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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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NASA NTRS2017

Inconsistent Regolith Thermal Control of Hydrogen Distributions at the Moons South Pole

Introduction: For over fifty years, intense interest has focused on determining if, where, and how much hydrogen (H) may be found near the Moons poles [1]. Driving the ongoing interest has been the critical role that H volatiles must play as a resource for human missions [2]. Now, with several lines of evidence consistently indicating that H concentrations are enhanced in some permanently shadowed regions (PSRs), plus the possibility of diurnally-dependent volatile H concentrations [3-8], investigations are shifting towards understanding the sources of H and factors that govern concentrations. For the last seven-plus years, the Lunar Reconnaissance Orbiter (LRO) has collected an unparalleled temporal and spatial record of geophysical factors that may govern the Moons H distribution [9]. XXXX

Moon↗
NASA NTRS2015

An Updated Process for Automated Deepspace Conjunction Assessment

There is currently a high level of interest in the areas of conjunction assessment and collision avoidance from organizations conducting space operations. Current conjunction assessment activity is mainly focused on spacecraft and debris in the Earth orbital environment [1]. However, collisions are possible in other orbital environments as well [2]. This paper will focus on the current operations of and recent updates to the Multimission Automated Deep Space Conjunction Assessment Process (MADCAP) used at the Jet Propulsion Laboratory for NASA to perform conjunction assessment at Mars and the Moon. Various space agencies have satellites in orbit at Mars and the Moon with additional future missions planned. The consequences of collisions are catastrophically high. Intuitive notions predict low probability of collisions in these sparsely populated environments, but may be inaccurate due to several factors. Orbits of scientific interest often tend to have similar characteristics as do the orbits of spacecraft that provide a communications relay for surface missions. The MADCAP process is controlled by an automated scheduler which initializes analysis based on a set timetable or the appearance of new ephemeris files either locally or on the Deep Space Network (DSN) Portal. The process then generates and communicates reports which are used to facilitate collision avoidance decisions. The paper also describes the operational experience and utilization of the automated tool during periods of high activity and interest such as: the close approaches of NASA's Lunar Atmosphere & Dust Environment Explorer (LADEE) and Lunar Reconnaissance Orbiter (LRO) during the LADEE mission. In addition, special consideration was required for the treatment of missions with rapidly varying orbits and less reliable long term downtrack estimates; in particular this was necessitated by perturbations to MAVEN's orbit induced by the Martian atmosphere. The application of special techniques to non-operational spacecraft with large uncertainties is also studied. Areas for future work are also described. Although the applications discussed in this paper are in the Martian and Lunar environments, the techniques are not unique to these bodies and could be applied to other orbital environments.

collision↗
NASA NTRS2017

Meteoroids are Dangerous to Spacecraft

Meteoroids put dents in Shuttle windows much like bouncing gravel puts dents in your car's windshield. However, meteoroids move at such high speeds that they can partly vaporize the surfaces they strike! A dust particle (smaller than a meteoroid) hit the STEREO spacecraft and produced this fountain of smaller particles. When a meteoroid breaks up, its "shrapnel" can also be dangerous. Even when meteoroids don't damage a spacecraft, they can cause problems. Here, a small meteoroid bumped a camera on the Lunar Reconnaissance Orbiter (LRO), causing wiggles in this scan of the lunar surface. Meteoroids and pieces of space junk create rough edges on the outside of the Space Station that can damage space suits. The astronauts' gloves had to be thickened to help prevent them from ripping.

Moorhead, Althea V.↗
NASA NTRS2017

Lunar Exploration Missions Since 2006

The announcement of the Vision for Space Exploration in 2004 sparked a resurgence in lunar missions worldwide. Since the publication of the first "New Views of the Moon" volume, as of 2017 there have been 11 science-focused missions to the Moon. Each of these missions explored different aspects of the Moon's geology, environment, and resource potential. The results from this flotilla of missions have revolutionized lunar science, and resulted in a profoundly new emerging understanding of the Moon. The New Views of the Moon II initiative itself, which is designed to engage the large and vibrant lunar science community to integrate the results of these missions into new consensus viewpoints, is a direct outcome of this impressive array of missions. The "Lunar Exploration Missions Since 2006" chapter will "set the stage" for the rest of the volume, introducing the planetary community at large to the diverse array of missions that have explored the Moon in the last decade. Content: This chapter will encompass the following missions: Kaguya; ARTEMIS (Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon’s Interaction with the Sun); Chang’e-1; Chandrayaan-1; Moon Impact Probe; Lunar Reconnaissance Orbiter (LRO); Lunar Crater Observation Sensing Satellite (LCROSS); Chang’e-2; Gravity Recovery and Interior Laboratory (GRAIL); Lunar Atmosphere and Dust Environment Explorer (LADEE); Chang’e-3.

LUNAR EXPLORATION MISSIONS 200↗
NASA NTRS2011

The Lunar Orbiter Laser Altimeter (LOLA) Laser Transmitter

The Lunar Orbiter Laser Altimeter instrument on board the Lunar Reconnaissance Orbiter (LRO) mission has been in operation since it was launched in 18 June 2009. Thus far the laser transmitter system, which consists of two individual lasers, has accumulated over 1.3 Billion shots and provided an unprecedented view of the lunar surface.[ I] In this paper we present the final configuration of the space flight laser transmitter as delivered to the LOLA instrument along with some in-space operation performance data.

Yu, Anthony W.↗
NASA NTRS2011

High Gain Antenna Calibration on Three Spacecraft

This paper describes the alignment calibration of spacecraft High Gain Antennas (HGAs) for three missions. For two of the missions (the Lunar Reconnaissance Orbiter and the Solar Dynamics Observatory) the calibration was performed on orbit. For the third mission (the Global Precipitation Measurement core satellite) ground simulation of the calibration was performed in a calibration feasibility study. These three satellites provide a range of calibration situations-Lunar orbit transmitting to a ground antenna for LRO, geosynchronous orbit transmitting to a ground antenna fer SDO, and low Earth orbit transmitting to TDRS satellites for GPM The calibration results depend strongly on the quality and quantity of calibration data. With insufficient data the calibration Junction may give erroneous solutions. Manual intervention in the calibration allowed reliable parameters to be generated for all three missions.

Hashmall, Joseph A.↗
NASA NTRS2017

Systems Engineering Challenges for GSFC Space Science Mission Operations

The NASA Goddard Space Flight Center Space Science Mission Operations (SSMO) project currently manages19 missions for the NASA Science Mission Directorate, within the Planetary, Astrophysics, and Heliophysics Divisions. The mission lifespans range from just a few months to more than20 years. The WIND spacecraft, the oldest SSMO mission, was launched in 1994. SSMO spacecraft reside in low earth, geosynchronous,highly elliptical, libration point, lunar, heliocentric,and Martian orbits. SSMO spacecraft range in size from 125kg (Aeronomy of Ice in the Mesosphere (AIM)) to over 4000kg (Fermi Gamma-Ray Space Telescope (Fermi)). The attitude modes include both spin and three-axis stabilized, with varying requirements on pointing accuracy. The spacecraft are operated from control centers at Goddard and off-site control centers;the Lunar Reconnaissance Orbiter (LRO), the Solar Dynamics Observatory (SDO) and Magnetospheric MultiScale (MMS)mission were built at Goddard. The Advanced Composition Explorer (ACE) and Wind are operated out of a multi-mission operations center, which will also host several SSMO-managed cubesats in 2017. This paper focuses on the systems engineeringchallenges for such a large and varied fleet of spacecraft.

Spacecraft↗
NASA NTRS2017

Background and Lunar Neutron Populations Detected by LEND and Average Concentration of Near-Surface Hydrogen near the Moon's Poles

Neutron flux measurements by the Lunar Exploration Neutron Detector (LEND) on the Lunar Reconnaissance Orbiter (LRO) enable quantifying hydrogen-bearing volatiles in the lunar surface from orbit. Accurately determining hydrogen abundance requires discriminating between the instrument background detection rate and the population of lunar-sourced neutrons that are sensitive to surficial hydrogen. We have investigated the detection rate for lunar and non-lunar (spacecraft-sourced) neutrons in LEND by modeling maps of measured count rate in three LEND detector systems using linear combinations of maps compiled from LEND detectors and from the Lunar Prospector Neutron Spectrometer. We find that 30% of the global-average 24.926 +/- 0.020 neutron counts per second (cps) detected by the LEND STN3 thermal-energy neutron sensor are lunar-sourced neutrons in the thermal energy range (E < 0.4 eV), 65% are lunar-sourced neutrons in the epithermal and fast energy range (E > 0.4 eV), and 5% are from spacecraft-sourced background signal. In the SETN epithermal neutron detector, 90% of the 10.622 +/- 0.002 neutron detections per second are consistent with a lunar source of epithermal and fast neutrons combined (E > 0.4 eV), with 3% due to lunar-sourced thermal neutron leakage into the detector (E < 0.4 eV), and background signal accounting for 7% of total detections. Background signal due to spacecraft-derived neutrons is substantial in the CSETN collimated detector system, accounting for 57% of the global average detection rate of 5.082 +/- 0.001 cps, greater than the 48% estimated from cruise-phase data. Lunar-sourced epithermal and fast neutrons account for 43% of detected neutrons, including neutrons in collimation as well as neutrons that penetrate the collimator wall to reach the detector. We estimate a lower limit of 17% of lunar-sourced neutrons detected by CSETN are epithermal neutrons in collimation (0.37 cps), with an upper limit estimate of 54 +/- 11% of lunar-sourced neutrons received in collimation, or 1.2 +/- 0.2 cps global average. The pole-to-equator contrast ratio in epithermal and high-energy epithermal neutron flux indicates that the average concentration of hydrogen in the polar regolith above 80deg north or south latitude is ∼105 ppmw (parts per million by weight), or 0.095 +/- 0.01 wt% water-equivalent hydrogen. Above 88deg north or south, the concentration increases to ∼140 ppmw, or 0.13 +/- 0.02 wt% water-equivalent hydrogen. The similar pattern of neutron flux suppression at both poles suggests that hydrogen concentration generally increases nearer the pole and is not closely associated with a specific feature such as Shackleton Crater at the lunar south pole that has no northern counterpart. Epithermal neutron flux decreases with increasing latitude outside the polar regions, consistent with surface hydration that increases with latitude if that hydration extends to ∼13-40 cm into the surface.

T A Livengood↗
NASA NTRS2018

Time and Laser Ranging: A Window of Opportunity for Geodesy, Navigation and Metrology

Recent progress in the domain of time and frequency (T/F) standards requires important improvements of existing time distribution links. Among these, the accuracy of time transfer is actually an important part of the concerns in order to establish and maintain time & space references from ground and/or space facilities. Several time transfers by laser link projects have been carried out over the past 10 years with numerous scientific and metrological objectives. Satellite Laser ranging (SLR) has proven to be a fundamental tool, offering a straightforward, conceptually simple, highly accurate and unambiguous observable. Depending on the mission, LR is used to transmit time over two-way or one-way distances from 500 to several millions of km. The following missions and their objectives employed this technique: European Laser Timing (ELT) at 450 km, Time Transfer by Laser Link (T2L2) at 1,336 km, Laser Time Transfer (LTT) at 36,000 km, Lunar Reconnaissance Orbiter (LRO) at 350,000 km, and MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) at tens of million km. This article describes the synergy between SLR and T/F technologies developed on the ground and in space and as well as the state of the art of their exploitation. The performance and sources of limitation of such space missions are analyzed. It shows that current and future challenges lie in the improvement of the time accuracy and stability of the time for ground geodetic observatories. The role of the next generation of SLR systems is emphasized both in space and at ground level, from the point of view of GGOS and valuable exploitation of the synergy between time synchronization, ranging and data transfer.

P. Exertier↗
NASA NTRS2018

CubeX: A Compact X-Ray Telescope Enables Both X-Ray Fluorescence Imaging Spectroscopy and Pulsar Timing Based Navigation

This paper describes the benefits of a miniaturized X-ray telescope payload in the context of a lunar mission. The first part describes the payload in detail, the second part summarizes a small satellite mission concept that utilizes its compact form factor and performance. The CubeX instrument can be used for both X-ray fluorescence (XRF) imaging spectroscopy and X-ray pulsar timing based navigation (XNAV). Using our recent technological advances in X-ray optics and sensors, CubeX combines high angular resolution (<1 arcminutes) Miniature Wolter-I X-ray optics (MiXO) with a common focal plane consisting of high spectral resolution (<150 eV at 1 keV) CMOS X-ray sensors and a high timing resolution (< 1 usec) SDD X-ray sensor. This novel combination of the instruments enables both XRF measurements and XNAV operations without moving parts. The high angular resolution of the MiXO opens a wide range of orbital configurations for observation. Given that performance, the instrument has unprecedented small volume (~1×1×6U), mass (<6 kg), and power (<9W) requirements and opens a wide range of applications for a variety of targets and missions including NEOs and Martian moons. In this paper we illustrate one potential application for a lunar mission concept: The elemental composition of the Moon holds keys to understanding the origin and evolution of both the Moon and the Earth. X-ray fluorescence (XRF), induced either by solar X-ray flux or energetic ions, carries decisive signatures of surface elemental composition. X-ray observations, therefore, give a unique, powerful diagnostic tool for remotely determining elemental abundances including major rock forming elements such as Mg, Al, Na, Si, Fe, and Ca. Through high-resolution XRF imaging spectroscopy, CubeX searches for small patches of elusive lower crust and mantle material excavated within and around impact craters. CubeX identifies regional compositional variations and allows straightforward comparison of elemental distributions with the surface topography from LRO and the gravity data from GRAIL. The elemental compositions of the lower crust and the mantle are sensitive to the conditions of the giant impact which led to the Moon's formation and the subsequent lunar magma ocean (LMO), and thus they are key missing pieces in understanding the formation and early evolution of the Moon. In between XRF observations, CubeX also leverages the technology of high resolution X-ray imaging and time series measurements to conduct XNAV operations and evaluate their performance. Deep space navigation is a critical issue for small planetary missions. XNAV can enable low-cost autonomous deep-space navigation, and has the potential to greatly assist, or even outperform, NASA's Deep Space Network (DSN) or ESA's European Space Tracking (ESTRACK). CubeX is designed to perform sequential observations of 3-4 millisecond pulsars (MSPs) to solve the spacecraft trajectory for absolute navigation, and explore the remote sensing capability of XNAV. In the presented mission concept, the Moon's relative proximity enables a straightforward evaluation of the XNAV performance through DSN.

x-ray spectroscopy↗
NASA NTRS2018

Enhanced Stationkeeping Maneuver Control Technique for Delta-V Cost Reduction in the Korea Pathfinder Lunar Orbiter

Final document is attached. This paper proposes an enhanced control technique for stationkeeping maneuvers to reduce delta-v costs for the Korea Pathfinder Lunar Orbiter (KPLO). A scheduled circularization control technique exploits patterns in the evolution of the line of apsides and eccentricity to achieve a significant reduction in stationkeeping delta-v costs based on spacecraft requirements. The technique is compared against previous algorithms implemented for maneuver operations of the Lunar Prospector and Lunar Reconnaissance Orbiter (LRO) missions in the USA and KAGUYA in Japan. Through Monte Carlo analysis, the efficacy and robustness of the proposed method are verified, and the technique is shown to meet the operational requirements of KPLO.

Davis, Diane C.↗
NASA NTRS2018

Polar Volatiles Exploration in Peary Crater Enabled by NASA's Kilopower Project

For more than 50 years, scientists have discussed the possibility of the existence of water ice and other frozen volatiles at the lunar poles [1]. However, it was not until the 1990s when the polar orbiting spacecraft Clementine and Lunar Prospector collected data supporting these hypotheses [2]. Subsequent missions, including the Lunar Reconnaissance Orbiter (LRO) mission [3], and the Lunar Crater Observation and Sensing Satellite (LCROSS) mission [4], provided further evidence that supports the existence of water ice deposits at the lunar poles. During NASA's Constellation Program, several areas at both lunar poles polar were included in 50 Regions of Interest (ROI) for intensive study by the Lunar Reconnaissance Orbiter Camera (LROC) [5]. These polar ROI focused on peaks and craters rims that received high amounts of solar illumination, assuming initial missions back to the lunar surface would utilize solar arrays to generate electricity. Recently, the successful demonstration of NASA's Kilopower Project at the National Nuclear Security Administration (NNSA) Nevada National Security Site makes it possible to consider lunar polar missions at locations other than highly illuminated regions. The Kilopower Project was initiated in 2015 to demonstrate subsystem-level technology readiness of a small space fission power system [6]. This abstract describes the science objectives and operations for a mission concept developed at NASA Glenn Research Center's COMPASS Concurrent Engineering Team for a 1-year exploration of Peary Crater focused on prospecting for lunar polar volatiles.

Gruener, J. E.↗
NASA NTRS2018

Background and Lunar Neutron Populations Detected by LEND and Average Concentration of Near-Surface Hydrogen near the Moon's Poles

Neutron flux measurements by the Lunar Exploration Neutron Detector (LEND) on the Lunar Reconnaissance Orbiter (LRO) enable quantifying hydrogen-bearing volatiles in the lunar surface from orbit. Accurately determining hydrogen abundance requires discriminating between the instrument background detection rate and the population of lunar-sourced neutrons that are sensitive to surficial hydrogen. We have investigated the detection rate for lunar and non-lunar (spacecraft-sourced) neutrons in LEND by modeling maps of measured count rate in three LEND detector systems using linear combinations of maps compiled from LEND detectors and from the Lunar Prospector Neutron Spectrometer. We find that 30% of the global-average 24.926 0.020 neutron counts per second (cps) detected by the LEND STN3 thermal-energy neutron sensor are lunar-sourced neutrons in the thermal energy range (E < 0.4 eV), 65% are lunar-sourced neutrons in the epithermal and fast energy range (E > 0.4 eV), and 5% are from spacecraft-sourced background signal. In the SETN epithermal neutron detector, 90% of the 10.622 0.002 neutron detections per second are consistent with a lunar source of epithermal and fast neutrons combined (E > 0.4 eV), with 3% due to lunar-sourced thermal neutron leakage into the detector (E < 0.4 eV), and background signal accounting for 7% of total detections. Background signal due to spacecraft-derived neutrons is substantial in the CSETN collimated detector system, accounting for 57% of the global average detection rate of 5.082 0.001 cps, greater than the 48% estimated from cruise-phase data. Lunar-sourced epithermal and fast neutrons account for 43% of detected neutrons, including neutrons in collimation as well as neutrons that penetrate the collimator wall to reach the detector. We estimate a lower limit of 17% of lunar-sourced neutrons detected by CSETN are epithermal neutrons in collimation (0.37 cps), with an upper limit estimate of 54 11% of lunar-sourced neutrons received in collimation, or 1.2 0.2 cps global average. The pole-to-equator contrast ratio inepithermal and high-energy epithermal neutron flux indicates that the average concentration of hydrogen in the polar regolith above 80 north or south latitude is ~105 ppmw (parts per million by weight), or 0.095 0.01 wt% water-equivalent hydrogen. Above 88 north or south, the concentration increases to ~140 ppmw, or 0.13 0.02 wt% water-equivalent hydrogen. The similar pattern of neutron flux suppression at both poles suggests that hydrogen concentration generally increases nearer the pole and is not closely associated with a specific feature such as Shackleton Crater at the lunar south pole that has no northern counterpart. Epithermal neutron flux decreases with increasing latitude outside the polar regions, consistent with surface hydration that increases with latitude if that hydration extends to ~13-40 cm into the surface.

Livengood, Timothy A.↗
NASA NTRS2019

Wrinkle Ridges on Mercury and the Moon Within and Outside of Mascons

Found on all terrestrial planets, wrinkle ridges are anticlines formed by thrust faulting and folding resulting from crustal shortening. The MErcury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER) spacecraft's orbital phase returned high resolution images and topographic data of the previously unimaged northern high latitudes of Mercury where there are large expanses of smooth plains deformed by wrinkle ridges. Concurrently, the Lunar Reconnaissance Orbiter (LRO) is obtaining high resolution images and topographic data covering lunar mare wrinkle ridges. These data allow quantitative comparison of the scale of wrinkle ridges in smooth plains volcanic units on Mercury with mare wrinkle ridges. We evaluate the topographic relief of 300 wrinkle ridges within and outside of mascon basins on the Moon and Mercury. Measured wrinkle ridges range from ~112 to 776 m in relief with a mean of ~350 m (median = ~340 m, n = 150) on Mercury and from ~47 to 678 m in relief with a mean of ~198 m (median = ~168 m, n = 150) on the Moon. Wrinkle ridges on Mercury thus are approximately twice as large in mean relief compared to their counterparts on the Moon. The larger scale of Mercury's wrinkle ridges suggests that their formation can be attributed, in part, to global contraction. As global contraction on the Moon is estimated to be an order of magnitude smaller than on Mercury, the smaller scale of lunar wrinkle ridges suggests they most likely form primarily by load induced subsidence of the mare basalt. Wrinkle ridges located in lunar mascon basins and in the Caloris mascon on Mercury are not statistically significantly different in relief than ridges in non-mascon regions, suggesting comparable levels of contractional strain. The fact that mascon basins do not host wrinkle ridges with greater structural relief relative to non-mascon units may indicate the critical role lithospheric thickness plays in controlling subsidence and contraction of thick volcanic sequences on the Moon and Mercury.

Global contraction↗
NASA NTRS2019

Percentage of Water Retained in Icy Lunar Regolith Simulant During Transfer into a Sample Container

We now know that water ice exists on the lunar surface thanks to the findings of multiple lunar missions such as LRO and LCROSS. However, before we develop systems that can utilize this precious resource at a useful scale, we need to acquire more data about the concentration of water in the lunar regolith and how it may vary by depth and location. The OVEN (Optimized Volatile Extraction Node) system is designed to determine the concentration of water as part of an instrument called WAVE (Water Analysis & Volatile Extraction) which can be deployed during a lunar resource prospecting mission. Experiments were carried out at the Johnson Space Center in order to better understand the potential losses of water that may occur during a prospecting mission when a sample is transferred from a drill to the OVEN. A description of the experiment as well as the results will be presented here.

ISRU↗
NASA NTRS2019

Performance Improvements for the Lunar Reconnaissance Orbiter Gyroless Extended Kalman Filter

In late 2017, the laser intensity monitor (LIM) current began to decline on the Lunar Reconnaissance Orbiter (LRO) miniature inertial measurement unit (MIMU). The MIMU was powered off in March 2018 and has only been used during extended eclipses, a pre-eclipse orbit phasing maneuver, and critical momentum unloads. Science slews were suspended, and the onboard extended Kalman filter (EKF) was disabled. A coarse rate was estimated through star tracker quaternion differentiation, and attitude was provided directly from a single star tracker. A complementary filter, combining the differentiated quaternions with the integrated acceleration derived from the attitude control torque, was developed, tested, and uploaded to the spacecraft in December 2018. The EKF has been enabled, using the complementary filter rate in place of the MIMU and science slews are now being performed. This paper presents an overview of the complementary filter rate estimation and EKF changes, fault detection updates without the MIMU, and inflight performance improvements.

Halverson, Julie↗
NASA NTRSDate not supplied

VIPER: PATHFINDING IN-SITU RESOURCE UTILIZATION

With the Artemis Program, NASA plans to return humans to the Moon to stay. To help support extended stays on the moon, use of local materials - so-called in-situ resources could be invaluable. Since the moon’s polar regions have confirmed the presence of volatiles, as revealed by LCROSS, LRO and other lunar missions, the next step is to understand the nature and distribution of those candidate resources and how they might be extracted. Recent studies have even indicated that if those volatiles are practically available for harvesting, they could be processed into propellants and human life-support resources, significantly aiding in sustaining humans on the Moon, and eventually and later to sup-port missions to Mars

resource utilization↗
NASA NTRSDate not supplied

VIPER: Pathfinding Lunar Resource Understanding

With the Artemis Program, NASA plans to return humans to the Moon to stay. To help support extended stays on the moon, use of local materials -so-called in-situ resources could be invaluable. Since the moon’s polar regions have confirmed the presence of volatiles, as revealed by LCROSS, LRO and other lunar missions, the next step is to understand the nature and distribution of those candidate resources and how they might be extracted. Recent studies have even indicated that if those volatiles are practically available for harvesting, they could be processed into propellants and human life-support resources, significantly aiding in sustaining humans on the Moon, and eventually and later to sup-port missions to Mars.

Daniel Andrews↗