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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 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
NASA NTRS2019

Predicted Performance of an X-Ray Navigation System for Future Deep Space and Lunar Missions

In November 2017, the NASA Goddard Space Flight Center (GSFC) Station Explorer for X-ray Timing and Navigation Technology (SEXTANT) experiment successfully demonstrated the feasibility of X-ray Pulsar Navigation (XNAV) as part of the Neutron Star Interior Composition Explorer (NICER) mission, which is an X-ray Astrophysics Mission of Opportunity currently operating onboard the International Space Station (ISS). XNAV provides a GPS-like absolute autonomous navigation and timing capability available anywhere in the Solar System and beyond. While the most significant benefits of XNAV are expected to come in support of very deep-space missions, the absolute autonomous navigation and timing capability also has utility for inner Solar System missions where increased autonomy or backup navigation and timing services are required, e.g., address loss of communication scenarios.The NASA commitment to develop a Gateway to support exploration of the Moon and eventually Mars, as well as current and future robotic missions such as James Webb Space Telescope (JWST), New Horizons, and much more, certainly will tax the existing ground based infrastructure in terms of availability. There- fore, an extended look at the feasibility and potential performance of XNAV for comparable missions is warranted. In this paper, we briefly review the XNAV concept and present case studies of its utility and performance for a Gateway orbit, Sun-Earth libration orbit, and a deep space transit trajectory.

Getchius, Joel↗
NASA NTRS2018

Journey 'Round the Sun: STEREO Science and Spacecraft Performance Results

The Solar TErrestrial RElations Observatory (STEREO) was originally designed as a two- to five-year heliocentric orbit mission to study coronal mass ejections (CMEs), solar energetic particles (SEPs), and the solar wind. After over ten years of continuous science data collection, the twin NASA STEREO observatories have significantly advanced the understanding of Heliophysics. This mission was the first to image CMEs all the way from the Sun to Earth and to observe the entire sphere of the Sun at one time. STEREO has demonstrated the importance of a point of view beyond the Sun-Earth line to significantly improve CME arrival time estimates and in understanding CME structure and trajectories and the longitudinal distribution of SEPs. STEREO was also the first to use one launch vehicle to insert two spacecraft into opposing heliocentric orbits, undergo a 3.5-month-long superior solar conjunction, implement unattended daily science operations on two deep space observatories, maintain 7 arcsec continuous pointing without gyros, and detect and attempt to recover a spacecraft after a 22-month long communications anomaly at a range of 2 AU (Astronomical Units). This paper discusses the significant performance results after the first ten years of operations of the STEREO mission from its journey around the Sun.

Ossing, Daniel A.↗
NASA NTRS2018

Interstellar Mapping and Acceleration Probe (IMAP): A New NASA Mission

The Interstellar Mapping and Acceleration Probe (IMAP) is a revolutionary mission that simultaneously investigates two of the most important overarching issues in Heliophysics today: the acceleration of energetic particles and interaction of the solar wind with the local interstellar medium. While seemingly disparate, these are intimately coupled because particles accelerated in the inner heliosphere play critical roles in the outer heliospheric interaction. Selected by NASA in 2018, IMAP is planned to launch in 2024. The IMAP spacecraft is a simple sun-pointed spinner in orbit about the Sun-Earth L1 point. IMAP's ten instruments provide a complete and synergistic set of observations to simultaneously dissect the particle injection and acceleration processes at 1 AU while remotely probing the global heliospheric interaction and its response to particle populations generated by these processes. In situ at 1 AU, IMAP provides detailed observations of solar wind electrons and ions; suprathermal, pickup, and energetic ions; and the interplanetary magnetic field. For the outer heliosphere interaction, IMAP provides advanced global observations of the remote plasma and energetic ions over a broad energy range via energetic neutral atom imaging, and precise observations of interstellar neutral atoms penetrating the heliosphere. Complementary observations of interstellar dust and the ultraviolet glow of interstellar neutrals further deepen the physical understanding from IMAP. IMAP also continuously broadcasts vital real-time space weather observations. Finally, IMAP engages the broader Heliophysics community through a variety of innovative opportunities. This papersummarizes the IMAP mission at the start of Phase A development.

McComas, D. J.↗
NASA NTRS2014

Contingency Trajectory Design for a Lunar Orbit Insertion Maneuver Failure by the LADEE Spacecraft

A contingency trajectory analysis was performed for NASA Ames Research Center’s (ARC’s) Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft in case of a missed lunar orbit insertion (LOI) maneuver. Recovery trajectory options are shown to exist for all LADEE launch opportunities throughout a one year period. Recovery ΔV costs primarily depended on the spacecraft’s apogee location on or near the Sun-Earth weak stability boundary (WSB) and the time needed by the spacecraft to recover (e.g. to “wake up” from “safe” mode) to perform an escape prevention maneuver after the missed LOI.

Genova, A. L.↗
NASA NTRS2019

Libration Orbit Eclipse Avoidance Maneuver Study for the James Webb Space Telescope Mission

Mission analysis of libration orbit trajectories at Sun-Earth/Moon L2 typically includes predictions of lunar and Earth eclipses during the mission life-time. The NASA James Webb Space Telescope (JWST) trajectory, by design, avoids these eclipses by pruning its launch window. In an off-nominal scenario where an eclipse is predicted, a maneuver strategy is needed. In this paper, trade studies are examined for JWST that characterize the burn magnitude, location, and epochs of multiple maneuver plans to avoid an eclipse. The results enable analysts to explore the space of feasible maneuver strategies during routine operations.

Maneuver design↗
NASA NTRS2019

Meteor Shower Forecasting in Near-Earth Space

NASA’s Meteoroid Environment Office (MEO) produces an annual meteor shower forecast in order to help spacecraft operators assess the risk posed by meteoroid streams. Previously, this forecast focused on the International Space Station and therefore reported meteoroid fluxes and enhancement factors at an orbital altitude of 400 km. This paper presents an updated forecast algorithm that has an improved calculation of the flux enhancement produced by showers and can calculate fluxes at any selected Earth or lunar orbital altitude. Finally, we discuss and generate forecasted fluxes for the 2018 Draconid meteor shower, which is expected to produce meteoroid flux enhancements near the Sun-Earth L1 and L2 Lagrange points but not at Earth.

Althea V Moorhead↗
NASA NTRS2004

The L1 diamond affair

The L1 Diamond is a configuration of four solar sail spacecraft traveling in approximately a diamond arrangement and situated on the Sun side of the Sun-Earth L1 Lagrange point. The purpose of this diamond arrangement will be to determine the large scale three-dimensional structure of solar disturbances propagated toward the Earth. These spacecraft will have a wide separation of 100 to 500 Earth radii and solar sails will maintain this separation in non-Keplarian orbits. In this paper equations are derived to calculate the solar sail characteristic acceleration as a function of the position in the L1 Diamond formation.

Sauer, Carl G. Jr.↗
NASA NTRS1999

Genesis Trajectory Design

The Genesis mission will launch in 2001, sending a spacecraft into an L1 halo orbit in the Sun-Earth system to collect solar wind samples.

Genesis↗
NASA NTRS1997

Halo Orbit Generation Using the Center Manifold

In recent years, halo orbits around the Sun-Earth Lagrange points, L1 and L2, have become extremely opular for NASA missions due to the ideal observation environment and low launch energy.

periodic↗
NASA NTRS1997

Trajectory Design Using a Dynamical Systems Approach With Application to Genesis

A number of missions have recently been proposed that aim to take advantage of the growing scientific interest in the region of space near libration points in the Sun-Earth system. In support of missions that include increasingly complex trajectories and incorporate libration point orbits, more efficient techniques and new philosophies for design must be considered.

Genesis↗
NASA NTRS1998

Genesis Mission Design

The Genesis spacecraft will collect solar wind samples from a halo orbit about the Sun-Earth L1 point for two years, returning those samples to Earth in 2003 for on-Earth analysis and examination.

Genesis↗
NASA NTRS2018

Deep Space Relay Terminals for Mars Superior Conjunction

The Sun periodically blocks direct communication between the Earth and Mars, creating a need for a relay when missions have a critical need for communication during these times. We examined several approaches based on optical or radio-frequency relays placed in deep space between the Earth and Mars, exploring multiple possible placements of relays, including periodic orbits in the Sun-Earth and Sun-Mars rotating frames, and eccentric, sun-centered orbits. L4 and L5 long-period orbits in the sun-Mars system provide suitable communications geometry continuously for very long durations. In such an orbit, a deep space relay terminal with two 50 cm optical telescopes and two 75 cm Ka-band dish antennas, along with associated receivers and transmitters, would be capable of supporting Mars superior conjunctions with an optical data rate of 28 to 44 Mbps for return links, and 30-36 Mbps in the forward direction. The relay should use efficient, low-noise optical detectors, such as appropriately cooled Avalanche Photo Diode or Superconducting Nanowire Single Photon Detectors, to achieve these data rates. The single relay discussed in this study might have additional value beyond communications, providing a synergistic platform for solar observation, solar wind observation, gravitational studies, the search for near-earth asteroids, or a navigational beacon.

Lau, Chi-Wung↗
NASA NTRS2019

Remote Sensing of Daytime Water Leaving Reflectances of Oceans and Large Inland Lakes from EPIC onboard the DSCOVR Spacecraft at Lagrange-1 Point

The NASA’s Earth Polychromatic Imaging Camera (EPIC) on board the Deep Space Climate Observatory (DSCOVR) satellite has been making multiple observations of the entire sunlit Earth in a given day from the Sun-Earth Lagrangian L1 point since the summer of 2015. EPIC contains 10 narrow channels in the 317–780 nm solar spectral range. The data acquired with EPIC have already been used in a variety of scientific investigations, including the study of the global ozone levels, aerosol index and aerosol optical depth, UV reflectivity of clouds over land and ocean, cloud height over land and ocean, and vegetation indices. In this article, we report that EPIC data, particularly for the data measured with narrow channels centered near 443, 551, and 680 nm, can also have important applications in remote sensing of ocean color in different geographical regions. We have modified a version of a multi-channel atmospheric correction algorithm for Moderate Resolution Imaging Spectro Radiometer (MODIS) ocean color applications and adapted the algorithm for processing EPIC data. We present three case studies on water leaving reflectance retrievals from EPIC data acquired over a large turbid river, inland lakes, and oceans. We conclude that a future ocean color instrument on board a satellite at the L1 point, which provides continuous view of the full sunlit disk of the Earth, will complement and extend ocean color observations with the low Earth observing polar orbital and geostationary satellite instruments in both the spatial and time domains.

remote sensing↗
NASA NTRS2000

Multimission Space and Solar Physics Microspacecraft

The solar fields and particles environment and its interaction with planetary magnetospheres are not only of considerable scientific interest, they can impact human endeavors as well.

microspacecraft space weather space physics solar ↗
NASA NTRS2006

Near Sun Free-Space Optical Communications from Space

Free-space optical communications offers expanded data return capacity, from probes distributed throughout the solar system and beyond. Space-borne and Earth-based optical transceivers used for communicating optically, will periodically encounter near Sun pointing. This will result in an increase in the scattered background light flux, often contributing to degraded link performance. The varying duration of near Sun pointing link operations relative to the location of space-probes, is discussed in this paper. The impact of near Sun pointing on link performance for a direct detection photon-counting communications system is analyzed for both ground- and space-based Earth receivers. Finally, impact of near Sun pointing on spaceborne optical transceivers is discussed.

free-space↗
NASA NTRS2014

How the Sun Knocks Out My Cell Phone from 150 Million Kilometers Away

Large solar particle events (SPE) threaten many elements of critical infrastructure. A 2013 study by Lloyds of London and Atmospheric and Environmental Research recently found that if a worst-case solar event like the 1859 Carrington Event struck our planet now, it could result on $0.6-$2.36 trillion in damages to the economy. In March 2014, researchers Y. D. Liu et al. revealed that just such an event had narrowly missed Earth in July 2012. The event was observed by the STEREO A spacecraft. In this presentation, we examine how the sun can pack such a punch from 150 million km away, the threats such solar particle events pose, their mechanisms and the efforts NASA and other space agencies are carrying out to understand and mitigate such risks.

geomagnetic storms↗
NASA NTRS2000

NASA's Interstellar Probe Mission

NASA's Interstellar Probe will be the first spacecraft designed to explore the nearby interstellar medium and its interaction with our solar system.

Interstellar↗