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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

Complementary Roles of LEO and GEO IR Sounders in NWP Evaluated using an OSSE Framework

The United States is currently preparing for the next-generation weather satellite program. Building off the multi-decadal successes of the Low-Earth Orbit (LEO) infrared (IR) sounder program, NOAA and NASA are planning for the Geostationary eXtended Observations (GeoXO) Sounder (GXS) that will join international counterparts to form a global ring from geosynchronous orbit (GEO). To address questions about the complementarities and roles of these two platform types in the context of numerical weather prediction (NWP) and forecast accuracy, NASA’s Global Modeling and Assimilation Office (GMAO) Observing System Simulation Experiment (OSSE) framework was used to test their impact individually and in concert. Analyses, forecasts, and forecast sensitivity-based observations impact (FSOI) are examined. Overall, each has a role in forecast error reduction with the most beneficial impacts occurring when both LEO and GEO sounders are used together to address the needs of global skill and targeted regional weather phenomena.

Erica Mcgrath-Spangler↗
NASA NTRS2019

Navigation tracking with multiple baselines Part 1: high-level theory and system concepts

We describe a system concept that detects and locates dead and non-cooperatively spacecraft in the Geostationary Orbit (GEO). This can be done by making use of an existing GEO satellite with accurately known location as a reference, and/or by placing a dedicated “reference” spacecraft into an eccentric geosynchronous orbit over a region of interest (e.g. above North America).

Lee, Charles↗
NASA NTRS1976

IUS capability for earth orbital spacecraft

A basic element of the Space Transportation System (STS) is the Interim Upper Stage (IUS) currently being planned by the USAF. The prime use of the basic two-stage IUS vehicle by both NASA and DoD will be to place satellites in geosynchronous orbit. High energy missions such as planetary will be accomplished by three- and four-stage vehicles. Various other configurations such as tandem vehicles in a single Shuttle and multiple spacecraft are being planned. Also under study is a smaller stage that can be flown with other payloads on a space available basis. The various concepts being studied offer economical transportation alternatives to potential users. This paper describes details of the IUS program status, design requirements, concepts and applications to Earth orbital spacecraft.

Huber, W. G.↗
NASA NTRS1980

An accelerated test design for use with synchronous orbit

The Naval Weapons Support Center at Crane, Indiana has conducted a large scale accelerated test of 6.0 Ah Ni-Cd cells. Data from the Crane test have been used to develop an equation for the description of Ni-Cd cell behavior in geosynchronous orbit. This equation relates the anticipated time to failure for a cell in synchronous orbit to temperature and overcharge rate sustained by the cell during the light period. A test design is suggested which uses this equation for setting test parameters for future accelerated testing.

Mcdermott, P. P.↗
NASA NTRS1983

Booster and orbiter configurations

In the recent Future Space Transportation System (FSFS) study, a mission model was selected and a baseline vehicle which best met model requirements was shaped. This baseline was then analyzed for flight performance, structural and subsystem weight, and operation. Figures related to a payload of 150,000 lb in a 20-ft-diam by 90-ft-long envelope became the baseline. The existence of both space-based orbital transfer vehicles (OTVs) and a space station was assumed, taking into account a transfer of the payload from the launch vehicle to OTVs at the space station for final delivery to geosynchronous orbit (GEO). A computer-aided engineering system called Aerospace Vehicle Interactive Design (AVID) was employed in connection with baseline vehicle development. It was found that approximately three-fifth of the payload weight would be cryogenic propellants for OTVs. Attention is given to problems regarding the packaging of cryogenic tankage, a payload shroud, and studies of staging for two different booster propulsion units.

Wilhite, A. W.↗
NASA NTRS1984

Selected tether applications in space: An analysis of five selected concepts

Ground rules and assumptions; operations; orbit considerations/dynamics; tether system design and dynamics; functional requirements; hardware concepts; and safety factors are examined for five scenarios: tethered effected separation of an Earth bound shuttle from the space station; tether effected orbit boost of a spacecraft (AXAF) into its operational orbit from the shuttle; an operational science/technology platform tether deployed from space station; a tether mediated rendezvous involving an OMV tether deployed from space station to rendezvous with an aerobraked OTV returning to geosynchronous orbit from a payload delivery mission; and an electrodynamic tether used in a dual motor/generator mode to serve as the primary energy storage facility for space station.

Source record↗
NASA NTRS1989

Working group written presentation: Meteoroid/orbital debris effects on materials

Low earth orbit (LEO) is the most significant region relative to orbital debris, since the flux of orbital debris peaks in the region from 800 to 1000 kilometers, and the relative velocities of objects in LEO are about 10 kilometers per second. The flux and relative velocities of objects in geosynchronous orbit (GEO) are small, so that debris is not considered to be a problem in GEO. The meteoroid environment is independent of orbit or altitude, so that its effects are the same in LEO and GEO. The effects of orbital debris and meteoroid impacts can be divided into two broad regions: (1) Erosion and pitting; Small particles (less than 100 microns) are very numerous. Impacts from these generally do not lead to penetration of surfaces, but cause pitting and erosion. The Solar Max surfaces were peppered with thousands of tiny impact pits. (2) Catastrophic impacts; Large debris particles are few in number relative to small debris, so that the probability of an impact is low. However, the effects of an impact of a large particle at 10 kilometers per second are devastating. These effects are examined.

Potter, Andrew↗
NASA NTRS1977

Provisional specification for satellite time in a geomagnetic environment

Satellites in geosynchronous orbit were experiencing operational anomalies. These anomalies are believed to be due to the environment charging the spacecraft surfaces to a point where discharges occur. In designing future satellites for long term operation at geosynchronous altitude, it is important that designers have a specification that will give the total time per year, the particle flux density and particle energies that their satellites can be expected to encounter in these substorm environmental conditions. The limited data currently available on the environmental conditions are used to generate the provisional specification given in this report.

Stevens, N. J.↗
NASA NTRS1983

Second Shuttle Join NASA's STS Fleet: Challenger Launches First New Tracking Satellite

NASA made a major stride in readying a second delivery vehicle for its Space Transportation System (STS) fleet with the perfect landing of Shuttle Orbiter Challenger at Edwards Air Force Base, California, April 9, 1983. Besides being the first flight test of Challenger's performance, the mission marked the orbiting of the first spacecraft in NASA's new Tracking and Data Relay Satellite System (TDRSS). The new family of orbiting space communications platforms is essential to serve future Shuttle missions. Although the Inertial Upper Stage (IUS) second stage engine firing failed to place TDRS in its final 35,888 kilometer (22,300 mile) geosynchronous orbit, its release from the orbiter cargo bay went as planned. Launch officials were confident they can achieve its planned orbit in a matter of weeks.

Source record↗
NASA NTRS1987

Regenerative fuel cell systems for mid- to high-orbit satellites

An assessment of the present and projected capabilities of selected hydrogen-oxygen and hydrogen-halogen fuel cell and electrolyzer combinations for energy storage systems (ESS) in configurations useful for spacecraft missions operating in the 10- to 50-kW range for many years in midaltitude to geosynchronous orbits has recently been completed. Results of the study indicate that regenerative fuel cell ESS are feasible for the intended application. A computer model was used to provide tradeoff analyses for optimizing the various ESS fuel cell concepts. When appropriately configured to be compatible with the mission needs of the selected model spacecraft, the specific energy for these ESS are intermediate between that presently available for nickel-hydrogen batteries and that expected for the newly emerging sodium-sulfur technology.

Taenaka, R. K.↗
NASA NTRS1976

Provisional specification for satellite time in a geomagnetic substorm environment

Satellites in geosynchronous orbit have been experiencing operational anomalies. These anomalies are believed to be due to the environment charging the spacecraft surfaces to a point where discharges occur. In designing future satellites for long term operation at geosynchronous altitude, it is important that designers have a specification that will give the total time per year, the particle flux density, and particle energies that their satellites can be expected to encounter in these substorm environmental conditions. The limited data currently available on the environmental conditions was used to generate the provisional specification given.

Stevens, N. J.↗
NASA NTRS1997

Wide-Field High-Performance Geosynchronous Imaging

The NASA Mission to Planet Earth (MTPE) Program and the National Oceanographic and Atmospheric Administration (NOAA) are sponsoring the Advanced Geosynchronous Studies (AGS) to develop technologies and system concepts for Earth observation from geosynchronous orbit. This series of studies is intended to benefit both MTPE science and the NOAA GOES Program. Within the AGS program, advanced imager trade studies have investigated two candidate concepts for near-term advanced geosynchronous imagers. One concept uses a scan mirror to direct the line of sight from a 3-axis stabilized platform. Another eliminates the need for a scan mirror by using an agile spacecraft bus to scan the entire instrument. The purpose of this paper is to discuss the optical design trades and system issues encountered in evaluating the two scanning approaches.

Wood, H. John↗
NASA NTRS1973

The calculation of efficient high precision orbits by optimum matching of the formulation and numerical integrator

The development of improved computer algorithms is considered for calculating earth satellite orbital trajectories by optimum selection of the analytical method that minimizes the number of perturbative acceleration computations for a given accuracy. A variation of parameter algorithm considering the equation of motion for a satellite proved superior for the geosynchronous orbit.

Velez, C. E.↗
NASA NTRS1988

Short- and long-term determination of the TDRS solar reflectivity parameter using the Goddard trajectory determination system

Two aspects of the orbit determination of the Tracking and Data Relay Satellite-East (TDRS-E) are considered. The TDRS-E solar reflectivity parameter, as it affects the accuracy of the determination and propagation of the TDRS-E geosynchronous orbit, varies seasonally due to the changing declination of the sun. Orbit solutions are carried out using varying tracking data arc lengths to ascertain the minimum arc length needed for an accurate determination of the TDRS-E orbital elements and the solar reflectivity parameter.

Bobrowsky, M.↗
NASA NTRS2011

On-Orbit Solar Dynamics Observatory (SDO) Star Tracker Warm Pixel Analysis

This paper describes the process of identification and analysis of warm pixels in two autonomous star trackers on the Solar Dynamics Observatory (SDO) mission. A brief description of the mission orbit and attitude regimes is discussed and pertinent star tracker hardware specifications are given. Warm pixels are defined and the Quality Index parameter is introduced, which can be explained qualitatively as a manifestation of a possible warm pixel event. A description of the algorithm used to identify warm pixel candidates is given. Finally, analysis of dumps of on-orbit star tracker charge coupled devices (CCD) images is presented and an operational plan going forward is discussed. SDO, launched on February 11, 2010, is operated from the NASA Goddard Space Flight Center (GSFC). SDO is in a geosynchronous orbit with a 28.5 inclination. The nominal mission attitude points the spacecraft X-axis at the Sun, with the spacecraft Z-axis roughly aligned with the Solar North Pole. The spacecraft Y-axis completes the triad. In attitude, SDO moves approximately 0.04 per hour, mostly about the spacecraft Z-axis. The SDO star trackers, manufactured by Galileo Avionica, project the images of stars in their 16.4deg x 16.4deg fields-of-view onto CCD detectors consisting of 512 x 512 pixels. The trackers autonomously identify the star patterns and provide an attitude estimate. Each unit is able to track up to 9 stars. Additionally, each tracker calculates a parameter called the Quality Index, which is a measure of the quality of the attitude solution. Each pixel in the CCD measures the intensity of light and a warns pixel is defined as having a measurement consistently and significantly higher than the mean background intensity level. A warns pixel should also have lower intensity than a pixel containing a star image and will not move across the field of view as the attitude changes (as would a dim star image). It should be noted that the maximum error introduced in the star tracker attitude solution during suspected warm pixel corruptions is within the specified 36 attitude error budget requirement of [35, 70, 70] arcseconds. Thus, the star trackers provided attitude accuracy within the specification for SDO. The star tracker images are intentionally defocused so each star image is detected in more than one CCD pixel. The position of each star is calculated as an intensity-weighted average of the illuminated pixels. The exact method of finding the positions is proprietary to the tracker manufacturer. When a warm pixel happens to be in the vicinity of a star, it can corrupt the calculation of the position of that particular star, thereby corrupting the estimate of the attitude.

Felikson, Denis↗
NASA NTRS1985

System technology analysis of aeroassisted orbital transfer vehicles: Moderate lift/drag (0.75-1.5),volume 1B, part 1, study results

Significant performance benefits can be realized via aerodynamic breaking and/or aerodynamic maneuvering on return from higher altitude orbits to low Earth orbit. This approach substantially reduces the mission propellant requirements by using the aerodynamic drag, D, to brake the vehicle to near circular velocity and the aerodynamic lift, L, to null out accumulated errors as well as change the orbital inclination to that required for rendezous with the Space Shuttle Orbiter. A study was completed where broad concept evaluations were performed and the technology requirements and sensitivities for aeroassisted Orbital Transfer Vehicles (AOTVs) over a range of vehicle hypersonic L/D from 0.75 to 1.5 were systematically identified and assessed. The AOTV is capable of evolving from an initial delivery only system to one eventually capable of supporting manned roundtrip missions to geosynchronous orbit. Concept screenings were conducted on numerous configurations spanning the L/D = 0.75 to 1.5 range, and several with attractive features were identified. Initial payload capability was evaluated for a baseline of delivery to GEO, six hour polar, and Molniya orbits with return and recovery of the AOTV at LEO. Evolutionary payload requirements that were assessed include a GEO servicing mission and a manned GEO mission.

Source record↗
NASA NTRS1985

Systems analysis and technology development for the NASA Orbit Transfer Vehicle

The benefits derived from aerobraking technology development for the Orbit Transfer Vehicle (OTV) are analyzed. The relative advantages of several other candidate OTV technologies are evaluated, and a relative ranking on the basis of performance considerations is presented. It is shown that aerobraking technologies can provide significant cost reductions for delivery of payloads to geosynchronous orbit, and that new and unique design concepts for OTVs must be pursued in order to realize the promised cost benefits. The goal for an aerobraked vehicle is an upper limit of 20 percent of the vehicle devoted to aero systems. Practical OTV configurations based on a concept of integrated structural design that can achieve this goal are suggested. A concept for a flight experiment to acquire the data needed to advance the discussed aeroassist technologies is proposed.

Roberts, B. B.↗
NASA NTRS2015

Intelligent Observation Strategies for Geosynchronous Remote Sensing for Natural Hazards

Geosynchronous satellites offer a unique perspective for monitoring environmental factors important to understanding natural hazards and supporting the disasters management life cycle, namely forecast, detection, response, recovery and mitigation. In the NASA decadal survey for Earth science, the GEO-CAPE mission was proposed to address coastal and air pollution events in geosynchronous orbit, complementing similar initiatives in Asia by the South Koreans and by ESA in Europe, thereby covering the northern hemisphere. In addition to analyzing the challenges of identifying instrument capabilities to meet the science requirements, and the implications of hosting the instrument payloads on commercial geosynchronous satellites, the GEO-CAPE mission design team conducted a short study to explore strategies to optimize the science return for the coastal imaging instrument. The study focused on intelligent scheduling strategies that took into account cloud avoidance techniques as well as onboard processing methods to reduce the data storage and transmission loads. This paper expands the findings of that study to address the use of intelligent scheduling techniques and near-real time data product acquisition of both the coastal water and air pollution events. The topics include the use of onboard processing to refine and execute schedules, to detect cloud contamination in observations, and to reduce data handling operations. Analysis of state of the art flight computing capabilities will be presented, along with an assessment of cloud detection algorithms and their performance characteristics. Tools developed to illustrate operational concepts will be described, including their applicability to environmental monitoring domains with an eye to the future. In the geostationary configuration, the payload becomes a networked thing with enough connectivity to exchange data seamlessly with users. This allows the full field of view to be sensed at very high rate under the control of ground infrastructure, resulting in improved efficiencies, accuracy and science benefits. Hence a remote sensing payload and its data may become one of millions of connected objects in the emerging Internet of Things (IoT), and be as easily accessible by a users smart phone as any other smart appliance.

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