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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

A feasibility study of unmanned rendezvous and docking in Mars orbit: Midterm review

The ascent, rendezvous, docking and sample transfer operations in a potential MSSR mission that uses the Mars orbital rendezvous mode are considered. In order that the design choices made for these operations remain compatible with the rest of the mission, the impact on the Earth launch, Mars landing and orbiting and Earth return phase are also being assessed. The selection and description of a preliminary baseline concept are presented.

Source record↗
NASA NTRS2002

Analysis of Mars Orbiter Camera Stereo Pairs

We have developed stereo image processing procedure for the Mars Orbiter Camera based on VICAR software package. We will present topography and shaded relief maps, extracted from both Wide and Narrow Angle stereo image pairs. Additional information is contained in the original extended abstract.

Ivanov, Anton B.↗
NASA NTRS2023

Observation of the Radiation Environment and Solar Energetic Particle Events in Mars Orbit in May 2018- June 2022

Epithermal Neutron Detector (FREND). Here we present results from measurements of the charged particle fluxes, dose rates and estimation of dose equivalent rates at ExoMars TGO Mars science orbit, provided by Liulin-MO from May 2018 to June 2022. The period of measurements covers the declining and minimum phases of the solar activity in 24th solar cycle and the rising phase of the 25th cycle. Compared are the radiation values of the galactic cosmic rays (GCR) obtained during the different phases of the solar activity. The highest values of the dose rate and flux from GCR are registered from March to August 2020. At the minimum of 24th and transition to 25th solar cycle the dose rate from GCR is 15.9 ± 1.6 µGy h−1, particle flux is 3.3 ± 0.17 cm−2 s−1, dose equivalent rate is 72.3 ± 14.4 µSv h−1. Since September 2020 the dose rate and flux of GCR decrease. Particular attention is drawn to the observation of the solar energetic particle (SEP) events in July, September and October 2021, February and March 2022 as well as their effects on the radiation environment on TGO during the corresponding periods. The SEP event during15–19 February 2022 is the most powerful event observed in our data. The SEP dose during this event is 13.8 ± 1.4 mGy (in Si), the SEP dose equivalent is 21.9 ± 4.4 mSv. SEP events recorded in Mars orbit are related to coronal mass ejections (CME) observed by SOHO and STEREO A coronagraphs. Compared are the time profiles of the count rates measured by Liulin-MO, the neutron detectors of FREND and neutron detectors of the High Energy Neutron Detector (HEND) aboard Mars Odyssey during 15–19 February 2022 event. The data obtained is important for the knowledge of the radiation environment around Mars, regarding future manned and robotic flights to the planet. The data for SEP events in Mars orbit during July 2021-March 2022 contribute to the details on the solar activity at a time when Mars is on the opposite side of the Sun from Earth.

Jordanka Semkova↗
NASA NTRS2001

Low Albedo Surfaces and Eolian Sediment: Mars Orbiter Camera Views of Western Arabia Terra Craters and Wind Streaks

High spatial resolution (1.5 to 12 m/pixel) Mars Global Surveyor Mars Orbiter Camera images obtained September 1997 through June 2001 indicate that the large, dark wind streaks of western Arabia Terra each originate at a barchan dune field on a crater floor. The streaks consist of a relatively thin coating of sediment deflated from the dune fields and their vicinity. This sediment drapes a previous mantle that more thickly covers nearly all of western Arabia Terra. No dunes or eolian bedforms are found within the dark wind streaks, nor do any of the intracrater dunes climb up crater walls to provide sand to the wind streaks. The relations between dunes, wind streak, and subjacent terrain imply that dark-toned grains finer than those which comprise the dunes are lifted into suspension and carried out of the craters to be deposited on the adjacent terrain. Such grains are most likely in the silt size range (3.9-62.5 micrometers). The streaks change in terms of extent, relative albedo, and surface pattern over periods measured in years, but very little evidence for recent eolian activity (dust plumes, storms, dune movement) has been observed.

Edgett, Kenneth S.↗
NASA NTRS1982

Mars orbiter conceptual systems design study

Spacecraft system and subsystem designs at the conceptual level to perform either of two Mars Orbiter missions, a Climatology Mission and an Aeronomy Mission were developed. The objectives of these missions are to obtain and return data.

Dixon, W.↗
NASA NTRS2003

The Mars Orbiter Laser Altimeter Archive: Final Precision Experiment Data Record Release and Status of Radiometry

A final release (Version L) of the Mars Orbiter Laser Altimeter (MOLA) Precision Experiment Data Record (PEDR) has been submitted to the Planetary Data System (PDS). Additional gridded data record products are forthcoming. These products have evolved since their original description, owing in part to improved gravity modeling and cartographic reference frames, and in part to refinements in calibration. An additional component, the 1064 nm narrowband radiometry data, is also being archived. These data will be invaluable for future studies by Mars explorers and scientists.

Neumann, Gregory A.↗
NASA NTRS1982

Mars Orbiter Study. Volume 1: Summary

Spacecraft system and subsystem designs were developed at the conceptual level to perform either of two Mars orbiter missions, a climatology mission and an aeronomy mission. The HS 376 spacecraft is the basis for the design because it has the lowest cost due to its production line status. The mission design, science instrument accommodation, and spacecraft design are summarized.

Drean, R.↗
NASA NTRS2003

Research Participation in the Mars Orbiter Laser Altimeter Experiment

This report describes the tasks that have been completed by the Principal Investigator, Gordon Pettengill, and his team during the first year of this grant. Dr. Pettengill was assisted by Dr. Peter Ford and Ms. Joan Quigley. Our main task has been to analyze the polar clouds detected by MOLA (Mars Orbiter Laser Altimeter) during the nominal mission of the Mars Global Surveyor (MGS) in 1999-2001 and to correlate the results with other data sets, in particular that from TES, the MGS thermal emission spectrometer. Starting with the Martian cloud database that we constructed prior to the start of this grant, we have examined all TES footprints that overlap MOLA clouds in time and space, correlating the thermal signature against specific categories that we assign to MOLA clouds on the basis of visual inspection. We are particularly interested in clouds in the region of "cold spots", areas of anomalously low thermal brightness temperature that have been detected in the polar winter by several instruments beginning with IRIS on Mariner 9. They are thought to indicate regions of active CO2 sublimation or snowfall, and it is hoped that MOLA measurements may tell us more about these regions.

Pettengill, Gordon H.↗
NASA NTRS2002

Participation in the Mars Orbiting Laser Altimeter Experiment

This NASA Grant, 5-4434, has covered the active participation of the Principal Investigator, Prof. Gordon Pettengill, and his Co-Investigator, Peter Ford, in the Mars Orbiting Laser Altimeter (MOLA) Experiment, over a period of five years. This participation has included attending team meetings, planning observing operations, developing data-reduction software algorithms, and processing data, as well as presenting a number of oral reports at scientific meetings and published papers in refereed journals. This research has concentrated on the various types of Martian clouds that were detected by the laser altimeter.

Pettengill, Gordon H.↗
NASA NTRS1999

Mars Orbiter Sample Return Power Design

The NASA/JPL 2003/2005 Mars Sample Return (MSR) Missions will each have a sample return canister that will be filled with samples cored from the surface of MARS. These spherical canisters will be 14.8 cm in diameter and must be powered only by solar cells on the surface and must communicate using RF transmission with the recovery vehicle that will be coming in 2006 or 2009 to retrieve the canister. This paper considers the aspect and conclusion that went into the design of the power system that achieves the maximum power with the minimum risk. The power output for the spherical orbiting canister was modeled and plotted in various views of the orbit by the SOAP program developed by JPL. The requirements and geometry for a solar array on a sphere are unique and place special constraints on the design. These requirements include 1) accommodating a lid for sample loading into the canister, surface area was restricted from use on the Northern pole of the spherical canister. 2) minimal cell surface coverage (maximum cell efficiency), less than 40%, for recovery vehicle to locate the canister by optical techniques. 3) a RF transmission during 50% of MARS orbit time on any spin axis, which requires optimum circuit placement of the solar cell onto the spherical canister. The best configuration would have been a 4.5 volt round cell, but in the real world we compromised with six triangular silicon cells connected in series to form a hexagon. These hexagon circuits would be mounted onto a flat facet cut into the spherical canister. The surface flats are required in order to maximize power, the surface of the cells connected in series must be at the same angle relative to the sun. The flat facets intersect each other to allow twelve circuits evenly spaced just North and twelve circuits South of the equator of the spherical canister. Connecting these circuits in parallel allows sufficient power to operate the transmitter at minimum solar exposure, Northern pole of the canister facing the sun. Additional power, as much as 20%, is also generated by the circuits facing MARS due to albedo of MARS.

Mardesich, N.↗
NASA NTRS2004

MARIE Dose and Flux Measurements in Mars Orbit

We present results from the Martian Radiation Environment Experiment (MARIE), aboard the 2001 Mars Odyssey spacecraft in orbit around Mars. MARIE operated successfully from March 2002 through October 2003. At the time of this writing, the instrument is off due to a loss of communications during an extremely intense Solar Particle Event. Efforts to revive MARIE are planned for Spring 2004, when Odyssey's role as a communications relay for the MER rovers is completed. During the period of successful operation, MARIE returned the first detailed energetic charged particle data from Mars. Due to limitations of the instrument, normalizing MARIE data to flux or dose is not straightforward - several large corrections are needed. Thus normalized results (like dose or flux) have large uncertainties and/or significant model-dependence. The problems in normalization are mainly due to inefficiency in detecting high-energy protons (signal-to-noise problems force the trigger threshold to be higher than optimal), to the excessively high gains employed in the signal processing electronics (many ions deposit energy sufficient to saturate the electronics, and dE/dx information is lost), and to artifacts associated with the two trigger detectors (incomplete registration of dE/dx). Despite these problems, MARIE is efficient for detecting helium ions with kinetic energies above about 30 MeV/nucleon, and for detecting high-energy ions (energies above about 400 MeV/nucleon) with charges from 5 to 10. Fluxes of these heavier ions can be compared to fluxes obtained from the ACE/CRIS instrument, providing at least one area of direct comparison between data obtained at Earth and at Mars; this analysis will be presented as a work in progress. We will also present dose-rate data, with a detailed explanation of the many sources of uncertainty in normalization. The results for both flux and dose will be compared to predictions of the HZETRN model of the GCR.

Zeitlin, C.↗