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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 NTRS2016

Assessing the Formation of Ungrouped Achondrite Northwest Africa 8186: Residue, Crystallization Product, or Recrystallized Chondrite?

The recent discoveries of primitive achondrites, metachondrites, and type 7 chondrites challenge the long held idea that all chondrites and achondrites form on separate parent bodies. These meteorites have experienced metamorphic temperatures above petrologic type 6 and have partially melted to various degrees. However, because of their isotopic and compositional similarities to both undifferentiated and differentiated groups, the provenance of these 'type 6+' meteorites remains largely unknown. CK and CV chondrites have recently been linked to a few achondrites due to their strong compositional, mineralogical, and isotopic similarities], suggesting a common origin between these meteorites. Although CVs have generally undergone low degrees of alteration near petrologic type 3, CKs have experienced a wide range of thermal alteration from petrologic type 3 to 6. Thermal evolution models on early accreting bodies predict that an early forming body can partially differentiate due to radiogenic heating, and, as a result, form radial layers of material increasing in thermal grade (types 3 to 6+) from the unmelted chondritic surface towards the differentiated core.Northwest Africa (NWA) 8186 is an ungrouped achondrite that provides compelling evidence for higher degrees of thermal processing and/or melting and differentiation on some CK/CV parent bodies. NWA 8186 plots on the CCAM line on a 3-oxygen isotope diagram directly with CK and CV chondrites and also plots with the CKs in regards to Cr isotopes. This meteorite is dominated by Nickel(II)Oxygen-rich olivine (less than 80%), lacks iron metal, and contains four oxide phases, indicating a high fOxygen (above FMQ) similar to the CKs. Additionally, NWA 8186 does not contain chondrules. We have further investigated the origins of NWA 8186 by examining and comparing the bulk composition of this CK-like achondrite with CK and CV chondrites, allowing us to assess the various scenarios in which NWA 8186 may have formed from CK/CV precursor material.

Srinivasan, P.↗
NASA NTRS2020

System Engineering a Solar Thermal Propulsion Mission Concept for Rapid Interstellar Medium Access

The interstellar medium (ISM) represents the next frontier in space exploration, with many new discoveries to be made. The challenge, being so far away from Earth, the ISM requires many decades to reach. To advance our knowledge of what exists beyond our Solar System, new approaches for rapid access are required. One such approach is solar thermal propulsion (STP). The approach uses several Venus and Earth gravity assists to fly to Jupiter and use its gravity well to dive towards the Sun. Approaching within 3 solar radii a perihelion burn would be performed, maximizing the spacecraft’s ΔV to achieve high Solar System escape velocities. A unique aspect of the STP mission concept is that the Sun is not only used as a gravity well for an Oberth manoeuvre, but also to heat the fuel to ultra-high-temperatures (>3000 K), enabling a monopropellant burn with high specific impulse (Isp). Prior preliminary studies indicated escape velocities of over 20 astronomical unit (AU)/yr would be possible. An in-depth modelling exercise was undertaken to determine how such a system would perform. The model in this paper showed the current STP design is capable of providing just under 9±1 AU/yr, but there are many technology developments that could increase escape velocity. The technologies vary from items that could be implemented in the near term, like turbo-pumps driven by the hydrogen, to items requiring more extensive development programs like thin coatings which do not erode in superheated hydrogen. After reviewing the STP approach, and comparing it to a solid rocket motor (SRM), it was found that with currently available technology, SRM outperforms STP with an escape velocity of approximately 10-12 AU/yr. However, future advances in heat exchanger lining materials, turbo pumps, and advanced heat exchanger geometries may enable solar thermal propulsion to provide higher escape velocities, providing one of the fastest ways to exit the solar system. Ultimately, if all technology paths could be implemented with minimal side effects, the performance in a best-case scenario could reach up to 16 AU/yr.

Alkalai, Leon↗
NASA NTRS2003

National Aeronautics and Space Administration. 2003 Strategic Plan

As the 21st century begins to unfold, NASA will focus, with renewed vigor, on the challenges and opportunities before us and on developing the unique capabilities that strengthen America and address our national needs. Our Mission is driven by science, exploration, and discovery, and it will be carried out with a firm commitment to fiscal responsibility. We will study climate change and the natural and human-induced hazards to Earth's ecosystem. We will help to counter the threat of international terrorism by developing technologies that can improve the security and safety of our air transportation system. We will lead the world into a new understanding of our planet, our solar system, and the universe around us, and in so doing, we will begin to understand whether life may have developed elsewhere in the cosmos. This strategic plan lays out our hopes for the future and the important things we seek to accomplish for America. We are privileged to be entrusted with these pursuits and thrilled to be able to carry them out. We invite you to join us on this great adventure. Releasing this strategic plan with our 2004 budget request represents our new commitment to the integration of budget and performance reporting. In this way, we will ensure that strategic priorities are aligned with and influence budget priorities. Our new Integrated Budget and Performance Document, a companion volume to this strategic plan, expands on the goals and objectives presented here and identifies the specific long-term and annual performance measures for which we will be held accountable.

STRATEGIC PLANNING↗
NASA NTRS2007

Science and the Constellation Systems Program Office

An underlying tension has existed throughout the history of NASA between the human spaceflight programs and the external scientific constituencies of the robotic exploration programs. The large human space projects have been perceived as squandering resources that might otherwise be utilized for scientific discoveries. In particular, the history of the relationship of science to the International Space Station Program has not been a happy one. The leadership of the Constellation Program Office, created in NASA in October, 2005, asked me to serve on the Program Manager s staff as a liaison to the science community. Through the creation of my position, the Program Manager wanted to communicate and elucidate decisions inside the program to the scientific community and, conversely, ensure that the community had a voice at the highest levels within the program. Almost all of my technical contributions at NASA, dating back to the Apollo Program, has been within the auspices of what is now known as the Science Mission Directorate. However, working at the Johnson Space Center, where human spaceflight is the principal activity, has given me a good deal of incidental contact and some more direct exposure through management positions to the structures and culture of human spaceflight programs. I entered the Constellation family somewhat naive but not uninformed. In addition to my background in NASA science, I have also written extensively over the past 25 years on the topic of human exploration of the Moon and Mars. (See, for example, Mendell, 1985). I have found that my scientific colleagues generally have little understanding of the structure and processes of a NASA program office; and many of them do not recognize the name, Constellation. In many respects, the international ILEWG community is better informed. Nevertheless, some NASA decision processes on the role of science, particularly with respect to the formulation of a lunar surface architecture, are not well known, even in ILEWG. At the recent annual Lunar and Planetary Science Conference, I reviewed the evolution of the program as a function of Agency leadership and the constraints put on NASA by the President in his 2004 announcement. I plan to continue my long-time ILEWG tradition of reporting a personal view of the state of development of human exploration of the solar system, this time coming from within the program office tasked to implement the vision for the United States. The current NASA implementation of the Vision for Space Exploration is consistent with certain classical scenarios that have been discussed extensively in the literature. I will discuss the role of science within the Vision, both from official policy and from a de facto interaction. While science goals are not officially driving the implementation of the Vision, the tools of scientific exploration are integral to defining the extraterrestrial design environments. In this respect the sharing of results from international missions to the Moon can make significant contributions to the success of the future human activities.

Mendell, Wendell↗
NASA NTRS2022

Moon to Mars (M2M) Habitation Considerations: A Snap Shot As of January 2022

The following NASA Technical Memorandum (TM) is intended to provide a snapshot in time of NASA’s current considerations (ground rules and assumptions, functional allocations, logistics) for habitation systems for the lunar surface (non-roving) and Mars transits. As NASA continues to refine the reference designs to meet the needs of an evolving architecture, it is expected that this information will also be updated as a result. Where appropriate, relevant publicly released documents will be referenced to provide further detail. NASA’s human lunar exploration plan under the Artemis program calls for achieving the goal of sending the first woman and first person of color to the surface of the Moon in the mid- 2020s and working toward sustainable exploration by the end of the decade. Working with both commercial and international partners, NASA will establish a permanent human presence on the Moon to uncover new scientific discoveries and lay the foundation for private companies to build a lunar economy. Longer duration missions on the lunar surface and in lunar orbit will also serve as a test bed for technologies to support future Mars exploration campaigns. The agency will use what we learn on the Moon to prepare for humanity's next giant leap – sending astronauts to Mars. NASA intends to establish a sustained lunar presence with the development of the Artemis Base Camp to prove technologies and capabilities that will one day enable humans to live and work on Mars, beginning with core elements including the Lunar Terrain Vehicle (LTV), the Pressurized Rover (PR), the lunar Surface Habitat (SH), power systems, and in-situ resource utilization (ISRU) systems. For in space operations and eventual transport of humans to Mars, NASA will utilize a Mars Transit Habitat (TH). Following deployment, the TH will complete a series of longer duration missions and shakedown testing while docked at Gateway, leveraging Gateway’s habitation redundancy for safety measures. Proposed Gateway-TH missions will far exceed the longest duration cislunar human missions to date. They will be the first operational readiness tests of our long-duration deep space systems, and of the split crew (two crew on the surface, two crew in space) operations that are vital to the approach for the first human Mars mission. Both the SH and TH are major architectural elements of NASA’s Moon to Mars (M2M) approach, each with very different concepts of operation. The SH is intended for use on the lunar surface as a home for astronauts, surface operations base, science facility, hub for communications, extravehicular activity (EVA) equipment repair site, waste processing facility, and supply hub. It serves as an enabler for a sustained surface presence and preparation for partial gravity operations during Mars missions. The SH will be designed to be self-sufficient for operations on the lunar surface. The SH will independently provide several functions, including its own power generation, energy storage capability, sleep quarters, hygiene areas, work areas, and dining areas. It will be capable of communicating with surface assets, orbital assets, and directly with Earth ground stations. It is planned to operate with two crew in the habitat for ~28- day stays with crew swap-outs in which the PR crew of two trades places with the habitat crew. During the swap-out, the habitat will nominally support four crew for a short period of time. For contingency scenarios, the habitat must also be capable of supporting four crew for up to 7 days. The TH will be designed to be capable of up to ~1,200-day Mars missions with the ability to carry all food and supplies needed to support a crew of four for this duration. An assumed Mars mission profile for the TH is to carry crew and supplies for ~850-day roundtrips between Earth and Mars orbit that allows 30-day stays on the Martian surface. To test the systems for this long journey, the TH will be used to extend the duration of missions at Gateway, enabling the orbiting outpost to be used as a Mars analog. These analog missions will be accomplished by attaching the TH to Gateway and conducting lunar surface operations from the TH. The TH may also need to perform free-flying shakedown missions to test out all systems prior to leaving for Mars. The habitat provides many critical functions including: a contingency airlock, crew quarters, galley, hygiene areas, safe haven capability, and science equipment. It can receive docked items from either axial end or on a radial port.

Habitat↗