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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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At least 253 records · Page 14
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NASA NTRS2003

Unexplained Discontinuity in the US Radiosonde Temperature Data: Stratosphere - Part 2

In part I of this paper, the United States (US) radiosonde temperature data are shown to have significant and unexplained inhomogeneities in the mid-troposphere. This part discusses the differences between observations taken at 0 and 12 UTC especially in the stratosphere by the Vaisala RS80 radiosondes that are integrated within the National Weather Service's (NWS) Micro-ART system. The results show that there is a large maxima in the horizontal distribution of the monthly means of the 0/12 UTC differences over the central US that is absent over Canada and this maxima is as large as 5 C at 10 hPa. The vertical profiles of the root-mean-square of the monthly means are much larger in the US than those else where. The data clearly shows that the 0/12 UTC differences are largely artificial especially over the central US and originate in the post processing software at observing stations, thus confirming the findings in part I. Special flight data from the NWS's test facility at Sterling, Va. have been obtained. This data can be used to deduce the bias correction applied by Vaisala's post processing system. By analyzing the correction data, it can be shown that the inconsistencies with non-US Vaisala RS80 data as well as most of the large 0/12 UTC differences over the US can be accounted for by multiplying the reported elapsed time (i.e. time since launch) by the factor which is incorrectly applied by the post processing software. After being presented with the findings in this paper, Vaisala further isolated the source of the inconsistencies to a software coding error in the radiation bias correction scheme. The error effects only the software installed at US stations.

Redder, Christopher R.↗
NASA NTRS2003

When Earth Songs Filled the Void of Space

Before the late 50's we had the planets, our Sun, the stars, galaxies, spectacular clouds of dust and very little else in our universe. There was evidence for a highly tenuous "sea" of dust in interstellar space, but little else. Space was empty above the ionized gases of our upper atmosphere, a little like there was no color in the world before the 40's. The clues were there to think otherwise, however, and in the late 50's and early 60's a few researchers dared to challenge the conventional ideas about space. It was a time of discovery and, with our new ability to fly in space, a time that launched a new science. Today that science makes it possible to literally see some of the plasmas that populate near-Earth space, which are now known to exist everywhere.

Gallagher, Dennis L.↗
NASA NTRS2003

Factors Influencing Solar Electric Propulsion Vehicle Payload Delivery for Outer Planet Missions

Systems analyses were performed for missions utilizing solar electric propulsion systems to deliver payloads to outer-planet destinations. A range of mission and systems factors and their affect on the delivery capability of the solar electric propulsion system was examined. The effect of varying the destination, the trip time, the launch vehicle, and gravity-assist boundary conditions was investigated. In addition, the affects of selecting propulsion system and power systems characteristics (including primary array power variation, number of thrusters, thruster throttling mode, and thruster Isp) on delivered payload was examined.

Cupples, Michael↗
NASA NTRS2004

Chemical and Solar Electric Propulsion Systems Analyses for Mars Sample Return Missions

Conceptual in-space transfer stages, including those utilizing solar electric propulsion, chemical propulsion, and chemical propulsion with aerobraking or aerocapture assist at Mars, were evaluated. Roundtrip Mars sample return mission vehicles were analyzed to determine how specific system technology selections influence payload delivery capability. Results show how specific engine, thruster, propellant, capture mode, trip time and launch vehicle technology choices would contribute to increasing payload or decreasing the size of the required launch vehicles. Heliocentric low-thrust trajectory analyses for Solar Electric Transfer were generated with the SEPTOP code.

Donahue, Benjamin B.↗
NASA NTRS2001

Next-Generation Ion Propulsion Being Developed

The NASA Glenn Research Center ion-propulsion program addresses the need for high specific-impulse systems and technology across a broad range of mission applications and power levels. One activity is the development of the next-generation ion-propulsion system as a follow-on to the successful Deep Space 1 system. The system is envisioned to incorporate a lightweight ion engine that can operate over 1 to 10 kW, with a 550-kg propellant throughput capacity. The engine concept under development has a 40-cm beam diameter, twice the effective area of the Deep Space 1 engine. It incorporates mechanical features and operating conditions to maximize the design heritage established by the Deep Space 1 engine, while incorporating new technology where warranted to extend the power and throughput capability. Prototype versions of the engine have been fabricated and are under test at NASA, with an engineering model version in manufacturing. Preliminary performance data for the prototype engine have been documented over 1.1- to 7.3-kW input power. At 7.3 kW, the engine efficiency is 0.68, at 3615-sec specific impulse. Critical component temperatures, including those of the discharge cathode assembly and magnets, have been documented and are within established limits, with significant margins relative to the Deep Space 1 engine. The 1- to 10-kW ion thruster approach described here was found to provide the needed power and performance improvement to enable important NASA missions. The Integrated In-Space Transportation Planning (IISTP) studies compared many potential technologies for various NASA, Government, and commercial missions. These studies indicated that a high-power ion propulsion system is the most important technology for development because of its outstanding performance versus perceived development and recurring costs for interplanetary solar electric propulsion missions. One of the best applications of a highpower electric propulsion system was as an integral part of a solar electric propulsion (SEP) stage to send a payload to outer planet targets. The IISTP studies showed that either trip time or launch vehicle class could be significantly reduced when compared with state-of-the-art systems.

Patterson, Michael J.↗
NASA NTRS1997

Reengineering Space Projects

In an era of shrinking funds for space exploration, JPL is undergoing a significant reengineering effort designed to reduce costs of flight projects by 33 percent, and time to launch 50 percent.

design tools space applications COTS tools busines↗
NASA NTRS1997

Reengineering Space Projects

In an era of shrinking funds for space exploration, JPL is undergoing a significant reengineering effort designed to reduce costs of flight projects by 33 percent, and time to launch by 50 percent.

devlopment MSD DBAT VIVO↗
NASA NTRS2006

Fabrication of Extremely Lightweight Mirrors

Further progress in astronomy requires large.(approx. 10m class) space telescopes in all wavelength bands, from IR to X-rays. The enabling of this progress requires optical fabrication technologies that not only can make mirrors that are orders of magnitude less massive than the present ones, but also orders of magnitude less expensive. In the past five years, we have been developing lightweight X-ray mirrors to meet mission requirements of the Constellation-X, which is NASA s next major X-ray observatory scheduled for launch some time in the next decade. In this talk, I will describe in detail a glass forming, or slumping, technique that allows a high-fidelity copying of a mandrel s figure while preserving the microroughness of the float glass surface. In particular, I will address the possibility of applying this technique to making extremely large optical telescopes.

Zhang, William W.↗
NASA NTRS2007

DAWN Mission Bus and Waveguide Venting Analysis Review

A concern was raised regarding the time after launch when the DAWN Mission Communications Subsystem, which contains a 100 Watt X-Band Traveling Wave Tube Amplifier (TWTA) with a high voltage ((approximately 7 Kilo Volt (KV)) Electronic Power Converter (EPC), will be powered on for the first post-launch downlink. This activation is planned to be approximately one hour after launch. Orbital Sciences (the DAWN Mission spacecraft contractor) typically requires a 24-hour wait period prior to high voltage initiation for Earth-orbiting Science and GEO spacecraft. The concern relates to the issue of corona and/or radio frequency (RF) breakdown of the TWTA ((high voltage direct current (DC) and RF)), and of the microwave components (high voltage RF) in the presence of partial atmospheric pressures or outgassing constituents. In particular, generally the diplexer and circulator are susceptible to RF breakdown in the corona region due to the presence of small physical gaps ((~ 2.5 millimeter (mm)) between conductors that carry an RF voltage. The NESC concurred the DAWN Mission communication system is safe for activation.

Cragg, Clinton H.↗
NASA NTRS2008

Hubble 2007: Science Year in Review

This book epitomizes Hubbles continuing years of glorious accomplishments, presenting a sample of the activities, operations and observations, and scientific findings from 2007. Here is our observatory. Here are a few of our talented people. Here is what we have done. NASA plans a final servicing mission to Hubble in 2008. Two powerful new instruments are to be installed, and repairs made. After the astronauts do their wonderful work, Hubble will be more capable than at any time since launch. The science community eagerly anticipates the new opportunities for research offered by a refurbished observatory. While we do not know exactly what new science stories will appear in future editions of this book, we are certain that the frontiers of science will continue to be pushed outward by the forces of human curiosity and cleverness, channeled by the Hubble Space Telescope.

Hubble space telescope↗
NASA NTRS2006

Spacecraft Escape Capsule

A report discusses the Gumdrop capsule a conceptual spacecraft that would enable the crew to escape safely in the event of a major equipment failure at any time from launch through atmospheric re-entry. The scaleable Gumdrop capsule would comprise a command module (CM), a service module (SM), and a crew escape system (CES). The CM would contain a pressurized crew environment that would include avionic, life-support, thermal control, propulsive attitude control, and recovery systems. The SM would provide the primary propulsion and would also supply electrical power, life-support resources, and active thermal control to the CM. The CES would include a solid rocket motor, embedded within the SM, for pushing the CM away from the SM in the event of a critical thermal-protection-system failure or loss of control. The CM and SM would normally remain integrated with each other from launch through recovery, but could be separated using the CES, if necessary, to enable the safe recovery of the crew in the CM. The crew escape motor could be used, alternatively, as a redundant means of de-orbit propulsion for the CM in the event of a major system failure in the SM.

Robertson, Edward A.↗
NASA NTRS2011

Lightning Initiation Forecasting: An Operational Dual-Polarimetric Radar Technique

The objective of this NASA MSFC and NOAA CSTAR funded study is to develop and test operational forecast algorithms for the prediction of lightning initiation utilizing the C-band dual-polarimetric radar, UAHuntsville's Advanced Radar for Meteorological and Operational Research (ARMOR). Although there is a rich research history of radar signatures associated with lightning initiation, few studies have utilized dual-polarimetric radar signatures (e.g., Z(sub dr) columns) and capabilities (e.g., fuzzy-logic particle identification [PID] of precipitation ice) in an operational algorithm for first flash forecasting. The specific goal of this study is to develop and test polarimetric techniques that enhance the performance of current operational radar reflectivity based first flash algorithms. Improving lightning watch and warning performance will positively impact personnel safety in both work and leisure environments. Advanced warnings can provide space shuttle launch managers time to respond appropriately to secure equipment and personnel, while they can also provide appropriate warnings for spectators and players of leisure sporting events to seek safe shelter. Through the analysis of eight case dates, consisting of 35 pulse-type thunderstorms and 20 non-thunderstorm case studies, lightning initiation forecast techniques were developed and tested. The hypothesis is that the additional dual-polarimetric information could potentially reduce false alarms while maintaining high probability of detection and increasing lead-time for the prediction of the first lightning flash relative to reflectivity-only based techniques. To test the hypothesis, various physically-based techniques using polarimetric variables and/or PID categories, which are strongly correlated to initial storm electrification (e.g., large precipitation ice production via drop freezing), were benchmarked against the operational reflectivity-only based approaches to find the best compromise between forecast skill and lead-time. Forecast skill is determined by statistical analysis of probability of detection (POD), false alarm ratio (FAR), Operational Utility Index (OUI), and critical success index (CSI).

Woodard, Crystal J.↗
NASA NTRS2017

Analyzing JAVAD TR-G2 GPS Receiver's Sensitivities to SLS Trajectory

Automated guidance and navigation systems are an integral part to successful space missions. Previous researchers created Python tools to receive and parse data from a JAVAD TR-G2 space-capable GPS receiver. I improved the tool by customizing the output for plotting and comparing several simulations. I analyzed position errors, data loss, and signal loss by comparing simulated receiver data from an IFEN GPS simulator to ‘truth data’ from a proposed trajectory. By adjusting the trajectory simulation’s gain, attitude, and start time, NASA can assess the best time to launch the SLS, where to position the antennas on the Block 1-B, and which filter to use. Some additional testing has begun with the Novatel SpaceQuestGPS receiver as well as a GNSS SDR receiver.

Schuler, Tristan↗
NASA NTRS2023

Managing the Lucy Mission

Lucy is NASA’s 13th Discovery-class mission. It will be the first mission to encounter seven Trojan asteroids in a series of five flybys. Lucy is led by Dr. Hal Levison of the Southwest Research Institute. As the Principal Investigator, Dr. Levison is accountable to NASA for the success of the investigation, with full responsibility for its scientific integrity and execution within committed cost and schedule. Day to day management of the Lucy project is delegated to Goddard Space Flight Center. During Lucy’s development, the project experienced a once-in-a-lifetime pandemic that threatened the team’s ability to meet the planetary launch window. Despite this challenge, Lucy launched on time and under budget. This chapter discusses key factors that enabled project success.

Project Management↗
NASA NTRSDate not supplied

Global Rescue Response to a Multivehicle Deorbit from the International Space Station

The U.S. Department of Defense (DoD) has been tasked to support rescue efforts in the event of an off-nominal landing of a Commercial Crew Program vehicle transporting NASA crewmembers to or from the International Space Station. The DoD is further tasked to support returning U.S. and International Partner crewmembers on Russian Soyuz spacecraft missions, specifically to ensure aeromedical evacuation capability in the event of a crewmember injury at the time of launch or landing. This DoD mission is primarily considered during planned launch and landing operations, with forces placed in an alert posture to support if needed. However, overall mission concept of operations encompasses a no-notice rescue capability in the event of an on-orbit emergency. Such contingency scenarios are pre-coordinated and simulated to ensure a ready posture of associated DoD assets and to promote coordination of government, commercial, and military stakeholders. To date, planning and simulations have focused on execution of a single rescue mission; the possibility of a multi-vehicle evacuation and rescue scenario has not been adequately explored. This presentation will examine the process of responding to an emergency onboard the International Space Station that results in the early departure and deorbit of multiple docked vehicles to preserve the health and safety of the crew. We will highlight the complexity of this recovery scenario and discuss potential complications that could arise, as well as identify areas in which deliberate planning and simulation can better ensure successful preparation for such a multifaceted recovery operation.

Travis Levon Houser↗
NASA NTRSDate not supplied

Solar Storms and Flying to Mars

Solar energetic particles (SEP) are a significant concern for interplanetary human spaceflight. Here we consider SEP radiation hazards for humans on long-duration deep space missions, such as NASA’s 850-day mission concept set to launch in time to get there by 2040. Astronauts must deal not only with possible accumulated dose, but also with acute hazards that can develop in approximately the same time scale as the speed-of-light communications time. We discuss the space weather infrastructure needed in the vicinity of the spacecraft and/or Mars to alleviate the SEP radiation hazard.

space weather↗
NASA NTRS2024

Stellar Occultation Observations to Constrain the Stratosphere of Uranus for Aerocapture

Background on Uranus: Voyager 2 (V2) UV stellar and solar occultations at Uranus detected a warm stratosphere and extremely hot thermosphere [1, 2], far in excess of solar irradiance [3, 4] and internal heating [5, 6]. New theories to explain similar heating at Jupiter [7] and Saturn [8] cannot be tested at Uranus due to a dearth of reliable measurements. In [9, 10], we reprocessed 26 archival Earth-based stellar occultations by Uranus (1977-1996), finding stratospheric temperatures (~200 K) warmer than the original (~100 K), but in stark tension with V2 (~300-500 K). In [10], we built a physics-based, 1-D atmospheric model (see Fig 1) that finds a nearly isothermal stratosphere and a dynamic heat sink in the lower thermosphere. Aerocapture: Aerocapture is spacecraft maneuver that uses a single deep dip to enter orbit. It could decrease cruise time and launch mass for a Uranus mission, but the greatest impediment is uncertain stratospheric densities of Uranus [11]. Aims: 1) Observe and process many high S/N Uranus stellar occultations in the next decade; 2) constrain stratospheric densities for aerocapture; 3) better understand the energy balance; 4) determine stratospheric changes since 1996. Upcoming Occultations: We will present our observing plan for the 2025 April Uranus occultation (K mag 8) and discuss the best-in-a-century 2031 event (K mag 4). We will discuss other events in the early 2030s [12] [13], predicted constraints on density, and simulations of aerocapture for UOP. We will discuss the Shadow Chaser, a small satellite concept for observing occultations from Earth orbit [12]. Conclusions: New stellar occultations can vastly improve profiles of the stratosphere of Uranus; this is critical for understanding energy circulation and constraining densities for using aerocapture on UOP. References: [1] Herbert, F. et al. (1987). JGR. [2] Stevens, M. et al. (1993). Icarus. [3] Marley, M. & McKay, C. (1999). Icarus, [4] Li, C. et al. (2018). JQRST. [5] Pearl, J. et al. (1990). Icarus. [6] Melin, H (2020). Nat Astron. [7] O’Donoghue, J. et al. (2021) Nature. [8] Mueller-Wodarg, I. et al. (2019) GRL. [9] Saunders, W. et al. (2023). PSJ. [10] Saunders, W. et al. (2024). PSJ. [11] Report of the Aerocapture Demonstration Relevance Assessment Team (2023). [12] Saunders, W. et al. (2022). P&SS. [13] French, R. & Souami, D. (2023) PSJ.

William Saunders↗