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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 253 records · Page 14
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NASA NTRS2014

The Mars 2020 Rover Mission: EISD Participation in Mission Science and Exploration

The Mars 2020 Rover mission will search for potential biosignatures on the martian surface, use new techniques to search for and identify tracelevel organics, and prepare a cache of samples for potential return to Earth. Identifying trace organic compounds is an important tenet of searching for potential biosignatures. Previous landed missions have experienced difficulty identifying unambiguously martian, unaltered organic compounds, possibly because any organic species have been destroyed on heating in the presence of martian perchlorates and/or other oxidants. The SHERLOC instrument on Mars 2020 will use ultraviolet (UV) fluorescence and Raman spectroscopy to identify trace organic compounds without heating the samples.

Fries, M.↗
NASA NTRS2015

Global Precipitation Measurement (GPM) Mission: Precipitation Processing System (PPS) GPM Mission Gridded Text Products Provide Surface Precipitation Retrievals

In February 2015, the Global Precipitation Measurement (GPM) mission core satellite will complete its first year in space. The core satellite carries a conically scanning microwave imager called the GPM Microwave Imager (GMI), which also has 166 GHz and 183 GHz frequency channels. The GPM core satellite also carries a dual frequency radar (DPR) which operates at Ku frequency, similar to the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar, and a new Ka frequency. The precipitation processing system (PPS) is producing swath-based instantaneous precipitation retrievals from GMI, both radars including a dual-frequency product, and a combined GMIDPR precipitation retrieval. These level 2 products are written in the HDF5 format and have many additional parameters beyond surface precipitation that are organized into appropriate groups. While these retrieval algorithms were developed prior to launch and are not optimal, these algorithms are producing very creditable retrievals. It is appropriate for a wide group of users to have access to the GPM retrievals. However, for researchers requiring only surface precipitation, these L2 swath products can appear to be very intimidating and they certainly do contain many more variables than the average researcher needs. Some researchers desire only surface retrievals stored in a simple easily accessible format. In response, PPS has begun to produce gridded text based products that contain just the most widely used variables for each instrument (surface rainfall rate, fraction liquid, fraction convective) in a single line for each grid box that contains one or more observations.This paper will describe the gridded data products that are being produced and provide an overview of their content. Currently two types of gridded products are being produced: (1) surface precipitation retrievals from the core satellite instruments GMI, DPR, and combined GMIDPR (2) surface precipitation retrievals for the partner constellation satellites. Both of these gridded products are generated for a.25 degree x.25 degree hourly grid, which are packaged into daily ASCII (American Standard Code for Information Interchange) files that can downloaded from the PPS FTP (File Transfer Protocol) site. To reduce the download size, the files are compressed using the gzip utility.This paper will focus on presenting high-level details about the gridded text product being generated from the instruments on the GPM core satellite. But summary information will also be presented about the partner radiometer gridded product. All retrievals for the partner radiometer are done using the GPROF2014 algorithmusing as input the PPS generated inter-calibrated 1C product for the radiometer.

precipitation↗
NASA NTRS2017

Design Reference Missions (DRM): Integrated ODM 'Air-Taxi' Mission Features

Design Reference Missions (DRM): Integrated ODM Air-Taxi Mission Features, Hybrid Electric Integrated System Testbed (HEIST) flight control. Structural Health, Energy Storage, Electric Components, Loss of Control, Degraded Systems, System Health, Real-Time IO Operator Geo-Fencing, Regional Noise Abatement and Trusted Autonomy Inter-operability.

Kloesel, Kurt↗
NASA NTRS2019

NASA Exploration Mission 2 Mission Design

Exploration Mission 2 (EM-2) will be NASA’s first manned flight on the Space Launch System (SLS) and Orion Spacecraft. The mission has been changed from an SLS Block 1B configuration to Block 1. This change has necessitated a reexamination of the flight profile to determine what changes must be made in order to accommodate the reduced launch vehicle performance on the Block 1. Launch availability and orbital debris risk will be traded to find the best flight profile for both SLS and Orion.

Craig, A. S.↗
NASA NTRS2019

NASA Exploration Mission 2 Mission Design

Exploration Mission 2 (EM-2) will be NASA’s first manned flight on the Space Launch System (SLS) and Orion Spacecraft. The mission has been changed from an SLS Block 1B configuration to Block 1. This change has necessitated a reexamination of the flight profile to determine what changes must be made in order to accommodate the reduced launch vehicle performance on the Block 1. Launch availability and orbital debris risk will be traded to find the best flight profile for both SLS and Orion.

Craig, Scott↗
NASA NTRS1998

Mission Design for the Deep Space 4/Champollion Comet Sample Return Mission

The Deep Space 4/Champollion mission will be the first to land a spacecraft on the surface of a comet, perform in-situ science, and collect a subsurface sample which it will return to Earth for analysis. This paper describes the trade studies resulting in the current reference mission, which uses solar electric propulsion to rendezvous with the comet Tempel 1 in December 2005 after launching in April 2003. An option which uses a chemical propulsion system to return to Earth is discussed.

4/Champollion↗
NASA NTRS2017

The Cassini Grand Finale Mission: Planning for a New Mission Environment

The Cassini F-Ring & Proximal Orbits (FRPO) is a new and unique mission; to ensure the highest priority science gets implemented, the POST (Proximal Orbit Science Team) was created to pre-allocate the time around periapse for all 22 proximal orbits. The F-ring orbits, and proximal time outside of POST, were handled similar to Cassini’s Solstice Mission using the Pre-Integrated Event (PIE) process. The new and unique properties of the spacecraft’s trajectory required much forethought to be flown safely while still planning for the most and best science return possible. Some ring-plane crossings (RPX) will be protected against dust impacts by turning the high gain antenna (HGA) to the dust RAM direction (HGA2RAM). If on the first proximal RPX higher than expected dust readings are seen then the Project Office may choose to require more (all) subsequent RPX to be HGA2RAM, implemented via a real-time command overlay for uplinked sequences. The pointing uncertainties will be larger than usual after the final targeted flyby; some of the process changes to address this include adding extra orbit trim maneuvers (OTMs) (fuel permitting) to resync to the reference trajectory and reduce pointing uncertainties; and movable blocks of commands to be used for some periapses where atmospheric drag may cause large timing shifts Changes made for FRPO to address perceptions that these sequences will be hard to implement include requiring early pointing designs (during integration) for certain types of observations, requiring teams to check early on that they can turn to and from their observation attitude, and that their attitude is safe, and adjusting the Implementation process to give more time for science observation designers. This paper will discuss these process changes and lessons learned so far.

Ray, Trina↗
NASA NTRS2002

High-precision early mission narrow angle sciene with the Space Interferometry Mission

We have developed a technique that allows SIM to measure relative stellar positions with an accuracy of 1 micro-arcsecond at any time during its 5-yr mission. Unlike SIM's standard narrow-angle approach, Gridless Narrow Angle Astrometry (GNAA) does not rely on the global reference frame of grid stars that reaches full accuracy after 5 years. GNAA is simply the application of traditional single-telescope narrow angle techniques to SIM's narrow angle optical path delay measurements. In GNAA, a set of reference stars and a target star are observed at several baseline orientations. A linearized model uses delay measurements to solve for star positions and baseline orientations. A conformal transformation maps observations at different epochs to a common reference frame. The technique works on short period signals (P=days to months), allowing it to be applied to many of the known extra-solar planets, intriguing radio/X- ray binaries, and other periodic sources. The technique's accuracy is limited in the long-term by false acceleration due to a combination of reference star and target star proper motion. The science capability 1 micro-arcsecond astrometric precision - is unique to SIM.

Space Interferometry Mission↗