey A. Landis will present experiences on the Pathfinder mission, the challenges of using solar power on the surface of Mars, and present future missions to Mars such as the upcoming Mars Twin Rovers, which will launch two highly-capable vehicles in 2003 to explore the surface of Mars.

Imager for Mars Pathfinder (IMP) image calibration

USGS Publications Warehouse

Reid, R.J.; Smith, P.H.; Lemmon, M.; Tanner, R.; Burkland, M.; Wegryn, E.; Weinberg, J.; Marcialis, R.; Britt, D.T.; Thomas, N.; Kramm, R.; Dummel, A.; Crowe, D.; Bos, B.J.; Bell, J.F.; Rueffer, P.; Gliem, F.; Johnson, J. R.; Maki, J.N.; Herkenhoff, K. E.; Singer, Robert B.

1999-01-01

The Imager for Mars Pathfinder returned over 16,000 high-quality images from the surface of Mars. The camera was well-calibrated in the laboratory, with <5% radiometric uncertainty. The photometric properties of two radiometric targets were also measured with 3% uncertainty. Several data sets acquired during the cruise and on Mars confirm that the system operated nominally throughout the course of the mission. Image calibration algorithms were developed for landed operations to correct instrumental sources of noise and to calibrate images relative to observations of the radiometric targets. The uncertainties associated with these algorithms as well as current improvements to image calibration are discussed. Copyright 1999 by the American Geophysical Union.

Making a home in space

NASA Technical Reports Server (NTRS)

Aaron, John; Gabris, Edward A.; Sulzman, Frank M.; Connors, Mary M.; Pilcher, Carl

1989-01-01

NASA's Office of Aeronautics and Space Technology has undertaken a series of manned space presence-development efforts under the aegis of the Civil Space Technology Initiative (CSTI) and Project Pathfinder. Typical of these CSTI efforts is the Aeroassist Flight Experiment, which will demonstrate techniques suitable in aerobrake design for slow trajectories to Mars and for lunar mission return. Long-duration human operations in space are a major element of Pathfinder, giving attention to such problems as space radiation exposure effects that could be several orders of magnitude greater on interplanetary exploration missions than on typical Space Shuttle flights. Mars Observer and Lunar Observer orbital missions are planned as a steppingstone to manned planetary exploration.

Performance of the Primary Mirror Center-of-Curvature Optical Metrology System during Cryogenic Testing of the JWST Pathfinder Telescope

NASA Technical Reports Server (NTRS)

Hadaway, James B.; Wells, Conrad; Olczak, Gene; Waldman, Mark; Whitman, Tony; Cosentino, Joseph; Connolly, Mark; Chaney, David; Telfer, Randal

2016-01-01

The JWST primary mirror consists of 18 1.5 m hexagonal segments, each with 6-DoF and RoC adjustment. The telescope will be tested at its cryogenic operating temperature at Johnson Space Center. The testing will include center-of-curvature measurements of the PM, using the Center-of-Curvature Optical Assembly (COCOA) and the Absolute Distance Meter Assembly (ADMA). The performance of these metrology systems, including hardware, software, procedures, was assessed during two cryogenic tests at JSC, using the JWST Pathfinder telescope. This paper describes the test setup, the testing performed, and the resulting metrology system performance.

Mineralogy, Abundance, and Hydration State of Sulfates and Chlorides at the Mars Pathfinder Landing Site

NASA Technical Reports Server (NTRS)

Zolotov, M. Y.; Kuzmin, R. O.; Shock, E. L.

2004-01-01

Detection of elevated concentrations of S and Cl at the landing sites of Viking 1 and 2 [1], and Mars Pathfinder (MP) [2-5] reveals the presence of sulfates and chlorides in soil and rock samples [1-10]. These data are consistent with the findings of Ca sulfates and NaCl in Martian meteorites [11,12], and with Earth-based spectroscopic observations [13,14] tentatively indicating the presence of sulfates on Mars. Although the correlation of S and Mg in Viking and MP samples could reveal the occurrence of Mg sulfate [1-10], the mineralogy of sulfates and chlorides remains unclear.

Geologic Measurements using Rover Images: Lessons from Pathfinder with Application to Mars 2001

NASA Technical Reports Server (NTRS)

Bridges, N. T.; Haldemann, A. F. C.; Herkenhoff, K. E.

1999-01-01

The Pathfinder Sojourner rover successfully acquired images that provided important and exciting information on the geology of Mars. This included the documentation of rock textures, barchan dunes, soil crusts, wind tails, and ventifacts. It is expected that the Marie Curie rover cameras will also successfully return important information on landing site geology. Critical to a proper analysis of these images will be a rigorous determination of rover location and orientation. Here, the methods that were used to compute rover position for Sojourner image analysis are reviewed. Based on this experience, specific recommendations are made that should improve this process on the '01 mission.

Wheel Abrasion Experiment Metals Selection for Mars Pathfinder Mission

NASA Technical Reports Server (NTRS)

Hepp, Aloysius F.; Fatemi, Navid S.; Wilt, David M.; Ferguson, Dale C.; Hoffman, Richard; Hill, Maria M.; Kaloyeros, Alain E.

1996-01-01

A series of metals was examined for suitability for the Wheel Abrasion Experiment, one of ten microrover experiments of the Mars Pathfinder Mission. The seven candidate metals were: Ag, Al, Au, Cu, Ni, Pt, and W. Thin films of candidate metals from 0.1 to 1.0 micrometer thick were deposited on black anodized aluminum coupons by e-beam and resistive evaporation and chemical vapor deposition. Optical, corrosion, abrasion, and adhesion criteria were used to select Al, Ni, and Pt. A description is given of the deposition and testing of thin films, followed by a presentation of experimental data and a brief discussion of follow-on testing and flight qualification.

Mars Pathfinder flight system integration and test.

NASA Astrophysics Data System (ADS)

Muirhead, B. K.

This paper describes the system integration and test experiences, problems and lessons learned during the assembly, test and launch operations (ATLO) phase of the Mars Pathfinder flight system scheduled to land on the surface of Mars on July 4, 1997. The Mars Pathfinder spacecraft consists of three spacecraft systems: cruise stage, entry vehicle and lander. The cruise stage carries the entry and lander vehicles to Mars and is jettisoned prior to entry. The entry vehicle, including aeroshell, parachute and deceleration rockets, protects the lander during the direct entry and reduces its velocity from 7.6 to 0 km/s in stages during the 5 min entry sequence. The lander's touchdown is softened by airbags which are retracted once stopped on the surface. The lander then uprights itself, opens up fully and begins surface operations including deploying its camera and rover. This paper overviews the system design and the results of the system integration and test activities, including the entry, descent and landing subsystem elements. System test experiences including science instruments, the microrover, Sojourner, and software are discussed. The final qualification of the entry, descent and landing subsystems during this period is also discussed.

The Stratospheric Aerosol and Gas Experiment (SAGE) IV Pathfinder

NASA Astrophysics Data System (ADS)

Hill, C. A.; Damadeo, R. P.; Gasbarre, J. F.

2017-12-01

Stratospheric ozone has been the subject of observation and research for decades. Measurements from satellites provided data on the initial decline in the late 1970s and early 1980s that supported the adoption of the Montreal Protocol to current observations hinting at potential recovery. Adequate determination of that recovery requires continuous and, in the case of multiple instruments, overlapping data records. However, most current satellite systems are well beyond their expected lifetimes and thus, with only a few "younger" instruments available, we look towards the future of satellite observations of stratospheric ozone to develop the Stratospheric Aerosol and Gas Experiment (SAGE) IV Pathfinder. The SAGE IV Pathfinder project will develop and validate a technology demonstration that will pave the way for a future SAGE IV mission. Utilizing solar occultation imaging, SAGE IV will be capable of measuring ozone, aerosol, and other trace gas species with the same quality as previous SAGE instruments but with greatly improved pointing knowledge. Furthermore, current technological advancements allow SAGE IV to fit within a CubeSat framework and make use of commercial hardware, significantly reducing the size and cost when compared with traditional missions and enabling sustainability of future measurements.

The Radiative Effects of Martian Water Ice Clouds on the Local Atmospheric Temperature Profile

NASA Technical Reports Server (NTRS)

Colaprete, Anthony; Toon, Owen B.

2000-01-01

Mars Pathfinder made numerous discoveries, one of which was a deep temperature inversion that extended from about 15 km down to 8 km above the surface. It has been suggested by Haberle et al. (1999. J. Geophys. Res. 104, 8957-8974.) that radiative cooling by a water ice cloud may generate such an inversion. Clouds can strongly affect the local air temperature due to their ability to radiate efficiently in the infrared and due to the low air mass of the martian atmosphere, which allows the temperature to change during the relatively short lifetime of a cloud. We utilize a time-dependent microphysical aerosol model coupled to a radiative--convective model to explore the effects water ice clouds have on the local martian temperature profile. We constrain the dust and water vapor abundance using data from the Viking Missions and Mars Pathfinder. Water t ice clouds with visible optical depths of r > 0.1 form readily in these simulations. These clouds alter the local air temperature directly, through infrared cooling, and indirectly, by redistributing atmospheric dust. With this model we are able to reproduce the temperature inversions observed by Mars Pathfinder and Mars Global t Surveyor 2000 Academic Press

Design of the MESUR/pathfinder microrover

NASA Technical Reports Server (NTRS)

Stone, Henry W.

1994-01-01

The use of unmanned robotic vehicles to assist in the exploration of Mars and other planets has been of interest to the National Aeronautics and Space Administration (NASA) for several decades and has been the focus of an ongoing research program at the Jet Propulsion Laboratory (JPL) for a similar period of time. As a result of these research activities, JPL is in the process of designing and building a small (7-9 kg) microrover to be flown aboard the Mars Environmental Survey Mission (MESUR)/Pathfinder spacecraft, which is tentatively to be launched to Mars in late 1997. The microrover will perform a variety of technology experiments designed to provide information critical to the design of future planetary rovers. In addition, the microrover will perform several science and lander related experiments using specialized onboard instruments. To enable the microrover to perform these experiments at selected target areas and at the same time deal with the long time delays (and limited communications bandwidth), a control/navigation approach combining the use of operator-designated waypoints and onboard behavior control has been adopted. The design of the MESUR/Pathfinder microrover and the overall manner in which it is controlled are described herein.

Windblown Dunes and Ripples

NASA Technical Reports Server (NTRS)

2003-01-01

MGS MOC Release No. MOC2-411, 4 July 2003

July 4, 2003, is the 6th anniversary of the Mars Pathfinder landing. One of the elements carried to the red planet by Pathfinder was the Wind Sock Experiment. This project was designed to measure wind activity by taking pictures of three aluminum 'wind socks.' While the winds at the Mars Pathfinder site did not blow particularly strong during the course of that mission, dust storms seen from orbit and Earth-based telescopes attest to the fact that wind is a major force of change on the dry, desert surface of Mars today. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) narrow angle image shows dark sand dunes and lighter-toned ripples trapped among the mountainous central peak of an old impact crater in Terra Tyrrhena near 13.9oS, 246.7oW. The dune slip faces--the steepest slope on the larger dunes--indicate sand transport is from the top/upper left toward the bottom/lower right. North is toward the top/upper right; the picture is 3 km (1.9 mi) across. Sunlight illuminates the scene from the upper left. This picture was obtained in April 2003.

PathfinderTURB: an automatic boundary layer algorithm. Development, validation and application to study the impact on in situ measurements at the Jungfraujoch

NASA Astrophysics Data System (ADS)

Poltera, Yann; Martucci, Giovanni; Collaud Coen, Martine; Hervo, Maxime; Emmenegger, Lukas; Henne, Stephan; Brunner, Dominik; Haefele, Alexander

2017-08-01

We present the development of the PathfinderTURB algorithm for the analysis of ceilometer backscatter data and the real-time detection of the vertical structure of the planetary boundary layer. Two aerosol layer heights are retrieved by PathfinderTURB: the convective boundary layer (CBL) and the continuous aerosol layer (CAL). PathfinderTURB combines the strengths of gradient- and variance-based methods and addresses the layer attribution problem by adopting a geodesic approach. The algorithm has been applied to 1 year of data measured by two ceilometers of type CHM15k, one operated at the Aerological Observatory of Payerne (491 m a.s.l.) on the Swiss plateau and one at the Kleine Scheidegg (2061 m a.s.l.) in the Swiss Alps. The retrieval of the CBL has been validated at Payerne using two reference methods: (1) manual detections of the CBL height performed by human experts using the ceilometer backscatter data; (2) values of CBL heights calculated using the Richardson's method from co-located radio sounding data. We found average biases as small as 27 m (53 m) with respect to reference method 1 (method 2). Based on the excellent agreement between the two reference methods, PathfinderTURB has been applied to the ceilometer data at the mountainous site of the Kleine Scheidegg for the period September 2014 to November 2015. At this site, the CHM15k is operated in a tilted configuration at 71° zenith angle to probe the atmosphere next to the Sphinx Observatory (3580 m a.s.l.) on the Jungfraujoch (JFJ). The analysis of the retrieved layers led to the following results: the CAL reaches the JFJ 41 % of the time in summer and 21 % of the time in winter for a total of 97 days during the two seasons. The season-averaged daily cycles show that the CBL height reaches the JFJ only during short periods (4 % of the time), but on 20 individual days in summer and never during winter. During summer in particular, the CBL and the CAL modify the air sampled in situ at JFJ, resulting in an unequivocal dependence of the measured absorption coefficient on the height of both layers. This highlights the relevance of retrieving the height of CAL and CBL automatically at the JFJ.

Dynamic Control System Mode Performance of the Space Technology-7 Disturbance Reduction System

NASA Technical Reports Server (NTRS)

O'Donnell, James R., Jr.; Hsu, Oscar; Maghami, Peiman

2017-01-01

The Space Technology-7 (ST-7) Disturbance Reduction System (DRS) is an experiment package aboard the European Space Agency (ESA) LISA Pathfinder spacecraft, launched on December 3, 2015. DRS consists of three primary components: Colloidal MicroNewton Thrusters (CMNTs), an Integrated Avionics Unit (IAU), and flight-software implementing the Command and Data Handling (C&DH) and Dynamic Control System (DCS) algorithms. The CMNTs were designed to provide thrust from 5 to 30 micro Newton, with thrust controllability and resolution of 0.1 micro Newton and thrust noise of 0.1 micro Newton/(square root of (Hz)) in the measurement band from 1-30 mHz. The IAU hosts the C&DH and DCS flight software, as well as interfaces with both the CMNT electronics and the LISA Pathfinder spacecraft. When in control, the DCS uses star tracker attitude data and capacitive or optically-measured position and attitude information from LISA Pathfinder and the LISA Technology Package (LTP) to control the attitude and position of the spacecraft and the two test masses inside the LTP. After completion of the nominal ESA LISA Pathfinder mission, the DRS experiment was commissioned followed by its nominal mission. DRS operations extended over the next five months, interspersed with station keeping, anomaly resolution, and periods where control was handed back to LISA Pathfinder for them to conduct further experiments. The primary DRS mission ended on December 6, 2016, with the experiment meeting all of its Level 1 requirements. The DCS, developed at the NASA Goddard Space Flight Center, consists of five spacecraft control modes and six test mass control modes, combined into six 'DRS Mission Modes'. Attitude Control and Zero-G were primarily used to control the spacecraft during initial handover and during many of the CMNT characterization experiments. The other Mission Modes, Drag Free Low Force, 18-DOF Transitional, and 18-DOF, were used to provide drag-free control of the spacecraft about the test masses. This paper will discuss the performance of these DCS spacecraft and test mass control modes. Flight data will be shown from each mode throughout the mission, both from nominal operations and during various flight experiments. The DCS team also made some changes to controller, filter, and limit parameters during operations; the motivation and results of these changes will be shown and discussed.

Rock and Soil Types at Pathfinder Landing Site

NASA Technical Reports Server (NTRS)

1997-01-01

Type areas of rocks and soils. (A) Dark rock type and bright soil type: Shown is the dark rock Barnacle Bill. Reflectance spectra typical of fresh basalt and APXS spectra indicating more silica-rich basaltic andesite compositions characterize this type. These rocks are typically the small boulders and intermediate-sized cobbles at the Pathfinder site. The bright soil type is very common and in this case comprises Barnacle Bill's wind tail and much of the surround soil area. This soil has a high reflectance and a strongly reddened spectrum indicative of oxidized ferric minerals. (B) Bright rock type: Shown is the bright rock Wedge. Reflectance spectra typical of weathered basalt and APXS spectra indicating basaltic compositions characterize this type. These rocks are typically larger than 1 meter in diameter and many display morphologies indicating flood deposition. (C) Pink rock type: Shown is the pink rock Scooby Doo. APXS and reflectance spectra indicate a composition and optical characteristics similar to the drift soil. However, the morphology of the pink rock type indicates a cemented or rocklike structure. This material may be a chemically cemented hardpan that underlies much of the Pathfinder site. (D) Dark soil type: The dark soil type is typically found on the windward sides of rocks or in rock-free areas like Photometry Flats (shown here) where the bright soil has been striped away by aeolian action or in open areas. Other locations include the Mermaid Dune. (E) Disturbed soil type: The darkening of disturbed soil relative to its parent material, bright soil, as a result of changes in soil texture and compaction caused by movement of the rover and retraction of the lander airbag. (F) Lamb-like soil type: This soil type shows reflectance and spectral characteristics intermediate between the bright and dark soils. Its distinguishing feature is a weak spectral absorption near 900 nanometers not seen in either the bright or dark soils.

NOTE: original caption as published in Science Magazine

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

NASA's Helios Prototype aircraft taking off from the Pacific Missile Range Facility, Kauai, Hawaii,

NASA Technical Reports Server (NTRS)

2001-01-01

As a follow-on to the Centurion (and earlier Pathfinder and Pathfinder-Plus) aircraft, the solar-powered Helios Prototype is the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions in the stratosphere. Developed by AeroVironment, Inc., of Monrovia, California, under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, the unique craft is intended to demonstrate two key missions: the ability to reach and sustain horizontal flight at 100,000 feet altitude on a single-day flight in 2001, and to maintain flight above 50,000 feet altitude for at least four days in 2003, with the aid of a regenerative fuel cell-based energy storage system now in development. Both of these missions will be powered by electricity derived from non-polluting solar energy. The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at NASA's Dryden Flight Research Center in late 1998. The craft has a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of its solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. The remotely piloted, electrically powered Helios Prototype went aloft on its maiden low-altitude checkout flight Sept. 8, 1999, over Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center in the Southern California desert. The initial flight series was flown on battery power as a risk-reduction measure. In all, six flights were flown in the Helios Protoype's initial development series. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved aerodynamic efficiency, allowing the Helios Prototype to fly higher, longer and with a larger payload than the smaller craft. In addition, project engineers added a differential Global Positioning Satellite (GPS) system to improve navigation, an extensive turbulence monitoring system payload to record structural loads on the aircraft both in the air and on the ground, and radiator plates to assist in cooling the avionics at high altitudes where there is little air to dissipate heat. During 2000, more than 65,000 solar cells in 1,800 groups were mounted on the upper surface of Helios' wing. Produced by SunPower, Inc., these bi-facial silicon cells are about 19 percent efficient in the flight regime in which the helios is designed to operate, converting about 19 percent of the solar energy they receive into electrical current. The entire array is capable of producing a maximum output of about 35 kw at high noon on a summer day. The mission to reach and sustain flight at 100,000 feet in 2001 requires use of all 14 motors and minimal ballast to save weight, with the aircraft weighing in at only a little more than 1,600 lbs. The four-day mission above 50,000 feet envisioned for the Helios Prototype in 2003will see only eight motors powering the craft and the addition of the regenerative energy storage system now in development. The system will increase the Helios Prototype's flight weight to a little over 2,000 lbs. Fewer motors are needed for the long-endurance mission due to the lesser altitude requirements, and the excess electrical energy generated by the solar arrays during the daytime will be diverted to the hydrogen-oxygen fuel cell energy storage system, which will release the electricity to power the Helios after dark. With other system reliability improvements, production versions of the Helios are expected to fly missions lasting months at a time, becoming true 'atmospheric satellites.'

The Helios Prototype aircraft during initial climb-out to the west over the Pacific Ocean.

NASA Technical Reports Server (NTRS)

2001-01-01

As a follow-on to the Centurion (and earlier Pathfinder and Pathfinder-Plus) aircraft, the solar-powered Helios Prototype is the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions in the stratosphere. Developed by AeroVironment, Inc., of Monrovia, California, under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, the unique craft is intended to demonstrate two key missions: the ability to reach and sustain horizontal flight at 100,000 feet altitude on a single-day flight in 2001, and to maintain flight above 50,000 feet altitude for at least four days in 2003, with the aid of a regenerative fuel cell-based energy storage system now in development. Both of these missions will be powered by electricity derived from non-polluting solar energy. The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at NASA's Dryden Flight Research Center in late 1998. The craft has a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of its solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. The remotely piloted, electrically powered Helios Prototype went aloft on its maiden low-altitude checkout flight Sept. 8, 1999, over Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center in the Southern California desert. The initial flight series was flown on battery power as a risk-reduction measure. In all, six flights were flown in the Helios Protoype's initial development series. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved aerodynamic efficiency, allowing the Helios Prototype to fly higher, longer and with a larger payload than the smaller craft. In addition, project engineers added a differential Global Positioning Satellite (GPS) system to improve navigation, an extensive turbulence monitoring system payload to record structural loads on the aircraft both in the air and on the ground, and radiator plates to assist in cooling the avionics at high altitudes where there is little air to dissipate heat. During 2000, more than 65,000 solar cells in 1,800 groups were mounted on the upper surface of Helios' wing. Produced by SunPower, Inc., these bi-facial silicon cells are about 19 percent efficient in the flight regime in which the helios is designed to operate, converting about 19 percent of the solar energy they receive into electrical current. The entire array is capable of producing a maximum output of about 35 kw at high noon on a summer day. The mission to reach and sustain flight at 100,000 feet in 2001 requires use of all 14 motors and minimal ballast to save weight, with the aircraft weighing in at only a little more than 1,600 lbs. The four-day mission above 50,000 feet envisioned for the Helios Prototype in 2003will see only eight motors powering the craft and the addition of the regenerative energy storage system now in development. The system will increase the Helios Prototype's flight weight to a little over 2,000 lbs. Fewer motors are needed for the long-endurance mission due to the lesser altitude requirements, and the excess electrical energy generated by the solar arrays during the daytime will be diverted to the hydrogen-oxygen fuel cell energy storage system, which will release the electricity to power the Helios after dark. With other system reliability improvements, production versions of the Helios are expected to fly missions lasting months at a time, becoming true 'atmospheric satellites.'

The Helios Prototype aircraft in a northerly climb over Niihau Island, Hawaii, at about 8,000 feet a

NASA Technical Reports Server (NTRS)

2001-01-01

As a follow-on to the Centurion (and earlier Pathfinder and Pathfinder-Plus) aircraft, the solar-powered Helios Prototype is the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions in the stratosphere. Developed by AeroVironment, Inc., of Monrovia, California, under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, the unique craft is intended to demonstrate two key missions: the ability to reach and sustain horizontal flight at 100,000 feet altitude on a single-day flight in 2001, and to maintain flight above 50,000 feet altitude for at least four days in 2003, with the aid of a regenerative fuel cell-based energy storage system now in development. Both of these missions will be powered by electricity derived from non-polluting solar energy. The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at NASA's Dryden Flight Research Center in late 1998. The craft has a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of its solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. The remotely piloted, electrically powered Helios Prototype went aloft on its maiden low-altitude checkout flight Sept. 8, 1999, over Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center in the Southern California desert. The initial flight series was flown on battery power as a risk-reduction measure. In all, six flights were flown in the Helios Protoype's initial development series. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved aerodynamic efficiency, allowing the Helios Prototype to fly higher, longer and with a larger payload than the smaller craft. In addition, project engineers added a differential Global Positioning Satellite (GPS) system to improve navigation, an extensive turbulence monitoring system payload to record structural loads on the aircraft both in the air and on the ground, and radiator plates to assist in cooling the avionics at high altitudes where there is little air to dissipate heat. During 2000, more than 65,000 solar cells in 1,800 groups were mounted on the upper surface of Helios' wing. Produced by SunPower, Inc., these bi-facial silicon cells are about 19 percent efficient in the flight regime in which the helios is designed to operate, converting about 19 percent of the solar energy they receive into electrical current. The entire array is capable of producing a maximum output of about 35 kw at high noon on a summer day. The mission to reach and sustain flight at 100,000 feet in 2001 requires use of all 14 motors and minimal ballast to save weight, with the aircraft weighing in at only a little more than 1,600 lbs. The four-day mission above 50,000 feet envisioned for the Helios Prototype in 2003will see only eight motors powering the craft and the addition of the regenerative energy storage system now in development. The system will increase the Helios Prototype's flight weight to a little over 2,000 lbs. Fewer motors are needed for the long-endurance mission due to the lesser altitude requirements, and the excess electrical energy generated by the solar arrays during the daytime will be diverted to the hydrogen-oxygen fuel cell energy storage system, which will release the electricity to power the Helios after dark. With other system reliability improvements, production versions of the Helios are expected to fly missions lasting months at a time, becoming true 'atmospheric satellites.'

A survey of the cold molecular gas in gravitationally lensed star-forming galaxies at z > 2

NASA Astrophysics Data System (ADS)

Aravena, M.; Spilker, J. S.; Bethermin, M.; Bothwell, M.; Chapman, S. C.; de Breuck, C.; Furstenau, R. M.; Gónzalez-López, J.; Greve, T. R.; Litke, K.; Ma, J.; Malkan, M.; Marrone, D. P.; Murphy, E. J.; Stark, A.; Strandet, M.; Vieira, J. D.; Weiss, A.; Welikala, N.; Wong, G. F.; Collier, J. D.

2016-04-01

Using the Australia Telescope Compact Array, we conducted a survey of CO J = 1 - 0 and J = 2 - 1 line emission towards strongly lensed high-redshift dusty star-forming galaxies (DSFGs) previously discovered with the South Pole Telescope (SPT). Our sample comprises 17 sources that had CO-based spectroscopic redshifts obtained with the Atacama Large Millimeter/submillimeter Array and the Atacama Pathfinder Experiment. We detect all sources with known redshifts in either CO J = 1 - 0 or J = 2 - 1. 12 sources are detected in the 7-mm continuum. The derived CO luminosities imply gas masses in the range (0.5-11) × 1010 M⊙ and gas depletion time-scales tdep < 200 Myr, using a CO to gas mass conversion factor αCO = 0.8 M⊙ (K km s-1 pc2)-1. Combining the CO luminosities and dust masses, along with a fixed gas-to-dust ratio, we derive αCO factors in the range 0.4-1.8 M⊙ (K km s-1 pc2)-1, similar to what is found in other starbursting systems. We find small scatter in αCO values within the sample, even though inherent variations in the spatial distribution of dust and gas in individual cases could bias the dust-based αCO estimates. We find that lensing magnification factors based on the CO linewidth to luminosity relation (μCO) are highly unreliable, but particularly when μ < 5. Finally, comparison of the gas and dynamical masses suggest that the average molecular gas fraction stays relatively constant at z = 2-5 in the SPT DSFG sample.

Polarized point sources in the LOFAR Two-meter Sky Survey: A preliminary catalog

NASA Astrophysics Data System (ADS)

Van Eck, C. L.; Haverkorn, M.; Alves, M. I. R.; Beck, R.; Best, P.; Carretti, E.; Chyży, K. T.; Farnes, J. S.; Ferrière, K.; Hardcastle, M. J.; Heald, G.; Horellou, C.; Iacobelli, M.; Jelić, V.; Mulcahy, D. D.; O'Sullivan, S. P.; Polderman, I. M.; Reich, W.; Riseley, C. J.; Röttgering, H.; Schnitzeler, D. H. F. M.; Shimwell, T. W.; Vacca, V.; Vink, J.; White, G. J.

2018-06-01

The polarization properties of radio sources at very low frequencies (<200 MHz) have not been widely measured, but the new generation of low-frequency radio telescopes, including the Low Frequency Array (LOFAR: a Square Kilometre Array Low pathfinder), now gives us the opportunity to investigate these properties. In this paper, we report on the preliminary development of a data reduction pipeline to carry out polarization processing and Faraday tomography for data from the LOFAR Two-meter Sky Survey (LOTSS) and present the results of this pipeline from the LOTSS preliminary data release region (10h45m-15h30m right ascension, 45°-57° declination, 570 square degrees). We have produced a catalog of 92 polarized radio sources at 150 MHz at 4.'3 resolution and 1 mJy rms sensitivity, which is the largest catalog of polarized sources at such low frequencies. We estimate a lower limit to the polarized source surface density at 150 MHz, with our resolution and sensitivity, of 1 source per 6.2 square degrees. We find that our Faraday depth measurements are in agreement with previous measurements and have significantly smaller errors. Most of our sources show significant depolarization compared to 1.4 GHz, but there is a small population of sources with low depolarization indicating that their polarized emission is highly localized in Faraday depth. We predict that an extension of this work to the full LOTSS data would detect at least 3400 polarized sources using the same methods, and probably considerably more with improved data processing.

Science with a lunar low-frequency array: From the dark ages of the Universe to nearby exoplanets

NASA Astrophysics Data System (ADS)

Jester, Sebastian; Falcke, Heino

2009-05-01

Low-frequency radio astronomy is limited by severe ionospheric distortions below 50 MHz and complete reflection of radio waves below 10-30 MHz. Shielding of man-made interference from long-range radio broadcasts, strong natural radio emission from the Earth's aurora, and the opportunity to set up a large distributed antenna array make the lunar far side a supreme location for a low-frequency radio array. A number of new scientific drivers for such an array, such as the study of the dark ages and epoch of reionization, exoplanets, and ultra-high energy cosmic rays, have emerged and need to be studied in greater detail. Here we review the scientific potential and requirements of these new scientific drivers and discuss the constraints for various lunar surface arrays. In particular, we describe observability constraints imposed by the interstellar and interplanetary medium, calculate the achievable resolution, sensitivity, and confusion limit of a dipole array using general scaling laws, and apply them to various scientific questions. Of particular interest for a lunar array are studies of the earliest phase of the universe which are not easily accessible by other means. These are the epoch of reionization at redshifts z = 6-20, during which the very first stars and galaxies ionized most of the originally neutral intergalactic hydrogen, and the dark ages prior to that. For example, a global 21-cm wave absorption signature from primordial hydrogen in the dark ages at z = 30-50 could in principle be detected by a single dipole in an eternally dark crater on the moon, but foreground subtraction would be extremely difficult. Obtaining a high-quality power spectrum of density fluctuations in the epoch of reionization at z = 6-20, providing a wealth of cosmological data, would require about 103-105 antenna elements on the moon, which appears not unreasonable in the long term. Moreover, baryonic acoustic oscillations in the dark ages at z = 30-50 could similarly be detected, thereby providing pristine cosmological information, e.g., on the inflationary phase of the universe. With a large array also exoplanet magnetospheres could be detected through Jupiter-like coherent bursts. Smaller arrays of order 102 antennas over ˜100 km, which could already be erected robotically by a single mission with current technology and launchers, could tackle surveys of steep-spectrum large-scale radio structures from galaxy clusters and radio galaxies. Also, at very low frequencies the structure of the interstellar medium can be studied tomographically. Moreover, radio emission from neutrino interactions within the moon can potentially be used to create a neutrino detector with a volume of several cubic kilometers. An ultra-high energy cosmic ray detector with thousands of square kilometer area for cosmic ray energies >1020eV could in principle be realized with some hundred antennas. In any case, pathfinder arrays are needed to test the feasibility of these experiments in the not too distant future. Lunar low-frequency arrays are thus a timely option to consider, offering the potential for significant new insights into a wide range of today's crucial scientific topics. This would open up one of the last unexplored frequency domains in the electromagnetic spectrum.

Terrain Modelling for Immersive Visualization for the Mars Exploration Rovers

NASA Technical Reports Server (NTRS)

Wright, J.; Hartman, F.; Cooper, B.; Maxwell, S.; Yen, J.; Morrison, J.

2004-01-01

Immersive environments are being used to support mission operations at the Jet Propulsion Laboratory. This technology contributed to the Mars Pathfinder Mission in planning sorties for the Sojourner rover and is being used for the Mars Exploration Rover (MER) missions. The stereo imagery captured by the rovers is used to create 3D terrain models, which can be viewed from any angle, to provide a powerful and information rich immersive visualization experience. These technologies contributed heavily to both the mission success and the phenomenal level of public outreach achieved by Mars Pathfinder and MER. This paper will review the utilization of terrain modelling for immersive environments in support of MER.

Sockets and Pebbles

NASA Technical Reports Server (NTRS)

1997-01-01

This close-up Sojourner rover image of a small rock shows that weathering has etched-out pebbles to produce sockets. In the image, sunlight is coming from the upper left. Sockets (with shadows on top) are visible at the lower left and pebbles (with bright tops and shadowed bases) are seen at the lower center and lower right. Two pebbles (about 0.5 cm across) are visible at the lower center.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

SRB Processing Facilities Media Event

NASA Image and Video Library

2016-03-01

Members of the news media watch as two cranes are used to lift one of two pathfinders, or test versions, of solid rocket booster segments for NASA’s Space Launch System (SLS) rocket into the vertical position inside the Rotation, Processing and Surge Facility at NASA’s Kennedy Space Center in Florida. The pathfinder booster segment will be moved to the other end of the RPSF and secured on a test stand. The Ground Systems Development and Operations Program and Jacobs Engineering, on the Test and Operations Support Contract, will prepare the booster segments, which are inert, for a series of lifts, moves and stacking operations to prepare for Exploration Mission-1, deep-space missions and the journey to Mars.

Sojourner View of Yogi

NASA Image and Video Library

1997-11-04

This Sojourner image, taken on Sol 70, shows rocks and rover-disturbed soil. Cleats on Sojourner's left front wheel are seen at lower left. The large rock in the distance is "Yogi." Much of Yogi visible in this image cannot be seen from the perspective of the Pathfinder lander. Sojourner spent 83 days of a planned seven-day mission exploring the Martian terrain, acquiring images, and taking chemical, atmospheric and other measurements. The final data transmission received from Pathfinder was at 10:23 UTC on September 27, 1997. Although mission managers tried to restore full communications during the following five months, the successful mission was terminated on March 10, 1998. http://photojournal.jpl.nasa.gov/catalog/PIA00998

Studies of MGS TES and MPF MET Data

NASA Technical Reports Server (NTRS)

Barnes, Jeff R.

2003-01-01

The work supported by this grant was divided into two broad areas: (1) mesoscale modeling of atmospheric circulations and analyses of Pathfinder, Viking, and other Mars data, and (2) analyses of MGS TES temperature data. The mesoscale modeling began with the development of a suitable Mars mesoscale model based upon the terrestrial MM5 model, which was then applied to the simulation of the meteorological observations at the Pathfinder and Viking Lander 1 sites during northern summer. This extended study served a dual purpose: to validate the new mesoscale model with the best of the available in-situ data, and to use the model to aid in the interpretation of the surface meteorological data.

Gravitational Reference Sensor Front-End Electronics Simulator for LISA

NASA Astrophysics Data System (ADS)

Meshksar, Neda; Ferraioli, Luigi; Mance, Davor; ten Pierick, Jan; Zweifel, Peter; Giardini, Domenico; ">LISA Pathfinder colaboration, Pathfinder autonomous rendezvous and docking project

NASA Technical Reports Server (NTRS)

Lamkin, Stephen (Editor); Mccandless, Wayne (Editor)

1990-01-01

Capabilities are being developed and demonstrated to support manned and unmanned vehicle operations in lunar and planetary orbits. In this initial phase, primary emphasis is placed on definition of the system requirements for candidate Pathfinder mission applications and correlation of these system-level requirements with specific requirements. The FY-89 activities detailed are best characterized as foundation building. The majority of the efforts were dedicated to assessing the current state of the art, identifying desired elaborations and expansions to this level of development and charting a course that will realize the desired objectives in the future. Efforts are detailed across all work packages in developing those requirements and tools needed to test, refine, and validate basic autonomous rendezvous and docking elements.

Sojourner Rover View of Shark and Half Dome

NASA Technical Reports Server (NTRS)

1997-01-01

The rounded knobs (arrows) up to 3 or 4 cm wide on Shark (left; approximately 70 cm wide)) and Half Dome (upper right) and in the foreground could be pebbles in a cemented matrix of clays, silts, and sands; such rocks are called conglomerates. Well-rounded objects like these were not seen at the Viking sites.

NOTE: original caption as published in Science Magazine.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

Sojourner Rover Tracks in Compressible Soil

NASA Technical Reports Server (NTRS)

1997-01-01

Sojourner's observations in the Ares region on Mars raise and answer questions about the origins of the rocks and other deposits found there. Deposits are not the same everywhere. In compressible soil, a rover wheel produced ruts with steep walls, marginal slumps, and nearly perfect reflective casts of the spacing between the cleats.

NOTE: original caption as published in Science Magazine

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

Rock Statistics at the Mars Pathfinder Landing Site, Roughness and Roving on Mars

NASA Technical Reports Server (NTRS)

Haldemann, A. F. C.; Bridges, N. T.; Anderson, R. C.; Golombek, M. P.

1999-01-01

Several rock counts have been carried out at the Mars Pathfinder landing site producing consistent statistics of rock coverage and size-frequency distributions. These rock statistics provide a primary element of "ground truth" for anchoring remote sensing information used to pick the Pathfinder, and future, landing sites. The observed rock population statistics should also be consistent with the emplacement and alteration processes postulated to govern the landing site landscape. The rock population databases can however be used in ways that go beyond the calculation of cumulative number and cumulative area distributions versus rock diameter and height. Since the spatial parameters measured to characterize each rock are determined with stereo image pairs, the rock database serves as a subset of the full landing site digital terrain model (DTM). Insofar as a rock count can be carried out in a speedier, albeit coarser, manner than the full DTM analysis, rock counting offers several operational and scientific products in the near term. Quantitative rock mapping adds further information to the geomorphic study of the landing site, and can also be used for rover traverse planning. Statistical analysis of the surface roughness using the rock count proxy DTM is sufficiently accurate when compared to the full DTM to compare with radar remote sensing roughness measures, and with rover traverse profiles.

Slits are chemorepellents endogenous to hypothalamus and steer thalamocortical axons into ventral telencephalon.

PubMed

Braisted, Janet E; Ringstedt, Thomas; O'Leary, Dennis D M

2009-07-01

Thalamocortical axons (TCAs) originate in dorsal thalamus, extend ventrally along the lateral thalamic surface, and as they approach hypothalamus make a lateral turn into ventral telencephalon. In vitro studies show that hypothalamus releases a chemorepellent for TCAs, and analyses of knockout mice indicate that Slit chemorepellents and their receptor Robo2 influence TCA pathfinding. We show that Slit chemorepellents are the hypothalamic chemorepellent and act through Robos to steer TCAs into ventral telencephalon. During TCA pathfinding, Slit1 and Slit2 are expressed in hypothalamus and ventral thalamus and Robo1 and Robo2 are expressed in dorsal thalamus. In collagen gel cocultures of dorsal thalamus and Slit2-expressing cells, axon number and length are decreased on the explant side facing Slit2-expressing cells, overall axon outgrowth is diminished, and axons turn away from the Slit2-expressing cells. Thus, Slit2 is an inhibitor and chemorepellent for dorsal thalamic axons. Collagen gel cocultures of dorsal thalamus with sections of live diencephalon, with and without the hypothalamus portion overlaid with Robo2-fc-expressing cells to block Slit function, identify Slits as the hypothalamic chemorepellent. Thus, Slits are chemorepellents for TCAs endogenous to hypothalamus and steer TCAs from diencephalon into ventral telencephalon, a critical pathfinding event defective in Slit and Robo2 mutant mice.

Mars Pathfinder mission operations concepts

NASA Technical Reports Server (NTRS)

Sturms, Francis M., Jr.; Dias, William C.; Nakata, Albert Y.; Tai, Wallace S.

1994-01-01

The Mars Pathfinder Project plans a December 1996 launch of a single spacecraft. After jettisoning a cruise stage, an entry body containing a lander and microrover will directly enter the Mars atmosphere and parachute to a hard landing near the sub-solar latitude of 15 degrees North in July 1997. Primary surface operations last for 30 days. Cost estimates for Pathfinder ground systems development and operations are not only lower in absolute dollars, but also are a lower percentage of total project costs than in past planetary missions. Operations teams will be smaller and fewer than typical flight projects. Operations scenarios have been developed early in the project and are being used to guide operations implementation and flight system design. Recovery of key engineering data from entry, descent, and landing is a top mission priority. These data will be recorded for playback after landing. Real-time tracking of a modified carrier signal through this phase can provide important insight into the spacecraft performance during entry, descent, and landing in the event recorded data is never recovered. Surface scenarios are dominated by microrover activity and lander imaging during 7 hours of the Mars day from 0700 to 1400 local solar time. Efficient uplink and downlink processes have been designed to command the lander and microrover each Mars day.

Northeast View From Pathfinder Lander

NASA Technical Reports Server (NTRS)

1997-01-01

This panorama of the region to the northeast of the lander was constructed to support the Sojourner Rover Team's plans to conduct an 'autonomous traverse' to explore the terrain away from the lander after science objectives in the lander vicinity had been met. The large, relatively bright surface in the foreground, about 10 meters (33 feet) from the spacecraft, in this scene is 'Baker's Bench.' The large, elongated rock left of center in the middle distance is 'Zaphod.'

This view was produced by combining 8 individual 'Superpan' scenes from the left and right eyes of the IMP camera. Each frame consists of 8 individual frames (left eye) and 7 frames (right eye) taken with different color filters that were enlarged by 500% and then co-added using Adobe Photoshop to produce, in effect, a super-resolution panchromatic frame that is sharper than an individual frame would be.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Twin Peaks (B/W)

NASA Technical Reports Server (NTRS)

1997-01-01

The Twin Peaks are modest-size hills to the southwest of the Mars Pathfinder landing site. They were discovered on the first panoramas taken by the IMP camera on the 4th of July, 1997, and subsequently identified in Viking Orbiter images taken over 20 years ago. The peaks are approximately 30-35 meters (-100 feet) tall. North Twin is approximately 860 meters (2800 feet) from the lander, and South Twin is about a kilometer away (3300 feet). The scene includes bouldery ridges and swales or 'hummocks' of flood debris that range from a few tens of meters away from the lander to the distance of the South Twin Peak. The large rock at the right edge of the scene is nicknamed 'Hippo'. This rock is about a meter (3 feet) across and 25 meters (80 feet) distant.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

Drag-Free Performance of the ST7 Disturbance Reduction System Flight Experiment on the LISA Pathfinder

NASA Technical Reports Server (NTRS)

Maghami, Peiman; O'Donnell, James, Jr.; Hsu, Oscar; Ziemer, John; Dunn, Charles

2017-01-01

The Space Technology-7 Disturbance Reduction System (DRS) is an experiment package aboard the European Space Agency (ESA) LISA Pathfinder spacecraft. LISA Pathfinder launched from Kourou, French Guiana on December 3, 2015. The DRS is tasked to validate two specific technologies: colloidal micro-Newton thrusters (CMNT) to provide low-noise control capability of the spacecraft, and drag-free control flight. This validation is performed using highly sensitive drag-free sensors, which are provided by the LISA Technology Package of the European Space Agency. The Disturbance Reduction System is required to maintain the spacecrafts position with respect to a free-floating test mass to better than 10nmHz, along its sensitive axis (axis in optical metrology). It also has a goal of limiting the residual accelerations of any of the two test masses to below 30 (1 + [f3 mHz]) fmsHz, over the frequency range of 1 to 30 mHz.This paper briefly describes the design and the expected on-orbit performance of the control system for the two modes wherein the drag-free performance requirements are verified. The on-orbit performance of these modes are then compared to the requirements, as well as to the expected performance, and discussed.

Visualizing Mars Using Virtual Reality: A State of the Art Mapping Technique Used on Mars Pathfinder

NASA Technical Reports Server (NTRS)

Stoker, C.; Zbinden, E.; Blackmon, T.; Nguyen, L.

1999-01-01

We describe an interactive terrain visualization system which rapidly generates and interactively displays photorealistic three-dimensional (3-D) models produced from stereo images. This product, first demonstrated in Mars Pathfinder, is interactive, 3-D, and can be viewed in an immersive display which qualifies it for the name Virtual Reality (VR). The use of this technology on Mars Pathfinder was the first use of VR for geologic analysis. A primary benefit of using VR to display geologic information is that it provides an improved perception of depth and spatial layout of the remote site. The VR aspect of the display allows an operator to move freely in the environment, unconstrained by the physical limitations of the perspective from which the data were acquired. Virtual Reality offers a way to archive and retrieve information in a way that is intuitively obvious. Combining VR models with stereo display systems can give the user a sense of presence at the remote location. The capability, to interactively perform measurements from within the VR model offers unprecedented ease in performing operations that are normally time consuming and difficult using other techniques. Thus, Virtual Reality can be a powerful a cartographic tool. Additional information is contained in the original extended abstract.

Observations at the Mars Pathfinder site: Do they provide "unequivocal" evidence of catastrophic flooding?

USGS Publications Warehouse

Chapman, M.G.; Kargel, J.S.

1999-01-01

After Mars Pathfinder landed at the mouth of Ares Vallis, a large channel that drains into the Chryse Planitia basin, the mission reports unanimously supported the interpretation that the lander site is the locus of catastrophic flooding by noting that all aspects of the scene are consistent with this interpretation. However, alternatives cannot be ruled out by any site observations, as all aspects of the scene are equally consistent with other interpretations of origin, namely, ice and mass-flow processes subsequently modified by wind erosion. The authors discuss alternative explanations for the geologic history of the channel based on a regional view of the circum-Chryse channels from Viking images (our best broad-scale information to date) and the local view from the recent Pathfinder landing site. Mega-indicators of channel origin, the regional geomorphology, geology, and planetary climatic conditions, taken together suggest some combination of flood, mass flow, glacial, and eolian processes. The macro-indicators of channel origin (sedimentologic) are also not indicative of one process of emplacement, either as single criteria or taken cumulatively. Finally, the micro-indicators of channel origin (geochemical and mineralogic composition) do not provide very tight constraints on the deposits' possible origins other than that water was in some way involved.

A New Method for Analyzing Near-Field Faraday Probe Data in Hall Thrusters

NASA Technical Reports Server (NTRS)

Huang, Wensheng; Shastry, Rohit; Herman, Daniel A.; Soulas, George C.; Kamhawi, Hani

2013-01-01

This paper presents a new method for analyzing near-field Faraday probe data obtained from Hall thrusters. Traditional methods spawned from far-field Faraday probe analysis rely on assumptions that are not applicable to near-field Faraday probe data. In particular, arbitrary choices for the point of origin and limits of integration have made interpretation of the results difficult. The new method, called iterative pathfinding, uses the evolution of the near-field plume with distance to provide feedback for determining the location of the point of origin. Although still susceptible to the choice of integration limits, this method presents a systematic approach to determining the origin point for calculating the divergence angle. The iterative pathfinding method is applied to near-field Faraday probe data taken in a previous study from the NASA-300M and NASA-457Mv2 Hall thrusters. Since these two thrusters use centrally mounted cathodes the current density associated with the cathode plume is removed before applying iterative pathfinding. A procedure is presented for removing the cathode plume. The results of the analysis are compared to far-field probe analysis results. This paper ends with checks on the validity of the new method and discussions on the implications of the results.

A New Method for Analyzing Near-Field Faraday Probe Data in Hall Thrusters

NASA Technical Reports Server (NTRS)

Huang, Wensheng; Shastry, Rohit; Herman, Daniel A.; Soulas, George C.; Kamhawi, Hani

2013-01-01

This paper presents a new method for analyzing near-field Faraday probe data obtained from Hall thrusters. Traditional methods spawned from far-field Faraday probe analysis rely on assumptions that are not applicable to near-field Faraday probe data. In particular, arbitrary choices for the point of origin and limits of integration have made interpretation of the results difficult. The new method, called iterative pathfinding, uses the evolution of the near-field plume with distance to provide feedback for determining the location of the point of origin. Although still susceptible to the choice of integration limits, this method presents a systematic approach to determining the origin point for calculating the divergence angle. The iterative pathfinding method is applied to near-field Faraday probe data taken in a previous study from the NASA-300M and NASA-457Mv2 Hall thrusters. Since these two thrusters use centrally mounted cathodes, the current density associated with the cathode plume is removed before applying iterative pathfinding. A procedure is presented for removing the cathode plume. The results of the analysis are compared to far-field probe analysis results. This paper ends with checks on the validity of the new method and discussions on the implications of the results.

The Mars Pathfinder Mission

NASA Astrophysics Data System (ADS)

Golombek, M. P.

1996-09-01

The Mars Pathfinder mission is a Discovery class mission that will place a small lander and rover on the surface of Mars on July 4, 1997. The Pathfinder flight system is a single small lander, packaged within an aeroshell and back cover with a back-pack-style cruise stage. The vehicle will be launched, fly independently to Mars, and enter the atmosphere directly on approach behind the aeroshell. The vehicle is slowed by a parachute and 3 small solid rockets before landing on inflated airbags. Petals of a small tetrahedron shaped lander open up, to right the vehicle. The lander is solar powered with batteries and will operate on the surface for up to a year, downlinking data on a high-gain antenna. Pathfinder will be the first mission to use a rover, with 3 imagers and an alpha proton X-ray spectrometer, to characterize the rocks and soils in a landing area over hundreds of square meters on Mars, which will provide a calibration point or "ground truth" for orbital remote sensing observations. The rover (includes a series of technology experiments), the instruments (including a stereo multispectral surface imager on a pop up mast and an atmospheric structure instrument-surface meteorology package) and the telemetry system will allow investigations of: the surface morphology and geology at meter scale, the petrology and geochemistry of rocks and soils, the magnetic properties of dust, soil mechanics and properties, a variety of atmospheric investigations and the rotational and orbital dynamics of Mars. Landing downstream from the mouth of a giant catastrophic outflow channel, Ares Vallis, offers the potential of identifying and analyzing a wide variety of crustal materials, from the ancient heavily cratered terrain, intermediate-aged ridged plains and reworked channel deposits, thus allowing first-order scientific investigations of the early differentiation and evolution of the crust, the development of weathering products and early environments and conditions on Mars.

Laser modulator for LISA pathfinder

NASA Astrophysics Data System (ADS)

Voland, C.; Lund, G.; Coppoolse, W.; Crosby, P.; Stadler, M.; Kudielka, K.; Özkan, C.

2017-11-01

LISA Pathfinder is an ESA experiment to demonstrate the key technologies needed for the LISA mission to detect gravitational waves in space. The LISA Pathfinder spacecraft represents one arm of the LISA interferometer, containing an optical metrology system and two proof masses as inertial references for the drag-free control system. The LISA Pathfinder payload consists of two drag-free floating test masses located in the inertial sensors with their control electronics and an optical metrology subsystem. The optical metrology subsystem monitors the movement of both test masses relative to each other and to the spacecraft with very high sensitivity and resolution. This is achieved with a heterodyne Mach- Zehnder interferometer. This interferometer requires as input two coherent laser beams with a heterodyne frequency difference of a few kHz. To generate the two laser beams with a heterodyne frequency difference a Nd:YAG laser is used together with the Laser Modulator. The Nd:YAG laser generates a single coherent laser signal at a wavelength of 1064nm which is fibre coupled to the Laser Modulator. The Laser Modulator then generates the two optical beams with the required heterodyne frequency offset. In addition, the Laser Modulator is required to perform laser amplitude stabilization and optical path difference control for the two optical signals. The Laser Modulator consists of an optical unit - the LMU - and RF synthesiser, power amplification and control electronics. These electronics are all housed in the Laser Modulator Electronics (LME). The LMU has four primary functions: • Splitting of the input laser beam into two paths for later superposition in the interferometer. • Applying different frequency shifts to each of the beams. • Providing amplitude modulation control to each of the beams. • Providing active control of the optical path length difference between the two optical paths. The present paper describes the design and performance of the LMU together with a summary of the results of the Laser Modulator engineering model test campaign.

First look at rock & soil properties

NASA Technical Reports Server (NTRS)

1997-01-01

The earliest survey of spectral properties of the rocks and soils surrounding Pathfinder was acquired as a narrow strip covering the region just beyond the where the rover made its egress from the lander. The wavelength filters used, all in the binocular camera's right eye, cover mainly visible wavelengths. These data reveal at least five kinds of rocks and soil in the immediate vicinity of the lander. All of the spectra are ratioed to the mean spectrum of bright red drift to highlight the differences. Different occurrences of drift (pink spectra) are closely similar. Most of the rocks (black spectra) have a dark gray color, and are both darker and less red than the drift, suggesting less weathering. Typical soils (green spectra) are intermediate in properties to the rocks and drift. Both these data and subsequent higher resolution images show that the typical soil consists of a mixture of drift and small dark gray particles resembling the rock. However, two other kinds of materials are significantly different from the rocks and drift. Pinkish or whitish pebbles and crusts on some of the rocks (blue spectra) are brighter in blue light and darker in near-infrared light than is the drift, and they lack the spectral characteristics closely associated with iron minerals. Dark red soils in the lee of several rocks are about as red as the drift, but consistently darker. The curvature in the spectrum at visible wavelengths suggests either more ferric iron minerals than in the drift or a larger particle size.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is an operating division of the California Institute of Technology (Caltech).

Microtubule behavior in the growth cones of living neurons during axon elongation

PubMed Central

1991-01-01

To understand how microtubules are generated in the growth cone, we have imaged fluorescently tagged microtubules in living frog embryonic neurons. The neurons were labeled by injecting rhodamine-labeled tubulin into the fertilized egg and explanting the neurons from the neural tube. Microtubules extend deep into the growth cone periphery and adopt three characteristic distributions: (a) dispersed and splayed throughout much of the growth cone; (b) looped and apparently contorted by compression; and (c) bundled into tight arrays. These distributions interconvert on a time scale of several minutes and these interconversions are correlated with the behavior of the growth cone. We observed microtubule growth and shrinkage in growth cones, but are unable to determine their contribution to net assembly. However, translocation of polymer form the axon appears to be a major mechanism of generating new polymer in the growth cone, while bundling of microtubules in the growth cone appears to be the critical step in generating new axon. Neurons that were about to turn spontaneously generated microtubules in the future direction of growth, suggesting that orientation of microtubules might be an important early step in neuronal pathfinding. PMID:1918145

The Breakthrough Listen Search for Intelligent Life

NASA Astrophysics Data System (ADS)

Croft, Steve; Siemion, Andrew; De Boer, David; Enriquez, J. Emilio; Foster, Griffin; Gajjar, Vishal; Hellbourg, Greg; Hickish, Jack; Isaacson, Howard; Lebofsky, Matt; MacMahon, David; Price, Daniel; Werthimer, Dan

2018-01-01

The $100M, 10-year philanthropic "Breakthrough Listen" project is driving an unprecedented expansion of the search for intelligent life beyond Earth. Modern instruments allow ever larger regions of parameter space (luminosity function, duty cycle, beaming fraction, frequency coverage) to be explored, which is enabling us to place meaningful physical limits on the prevalence of transmitting civilizations. Data volumes are huge, and preclude long-term storage of the raw data products, so real-time and machine learning processing techniques must be employed to identify candidate signals as well as simultaneously classifying interfering sources. However, the Galaxy is now known to be a target-rich environment, teeming with habitable planets.Data from Breakthrough Listen can also be used by researchers in other areas of astronomy to study pulsars, fast radio bursts, and a range of other science targets. Breakthrough Listen is already underway in the optical and radio bands, and is also engaging with facilities across the world, including Square Kilometer Array precursors and pathfinders. I will give an overview of the technology, science goals, data products, and roadmap of Breakthrough Listen, as we attempt to answer one of humanity's oldest questions: Are we alone?

Multibeam Gpu Transient Pipeline for the Medicina BEST-2 Array

NASA Astrophysics Data System (ADS)

Magro, A.; Hickish, J.; Adami, K. Z.

2013-09-01

Radio transient discovery using next generation radio telescopes will pose several digital signal processing and data transfer challenges, requiring specialized high-performance backends. Several accelerator technologies are being considered as prototyping platforms, including Graphics Processing Units (GPUs). In this paper we present a real-time pipeline prototype capable of processing multiple beams concurrently, performing Radio Frequency Interference (RFI) rejection through thresholding, correcting for the delay in signal arrival times across the frequency band using brute-force dedispersion, event detection and clustering, and finally candidate filtering, with the capability of persisting data buffers containing interesting signals to disk. This setup was deployed at the BEST-2 SKA pathfinder in Medicina, Italy, where several benchmarks and test observations of astrophysical transients were conducted. These tests show that on the deployed hardware eight 20 MHz beams can be processed simultaneously for 640 Dispersion Measure (DM) values. Furthermore, the clustering and candidate filtering algorithms employed prove to be good candidates for online event detection techniques. The number of beams which can be processed increases proportionally to the number of servers deployed and number of GPUs, making it a viable architecture for current and future radio telescopes.

High Angular Resolution Imaging of Solar Radio Bursts from the Lunar Surface

NASA Technical Reports Server (NTRS)

MacDowall, Robert J.; Lazio, Joseph; Bale, Stuart; Burns, Jack O.; Farrell, William M.; Gopalswamy, Nat; Jones, Dayton L.; Kasper, Justin Christophe; Weiler, Kurt

2012-01-01

Locating low frequency radio observatories on the lunar surface has a number of advantages, including positional stability and a very low ionospheric radio cutoff. Here, we describe the Radio Observatory on the lunar Surface for Solar studies (ROLSS), a concept for a low frequency, radio imaging interferometric array designed to study particle acceleration in the corona and inner heliosphere. ROLSS would be deployed during an early lunar sortie or by a robotic rover as part of an unmanned landing. The preferred site is on the lunar near side to simplify the data downlink to Earth. The prime science mission is to image type II and type III solar radio bursts with the aim of determining the sites at and mechanisms by which the radiating particles are accelerated. Secondary science goals include constraining the density of the lunar ionosphere by measuring the low radio frequency cutoff of the solar radio emissions or background galactic radio emission, measuring the flux, particle mass, and arrival direction of interplanetary and interstellar dust, and constraining the low energy electron population in astrophysical sources. Furthermore, ROLSS serves a pathfinder function for larger lunar radio arrays. Key design requirements on ROLSS include the operational frequency and angular resolution. The electron densities in the solar corona and inner heliosphere are such that the relevant emission occurs below 10 M Hz, essentially unobservable from Earth's surface due to the terrestrial ionospheric cutoff. Resolving the potential sites of particle acceleration requires an instrument with an angular resolution of at least 2 deg at 10 MHz, equivalent to a linear array size of approximately one kilometer. The major components of the ROLSS array are 3 antenna arms, each of 500 m length, arranged in a Y formation, with a central electronics package (CEP) at their intersection. Each antenna arm is a linear strip of polyimide film (e.g., Kapton(TradeMark)) on which 16 single polarization dipole antennas are located by depositing a conductor (e.g., silver). The arms also contain transmission lines for carrying the radio signals from the science antennas to the CEP. Operations would consist of data acquisition during the lunar day, with data downlinks to Earth one or more times every 24 hours.

Detection and Characterization of Micrometeoroid Impacts on LISA Pathfinder

NASA Astrophysics Data System (ADS)

Hourihane, S.; Littenberg, T.; Baker, J. G.; Pagane, N.; Slutsky, J. P.; Thorpe, J. I.

2017-12-01

LISA Pathfinder (LPF) was a joint ESA/NASA technology demonstration mission for the Laser Interferometer Space Antenna (LISA) gravitational wave observatory. LPF, the most sensitive accelerometer ever flown in space, was launched in December 2015 and successfully concluded its mission in July 2017. Due in part to LPFs success, LISA was selected by the European Space Agency for launch in the early 2030s. An ancillary benefit of LPFs capabilities made it a sensitive detector of micrometeoroid impacts. We report on the capabilities of LPF to detect and characterize impacts, and progress towards using those inferences to advance our understanding of the micrometeoroid environment in the solar system. In doing so, we assess the prospect of space-based gravitational wave observatories as micrometeoroid detection instruments.

Size Scales for Thermal Inhomogeneities in Mars' Atmosphere Surface Layer: Mars Pathfinder

NASA Technical Reports Server (NTRS)

Mihalov, John D.; Haberle, Robert M.; Seiff, Alvin; Murphy, James R.; Schofield, John T.; DeVincenzi, Donald L. (Technical Monitor)

2000-01-01

Atmospheric temperature measurement at three heights with thin wire thermocouples on the 1.1 m Mars Pathfinder meteorology must allow estimates of the integral scale of the atmospheric thermal turbulence during an 83 sol period that begins in the summer. The integral scale is a measure for regions of perturbations. In turbulent media that roughly characterizes locations where the perturbations are correlated. Excluding some to intervals with violent excursions of the mean temperatures, integral scale values are found that increase relatively rapidly from a few tenths meters or less near down to several meters by mid-morning. During mid-morning, the diurnal and shorter time scale wind direction variations often place the meteorology mast in the thermal wake of the Lander.

Mars 2024/2026 Pathfinder Mission: Mars Architectures, Systems, and Technologies for Exploration and Resources Project

NASA Technical Reports Server (NTRS)

Zeitlin, Nancy; Mueller, Robert; Muscatello, Anthony

2015-01-01

Integrate In Situ Resource Utilization (ISRU) sub-systems and examine advanced capabilities and technologies to verify Mars 2024 Forward architecture precursor pathfinder options: Integrated spacecraft/surface infrastructure fluid architecture: propulsion, power, life support center dot Power system feed and propellant scavenging from propulsion system center dot High quality oxygen for life support and EVA Fluid/cryogenic zero-loss transfer and long-term storage center dot Rapid depot-to-rover/spacecraft center dot Slow ISRU plant-to-ascent vehicle Integration of ISRU consumable production center dot Oxygen only from Mars atmosphere carbon dioxide center dot Oxygen, fuel, water, from extraterrestrial soil/regolith Test bed to evaluate long duration life, operations, maintenance on hardware, sensors, and autonomy

A rotating arm using shape-memory alloy

NASA Technical Reports Server (NTRS)

Jenkins, Phillip P.; Landis, Geoffrey A.

1995-01-01

NASA's Mars Pathfinder mission, to be launched in 1996, reflects a new philosophy of exploiting new technologies to reduce mission cost and accelerate the pace of space exploration. One of the experiments on board Pathfinder will demonstrate the first use in space of a multi-cycle, electrically-activated, shape-memory alloy (SMA) actuator. SMA's are metal alloys which, when heated, undergo a crystalline phase change. This change in phase alters the alloy lattice-constant, resulting in a change of dimension. Upon cooling, the alloy returns to its original lattice formation. Wire drawn from an SMA contracts in length when heated. The reversible change in length is 3 percent to 5 percent. The wire used in this actuator is a nickel-titanium alloy known as nitinol.

Sojourner APXS at Moe - Left Eye

NASA Image and Video Library

1999-07-02

The Sojourner rover's Alpha Proton X-ray Spectrometer (APXS) is shown deployed against the rock "Moe" on the afternoon of Sol 64 (September 7). The rocks to the left of Moe are "Shark" (left of Sojourner) and "Half Dome" (behind Sojourner). They were previously measured by the APXS. The image was taken by the Imager for Mars Pathfinder (IMP). Sojourner spent 83 days of a planned seven-day mission exploring the Martian terrain, acquiring images, and taking chemical, atmospheric and other measurements. The final data transmission received from Pathfinder was at 10:23 UTC on September 27, 1997. Although mission managers tried to restore full communications during the following five months, the successful mission was terminated on March 10, 1998. http://photojournal.jpl.nasa.gov/catalog/PIA01560

Java PathFinder User Guide

NASA Technical Reports Server (NTRS)

Havelund, Klaus

1999-01-01

The JAVA PATHFINDER, JPF, is a translator from a subset of JAVA 1.0 to PROMELA, the programming language of the SPIN model checker. The purpose of JPF is to establish a framework for verification and debugging of JAVA programming based on model checking. The main goal is to automate program verification such that a programmer can apply it in the daily work without the need for a specialist to manually reformulate a program into a different notation in order to analyze the program. The system is especially suited for analyzing multi-threaded JAVA applications, where normal testing usually falls short. The system can find deadlocks and violations of boolean assertions stated by the programmer in a special assertion language. This document explains how to Use JPF.

Drill/borescope System for the Mars Polar Pathfinder

NASA Technical Reports Server (NTRS)

Paige, D. A.; Wood, S. E.; Vasavada, A. R.

1993-01-01

The primary goals of the Mars Polar Pathfinder (MPP) Discovery Mission are to characterize the composition and structure of Mars' north polar ice cap, and to determine whether a climate record may be preserved in layers of ice and dust. The MPP would land as close as possible to the geographic north pole of Mars and use a set of instruments similar to those used by glaciologists to study polar ice caps on Earth: a radar sounder, a drill/borescope system, and a thermal probe. The drill/borescope system will drill approximately 50 cm into the surface and image the sides of the hole at 10 micron resolution for compositional and stratigraphic analysis. Several uncertainties have guided the development of this instrument, and they are discussed.

Sojourner Rover View of Cloddy Deposits near Pooh Bear

NASA Technical Reports Server (NTRS)

1997-01-01

Sojourner's observations in the Ares region on Mars raise and answer questions about the origins of the rocks and other deposits found there. Deposits are not the same everywhere. Bright, fine-grained drifts (right center) are abundant as thin (less than a few centimeters), discontinuous ridged sheets and wind tails that overlie cloddy deposits of dust, clods, and tiny (less than 1 cm) rocks.

NOTE: original caption as published in Science Magazine

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

Mars Pathfinder Near-Field Rock Distribution Re-Evaluation

NASA Technical Reports Server (NTRS)

Haldemann, A. F. C.; Golombek, M. P.

2003-01-01

We have completed analysis of a new near-field rock count at the Mars Pathfinder landing site and determined that the previously published rock count suggesting 16% cumulative fractional area (CFA) covered by rocks is incorrect. The earlier value is not so much wrong (our new CFA is 20%), as right for the wrong reason: both the old and the new CFA's are consistent with remote sensing data, however the earlier determination incorrectly calculated rock coverage using apparent width rather than average diameter. Here we present details of the new rock database and the new statistics, as well as the importance of using rock average diameter for rock population statistics. The changes to the near-field data do not affect the far-field rock statistics.

Tough Textiles Protect Payloads and Public Safety Officers

NASA Technical Reports Server (NTRS)

2009-01-01

In order to create the Mars Pathfinder s mission-critical airbags in the 1990s, NASA s Jet Propulsion Laboratory collaborated with New Ipswich, New Hampshire s Warwick Mills Inc. to weave multi-layer textiles for the airbags for both Pathfinder and the Mars Exploration Rovers. Warwick Mills applied techniques from the collaboration to its puncture- and impact-resistant TurtleSkin product line. The company's metal flex armor (MFA) vests offer stab protection comparable with rigid steel plates and over 50,000 of the vests have sold. The SoftPlate body armor offers protection from handgun bullets, and like the MFA, is designed to be more comfortable than rigid vests. International public safety and military customers are now benefiting from the TurtleSkin products.

Pathfinder operations

NASA Technical Reports Server (NTRS)

Wilcher, J.; Stelzried, C.; Finley, S.

1986-01-01

In 1981, the Inter-Agency Consultative Group (composed of European, Soviet, Japanese and American space agency representatives) conceived the idea of using the two Soviet Vega spacecraft as pathfinders for Giotto since they would arrive at Halley's Comet approximately one week before Giotto. The Vega trajectory data and the Halley camera angle data were combined to improve the comet orbit accuracy. This was used to improve the Giotto fly-by targeting. The DSN performed delta DOR (VLBI) and one-way Doppler measurements of the Vega spacecraft for orbit determination. Although the early part-up phase had many problems, the results during the critical November 30, 1985 to March 4, 1986 operational phase had an overall 95 percent success rate, with 59 successes out of 62 two-station passes.

Mosaic of Wedge, Shark, Half-Dome, Moe and Flat Top

NASA Technical Reports Server (NTRS)

1997-01-01

The front cameras aboard the rover Sojourner imaged several prominent rocks on Sol 44. The highly-textured rock at left is Wedge, and in the background from left to right are Shark, Half-Dome, and Moe. The rectangular rock at right is Flat Top, which earlier close-up images revealed to be made up of elongated pits, possibly made by vesicles from volcanic outgassing or etches caused by weathering.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

Chimenea and other tools: Automated imaging of multi-epoch radio-synthesis data with CASA

NASA Astrophysics Data System (ADS)

Staley, T. D.; Anderson, G. E.

2015-11-01

In preparing the way for the Square Kilometre Array and its pathfinders, there is a pressing need to begin probing the transient sky in a fully robotic fashion using the current generation of radio telescopes. Effective exploitation of such surveys requires a largely automated data-reduction process. This paper introduces an end-to-end automated reduction pipeline, AMIsurvey, used for calibrating and imaging data from the Arcminute Microkelvin Imager Large Array. AMIsurvey makes use of several component libraries which have been packaged separately for open-source release. The most scientifically significant of these is chimenea, which implements a telescope-agnostic algorithm for automated imaging of pre-calibrated multi-epoch radio-synthesis data, of the sort typically acquired for transient surveys or follow-up. The algorithm aims to improve upon standard imaging pipelines by utilizing iterative RMS-estimation and automated source-detection to avoid so called 'Clean-bias', and makes use of CASA subroutines for the underlying image-synthesis operations. At a lower level, AMIsurvey relies upon two libraries, drive-ami and drive-casa, built to allow use of mature radio-astronomy software packages from within Python scripts. While targeted at automated imaging, the drive-casa interface can also be used to automate interaction with any of the CASA subroutines from a generic Python process. Additionally, these packages may be of wider technical interest beyond radio-astronomy, since they demonstrate use of the Python library pexpect to emulate terminal interaction with an external process. This approach allows for rapid development of a Python interface to any legacy or externally-maintained pipeline which accepts command-line input, without requiring alterations to the original code.

The use of x-ray pulsar-based navigation method for interplanetary flight

NASA Astrophysics Data System (ADS)

Yang, Bo; Guo, Xingcan; Yang, Yong

2009-07-01

As interplanetary missions are increasingly complex, the existing unique mature interplanetary navigation method mainly based on radiometric tracking techniques of Deep Space Network can not meet the rising demands of autonomous real-time navigation. This paper studied the applications for interplanetary flights of a new navigation technology under rapid development-the X-ray pulsar-based navigation for spacecraft (XPNAV), and valued its performance with a computer simulation. The XPNAV is an excellent autonomous real-time navigation method, and can provide comprehensive navigation information, including position, velocity, attitude, attitude rate and time. In the paper the fundamental principles and time transformation of the XPNAV were analyzed, and then the Delta-correction XPNAV blending the vehicles' trajectory dynamics with the pulse time-of-arrival differences at nominal and estimated spacecraft locations within an Unscented Kalman Filter (UKF) was discussed with a background mission of Mars Pathfinder during the heliocentric transferring orbit. The XPNAV has an intractable problem of integer pulse phase cycle ambiguities similar to the GPS carrier phase navigation. This article innovatively proposed the non-ambiguity assumption approach based on an analysis of the search space array method to resolve pulse phase cycle ambiguities between the nominal position and estimated position of the spacecraft. The simulation results show that the search space array method are computationally intensive and require long processing time when the position errors are large, and the non-ambiguity assumption method can solve ambiguity problem quickly and reliably. It is deemed that autonomous real-time integrated navigation system of the XPNAV blending with DSN, celestial navigation, inertial navigation and so on will be the development direction of interplanetary flight navigation system in the future.

Drag-Free Performance of the ST7 Disturbance Reduction System Flight Experiment on the LISA Pathfinder

NASA Technical Reports Server (NTRS)

Maghami, Peiman G.; O'Donnell, James R.; Hsu, Oscar H.; Ziemer, John K.; Dunn, Charles E.

2017-01-01

The Space Technology-7 Disturbance Reduction System (DRS) is an experiment package aboard the European Space Agency (ESA) LISA Pathfinder spacecraft. LISA Pathfinder launched from Kourou, French Guiana on December 3, 2015. The DRS is tasked to validate two specific technologies: colloidal micro-Newton thrusters (CMNT) to provide low-noise control capability of the spacecraft, and drag-free controlflight. This validation is performed using highly sensitive drag-free sensors, which are provided by the LISA Technology Package of the European Space Agency. The Disturbance Reduction System is required to maintain the spacecrafts position with respect to a free-floating test mass to better than 10nm/(square root of Hz), along its sensitive axis (axis in optical metrology). It also has a goal of limiting the residual accelerations of any of the two test masses to below 30 x 10(exp -14) (1 + ([f/3 mHz](exp 2))) m/sq s/(square root of Hz), over the frequency range of 1 to 30 mHz.This paper briefly describes the design and the expected on-orbit performance of the control system for the two modes wherein the drag-free performance requirements are verified. The on-orbit performance of these modes are then compared to the requirements, as well as to the expected performance, and discussed.

Longwave Radiative Flux Calculations in the TOVS Pathfinder Path A Data Set

NASA Technical Reports Server (NTRS)

Mehta, Amita; Susskind, Joel

1999-01-01

A radiative transfer model developed to calculate outgoing longwave radiation (OLR) and downwelling longwave, surface flux (DSF) from the Television and Infrared Operational Satellite (TIROS) Operational Vertical Sounder (TOVS) Pathfinder Path A retrieval products is described. The model covers the spectral range of 2 to 2800 cm in 14 medium medium spectral bands. For each band, transmittances are parameterized as a function of temperature, water vapor, and ozone profiles. The form of the band transmittance parameterization is a modified version of the approach we use to model channel transmittances for the High Resolution Infrared Sounder 2 (HIRS2) instrument. We separately derive effective zenith angle for each spectral band such that band-averaged radiance calculated at that angle best approximates directionally integrated radiance for that band. We develop the transmittance parameterization at these band-dependent effective zenith angles to incorporate directional integration of radiances required in the calculations of OLR and DSF. The model calculations of OLR and DSF are accurate and differ by less than 1% from our line-by-line calculations. Also, the model results are within 1% range of other line-by-line calculations provided by the Intercomparison of Radiation Codes in Climate Models (ICRCCM) project for clear-sky and cloudy conditions. The model is currently used to calculate global, multiyear (1985-1998) OLR and DSF from the TOVS Pathfinder Path A Retrievals.

Sensitivity of planetary cruise navigation to earth orientation calibration errors

NASA Technical Reports Server (NTRS)

Estefan, J. A.; Folkner, W. M.

1995-01-01

A detailed analysis was conducted to determine the sensitivity of spacecraft navigation errors to the accuracy and timeliness of Earth orientation calibrations. Analyses based on simulated X-band (8.4-GHz) Doppler and ranging measurements acquired during the interplanetary cruise segment of the Mars Pathfinder heliocentric trajectory were completed for the nominal trajectory design and for an alternative trajectory with a longer transit time. Several error models were developed to characterize the effect of Earth orientation on navigational accuracy based on current and anticipated Deep Space Network calibration strategies. The navigational sensitivity of Mars Pathfinder to calibration errors in Earth orientation was computed for each candidate calibration strategy with the Earth orientation parameters included as estimated parameters in the navigation solution. In these cases, the calibration errors contributed 23 to 58% of the total navigation error budget, depending on the calibration strategy being assessed. Navigation sensitivity calculations were also performed for cases in which Earth orientation calibration errors were not adjusted in the navigation solution. In these cases, Earth orientation calibration errors contributed from 26 to as much as 227% of the total navigation error budget. The final analysis suggests that, not only is the method used to calibrate Earth orientation vitally important for precision navigation of Mars Pathfinder, but perhaps equally important is the method for inclusion of the calibration errors in the navigation solutions.

Magnetohydrodynamic Power Generation in the Laboratory Simulated Martian Entry Plasma

NASA Technical Reports Server (NTRS)

Vuskovic, L.; Popovic, S.; Drake, J.; Moses, R. W.

2005-01-01

This paper addresses the magnetohydrodynamic (MHD) conversion of the energy released during the planetary entry phase of an interplanetary vehicle trajectory. The effect of MHD conversion is multi-fold. It reduces and redirects heat transferred to the vehicle, and regenerates the dissipated energy in reusable and transportable form. A vehicle on an interplanetary mission carries about 10,000 kWh of kinetic energy per ton of its mass. This energy is dissipated into heat during the planetary atmospheric entry phase. For instance, the kinetic energy of Mars Pathfinder was about 4220 kWh. Based on the loss in velocity, Mars Pathfinder lost about 92.5% of that energy during the plasma-sustaining entry phase that is approximately 3900 kWh. An ideal MHD generator, distributed over the probe surface of Mars Pathfinder could convert more than 2000 kWh of this energy loss into electrical energy, which correspond to more than 50% of the kinetic energy loss. That means that the heat transferred to the probe surface can be reduced by at least 50% if the converted energy is adequately stored, or re-radiated, or directly used. Therefore, MHD conversion could act not only as the power generating, but also as the cooling process. In this paper we describe results of preliminary experiments with light and microwave emitters powered by model magnetohydrodynamic generators and discuss method for direct use of converted energy.

Shuttle Laser Altimeter

NASA Technical Reports Server (NTRS)

Bufton, Jack L.; Harding, David J.; Garvin, James B.

1999-01-01

The Shuttle Laser Altimeter (SLA) is a Hitchhiker experiment that has flown twice; first on STS-72 in January 1996 and then on STS-85 in August 1997. Both missions produced successful laser altimetry and surface lidar data products from approximately 80 hours per mission of SLA data operations. A total of four Shuttle missions are planned for the SLA series. This paper documents SLA mission results and explains SLA pathfinder accomplishments at the mid-point in this series of Hitchhiker missions. The overall objective of the SLA mission series is the transition of the Goddard Space Flight Center airborne laser altimeter and lidar technology to low Earth orbit as a pathfinder for NASA operational space-based laser remote sensing devices. Future laser altimeter sensors will utilize systems and approaches being tested with SLA, including the Multi-Beam Laser Altimeter (MBLA) and the Geoscience Laser Altimeter System (GLAS). MBLA is the land and vegetation laser sensor for the NASA Earth System Sciences Pathfinder Vegetation Canopy Lidar (VCL) Mission, and GLAS is the Earth Observing System facility instrument on the Ice, Cloud, and Land Elevation Satellite (ICESat). The Mars Orbiting Laser Altimeter, now well into a multi-year mapping mission at the red planet, is also directly benefiting from SLA data analysis methods, just as SLA benefited from MOLA spare parts and instrument technology experience [5] during SLA construction in the early 1990s.

Weathering of rock 'Ginger'

NASA Technical Reports Server (NTRS)

1997-01-01

One of the more unusual rocks at the site is Ginger, located southeast of the lander. Parts of it have the reddest color of any material in view, whereas its rounded lobes are gray and relatively unweathered. These color differences are brought out in the inset, enhanced at the upper right. In the false color image at the lower right, the shape of the visible-wavelength spectrum (related to the abundance of weathered ferric iron minerals) is indicated by the hue of the rocks. Blue indicates relatively unweathered rocks. Typical soils and drift, which are heavily weathered, are shown in green and flesh tones. The very red color in the creases in the rock surface correspond to a crust of ferric minerals. The origin of the rock is uncertain; the ferric crust may have grown underneath the rock, or it may cement pebbles together into a conglomerate. Ginger will be a target of future super-resolution studies to better constrain its origin.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is an operating division of the California Institute of Technology (Caltech).

Rover Family Photo

NASA Technical Reports Server (NTRS)

2002-01-01

Members of the Mars Exploration Rovers Assembly, Test and Launch Operations team gather around Rover 2 and its predecessor, a flight spare of the Pathfinder mission's Sojourner rover, named Marie Curie.

Rover Family Photo

NASA Image and Video Library

2003-02-26

Members of the Mars Exploration Rovers Assembly, Test and Launch Operations team gather around NASA Rover 2 and its predecessor, a flight spare of the Pathfinder mission Sojourner rover, named Marie Curie.

Science Innovation

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EPA provides innovative research activities that help transform the protection of human health and the environment with high-risk, high-reward Pathfinder Innovation Projects, the P3 student competition, and low-cost air monitoring.

THE ALFALFA H I ABSORPTION PILOT SURVEY: A WIDE-AREA BLIND DAMPED Ly{alpha} SYSTEM SURVEY OF THE LOCAL UNIVERSE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Darling, Jeremy; Macdonald, Erin P.; Haynes, Martha P.

2011-11-20

We present the results of a pilot survey for neutral hydrogen (H I) 21 cm absorption in the Arecibo Legacy Fast Arecibo L-Band Feed Array (ALFALFA) Survey. This project is a wide-area 'blind' search for H I absorption in the local universe, spanning -650 km s{sup -1} < cz < 17, 500 km s{sup -1} and covering 517.0 deg{sup 2} (7% of the full ALFALFA survey). The survey is sensitive to H I absorption lines stronger than 7.7 mJy (8983 radio sources) and is 90% complete for lines stronger than 11.0 mJy (7296 sources). The total redshift interval sensitive tomore » all damped Ly{alpha} (DLA) systems (N{sub H{sub i}}{>=}2 Multiplication-Sign 10{sup 20} cm{sup -2}) is {Delta}z = 7.0 (129 objects, assuming T{sub s} = 100 K and covering fraction unity); for super-DLAs (N{sub H{sub i}}{>=}2 Multiplication-Sign 10{sup 21} cm{sup -2}) it is {Delta}z = 128.2 (2353 objects). We re-detect the intrinsic H I absorption line in UGC 6081 but detect no intervening absorption line systems. We compute a 95% confidence upper limit on the column density frequency distribution function f(N{sub H{sub i}},X) spanning four orders of magnitude in column density, 10{sup 19} (T{sub s} /100 K) (1/f) cm{sup -2}

Cerberus Plains: A most excellent Pathfinder landing site

NASA Technical Reports Server (NTRS)

Plescia, Jeff B.

1994-01-01

The Cerberus Plains in southeastern Elysium and western Amazonis cover greater than 10(exp 5) sq km, extending an east-west distance of approximately 3000 km and a north-south distance of up to 700 km near 195 deg. Crater numbers are 89 plus or minus 15 craters greater than 1 km/10(exp 6) sq km, indicating a stratigraphic age of Upper Amazonian and an absolute age of 200-500 Ma. The material forming the surface is referred to as the Cerberus Formation. The two ideas postulated about the unit's origin are fluvial and volcanic. Regardless of which interpretation is correct, the Cerberus Plains is an important candidate for a pathfinder landing site because it represents the youngest major geologic event (be it fluvial or volcanic) on Mars.

Pre-Dawn Clouds Over Mars

NASA Image and Video Library

1997-08-28

These are more wispy blue clouds from Sol 39 as seen by the Imager for Mars Pathfinder. The bright clouds near the bottom are about 30 degrees above the horizon. The clouds are believed to be at an altitude of 10 to 15 km, and are thought to be made of small water ice particles. The picture was taken about 35 minutes before sunrise. Sojourner spent 83 days of a planned seven-day mission exploring the Martian terrain, acquiring images, and taking chemical, atmospheric and other measurements. The final data transmission received from Pathfinder was at 10:23 UTC on September 27, 1997. Although mission managers tried to restore full communications during the following five months, the successful mission was terminated on March 10, 1998. http://photojournal.jpl.nasa.gov/catalog/PIA00919

Overview of the Mars Pathfinder mission and assessment of landing site predictions.

PubMed

Golombek, M P; Cook, R A; Economou, T; Folkner, W M; Haldemann, A F; Kallemeyn, P H; Knudsen, J M; Manning, R M; Moore, H J; Parker, T J; Rieder, R; Schofield, J T; Smith, P H; Vaughan, R M

1997-12-05

Chemical analyses returned by Mars Pathfinder indicate that some rocks may be high in silica, implying differentiated parent materials. Rounded pebbles and cobbles and a possible conglomerate suggest fluvial processes that imply liquid water in equilibrium with the atmosphere and thus a warmer and wetter past. The moment of inertia indicates a central metallic core of 1300 to 2000 kilometers in radius. Composite airborne dust particles appear magnetized by freeze-dried maghemite stain or cement that may have been leached from crustal materials by an active hydrologic cycle. Remote-sensing data at a scale of generally greater than approximately 1 kilometer and an Earth analog correctly predicted a rocky plain safe for landing and roving with a variety of rocks deposited by catastrophic floods that are relatively dust-free.

Overview of the Mars Pathfinder mission and assessment of landing site predictions

NASA Technical Reports Server (NTRS)

Golombek, M. P.; Cook, R. A.; Economou, T.; Folkner, W. M.; Haldemann, A. F.; Kallemeyn, P. H.; Knudsen, J. M.; Manning, R. M.; Moore, H. J.; Parker, T. J.;

Injection of a Body into a Geodesic: Lessons Learnt from the LISA Pathfinder Case

NASA Technical Reports Server (NTRS)

Bortoluzzi, Daniele; Armano, M.; Audley, H.; Auger, G.; Baird, J.; Binetruy, P.; Born, M.; Bortoluzzi, D.; Brandt, N.; Bursi, A.;

Characteristics and Energy Dependence of Recurrent Galactic Cosmic-Ray Flux Depressions and of a Forbush Decrease with LISA Pathfinder

NASA Astrophysics Data System (ADS)

Armano, M.; Audley, H.; Baird, J.; Bassan, M.; Benella, S.; Binetruy, P.; Born, M.; Bortoluzzi, D.; Cavalleri, A.; Cesarini, A.; Cruise, A. M.; Danzmann, K.; de Deus Silva, M.; Diepholz, I.; Dixon, G.; Dolesi, R.; Fabi, M.; Ferraioli, L.; Ferroni, V.; Finetti, N.; Fitzsimons, E. D.; Freschi, M.; Gesa, L.; Gibert, F.; Giardini, D.; Giusteri, R.; Grimani, C.; Grzymisch, J.; Harrison, I.; Heinzel, G.; Hewitson, M.; Hollington, D.; Hoyland, D.; Hueller, M.; Inchauspé, H.; Jennrich, O.; Jetzer, P.; Karnesis, N.; Kaune, B.; Korsakova, N.; Killow, C. J.; Laurenza, M.; Lobo, J. A.; Lloro, I.; Liu, L.; López-Zaragoza, J. P.; Maarschalkerweerd, R.; Mance, D.; Martín, V.; Martin-Polo, L.; Martino, J.; Martin-Porqueras, F.; Mateos, I.; McNamara, P. W.; Mendes, J.; Mendes, L.; Nofrarias, M.; Paczkowski, S.; Perreur-Lloyd, M.; Petiteau, A.; Pivato, P.; Plagnol, E.; Ramos-Castro, J.; Reiche, J.; Robertson, D. I.; Rivas, F.; Russano, G.; Sabbatini, F.; Slutsky, J.; Sopuerta, C. F.; Sumner, T.; Telloni, D.; Texier, D.; Thorpe, J. I.; Vetrugno, D.; Vitale, S.; Wanner, G.; Ward, H.; Wass, P.; Weber, W. J.; Wissel, L.; Wittchen, A.; Zambotti, A.; Zenoni, C.; Zweifel, P.

2018-02-01

Galactic cosmic-ray (GCR) energy spectra observed in the inner heliosphere are modulated by the solar activity, the solar polarity and structures of solar and interplanetary origin. A high counting rate particle detector (PD) aboard LISA Pathfinder, meant for subsystems diagnostics, was devoted to the measurement of GCR and solar energetic particle integral fluxes above 70 MeV n‑1 up to 6500 counts s‑1. PD data were gathered with a sampling time of 15 s. Characteristics and energy dependence of GCR flux recurrent depressions and of a Forbush decrease dated 2016 August 2 are reported here. The capability of interplanetary missions, carrying PDs for instrument performance purposes, in monitoring the passage of interplanetary coronal mass ejections is also discussed.

Jenkins Dune

NASA Technical Reports Server (NTRS)

1997-01-01

This image is of a landform informally called Jenkins Dune and is thought to be a small barchan dune. This feature is less than 1 foot (0.3 m) tall and perhaps 2-3 meters wide. Inferred wind direction is from the left to the right. Near the crest of the feature is a demarcation that may represent the exposure of a crust on the sediments; similar features were seen on sediments on the rock Big Joe at the Viking landing site.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

THE INTERACTION BETWEEN L1-TYPE PROTEINS AND ANKYRINS - A MASTER SWITCH FOR L1-TYPE CAM FUNCTION #

PubMed Central

HORTSCH, MICHAEL; NAGARAJ, KAKANAHALLI; GODENSCHWEGE, TANJA A.

2008-01-01

L1-type cell adhesion molecules (CAMs) are important mediators of neural differentiation, including axonal outgrowth and pathfinding and also of synapse formation and maintenance. In addition, their interactions with cytoskeletal components are highly conserved and regulated. How these different aspects of CAM functionality relate to each other is not well understood. Based on results from our and other laboratories we propose that Ankyrin-binding to L1-type CAMs provides a master switch. The interaction with Ankyrins directs L1-type adhesive proteins into different functional contexts, either Ankyrin-independent functions, such as neurite outgrowth and axonal pathfinding or into Ankyrin-dependent functions, such as L1’s role at axon initial segments (AIS), paranodal regions, synapses and in dendrites. PMID:18839070

Marie

NASA Image and Video Library

2003-02-03

Marie Curie rover drives down the rear ramp during Operational Readiness Test ORT 4. NASA Pathfinder, a low-cost Discovery mission, is the first of a new fleet of spacecraft that are planned to explore Mars.

Prominent Rocks - 3-D

NASA Image and Video Library

1997-07-13

Many prominent rocks near the Sagan Memorial Station are featured in this image from NASA Mars Pathfinder. Shark, Half-Dome, and Pumpkin are at center 3D glasses are necessary to identify surface detail.

Sojourner's First Images From Mars

NASA Technical Reports Server (NTRS)

2003-01-01

These images are views of the Mars Pathfinder Lander's forward ramp before (top image) and after (bottom image) deployment. Some data from the before image was lost due to rover-lander communication problems.

In-orbit performance of the LISA Pathfinder drag-free and attitude control system

NASA Astrophysics Data System (ADS)

Schleicher, A.; Ziegler, T.; Schubert, R.; Brandt, N.; Bergner, P.; Johann, U.; Fichter, W.; Grzymisch, J.

2018-04-01

LISA Pathfinder is a technology demonstrator mission that was funded by the European Space Agency and that was launched on December 3, 2015. LISA Pathfinder has been conducting experiments to demonstrate key technologies for the gravitational wave observatory LISA in its operational orbit at the L1 Lagrange point of the Earth-Sun system until final switch off on July 18, 2017. These key technologies include the inertial sensors, the optical metrology system, a set of µ-propulsion cold gas thrusters and in particular the high performance drag-free and attitude control system (DFACS) that controls the spacecraft in 15 degrees of freedom during its science phase. The main goal of the DFACS is to shield the two test masses inside the inertial sensors from all external disturbances to achieve a residual differential acceleration between the two test masses of less than 3 × 10-14 m/s2/√Hz over the frequency bandwidth of 1-30 mHz. This paper focuses on two important aspects of the DFACS that has been in use on LISA Pathfinder: the DFACS Accelerometer mode and the main DFACS Science mode. The Accelerometer mode is used to capture the test masses after release into free flight from the mechanical grabbing mechanism. The main DFACS Science Mode is used for the actual drag-free science operation. The DFACS control system has very strong interfaces with the LISA Technology Package payload which is a key aspect to master the design, development, and analysis of the DFACS. Linear as well as non-linear control methods are applied. The paper provides pre-flight predictions for the performance of both control modes and compares these predictions to the performance that is currently achieved in-orbit. Some results are also discussed for the mode transitions up to science mode, but the focus of the paper is on the Accelerometer mode performance and on the performance of the Science mode in steady state. Based on the achieved results, some lessons learnt are formulated to extend the results to the drag-free control system to be designed for future space-based gravity wave observatories like LISA.

Maps of the Martian Landing Sites and Rover Traverses: Viking 1 and 2, Mars Pathfinder, and Phoenix Landers, and the Mars Exploration Rovers.

NASA Astrophysics Data System (ADS)

Parker, T. J.; Calef, F. J., III; Deen, R. G.; Gengl, H.

2016-12-01

The traverse maps produced tactically for the MER and MSL rover missions are the first step in placing the observations made by each vehicle into a local and regional geologic context. For the MER, Phoenix and MSL missions, 25cm/pixel HiRISE data is available for accurately localizing the vehicles. Viking and Mars Pathfinder, however, relied on Viking Orbiter images of several tens of m/pixel to triangulate to horizon features visible both from the ground and from orbit. After Pathfinder, MGS MOC images became available for these landing sites, enabling much better correlations to horizon features and localization predictions to be made, that were then corroborated with HiRISE images beginning 9 years ago. By combining topography data from MGS, Mars Express, and stereo processing of MRO CTX and HiRISE images into orthomosaics (ORRs) and digital elevation models (DEMs), it is possible to localize all the landers and rover positions to an accuracy of a few tens of meters with respect to the Mars global control net, and to better than half a meter with respect to other features within a HiRISE orthomosaic. JPL's MIPL produces point clouds of the MER Navcam stereo images that can be processed into 1cm/pixel ORR/DEMs that are then georeferenced to a HiRISE/CTX base map and DEM. This allows compilation of seamless mosaics of the lander and rover camera-based ORR/DEMs with the HiRISE ORR/DEM that can be viewed in 3 dimensions with GIS programs with that capability. We are re-processing the Viking Lander, Mars Pathfinder, and Phoenix lander data to allow similar ORR/DEM products to be made for those missions. For the fixed landers and Spirit, we will compile merged surface/CTX/HiRISE ORR/DEMs, that will enable accurate local and regional mapping of these landing sites, and allow comparisons of the results from these missions to be made with current and future surface missions.

Constraints on Martian Soil Composition as Inferred from Viking XRFS and Pathfinder APXS and IMP Data

NASA Technical Reports Server (NTRS)

Bridges, N. T.; Crisp, J. A.

2000-01-01

With the successful operation of the Alpha Proton X-Ray Spectrometer (APXS) during 1997's Mars Pathfinder (MPF) mission, geochemistry data are now available from three sites on Mars. APXS raw spectra for six soils and five rocks have been converted to compositional abundances. The Viking Lander X-Ray Fluorescence Spectrometer (XRFS) successfully measured elemental abundances of nine soils at Viking 1 and eight soils at Viking 2. Although the three landing sites are located in different parts of Mars, the soils exhibit broad similarities, with an iron-rich chemistry similar to that of palagonite. However, the Pathfinder sods show some significant differences from Viking soils, notably an enrichment in silica and depletion in sulfur. The XRFS samples consisted of near-surface and deep (up to 22 cm) soils acquired by a collector head at the cod of a retractable boom. It was possible to collect and analyze pebbles as large a 2 cm, but only sod, some in the form of consolidated clods, was sampled. In contrast, the APXS measured materials in situ. This resulted in MPF "rock" analyses that probably had a significant dust component and, as explored here, "soil" analyses that may have contained a rocky component We examine several possibilities to explain these differences and other attributes of the APXS and XRFS data sets: 1) The APXS soil measurements actually sampled a mixture of Viking-like soil and small bits of high-silica, low-sulfur rock, 2) The soils were derived from high-silica rocks mixed with a minor component of globally-homogenized dust; these soils are chemically distinct and have a separate geologic history from the Viking soils. 3) The weathering environment was different at the Pathfinder landing site compared to the Viking sites, and 4) Uncertainties in the XRFS and APXS measurements result in reported elemental abundances different than those that are actually present We show that none of the possibilities can be discounted, but that an MPF soil distinct in composition from Viking sods is best supported by the available data.

Analysis of entry accelerometer data: A case study of Mars Pathfinder

NASA Astrophysics Data System (ADS)

Withers, Paul; Towner, M. C.; Hathi, B.; Zarnecki, J. C.

2003-08-01

Accelerometers are regularly flown on atmosphere-entering spacecraft. Using their measurements, the spacecraft trajectory and the vertical structure of density, pressure, and temperature in the atmosphere through which it descends can be calculated. We review the general procedures for trajectory and atmospheric structure reconstruction and outline them here in detail. We discuss which physical properties are important in atmospheric entry, instead of working exclusively with the dimensionless numbers of fluid dynamics. Integration of the equations of motion governing the spacecraft trajectory is carried out in a novel and general formulation. This does not require an axisymmetric gravitational field or many of the other assumptions that are present in the literature. We discuss four techniques - head-on, drag-only, acceleration ratios, and gyroscopes - for constraining spacecraft attitude, which is the critical issue in the trajectory reconstruction. The head-on technique uses an approximate magnitude and direction for the aerodynamic acceleration, whereas the drag-only technique uses the correct magnitude and an approximate direction. The acceleration ratios technique uses the correct magnitude and an indirect way of finding the correct direction and the gyroscopes technique uses the correct magnitude and a direct way of finding the correct direction. The head-on and drag-only techniques are easy to implement and require little additional information. The acceleration ratios technique requires extensive and expensive aerodynamic modelling. The gyroscopes technique requires additional onboard instrumentation. The effects of errors are briefly addressed. Our implementations of these trajectory reconstruction procedures have been verified on the Mars Pathfinder dataset. We find inconsistencies within the published work of the Pathfinder science team, and in the PDS archive itself, relating to the entry state of the spacecraft. Our atmospheric structure reconstruction, which uses only a simple aerodynamic database, is consistent with the PDS archive to about 4%. Surprisingly accurate profiles of atmospheric temperatures can be derived with no information about the spacecraft aerodynamics. Using no aerodynamic information whatsoever about Pathfinder, our profile of atmospheric temperature is still consistent with the PDS archive to about 8%. As a service to the community, we have placed simplified versions of our trajectory and atmospheric structure computer programmes online for public use.

Monitor and Control of the Deep-Space network via Secure Web

NASA Technical Reports Server (NTRS)

Lamarra, N.

1997-01-01

(view graph) NASA lead center for robotic space exploration. Operating division of Caltech/Jet Propulsion Laboratory. Current missions, Voyagers, Galileo, Pathfinder, Global Surveyor. Upcoming missions, Cassini, Mars and New Millennium.

Pathfinder Innovation Projects: Awardees for 2013

EPA Pesticide Factsheets

PIP3 awardees will tackle high-risk, high-reward research ideas with gated funding. Projects include PM toxicity for zebrafish, lab-grown neuron networks, research bias for pharmaceutical chemicals, and innovative chemical life cycle assessments.

Pathfinder

NASA Image and Video Library

2004-04-15

This picture is an artist's concept of an orbiting vehicle using the Electrodynamic Tethers Propulsion System. Relatively short electrodynamic tethers can use solar power to push against a planetary magnetic field to achieve propulsion without the expenditure of propellant.

Pathfinder Innovation Projects: Awardees for 2011

EPA Pesticide Factsheets

First-year PIP awardees pursue high-risk, high-reward research with project topics such as bacteria in drinking water pipes, biomarkers in sewage, endocrine disruption using glowing frogs, and testing water quality from space.

Pathfinder Innovation Projects: Awardees for 2012

EPA Pesticide Factsheets

PIP2 awardees include ten research projects aimed at high-risk, high-reward projects that include volatile chemical research with flies, water-borne virus testing, medical prescription pollution, and a mobile app for cyanobacteria outbreaks.

Phillips with National Lab Pathfinder (NLP) on Middeck (MDDK)

NASA Image and Video Library

2009-03-16

S119-E-006156 (16 March 2009) --- Astronaut John Phillips, STS-119 mission specialist, works with Group Activation Packs (GAP) on the middeck of Space Shuttle Discovery during flight day two activities.

Phillips with National Lab Pathfinder (NLP) on Middeck (MDDK)

NASA Image and Video Library

2009-03-16

S119-E-006157 (16 March 2009) --- Astronaut John Phillips, STS-119 mission specialist, works with Group Activation Packs (GAP) on the middeck of Space Shuttle Discovery during flight day two activities.

Prediction and Validation of Mars Pathfinder Hypersonic Aerodynamic Data Base

NASA Technical Reports Server (NTRS)

Gnoffo, Peter A.; Braun, Robert D.; Weilmuenster, K. James; Mitcheltree, Robert A.; Engelund, Walter C.; Powell, Richard W.

1998-01-01

Postflight analysis of the Mars Pathfinder hypersonic, continuum aerodynamic data base is presented. Measured data include accelerations along the body axis and axis normal directions. Comparisons of preflight simulation and measurements show good agreement. The prediction of two static instabilities associated with movement of the sonic line from the shoulder to the nose and back was confirmed by measured normal accelerations. Reconstruction of atmospheric density during entry has an uncertainty directly proportional to the uncertainty in the predicted axial coefficient. The sensitivity of the moment coefficient to freestream density, kinetic models and center-of-gravity location are examined to provide additional consistency checks of the simulation with flight data. The atmospheric density as derived from axial coefficient and measured axial accelerations falls within the range required for sonic line shift and static stability transition as independently determined from normal accelerations.

Actuation stability test of the LISA pathfinder inertial sensor front-end electronics

NASA Astrophysics Data System (ADS)

Mance, Davor; Gan, Li; Weber, Bill; Weber, Franz; Zweifel, Peter

In order to limit the residual stray forces on the inertial sensor test mass in LISA pathfinder, √ it is required that the fluctuation of the test mass actuation voltage is within 2ppm/ Hz. The actuation voltage stability test on the flight hardware of the inertial sensor front-end electronics (IS FEE) is presented in this paper. This test is completed during the inertial sensor integration at EADS Astrium Friedrichshafen, Germany. The standard measurement method using voltmeter is not sufficient for verification, since the instrument low frequency √ fluctuation is higher than the 2ppm/ Hz requirement. In this test, by using the differential measurement method and the lock-in amplifier, the actuation stability performance is verified and the quality of the IS FEE hardware is confirmed by the test results.

Exploring MEDLINE Space with Random Indexing and Pathfinder Networks

PubMed Central

Cohen, Trevor

2008-01-01

The integration of disparate research domains is a prerequisite for the success of the translational science initiative. MEDLINE abstracts contain content from a broad range of disciplines, presenting an opportunity for the development of methods able to integrate the knowledge they contain. Latent Semantic Analysis (LSA) and related methods learn human-like associations between terms from unannotated text. However, their computational and memory demands limits their ability to address a corpus of this size. Furthermore, visualization methods previously used in conjunction with LSA have limited ability to define the local structure of the associative networks LSA learns. This paper explores these issues by (1) processing the entire MEDLINE corpus using Random Indexing, a variant of LSA, and (2) exploring learned associations using Pathfinder Networks. Meaningful associations are inferred from MEDLINE, including a drug-disease association undetected by PUBMED search. PMID:18999236

Mutations in the Drosophila neuroglian cell adhesion molecule affect motor neuron pathfinding and peripheral nervous system patterning.

PubMed

Hall, S G; Bieber, A J

1997-03-01

We have identified and characterized three embryonic lethal mutations that alter or abolish expression of Drosophila Neuroglian and have used these mutations to analyze Neuroglian function during development. Neuroglian is a member of the immunoglobulin superfamily. It is expressed by a variety of cell types during embryonic development, including expression on motoneurons and the muscle cells that they innervate. Examination of the nervous systems of neuroglian mutant embryos reveals that motoneurons have altered pathfinding trajectories. Additionally, the sensory cell bodies of the peripheral nervous system display altered morphology and patterning. Using a temperature-sensitive mutation, the phenocritical period for Neuroglian function was determined to occur during late embryogenesis, an interval which coincides with the period during which neuromuscular connections and the peripheral nervous system pattern are established.

Exploring MEDLINE space with random indexing and pathfinder networks.

PubMed

Cohen, Trevor

2008-11-06

The integration of disparate research domains is a prerequisite for the success of the translational science initiative. MEDLINE abstracts contain content from a broad range of disciplines, presenting an opportunity for the development of methods able to integrate the knowledge they contain. Latent Semantic Analysis (LSA) and related methods learn human-like associations between terms from unannotated text. However, their computational and memory demands limits their ability to address a corpus of this size. Furthermore, visualization methods previously used in conjunction with LSA have limited ability to define the local structure of the associative networks LSA learns. This paper explores these issues by (1) processing the entire MEDLINE corpus using Random Indexing, a variant of LSA, and (2) exploring learned associations using Pathfinder Networks. Meaningful associations are inferred from MEDLINE, including a drug-disease association undetected by PUBMED search.

The Mars Pathfinder atmospheric structure investigation/meteorology (ASI/MET) experiment.

PubMed

Schofield, J T; Barnes, J R; Crisp, D; Haberle, R M; Larsen, S; Magalhães, J A; Murphy, J R; Seiff, A; Wilson, G

1997-12-05

The Mars Pathfinder atmospheric structure investigation/meteorology (ASI/MET) experiment measured the vertical density, pressure, and temperature structure of the martian atmosphere from the surface to 160 km, and monitored surface meteorology and climate for 83 sols (1 sol = 1 martian day = 24.7 hours). The atmospheric structure and the weather record are similar to those observed by the Viking 1 lander (VL-1) at the same latitude, altitude, and season 21 years ago, but there are differences related to diurnal effects and the surface properties of the landing site. These include a cold nighttime upper atmosphere; atmospheric temperatures that are 10 to 12 degrees kelvin warmer near the surface; light slope-controlled winds; and dust devils, identified by their pressure, wind, and temperature signatures. The results are consistent with the warm, moderately dusty atmosphere seen by VL-1.

Flight Reconstruction of the Mars Pathfinder Disk-Gap-Band Parachute Drag Coefficient

NASA Technical Reports Server (NTRS)

Desai, Prasun; Schofield, John T.; Lisano, Michael E.

2003-01-01

On July 4, 1997, the Mars Pathfinder (MPF) mission successfully landed on Mars. The entry, descent, and landing (EDL) scenario employed the use of a Disk-Gap-Band parachute design to decelerate the Lander. Flight reconstruction of the entry using MPF flight accelerometer data revealed that the MPF parachute decelerated faster than predicted. In the summer of 2003, the Mars Exploration Rover (MER) mission will send two Landers to the surface of Mars arriving in January 2004. The MER mission utilizes a similar EDL scenario and parachute design as that employed by MPF. As a result, characterizing the degree of underperformance of the MPF parachute system is critical for the MER EDL trajectory design. This paper provides an overview of the methodology utilized to estimate the MPF parachute drag coefficient as experienced on Mars.

Mars Pathfinder and the exploration of southern Amazonis Planitia

NASA Technical Reports Server (NTRS)

Barlow, Nadine G.

1994-01-01

The southern region of Amazonis Planitia provides a variety of target terrains for a roving vehicle such as the Mars Pathfinder Mission. A landing site is proposed at 4 deg N latitude 162 deg W longitude. This area has a reference altitude of between 0 and -1 km and consists of relatively smooth Amazonian-aged deposits within the entire 100 x 200 km landing ellipse. The proposed landing site is within the Upper Member Medusae Fossae Formation deposits (Amu) and near the boundary with Middle Member Medusae Fossae Formation deposits (Amm) and Member 1 Arcadia Formation plains (Aa(sub 1)). Slightly further afield are 107-km-diameter Nicholson crater, its ejecta deposits, and knobby terrain of proposed Hesperian age (HNu). Depending on the exact landing site of the spacecraft and the traverse distance of the rover, these materials also may be sampled.

Wake Flow About the Mars Pathfinder Entry Vehicle

NASA Technical Reports Server (NTRS)

Mitcheltree, R. A.; Gnoffo, P. A.

1995-01-01

A computational approach is used to describe the aerothermodynamics of the Mars Pathfinder vehicle entering the Mars atmosphere at the maximum heating and maximum deceleration points in its trajectory. Ablating and nonablating boundary conditions are developed which produce maximum recombination of CO2 on the surface. For the maximum heating trajectory point, an axisymmetric, nonablating calculation predicts a stagnation-point value for the convective heating of 115 W/cm(exp 2). Radiative heating estimates predict an additional 5-12 W/cm(exp 2) at the stagnation point. Peak convective heating on the afterbody occurs on the vehicle's flat stern with a value of 5.9% of the stagnation value. The forebody flow exhibits chemical nonequilibrium behavior, and the flow is frozen in the near wake. Including ablation injection on the forebody lowers the stagnation-point convective heating 18%.

Hydrogeology of Basins on Mars

NASA Technical Reports Server (NTRS)

Arvidson, Raymond E.

2001-01-01

This document summarizes the work accomplished under NASA Grant NAG5-3870. Emphasis was put on the development of the FIDO rover, a prototype for the twin-Mers which will be operating on the surface of Mars in 2004, specifically the primary work was the analysis of FIDO field trials. The grantees also analyzed VIKING Lander 1 XRFS and Pathfinder APXS data. Results show that the Viking site chemistry is consistent with an andesite, and the Pathfinder site is consistent with a basaltic andesite. The grantees also worked to demonstrate the capability to simulate annealing methods to apply to the inversion of remote sensing data. They performed an initial analyses of Sojourner engineering telemetry and imaging data. They performed initial analyses of Viking Lander Stereo Images, and of Hematite deposits in Terra Meridiani. They also acquired and analyzed the New Goldstone radar data.

False Color Processing to Enhance Differences Around Yogi

NASA Technical Reports Server (NTRS)

1997-01-01

In this scene showing the rover deployed at rock Yogi, the colors have similarly been enhanced to bring out differences. The same three kinds of rocks are recognized as in the distance. Yogi (red arrow), one of the large rocks with a weathered coating, exhibits a fresh face to the northeast, resulting perhaps from eolian scouring or from fracturing off of pieces to expose a fresher surface. Barnacle Bill and Cradle (blue arrows) are typical of the unweathered smaller rocks. During its traverse to Yogi the rover stirred the soil and exposed material from several cm in depth. During one of the turns to deploy Sojourner's Alpha Proton X-Ray Spectrometer (inset and white arrow), the wheels dug particularly deeply and exposed white material. Spectra of this white material show it is virtually identical to Scooby Doo, and such white material may underlie much of the site. The lander's rear ramp, which Sojourner used to descend to the Martian surface, is at lower left.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and managed the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is an operating division of the California Institute of Technology (Caltech).

Overhead View of Pathfinder Landing Site

NASA Technical Reports Server (NTRS)

1997-01-01

Planimetric (overhead view) map of the landing site, to a distance of 20 meters from the spacecraft. North is at the top in this and Plates 3-5. To produce this map, images were geometrically projected onto an assumed mean surface representing the ground. Features above the ground plane (primarily rocks) therefore appear displaced radially outward; the amount of distortion increases systematically with distance. The upper surfaces of the lander and rover also appear enlarged and displaced because of their height. Primary grid (white) is based on the Landing Site Cartographic (LSC) coordinate system, defined with X eastward, Y north, and Z up, and origin located at the mean ground surface immediately beneath the deployed position of the IMP camera gimbal center. Secondary ticks (cyan) are based on the Mars local level (LL) frame, which has X north, Y east, Z down, with origin in the center of the lander baseplate. Rover positions (including APXS measurements) are commonly reported in the LL frame. Yellow grid shows polar coordinates based on the LSC system. Cartographic image processing by U.S. Geological Survey.

NOTE: original caption as published in Science Magazine

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

Sub-Femto-g Free Fall for Space-Based Gravitational Wave Observatories: LISA Pathfinder Results.

PubMed

Armano, M; Audley, H; Auger, G; Baird, J T; Bassan, M; Binetruy, P; Born, M; Bortoluzzi, D; Brandt, N; Caleno, M; Carbone, L; Cavalleri, A; Cesarini, A; Ciani, G; Congedo, G; Cruise, A M; Danzmann, K; de Deus Silva, M; De Rosa, R; Diaz-Aguiló, M; Di Fiore, L; Diepholz, I; Dixon, G; Dolesi, R; Dunbar, N; Ferraioli, L; Ferroni, V; Fichter, W; Fitzsimons, E D; Flatscher, R; Freschi, M; García Marín, A F; García Marirrodriga, C; Gerndt, R; Gesa, L; Gibert, F; Giardini, D; Giusteri, R; Guzmán, F; Grado, A; Grimani, C; Grynagier, A; Grzymisch, J; Harrison, I; Heinzel, G; Hewitson, M; Hollington, D; Hoyland, D; Hueller, M; Inchauspé, H; Jennrich, O; Jetzer, P; Johann, U; Johlander, B; Karnesis, N; Kaune, B; Korsakova, N; Killow, C J; Lobo, J A; Lloro, I; Liu, L; López-Zaragoza, J P; Maarschalkerweerd, R; Mance, D; Martín, V; Martin-Polo, L; Martino, J; Martin-Porqueras, F; Madden, S; Mateos, I; McNamara, P W; Mendes, J; Mendes, L; Monsky, A; Nicolodi, D; Nofrarias, M; Paczkowski, S; Perreur-Lloyd, M; Petiteau, A; Pivato, P; Plagnol, E; Prat, P; Ragnit, U; Raïs, B; Ramos-Castro, J; Reiche, J; Robertson, D I; Rozemeijer, H; Rivas, F; Russano, G; Sanjuán, J; Sarra, P; Schleicher, A; Shaul, D; Slutsky, J; Sopuerta, C F; Stanga, R; Steier, F; Sumner, T; Texier, D; Thorpe, J I; Trenkel, C; Tröbs, M; Tu, H B; Vetrugno, D; Vitale, S; Wand, V; Wanner, G; Ward, H; Warren, C; Wass, P J; Wealthy, D; Weber, W J; Wissel, L; Wittchen, A; Zambotti, A; Zanoni, C; Ziegler, T; Zweifel, P

2016-06-10

We report the first results of the LISA Pathfinder in-flight experiment. The results demonstrate that two free-falling reference test masses, such as those needed for a space-based gravitational wave observatory like LISA, can be put in free fall with a relative acceleration noise with a square root of the power spectral density of 5.2±0.1  fm s^{-2}/sqrt[Hz], or (0.54±0.01)×10^{-15}  g/sqrt[Hz], with g the standard gravity, for frequencies between 0.7 and 20 mHz. This value is lower than the LISA Pathfinder requirement by more than a factor 5 and within a factor 1.25 of the requirement for the LISA mission, and is compatible with Brownian noise from viscous damping due to the residual gas surrounding the test masses. Above 60 mHz the acceleration noise is dominated by interferometer displacement readout noise at a level of (34.8±0.3)  fm/sqrt[Hz], about 2 orders of magnitude better than requirements. At f≤0.5  mHz we observe a low-frequency tail that stays below 12  fm s^{-2}/sqrt[Hz] down to 0.1 mHz. This performance would allow for a space-based gravitational wave observatory with a sensitivity close to what was originally foreseen for LISA.

Neural cell adhesion molecule, NCAM, regulates thalamocortical axon pathfinding and the organization of the cortical somatosensory representation in mouse

PubMed Central

Enriquez-Barreto, Lilian; Palazzetti, Cecilia; Brennaman, Leann H.; Maness, Patricia F.; Fairén, Alfonso

2012-01-01

To study the potential role of neural cell adhesion molecule (NCAM) in the development of thalamocortical (TC) axon topography, wild type, and NCAM null mutant mice were analyzed for NCAM expression, projection, and targeting of TC afferents within the somatosensory area of the neocortex. Here we report that NCAM and its α-2,8-linked polysialic acid (PSA) are expressed in developing TC axons during projection to the neocortex. Pathfinding of TC axons in wild type and null mutant mice was mapped using anterograde DiI labeling. At embryonic day E16.5, null mutant mice displayed misguided TC axons in the dorsal telencephalon, but not in the ventral telencephalon, an intermediate target that initially sorts TC axons toward correct neocortical areas. During the early postnatal period, rostrolateral TC axons within the internal capsule along the ventral telencephalon adopted distorted trajectories in the ventral telencephalon and failed to reach the neocortex in NCAM null mutant animals. NCAM null mutants showed abnormal segregation of layer IV barrels in a restricted portion of the somatosensory cortex. As shown by Nissl and cytochrome oxidase staining, barrels of the anterolateral barrel subfield (ALBSF) and the most distal barrels of the posteromedial barrel subfield (PMBSF) did not segregate properly in null mutant mice. These results indicate a novel role for NCAM in axonal pathfinding and topographic sorting of TC axons, which may be important for the function of specific territories of sensory representation in the somatosensory cortex. PMID:22723769

A Wind Tunnel Study on the Mars Pathfinder (MPF) Lander Descent Pressure Sensor

NASA Technical Reports Server (NTRS)

Soriano, J. Francisco; Coquilla, Rachael V.; Wilson, Gregory R.; Seiff, Alvin; Rivell, Tomas

2001-01-01

The primary focus of this study was to determine the accuracy of the Mars Pathfinder lander local pressure readings in accordance with the actual ambient atmospheric pressures of Mars during parachute descent. In order to obtain good measurements, the plane of the lander pressure sensor opening should ideally be situated so that it is parallel to the freestream. However, due to two unfavorable conditions, the sensor was positioned in locations where correction factors are required. One of these disadvantages is due to the fact that the parachute attachment point rotated the lander's center of gravity forcing the location of the pressure sensor opening to be off tangent to the freestream. The second and most troublesome factor was that the lander descends with slight oscillations that could vary the amplitude of the sensor readings. In order to accurately map the correction factors required at each sensor position, an experiment simulating the lander descent was conducted in the Martian Surface Wind Tunnel at NASA Ames Research Center. Using a 115 scale model at Earth ambient pressures, the test settings provided the necessary Reynolds number conditions in which the actual lander was possibly subjected to during the descent. In the analysis and results of this experiment, the readings from the lander sensor were converted to the form of pressure coefficients. With a contour map of pressure coefficients at each lander oscillatory position, this report will provide a guideline to determine the correction factors required for the Mars Pathfinder lander descent pressure sensor readings.

Science Programs for a 2-m Class Telescope at Dome C, Antarctica: PILOT, the Pathfinder for an International Large Optical Telescope

NASA Astrophysics Data System (ADS)

Burton, M. G.; Lawrence, J. S.; Ashley, M. C. B.; Bailey, J. A.; Blake, C.; Bedding, T. R.; Bland-Hawthorn, J.; Bond, I. A.; Glazebrook, K.; Hidas, M. G.; Lewis, G.; Longmore, S. N.; Maddison, S. T.; Mattila, S.; Minier, V.; Ryder, S. D.; Sharp, R.; Smith, C. H.; Storey, J. W. V.; Tinney, C. G.; Tuthill, P.; Walsh, A. J.; Walsh, W.; Whiting, M.; Wong, T.; Woods, D.; Yock, P. C. M.

2005-08-01

The cold, dry, and stable air above the summits of the Antarctic plateau provides the best ground-based observing conditions from optical to sub-millimetre wavelengths to be found on the Earth. Pathfinder for an International Large Optical Telescope (PILOT) is a proposed 2m telescope, to be built at Dome C in Antarctica, able to exploit these conditions for conducting astronomy at optical and infrared wavelengths. While PILOT is intended as a pathfinder towards the construction of future grand-design facilities, it will also be able to undertake a range of fundamental science investigations in its own right. This paper provides the performance specifications for PILOT, including its instrumentation. It then describes the kinds of projects that it could best conduct. These range from planetary science to the search for other solar systems, from star formation within the Galaxy to the star formation history of the Universe, and from gravitational lensing caused by exo-planets to that produced by the cosmic web of dark matter. PILOT would be particularly powerful for wide-field imaging at infrared wavelengths, achieving near diffraction-limited performance with simple tip-tilt wavefront correction. PILOT would also be capable of near diffraction-limited performance in the optical wavebands, as well be able to open new wavebands for regular ground-based observation, in the mid-IR from 17 to 40μm and in the sub-millimetre at 200μm.

Sub-Femto-g Free Fall for Space-Based Gravitational Wave Observatories: LISA Pathfinder Results

NASA Technical Reports Server (NTRS)

Armano, M.; Audley, H.; Auger, G.; Baird, J. T.; Bassan, M.; Binetruy, P.; Born, M.; Bortoluzzi, D.; Brandt, N.; Thorpe, J. I.

2016-01-01

We report the first results of the LISA Pathfinder in-flight experiment. The results demonstrate that two free-falling reference test masses, such as those needed for a space-based gravitational wave observatory like LISA, can be put in free fall with a relative acceleration noise with a square root of the power spectral density of 5.2 +/- 0.1 fm s(exp -2)/square root of Hz, or (0.54 +/- 0.01) x 10(exp -15) g/square root of Hz, with g the standard gravity, for frequencies between 0.7 and 20 mHz. This value is lower than the LISA Pathfinder requirement by more than a factor 5 and within a factor 1.25 of the requirement for the LISA mission, and is compatible with Brownian noise from viscous damping due to the residual gas surrounding the test masses. Above 60 mHz the acceleration noise is dominated by interferometer displacement readout noise at a level of (34.8 +/- 0.3) fm square root of Hz, about 2 orders of magnitude better than requirements. At f less than or equal to 0.5 mHz we observe a low-frequency tail that stays below 12 fm s(exp -2)/square root of Hz down to 0.1 mHz. This performance would allow for a space-based gravitational wave observatory with a sensitivity close to what was originally foreseen for LISA.

Correlation of Rock Spectra with Quantitative Morphologic Indices: Evidence for a Single Rock Type at the Mars Pathfinder Landing Site

NASA Technical Reports Server (NTRS)

Yingst, R. A.; Biedermann, K. L.; Pierre, N. M.; Haldemann, A. F. C.; Johnson, J. R.

2005-01-01

The Mars Pathfinder (MPF) landing site was predicted to contain a broad sampling of rock types varying in mineralogical, physical, mechanical and geochemical characteristics. Although rocks have been divided into several spectral categories based on Imager for Mars Pathfinder (IMP) visible/near-infrared data, efforts in isolating and classifying spectral units among MPF rocks and soils have met with varying degrees of success, as many factors influencing spectral signatures cannot be quantified to a sufficient level to be removed. It has not been fully determined which spectral categories stem from intrinsic mineralogical differences between rocks or rock surfaces, and which result from factors such as physical or chemical weathering. This has made isolation of unique rock mineralogies difficult. Morphology, like composition, is a characteristic tied to the intrinsic properties and geologic and weathering history of rocks. Rock morphologies can be assessed quantitatively and compared with spectral data, to identify and classify rock types at the MPF landing site. They can also isolate actual rock spectra from spectral types that are surficial in origin, as compositions associated with mantling dust or chemical coatings would presumably not influence rock morphology during weathering events. We previously reported on an initial classification of rocks using the quantitative morphologic indices of size, roundness, sphericity and elongation. Here, we compare this database of rock characteristics with associated rock surface spectra to improve our ability to discriminate between spectra associated with rock types and those from other sources.

Campaign 9 of the K2 Mission: Observational Parameters, Scientific Drivers, and Community Involvement for a Simultaneous Space- and Ground-based Microlensing Survey

NASA Technical Reports Server (NTRS)

Henderson, Calen B.; Poleski, Radoslaw; Penny, Matthew; Street, Rachel A.; Bennett, David P.; Hogg, David W.; Gaudi, B. Scott; Zhu, W.; Barclay, T.; Barentsen, G.;

PRECISE TULLY-FISHER RELATIONS WITHOUT GALAXY INCLINATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Obreschkow, D.; Meyer, M.

2013-11-10

Power-law relations between tracers of baryonic mass and rotational velocities of disk galaxies, so-called Tully-Fisher relations (TFRs), offer a wealth of applications in galaxy evolution and cosmology. However, measurements of rotational velocities require galaxy inclinations, which are difficult to measure, thus limiting the range of TFR studies. This work introduces a maximum likelihood estimation (MLE) method for recovering the TFR in galaxy samples with limited or no information on inclinations. The robustness and accuracy of this method is demonstrated using virtual and real galaxy samples. Intriguingly, the MLE reliably recovers the TFR of all test samples, even without using anymore » inclination measurements—that is, assuming a random sin i-distribution for galaxy inclinations. Explicitly, this 'inclination-free MLE' recovers the three TFR parameters (zero-point, slope, scatter) with statistical errors only about 1.5 times larger than the best estimates based on perfectly known galaxy inclinations with zero uncertainty. Thus, given realistic uncertainties, the inclination-free MLE is highly competitive. If inclination measurements have mean errors larger than 10°, it is better not to use any inclinations than to consider the inclination measurements to be exact. The inclination-free MLE opens interesting perspectives for future H I surveys by the Square Kilometer Array and its pathfinders.« less

A Sampling of Martian Soils

NASA Image and Video Library

2012-12-03

This collage shows the variety of soils found at landing sites on Mars. The elemental composition of the typical, reddish soils were investigated by NASA Viking, Pathfinder and Mars Exploration Rover missions, and now with the Curiosity rover.

A Plateau in Ares Vallis

NASA Image and Video Library

2015-01-15

This channelized area is near the source region of the huge outflow channel, Ares Vallis. It was at the distal end or long-ways down-river-area where the Pathfinder/Sojourner mission landed on 4 July 1997.

Pathfinder

NASA Image and Video Library

1997-06-09

A 40 K Fastrac II duration test performed at Marshall Test Stand 116. The purpose of this test was to gauge the length of time between contact of TEA (Triethylenealuminum) and LOX (liquid oxygen) as an ignitor for the Fastrac engine.

Mars Underground News.

NASA Astrophysics Data System (ADS)

Edgett, K.

Contents: Next entry to Mars (Mars Pathfinder and the microrover Sojourner). Hello, Mars, we're back! Mars Global Surveyor update. The Mars program - 2001 and beyond. Schedule of missions to Mars (as of June 11, 1997). Mars on the Web.

Marie

NASA Image and Video Library

2003-02-03

Marie Curie sits on the lander petal prior to deployment during the pre-launch Operations Readiness Test ORT 6. NASA Pathfinder, a low-cost Discovery mission, is the first of a new fleet of spacecraft that are planned to explore Mars.