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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 NTRSDate not supplied

Functional Volume Assessment of an Early Version of the Mars Transit Habitat

During the summer of 2020, the NASA Mars Architecture Team (MAT) conducted a functional volume assessment of the Transit Habitat (TH). The TH has evolved substantially since that time and the current TH does not share the same internal configuration, but the insights gained from the assessment remain relevant. In virtually all architectures involving chemical, electric, or nuclear propulsion, the majority of the crew mission is spent aboard the TH. The Earth to Mars transit durations may vary from architecture to architecture, but all are on the order of hundreds of days, regardless of whether an opposition or conjunction class trajectory is selected, and regardless of whether the propulsion system is chemical, electric, or nuclear. Thus, the TH must provide capabilities appropriate to a very long duration. So, despite significant changes in the current Mars architecture over the past few years, this evaluation still provides useful recommendations in the form of habitability guidance that can be applied to current and future TH concepts. This assessment had six primary objectives: provide a sanity check to the BOC-derived TH layout; understand if we can fit the hardware and functional tasks in the volume; provide a high-level assessment of how aggressive the layout is; generate a list of challenges or assumptions necessary to make it work; generate a list of future work to refine understanding; and identify proposed requirements. All of this information is critical to drive habitat sizing studies and key architecture decisions. It was clear that a human-in-the-loop (HITL) evaluation of some kind would be necessary, but several challenges were immediately identified. The most information could be gleaned from a Desert Research and Technology Studies (DRATS) type of mission operations test (MOT), but the TH concept was too low fidelity to construct the type of prototype necessary to conduct a MOT, nor were their financial resources to do so. The next best option – and really the one most appropriate for the BOC’s stage of maturity – is a Virtual Reality (VR) walk-through evaluation. However, NASA was in a shutdown state due to the COVID-19 pandemic and the VR labs were inaccessible. As a result, a tabletop evaluation was created, using .jpg imagery from the ECM CAD model along with Excel-based datasheets. High-level crew living and working functions within the habitat were identified for evaluation. Questionnaires using Likert scales assessed acceptability of habitat functions and sim quality – the degree to which the function was represented in CAD. This enabled the evaluation to be conducted by personnel working remotely. Each function was evaluated individually along with several overarching habitability parameters and vehicle subsystems. The results of this evaluation are discussed, including methodological challenges and rating challenges. Acceptability results are discussed for functions that the participants were able to rate and participant comments for functions that could not be related are also described. Final conclusions are described, including challenges or assumptions needed to make the TH design acceptable, future work needed to refine understanding of the TH, and proposed habitat requirements based on test data.

Transit Habitat↗
NASA NTRS1989

Escape of atmospheres and loss of water

The properties and limitations of several loss processes for atmospheric gases are presented and discussed. They include thermal loss (Jeans and hydrodynamic); nonthermal loss (all processes involve charged particles); and impact erosion, including thermal escape from a molten body heated by rapid accretion. Hydrodynamic escape, or 'blowoff', is of particular interest because it offers the prospect of processing large quantities of gas and enriching the remainder in heavy elements and isotopes. In a second part, the water budgets and likely evolutionary histories of Venus, Earth and Mars are assessed. Although it is tempting to associate the great D/H enrichment on Venus with loss of a large initial endowment, a steady state with juvenile water (perhaps from comets) is equally probable.

Hunten, D. M.↗
NASA NTRS1991

Preliminary assessment of Termoskan observations of Mars

The limited set of high-resolution observations of the 8-12 micron thermal emission from Mars' equatorial regions by the Termoskan instrument onboard the Phobos '88 spacecraft in February and March of 1989 is considered. Observations were also simultaneously acquired in the 0.5 to 1.0 micron region. A combined U.S. and Soviet scientific team made a preliminary quantitative evaluation of about 25 percent of the entire data set. It is found that there is a close agreement with the Viking Infrared Thermal Mapper brightness temperatures, confirming the accuracy of the Termoskan system and calibration. A novel pattern of emission from particles was observed in the morning and assumed to be water or ice. Thermal emission from surface features is varied and distinct down to the limit of resolution. The presence of unusually insulating material has been detected in the uppermost fraction of a millimeter of the Martian surface in places where the shadow of Phobos briefly eclipsed by the surface.

Murray, B.↗
NASA NTRS1992

Chemical models of volcanic outgassing on Mars

During the MSATT workshop in Boulder, CO, several participants emphasized the importance of constraints on the composition and temporal evolution of outgassed volatiles on Mars. I present the results of some preliminary calculations that model the composition of volcanic gases as a function of temperature, pressure, oxygen fugacity, and quench function of temperature. These results can be used in combination with cosmochemical models for the accretion of Mars to assess the plausibility of different atmospheric compositions during the planet's early history.

Fegley, Bruce, Jr.↗
NASA NTRS1995

Life on Mars? 1: The chemical environment

The origin of life at its abiotic evolutionary stage, requires a combination of constituents and environmental conditions that enable the synthesis of complex replicating macromolecules from simpler monomeric molecules. It is very likely that the early stages of this evolutionary process have been spontaneous, rapid and widespread on the surface of the primitive Earth, resulting in the formation of quite sophisticated living organisms within less than a billion years. To what extend did such conditions prevail on Mars? Two companion-papers will review and discuss the available information related to the chemical, physical and environmental conditions on Mars and assess it from the perspective of potential exobiological evolution.

Banin, A.↗
NASA NTRS1993

Risk from relativistic heavy ions on manned space missions

The risk from exposure to radiation posed to space travelers outside the magnetic shielding provided by the geomagnetosphere will come from two sources: the slowly varying but low intensity high-energy galactic cosmic rays and the more intense predominantly low-energy protons from large solar particle events associated with magnetic disturbances originating sporadically on or within the solar surface during the active period of the 11-year solar cycle. The energy spectra of the protons in solar particle events are quite soft, with large numbers of low-energy protons and a rather steep decrease of the energy spectra with increasing energy. This allows for the possibility to provide, within the space vehicle or habitat, a well-shielded area sometimes called a "storm shelter" or "safe haven" where the travelers could gather during the largest particle events. Intensity risetimes on the order of half an hour or more and overall event durations of 1 to 2 days would make actively seeking a well-shielded shelter for the duration a distinct possibility. The high-energy and penetrating nature and relative constancy of the galactic cosmic rays, on the other hand, do not allow the use of highly shielded areas as a means of protection against them. The first question to answer becomes: what is the risk to human health from the galactic cosmic rays? We need to have a good idea of the answer to this question before we can address the problem of how to best protect human health or, indeed, whether any specific measures need to be taken.

NASA Program NSCORT↗
NASA NTRS2016

Mars Surface Systems Common Capabilities and Challenges for Human Missions

This paper describes the current status of common systems and operations as they are applied to actual locations on Mars that are representative of Exploration Zones (EZ) - NASA's term for candidate locations where humans could land, live and work on the Martian surface. Given NASA's current concepts for human missions to Mars, an EZ is a collection of Regions of Interest (ROIs) located within approximately 100 kilometers of a centralized landing site. ROIs are areas that are relevant for scientific investigation and/or development/maturation of capabilities and resources necessary for a sustainable human presence. An EZ also contains a habitation site that will be used by multiple human crews during missions to explore and utilize the ROIs within the EZ. The Evolvable Mars Campaign (EMC), a description of NASA's current approach to these human Mars missions, assumes that a single EZ will be identified within which NASA will establish a substantial and durable surface infrastructure that will be used by multiple human crews. The process of identifying and eventually selecting this single EZ will likely take many years to finalized. Because of this extended EZ selection process it becomes important to evaluate the current suite of surface systems and operations being evaluated for the EMC as they are likely to perform at a variety of proposed EZ locations and for the types of operations - both scientific and development - that are proposed for these candidate EZs. It is also important to evaluate proposed EZs for their suitability to be explored or developed given the range of capabilities and constraints for the types of surface systems and operations being considered within the EMC. Four locations identified in the Mars Exploration Program Analysis Group (MEPAG)'s Human Exploration of Mars Science Analysis Group (HEM-SAG) report are used in this paper as representative of candidate EZs that will emerge from the selection process that NASA has initiated. A field station site plan is developed for each of these four HEM-SAG sites. Because of the difficulty in getting equipment and supplies to the surface of Mars, specific assessments have been conducted to identify those systems and processes that can perform in multiple, sometimes completely unrelated, situations. Examples of common systems that are assessed at all of these sites include: (a) habitation and associated logistics storage systems, (b) a centralized power plant capable of supplying power to a geographically distributed (but within the central habitation zone) set of systems, (c) mobility systems that can be used to off-load and move payloads to specific locations at the central field station location that could also be used to traverse long distances to reach some of the more remote ROIs and (d) robotic systems that can support various activities (such as system set up and maintenance) at the field station that could also be used to explore scientific ROIs and used to support site-specific ISRU (In Situ Resource Utilization) production activities.

Toups, Larry↗
NASA NTRS2015

Circumlunar Free-Return Cycler Orbits for a Manned Earth-Moon Space Station

Multiple free-return circumlunar cycler orbits were designed to allow regular travel between the Earth and Moon by a manned space station. The presented cycler orbits contain circumlunar free-return "figure-8" segments and yield lunar encounters every month. Smaller space "taxi" vehicles can rendezvous with (and depart from) the cycling Earth-Moon space station to enter lunar orbit (and/or land on the lunar surface), return to Earth, or reach destinations including Earth-Moon L1 and L2 halo orbits, near-Earth objects (NEOs), Venus, and Mars. To assess the practicality of the selected orbits, relevant cycler characteristics (including (Delta)V maintenance requirements) are presented and compared.

Circumlunar Free-Return↗
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

Program to Optimize Simulated Trajectories II (POST2) Surrogate Models for Mars Ascent Vehicle (MAV) Performance Assessment

The primary purpose of the multiPOST tool is to enable the execution of much larger sets of vehicle cases to allow for broader trade space exploration. However, this exploration is not achieved solely with the increased case throughput. The multiPOST tool is applied to carry out a Design of Experiments (DOE), which is a set of cases that have been structured to capture a maximum amount of information about the design space with minimal computational effort. The results of the DOE are then used to fit a surrogate model, ultimately enabling parametric design space exploration. The approach used for the MAV study includes both DOE and surrogate modeling. First, the primary design considerations for the vehicle were used to develop the variables and ranges for the multiPOST DOE. The final set of DOE variables were carefully selected in order to capture the desired vehicle trades and take into account any special considerations for surrogate modeling. Next, the DOE sets were executed through multiPOST. Following successful completion of the DOE cases, a manual verification trial was performed. The trial involved randomly selecting cases from the DOE set and running them by hand. The results from the human analyst's run and multiPOST were then compared to ensure that the automated runs were being executed properly. Completion of the verification trials was then followed by surrogate model fitting. After fits to the multiPOST data were successfully created, the surrogate models were used as a stand-in for POST2 to carry out the desired MAV trades. Using the surrogate models in lieu of POST2 allowed for visualization of vehicle sensitivities to the input variables as well as rapid evaluation of vehicle performance. Although the models introduce some error into the output of the trade study, they were very effective at identifying areas of interest within the trade space for further refinement by human analysts. The next section will cover all of the ground rules and assumptions associated with DOE setup and multiPOST execution. Section 3.1 gives the final DOE variables and ranges, while section 3.2 addresses the POST2 specific assumptions. The results of the verification trials are given in section 4. Section 5 gives the surrogate model fitting results, including the goodness-of-fit metrics for each fit. Finally, the MAV specific results are discussed in section 6.

Zwack, M. R.↗
NASA NTRS2020

Billion-year exposure ages in Gale crater (Mars) indicate Mount Sharp formed before the Amazonian period

The erosion rates and mechanisms operating on Mount Sharp in Gale crater, Mars were assessed via experiments performed by the SAM instrument to determine the cosmogenic noble gas contents of Murray mudstone formation samples Mojave 2 and Quela. Previous measurements of samples from the Aeolis Palus depression between Mount Sharp and the north rim of Gale crater indicate that scarp retreat-generated surfaces formed within the last 100 Ma. In contrast, Mojave 2 yielded exposure ages of 1,320±240 (3He), 910±420 (21Ne), and 310±60 Ma (36Ar). Quela gave a 3He age of 1,460±200 Ma; 21Ne and 36Ar from this sample could not be quantified due to isobaric interferences. The discordant and young 36Ar exposure age in Mojave 2 is likely the result of interaction with water which dissolved the chlorine-bearing host phases of this nuclide. The most probable exposure scenario is that both Mojave 2 and Quela have been at the surface for the most recent ∼1 Ga after the overlying few meters of rock were removed in a geologically rapid exhumation episode. Based on local geomorphology, scarp retreat is the most likely mechanism for the exposure at these two sites. The exposure ages measured throughout Curiosity’s traverse indicate that the net removal of rock has proceeded more recently on Aeolis Palus than on the lower slopes of Mount Sharp. The implied differential erosion rate is insufficient to explain how Mount Sharp formed, even over billions of years. Instead, given that the surfaces on Mount Sharp have existed for >1 Ga, the mountain must have formed early, likely during the Hesperian. This study provides direct quantitative support for inferences based on crater counts that Mount Sharp had eroded to close to its current form before onset of the Amazonian.

Peter E. Martin↗
NASA NTRSDate not supplied

The Mars 2020 Watson Imaging Subsystem of the Sherloc Investigation and Anticpated Early Results

In February 2021, the Mars 2020 Perseverance rover is anticipated to touch down in Jezero crater, Mars. Perseverance is unique in that it will conduct in situ science as well as cache samples for eventual return to Earth for analysis in terrestrial laboratories. It will explore the geologic setting within Jezero over a range of scales in order to address fundamental questions about the evolution of Mars and assess whether there is evidence of past or present Martian life. The Wide Angle Topographic Sensor for Operations and eNgineering (WATSON), one of two imaging subsystems within the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument[1,2], acquires images that support scientific study of Jezero crater and sample acquisition, as well as rover and instrument operations(Fig. 1).WATSON serves a number of roles; it 1) provides color context imaging of SHERLOC and Planetary Instrument for X-Ray Litho chemistry (PIXL)analysis locations, placing the spatial distribution of organics and mineralogy detected by SHERLOC and the elemental maps generated by PIXL within the context of rock texture and structure; 2)acquires stand-alone observations of rock structures and textures from the outcrop to the grain scale; and 3)images rover components and other instruments to monitor their health and condition. We plan to present images acquired within the first ~30 sols of operations.

M E Minitti↗
NASA NTRS1990

Space Station Freedom Transportation Node Concepts and Analysis

This viewgraph presentation explores scenarios in which the configuration of Space Station Freedom evolves to support lunar and Mars exploration. The document includes a Lunar Evolution Case Study Assessment and a Mars Evolution Case Study Assessment, as well as a Lunar/Mars Exploration Initiative Assessment and a Technology Needs Assessment.

Cirillo, William M.↗
NASA NTRS1992

Radiation health for a Mars mission

Uncertainties in risk assessments for exposure of a Mars mission crew to space radiation place limitations on mission design and operation. Large shielding penalties are imposed in order to obtain acceptable safety margins. Galactic cosmic rays (GCR) and solar particle events (SPE) are the major concern. A warning system and 'safe-haven' are needed to protect the crew from large SPE which produce lethal doses. A model developed at NASA Johnson Space Center (JSC) to describe solar modulation of GCR intensities reduces that uncertainty to less than 10 percent. Radiation transport models used to design spacecraft shielding have large uncertainties in nuclear fragmentation cross sections for GCR which interact with spacecraft materials. Planned space measurements of linear energy transfer (LET) spectra behind various shielding thicknesses will reduce uncertainties in dose-versus-shielding thickness relationships to 5-10 percent. The largest remaining uncertainty is in biological effects of space radiation. Data on effects of energetic ions in human are nonexistent. Experimental research on effects in animals and cell is needed to allow extrapolation to the risk of carcinogenesis in humans.

Robbins, Donald E.↗