Marshall Space Flight Center Research and Technology Report 2019

Today, our calling to explore is greater than ever before, and here at Marshall Space Flight Centerwe make human deep space exploration possible. A key goal for Artemis is demonstrating and perfecting capabilities on the Moon for technologies needed for humans to get to Mars. This years report features 10 of the Agencys 16 Technology Areas, and I am proud of Marshalls role in creating solutions for so many of these daunting technical challenges. Many of these projects will lead to sustainable in-space architecture for human space exploration that will allow us to travel to the Moon, on to Mars, and beyond. Others are developing new scientific instruments capable of providing an unprecedented glimpse into our universe. NASA has led the charge in space exploration for more than six decades, and through the Artemis program we will help build on our work in low Earth orbit and pave the way to the Moon and Mars. At Marshall, we leverage the skills and interest of the international community to conduct scientific research, develop and demonstrate technology, and train international crews to operate further from Earth for longer periods of time than ever before first at the lunar surface, then on to our next giant leap, human exploration of Mars. While each project in this report seeks to advance new technology and challenge conventions, it is important to recognize the diversity of activities and people supporting our mission. This report not only showcases the Centers capabilities and our partnerships, it also highlights the progress our people have achieved in the past year. These scientists, researchers and innovators are why Marshall and NASA will continue to be a leader in innovation, exploration, and discovery for years to come

In-Space Propulsion Technology Program Solar Electric Propulsion Technologies

NASA's In-space Propulsion (ISP) Technology Project is developing new propulsion technologies that can enable or enhance near and mid-term NASA science missions. The Solar Electric Propulsion (SEP) technology area has been investing in NASA s Evolutionary Xenon Thruster (NEXT), the High Voltage Hall Accelerator (HiVHAC), lightweight reliable feed systems, wear testing, and thruster modeling. These investments are specifically targeted to increase planetary science payload capability, expand the envelope of planetary science destinations, and significantly reduce the travel times, risk, and cost of NASA planetary science missions. Status and expected capabilities of the SEP technologies are reviewed in this presentation. The SEP technology area supports numerous mission studies and architecture analyses to determine which investments will give the greatest benefit to science missions. Both the NEXT and HiVHAC thrusters have modified their nominal throttle tables to better utilize diminished solar array power on outbound missions. A new life extension mechanism has been implemented on HiVHAC to increase the throughput capability on low-power systems to meet the needs of cost-capped missions. Lower complexity, more reliable feed system components common to all electric propulsion (EP) systems are being developed. ISP has also leveraged commercial investments to further validate new ion and hall thruster technologies and to potentially lower EP mission costs

In Situ Science and Instrumentation for Primitive Bodies

Our study began with the goal of developing new methods to test the radically new understanding of solar system formation that has recently emerged, and to identify innovative instrumentation targeted to this purpose. In particular, we were seeking to test predictions of dynamical models such as the Nice model (after the founding research group in Nice, France), and to do so through interdisciplinary collaboration between the planetary dynamics communities that have formulated (and largely dominated discussion of) these new ideas, and the meteoritics and cosmochemistry communities who will be most involved in any in situ mission to an outer solar system body. Our study was principally focused on coming up with explicit tests of the predictions of these new dynamical models of solar system evolution. The key outcome of our first workshop was the realization that fundamental work is needed before these two communities—dynamics and meteoritics/cosmochemistry—are really ready to come to a collective understanding of early solar system evolution. Planetary dynamics examines solar system history through the orbital properties of large populations of bodies, but says little specific about any one of them. In fact, at present it appears that there is nothing you could learn about any one body that this community would consider to be a concrete test of the Nice model (or another similarly broad model of solar system evolution). On the other hand, people who study planetary materials through meteoritics and in situ missions are strongly focused on the idiosyncratic properties of individual bodies but don’t actually know how to identify the properties of a primitive body that depend upon its orbital evolution. Without such tools, it isn’t clear how this community can turn insights regarding one body into statements about broad classes of related bodies. This is a frustrating moment in the study of solar system evolution—both the dynamics and meteoritics/cosmochemistry communities have well developed and consequential hypotheses about solar system evolution, but it isn’t obvious that either knows how to make a concrete statement that is testable by the other. Our reaction to this impasse was to step back from the narrow problem of testing the Nice model as a whole (or similar specific dynamical models) and ask whether there might be specific instances—particular bodies or groups of bodies—where we could forge a link between the dynamical and meteoritic/cosmochemical approaches. If so, this could serve as a foundation that will eventually lead to a synthesis of the dynamical and cosmochemical understanding of solar system evolution. The key, we imagine, is to find a case where dynamical approaches lead to clear predictions about mineralogical or chemical properties of individual bodies, so that mineralogical or cosmochemical approaches could test those predictions through in situ or remote observations. There was consensus amongst our team that we should be able to use dynamics to predict the chemistry of a primitive body based on knowledge of where the body originated in the solar nebula and the thermal history it has undergone. We are in a unique position to make this new type of connection between dynamical models and chemistry because of the diverse backgrounds represented in our group, which includes dynamicists, astronomers, geochemists, cosmochemists, spectroscopists, mineralogists, and instrument developers. For our second workshop, we further expanded our team to address new directions, specifically drawing on expertise in geochemistry of returned samples and meteorites. Throughout our study, we had extensive discussions about the composition of primitive bodies, where in many cases little is known from telescopic observations. Moreover, there is no known meteorite collection of materials from the most relevant group of parent bodies (e.g., D-types – Trojan asteroids, irregular satellites, Phobos and Deimos, and some outer main belt asteroids). Trojan asteroids were identified as the most interesting target because they represent a large reservoir of D-types that can potentially be linked to origins in the outer solar system (primitive Kuiper belt). Dynamical histories have not yet made specific predictions about the chemistry of these bodies because the field is still in its infancy and there has been little interaction between dynamicists and chemists. We concluded that we need to develop our own theoretical framework starting from the beginning—what are the starting materials? How were they processed during and after migration? Then, we need to actually do the lab work to simulate these materials and look for markers. A search for these markers would be the basis of the science motivation for future missions to these bodies. Because of the current lack of knowledge about the compositions of these bodies, we found that choosing a specific suite of in situ instruments to develop for such a mission would be premature at this point. (For a primer on in situ instruments for planetary surface exploration, see Appendix B). It is understood that any mission to the Trojans would operate under extreme constraints of mass and power so that it would not be possible to send all possible instrumentation to characterize the surface. Hence, we must develop the theoretical and laboratory framework first so that we can tailor the instruments to the most important measurements. The expected significance of the identification of these markers (the topic of our follow-on proposal) is that it would have implications for all future missions to small bodies (not just the Trojans). It is understood that in order to gain the most detailed knowledge of both chemical and isotopic compositions of small bodies, sample return would be preferred. However, if we can identify one or several very specific markers, it will become feasible to search for these with a small suite of in situ instruments at a number of target bodies. Or, even better, it may be possible for us to identify spectral properties that can be observed remotely. Our goal is to work our way to an understanding of these sorts of dynamically important signatures

Application of Solar-Electric Propulsion to Robotic and Human Missions in Near-Earth Space

No abstract availabl

Interplanetary Electric Propulsion Uranus Mission Trades Supporting the Decadal Survey

The Decadal Survey Committee was tasked to develop a comprehensive science and mission strategy for planetary science that updates and extends the National Academies Space Studies Board s current solar system exploration decadal survey. A Uranus orbiter mission has been evaluated as a part of this 2013-2022 Planetary Science Decadal Survey. A comprehensive Uranus orbiter mission design was completed, including a broad search of interplanetary electric propulsion transfer options. The scope of interplanetary trades was limited to electric propulsion concepts, both solar and radioisotope powered. Solar electric propulsion offers significant payloads to Uranus. Inserted mass into the initial science orbit due is highly sensitive to transfer time due to arrival velocities. The recommended baseline trajectory is a 13 year transfer with an Atlas 551, a 1+1 NEXT stage with 15 kW of power using an EEJU trajectory and a 1,000km EGA flyby altitude constraint. This baseline delivers over 2,000kg into the initial science orbit. Interplanetary trajectory trades and sensitivity analyses are presented herein

NASA's In-Space Propulsion Technology Project Overview, Near-term Products and Mission Applicability

The In-Space Propulsion Technology (ISPT) Project, funded by NASA's Science Mission Directorate (SMD), is continuing to invest in propulsion technologies that will enable or enhance NASA robotic science missions. This overview provides development status, near-term mission benefits, applicability, and availability of in-space propulsion technologies in the areas of aerocapture, electric propulsion, advanced chemical thrusters, and systems analysis tools. Aerocapture investments improved (1) guidance, navigation, and control models of blunt-body rigid aeroshells, 2) atmospheric models for Earth, Titan, Mars and Venus, and 3) models for aerothermal effects. Investments in electric propulsion technologies focused on completing NASA s Evolutionary Xenon Thruster (NEXT) ion propulsion system, a 0.6-7 kW throttle-able gridded ion system. The project is also concluding its High Voltage Hall Accelerator (HiVHAC) mid-term product specifically designed for a low-cost electric propulsion option. The primary chemical propulsion investment is on the high-temperature Advanced Material Bipropellant Rocket (AMBR) engine providing higher performance for lower cost. The project is also delivering products to assist technology infusion and quantify mission applicability and benefits through mission analysis and tools. In-space propulsion technologies are applicable, and potentially enabling for flagship destinations currently under evaluation, as well as having broad applicability to future Discovery and New Frontiers mission solicitations

Mission Assessment of the Faraday Accelerator with Radio-frequency Assisted Discharge (FARAD)

Pulsed inductive thrusters have typically been considered for future, high-power, missions requiring nuclear electric propulsion. These high-power systems, while promising equivalent or improved performance over state-of-the-art propulsion systems, presently have no planned missions for which they are well suited. The ability to efficiently operate an inductive thruster at lower energy and power levels may provide inductive thrusters near term applicability and mission pull. The Faraday Accelerator with Radio-frequency Assisted Discharge concept demonstrated potential for a high-efficiency, low-energy pulsed inductive thruster. The added benefits of energy recapture and/or pulse compression are shown to enhance the performance of the pulsed inductive propulsion system, yielding a system that con compete with and potentially outperform current state-of-the-art electric propulsion technologies. These enhancements lead to mission-level benefits associated with the use of a pulsed inductive thruster. Analyses of low-power near to mid-term missions and higher power far-term missions are undertaken to compare the performance of pulsed inductive thrusters with that delivered by state-of-the-art and development-level electric propulsion systems

The Economics of Advanced In-Space Propulsion

The cost of access to space is the single biggest driver is commercial space sector. NASA continues to invest in both launch technology and in-space propulsion. Low-cost launch systems combined with advanced in-space propulsion offer the greatest potential market capture. Launch market capture is critical to national security and has a significant impact on domestic space sector revenue. NASA typically focuses on pushing the limits on performance. However, the commercial market is driven by maximum net revenue (profits). In order to maximum the infusion of NASA investments, the impact on net revenue must be known. As demonstrated by Boeing's dual launch, the Falcon 9 combined with all Electric Propulsion (EP) can dramatically shift the launch market from foreign to domestic providers

Mission Benefits of Gridded Ion and Hall Thruster Hybrid Propulsion Systems

The NASA In-Space Propulsion Technology (ISPT) Project Office has been developing the NEXT gridded ion thruster system and is planning to procure a low power Hall system. The new ion propulsion systems will join NSTAR as NASA's primary electric propulsion system options. Studies have been performed to show mission benefits of each of the stand alone systems. A hybrid ion propulsion system (IPS) can have the advantage of reduced cost, decreased flight time and greater science payload delivery over comparable homogeneous systems. This paper explores possible advantages of combining various thruster options for a single mission