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NASA NTRS2023

Reconnection in a Pinch

A recently published analysis of current sheets has updated the classic Harris 1D static solution by considering multiple classes of charged particle trajectories in a generalized and dynamic current sheet. It uses a 1D PIC simulation to describe dynamic pinching and bifurcation of the current sheet. These 1D results strongly suggest that properties of the inflowing plasma, including the plasma beta, have an important effect on the equilibrium thickness of the pinched current sheet. Since 1D studies cannot describe magnetic reconnection, the time appears right to carry such 1D studies over to 2D or 3D simulations to explore current sheet thickness effects on reconnection. The Magnetospheric Multiscale Mission (MMS), with its well-resolved multipoint measurements of collisionless plasma and fields, has found that collisionless reconnection is accompanied by non-adiabatic motions of electrons that only occur in magnetic structures with a narrow scale comparable to electron inertial lengths (d e ). The recent 1D studies suggest that a plasma pinch to such scales may only occur for inflowing magnetized plasmas with relatively low plasma beta. We conclude that a parametric exploration of simulated and observed reconnection inflow conditions, particularly plasma beta, should shed light on the enablement of reconnection in collisionless plasmas.

reconnection↗

NASA NTRS2018

Payload Utilization in NASA's Space Launch System

With Space Policy Directive 1, the United States administration has directed the National Aeronautics and Space Administration’s (NASA’s) Human Exploration & Operations Mission Directorate (HEOMD) to return to the Moon with missions and infrastructure designed to support a sustained presence in cislunar space, with robotic and human lunar surface operations. NASA’s new deep space exploration system — the super heavy-lift Space Launch System (SLS), the Orion crew spacecraft and revamped launch facilities at Kennedy Space Center (KSC) — will enable NASA and its commercial and international partners to meet this goal for human exploration of deep space. SLS is the most capable launch vehicle for these efforts, as well as for sending robotic missions deep into the solar system, or even to interstellar space. The vehicle will be available in crew and cargo configurations in progressively more powerful block variants. The initial Block 1 lift capability of at least 26 metric tons (t) to trans-lunar injection (TLI) will be followed by a more powerful Block 1B with the power to loft more than 37 t to TLI. The ultimate Block 2 variant will lift more than 45 t to TLI. For payload accommodation, the Block 1 vehicle can utilize a 5 meter (m) fairing in its cargo configuration with the crew version also able to provide berths for 6U and 12U CubeSats as secondary payloads. The Block 1B crew vehicle will provide as much volume as the space shuttle payload bay in a Universal Stage Adapter (USA) for co-manifested payloads (CPLs). Block 1B cargo vehicles will offer 8.4 m-diameter fairings in 19.1 m and possibly longer lengths, with enough volume to accommodate lunar-orbiting habitat modules and other elements of NASA’s Gateway science outpost. For Mars-class payloads, larger fairings for the Block 2 cargo launcher are under consideration. For missions beyond the Earth-Moon system, SLS offers greater characteristic energy (C3) than any other launch vehicle, enabling shorter transit times or heavier payloads with more robust science packages for missions to the outer solar system. Indeed, the unmatched combination of thrust, payload volume and departure energy that SLS provides opens new opportunities for human and robotic exploration of deep space. This paper will provide an overview of the various vehicle block configurations, their capabilities and payload accommodations for sending primary, co-manifested and secondary payloads to deep space

Creech, Stephen D.↗

NASA NTRS2000

Mars Aerobot Missions

Mars aerobots constitute a class of mission nearly a factor of 10 smaller than earlier concepts for Mars balloons. A key goal is to achieve high payload mass fraction in a small total systems mass and to maximize the scientific potential of that payload. The "low and slow" attributes of aerobot flight paths afford advantages for many observations and measurements of Mars. Scientific objectives include surveys of remnant magnetism, studies of the surface with high resolution stereo imaging, and investigations of the structure and dynamics of the atmosphere with an in situ meteorology payload.

Greeley, R.↗

NASA NTRSDate not supplied

Brayton Cycle Power Conversion Model for MW-Class Nuclear Electric Propulsion Mars Missions

A Brayton cycle based power conversion system for a nuclear electric propulsion application was modeled in Simulink as part of NASA’s space nuclear program in order to explore the impact of technology assumptions on the power conversion system performance and capabilities. The thermodynamic processes and algorithms within the model are documented, including a higher fidelity reactor model. Assumptions are chosen based on literature and subject matter expert review, and example results and capabilities of the model are shown. The effects of the turbine inlet and compressor inlet temperature on radiator area and thermal efficiency are discussed. For a He-Xe closed Brayton cycle, radiator areas as low as 650 m2/MWe are shown, with corresponding thermal efficiences at roughly 20% for the minimal radiator area solutions.

Brayton↗

NASA NTRS2001

Midodrine prevents orthostatic intolerance associated with simulated spaceflight

Many astronauts after being weightless in space become hypotensive and presyncopal when they assume an upright position. This phenomenon, known as orthostatic intolerance, may interfere with astronaut function during reentry and after spaceflight and may limit the ability of an astronaut to exit a landed spacecraft unaided during an emergency. Orthostatic intolerance is more pronounced after long-term spaceflight and is a major concern with respect to the extended flights expected aboard the International Space Station and for interplanetary exploration class missions, such as a human mission to Mars. Fully effective countermeasures to this problem have not yet been developed. To test the hypothesis that alpha-adrenergic stimulation might provide an effective countermeasure, we conducted a 16-day head-down-tilt bed-rest study (an analog of weightlessness) using normal human volunteers and administered the alpha(1)-agonist drug midodrine at the end of the bed-rest period. Midodrine was found to significantly ameliorate excessive decreases in blood pressure and presyncope during a provocative tilt test. We conclude that midodrine may be an effective countermeasure for the prevention of orthostatic intolerance following spaceflight.

NASA Center JSC↗

NASA NTRS1990

The Advanced Composition Explorer

The Advanced Composition Explorer (ACE) was recently selected as one of two new Explorer-class missions to be developed for launch during the mid-1990s. ACE will observe particles of solar, interplanetary, interstellar, and Galactic origins, spanning the energy range from that of the solar wind to Galactic cosmic ray energies. Definitive studies will be made of the abundance of nearly all isotopes from H to Zn, with exploratory isotope studies extending to Zr. The scientific objectives, instrumentation, spacecraft, and mission approach that were defined for ACE during the Phase-A study period are summarized.

Stone, E. C.↗

NASA NTRS2022

The Mass Change Designated Observable Study: Overview and Results

The 2017–2027 United States National Academy of Sciences Decadal Survey (DS) for Earth Science and Applications from Space identified Mass Change (MC) as one of five Designated Observables (DOs) having the highest priority in terms of Earth observations required to advance Earth system science over the next decade. In response to this designation, NASA initiated several multi-center studies, with the goal of recommending observing system architectures for each DO for implementation within this decade. This paper provides an overview of the Mass Change Designated Observable (MCDO) Study along with key findings. The study process included: (a) generation of a Science and Applications Traceability Matrix (SATM) that maps required measurement parameters to the DS Science and Applications Objectives; (b) identification of three architecture classes relevant for measuring mass change: Precise Orbit Determination (POD), Satellite-Satellite-Tracking (SST) and Gravity Gradiometry (GG), along with variants within each architecture class; and (c) creation of a Value Framework process that considers science value, cost, risk, schedule, and partnership opportunities, to identify and recommend high value observing systems for further in-depth study. The study team recommended the implementation of an SST architecture, and identified variants that simultaneously (a) satisfy the baseline measurement parameters of the SATM; (b) maximize the probability of providing overlap with the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission currently in operation, accelerating science return from both missions; and (c) provide a pathway towards substantial improvements in resolution and accuracy of mass change data products relative to the program of record.

D N Wiese↗

NASA NTRSDate not supplied

Functional Task Tests in Partial Gravity During Parabolic Flight

BACKGROUND Critical mission tasks that are required by crews immediately after landing on a planetary surface are seat egress, jump, and walk. To be able to define an effective and comprehensive countermeasure strategy for preserving crew performance during exploration-class missions, there is a need to understand how these functional tasks are actually performed in partial gravity such as on the Moon or Mars. We propose to study the performance in the execution of these tasks during the partial gravity and hypergravity phases of parabolic flight. These tasks will be completed using the same equipment and procedures as the Standard Measures Sensorimotor protocol, which is performed by astronauts returning from spaceflight and by ground-based subjects after prolonged axial body unloading during bed rest. HYPOTHESIS We hypothesize that partial gravity during parabolic flight will cause acute changes in vestibular, proprioceptive, and sensorimotor functions, and these changes will impact the performance of mission critical tasks such as standing, walking, and jumping. The largest changes in performance are expected at the lowest gravity level (0.25g) because subjects will no longer be able to use the gravitational reference for the perception of vertical. Ultimately, this information could be used to assess performance risks and inform the design of countermeasures for NASA exploration-class human missions. METHODS Twelve subjects will be tested during three flights of 30 parabolas, including 10 parabolas at 0.25g, 10 parabolas at 0.5g and 10 parabolas at 0.75g. Subject also will perform tests in 1g between parabolas and in hypergravity (1.8g) during the pull-out phases. Subjects will perform the same tasks as those tested on astronauts returning from spaceflight: sit-to-stand and obstacle walk, tandem walk, jump down, and recovery from fall. Measurements will include: (a) the time for the subject to complete the test (sit-to-stand and obstacle walk, recovery from fall); (b) the time elapsed between the start of motion and the stabilization of upright posture (recovery from fall, jump down); (c) the mean sway speed during quiet standing (recovery from fall, jump down); (d) changes in heart rate and blood pressure (recovery from fall); (e) the percentage of correct steps and torso acceleration (tandem walk); and (f) the severity of motion sickness symptoms. RELEVANCE Although gravitational dose-response curves have been obtained for some biochemical systems in animals, these dose-responses are unknown for most human physiologic systems. Our study will compare the outcomes of 5 functional task tests in 0.25g, 0.5g, 0.75g, 1g, and 1.8g with those previously obtained in ground-based subjects after prolonged axial body unloading and in astronauts immediately after spaceflight. This comparison will help understanding the true extent of functional task performance deficits in partial gravity. The dose-response relationship between gravity level and task performance decrement also will help determining the gravity threshold for these functional tasks. ACKNOWLEDGEMENT This work is supported by the NASA’s Human Research Program Human Health Countermeasures Element

Gilles Clement↗

NASA NTRS2005

SHERPA Electromechanical Test Bed

SHERPA (Strap-on High-altitude Entry Reconnaissance and Precision Aeromaneuver system) is a concept for low-cost-high-accuracy Martian reentry guidance for small scout-class missions with a capsule diameter of approximately 1 meter. This system uses moving masses to change the center of gravity of the capsule in order to control the lift generated by the controlled imbalance. This project involved designing a small proof-of-concept demonstration system that can be used to test the concept through bench-top testing, hardware-in-the-loop testing, and eventually through a drop test from a helicopter. This project has focused on the Mechatronic design aspects of the system including the mechanical, electrical, computer, and low-level control of the concept demonstration system.

Wason, John D.↗

NASA NTRS2021

A Demand Access Paradigm for NASA’s Deep Space Network

NASA’s Deep Space Network (DSN) is the primary resource for communications and navigation for interplanetary space missions, for both NASA and partner agencies. As part of an investigation into improved efficiency and responsiveness, we have been exploring and prototyping the infusion of a ”demand access” model into the DSN scheduling process. Today, DSN is fully pre-scheduled in advance, and many users rely on a stable schedule to plan their own spacecraft activities, weeks in advance of execution. However, a new class of missions is emerging that may not be scheduled as far in advance, and may be event-driven in coming across science targets at unpredictable times. These users could take advantage of an on-demand mechanism to download data. Simulations have shown that such a mechanism could improve latency (time from data collection to download) by 2x, as well as more efficiently utilize the available DSN antennas. In this paper, we describe a prototype of a demand access process and how it addresses the challenges of co-existing with a staticallyscheduled body of missions, while providing the benefits of lower latency science data return.

Lucena, Girly↗

DOE OSTI2024

Keck Infrared Transient Survey. I. Survey Description and Data Release 1

Abstract We present the Keck Infrared Transient Survey, a NASA Key Strategic Mission Support program to obtain near-infrared (NIR) spectra of astrophysical transients of all types, and its first data release, consisting of 105 NIR spectra of 50 transients. Such a data set is essential as we enter a new era of IR astronomy with the James Webb Space Telescope (JWST) and the upcoming Nancy Grace Roman Space Telescope (Roman). NIR spectral templates will be essential to search JWST images for stellar explosions of the first stars and to plan an effective Roman SN Ia cosmology survey, both key science objectives for mission success. Between 2022 February and 2023 July, we systematically obtained 274 NIR spectra of 146 astronomical transients, representing a significant increase in the number of available NIR spectra in the literature. Here, we describe the first release of data from the 2022A semester. We systematically observed three samples: a flux-limited sample that includes all transients <17 mag in a red optical band (usually ZTF r or ATLAS o bands); a volume-limited sample including all transients within redshift z < 0.01 ( D ≈ 50 Mpc); and an SN Ia sample targeting objects at phases and light-curve parameters that had scant existing NIR data in the literature. The flux-limited sample is 39% complete (60% excluding SNe Ia), while the volume-limited sample is 54% complete and is 79% complete to z = 0.005. Transient classes observed include common Type Ia and core-collapse supernovae, tidal disruption events, luminous red novae, and the newly categorized hydrogen-free/helium-poor interacting Type Icn supernovae. We describe our observing procedures and data reduction using PypeIt , which requires minimal human interaction to ensure reproducibility.

Tinyanont, S. (ORCID:0000000214814676)↗

NASA NTRS2010

Present Challenges, Critical Needs, and Future Technological Directions for NASA's GN and C Engineering Discipline

The National Aeronautics and Space Administration (NASA) is currently undergoing a substantial redirection. Notable among the changes occurring within NASA is the stated emphasis on technology development, integration, and demonstration. These new changes within the Agency should have a positive impact on the GN&C discipline given the potential for sizeable investments for technology development and in-space demonstrations of both Autonomous Rendezvous & Docking (AR&D) systems and Autonomous Precision Landing (APL) systems. In this paper the NASA Technical Fellow for Guidance, Navigation and Control (GN&C) provides a summary of the present technical challenges, critical needs, and future technological directions for NASA s GN&C engineering discipline. A brief overview of the changes occurring within NASA that are driving a renewed emphasis on technology development will be presented as background. The potential benefits of the planned GN&C technology developments will be highlighted. This paper will provide a GN&C State-of-the-Discipline assessment. The discipline s readiness to support the goals & objectives of each of the four NASA Mission Directorates is evaluated and the technical challenges and barriers currently faced by the discipline are summarized. This paper will also discuss the need for sustained investments to sufficiently mature the several classes of GN&C technologies required to implement NASA crewed exploration and robotic science missions.

Dennehy, Cornelius J.↗

NASA NTRS2002

The Fourier-Kelvin Stellar Interferometer Mission Concept

The Fourier-Kelvin Stellar Interferometer (FKSI) is a mission concept for an imaging interferometer for the mid-infrared spectral region (5-30 microns). FKSI is conceived as a scientific and technological precursor to TPF as well as Space Infrared Interferometric Telescope (SPIRIT), Submillimeter Probe Evolution of Cosmic Structure (SPECS), and Single Aperture for Infrared Observatory (SAFIR). It will also be a high angular resolution system complementary to Next Generation Space Telescope (NGST). The scientific emphasis of the mission is on the evolution of protostellar systems, from just after the collapse of the precursor molecular cloud core, through the formation of the disk surrounding the protostar, the formation of planets in the disk, and eventual dispersal of the disk material. FKSI will also search for brown dwarfs and Jupiter mass and smaller planets, and could also play a very powerful role in the investigation of the structure of active galactic nuclei and extra-galactic star formation. We are in the process of studying alternative interferometer architectures and beam combination techniques, and evaluating the relevant science and technology tradeoffs. Some of the technical challenges include the development of the cryocooler systems necessary for the telescopes and focal plane array, light and stiff but well-damped truss systems to support the telescopes, and lightweight and coolable optical telescopes. The goal of the design study is to determine if a mid-infrared interferometry mission can be performed within the cost and schedule requirements of a Discovery class mission. At the present time we envision the FKSI as comprised of five one meter diameter telescopes arranged along a truss structure in a linear non-redundant array, cooled to 35 K. A maximum baseline of 20 meters gives a nominal resolution of 26 mas at 5 microns. Using a Fizeau beam combination technique, a simple focal plane camera could be used to obtain both Fourier and spectral data simultaneously for a given orientation of the array. The spacecraft will be rotated to give sufficient Fourier data to reconstruct complex images of a broad range of astrophysical sources.

Danchi, W. C.↗

NASA NTRS1984

Economic impact of fuel properties on turbine powered business aircraft

The principal objective was to estimate the economic impact on the turbine-powered business aviation fleet of potential changes in the composition and properties of aviation fuel. Secondary objectives include estimation of the sensitivity of costs to specific fuel properties, and an assessment of the directions in which further research should be directed. The study was based on the published characteristics of typical and specific modern aircraft in three classes; heavy jet, light jet, and turboprop. Missions of these aircraft were simulated by computer methods for each aircraft for several range and payload combinations, and assumed atmospheric temperatures ranging from nominal to extremely cold. Five fuels were selected for comparison with the reference fuel, nominal Jet A. An overview of the data, the mathematic models, the data reduction and analysis procedure, and the results of the study are given. The direct operating costs of the study fuels are compared with that of the reference fuel in the 1990 time-frame, and the anticipated fleet costs and fuel break-even costs are estimated.

Powell, F. D.↗

NASA NTRS1979

Study of an advanced General Aviation Turbine Engine (GATE)

The best technology program for a small, economically viable gas turbine engine applicable to the general aviation helicopter and aircraft market for 1985-1990 was studied. Turboshaft and turboprop engines in the 112 to 746 kW (150 to 1000 hp) range and turbofan engines up to 6672 N (1500 lbf) thrust were considered. A good market for new turbine engines was predicted for 1988 providing aircraft are designed to capitalize on the advantages of the turbine engine. Parametric engine families were defined in terms of design and off-design performance, mass, and cost. These were evaluated in aircraft design missions selected to represent important market segments for fixed and rotary-wing applications. Payoff parameters influenced by engine cycle and configuration changes were aircraft gross mass, acquisition cost, total cost of ownership, and cash flow. Significant advantage over a current technology, small gas turbine engines was found especially in cost of ownership and fuel economy for airframes incorporating an air-cooled high-pressure ratio engine. A power class of 373 kW (500 hp) was recommended as the next frontier for technology advance where large improvements in fuel economy and engine mass appear possible through component research and development.

Gill, J. C.↗

NASA NTRSDate not supplied

Field Tests With Trident Drill in Bishop Tuff Help Prepare for Future Missions to Moon and Mars

We performed drilling in volcanic deposits near Bishop California using an engineering model of the Honeybee Robotics TRIDENT (The Regolith and Ice Drill for Exploration of New Terrains) drill [1] a rotary percussive 1-meter class drill that is carried on the PRIME1and VIPER (Volatiles Investigating Polar Exploration Rover)[2] missions that launch in 2024. A similar drilling system was planned for the proposed Icebreaker Discovery class mission to Mars [3] and the Mars Life Explorer mission recommended by the 2020 Decadal Survey of planetary science [4]. The objectives of the project were (1) to use data collected by the drill for operational purposes as a probe of subsurface material properties in formations that are analogous to those that may be encountered on planetary surfaces; (2) correlate subsurface structures with those deduced from Ground Penetrating Radar (GPR); and (3) inspect the boreholes after they were drilled to test PERISCOPE (Probe for Exploring Regolith and Ice by Subsurface Classification of Organics, polycyclic aromatic hydrocarbons (PAHs), and Elements), a newly developed downhole UV fluorescence spectrometer [5].

Carol R. Stoker↗

NASA NTRS2000

Mars Mobile Lander Systems for 2005 and 2007 Launch Opportunities

A series of Mars missions are proposed for the August 2005 launch opportunity on a medium class Evolved Expendable Launch Vehicle (EELV) with a injected mass capability of 2600 to 2750 kg. Known as the Ranger class, the primary objective of these Mars mission concepts are: (1) Deliver a mobile platform to Mars surface with large payload capability of 150 to 450 kg (depending on launch opportunity of 2005 or 2007); (2) Develop a robust, safe, and reliable workhorse entry, descent, and landing (EDL) capability for landed mass exceeding 750 kg; (3) Provide feed forward capability for the 2007 opportunity and beyond; and (4) Provide an option for a long life telecom relay orbiter. A number of future Mars mission concepts desire landers with large payload capability. Among these concepts are Mars sample return (MSR) which requires 300 to 450 kg landed payload capability to accommodate sampling, sample transfer equipment and a Mars ascent vehicle (MAV). In addition to MSR, large in situ payloads of 150 kg provide a significant step up from the Mars Pathfinder (MPF) and Mars Polar Lander (MPL) class payloads of 20 to 30 kg. This capability enables numerous and physically large science instruments as well as human exploration development payloads. The payload may consist of drills, scoops, rock corers, imagers, spectrometers, and in situ propellant production experiment, and dust and environmental monitoring.

Sabahi, D.↗

NASA NTRS2019

Unmanned Aircraft Systems Integration in the National Airspace System Project - Phase 2 Abstracts - FY2017 to FY2019

There is an increasing need to fly Unmanned Aircraft Systems (UAS) in the National Airspace System (NAS) to perform missions of vital importance to national security and defense, emergency management, science, and to enable commercial applications. However, routine access by UAS into the NAS remains unrealized. The UAS community needs routine access to the global airspace for all classes of UAS. Based upon that need, the National Aeronautics and Space Administration (NASA) Aeronautics Research Mission Directorate (ARMD) Integrated Aviation Systems Program (IASP) UAS Integration in the NAS Project identified the following goal: To Provide research findings, utilizing simulation and flight tests, to support the development and validation of Detect and Avoid (DAA) and Command and Control (C2) technologies necessary for integrating UAS into the NAS. Because this is such a broad reaching challenge facing the UAS community, the UAS-NAS Project recognizes the importance of working together with others in Industry and Other Government Agencies to overcome the technical, operational, and public perception barriers.

bibliographic report↗