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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 NTRS1976

A direct measurement of the winter helium bulge

In late December 1975, the orbital configuration of the Atmosphere Explorer-D satellite made possible the measurement of the winter helium bulge within a single perigee pass. Shortly after the winter solstice, the perigee of the polar-orbiting AE-D satellite crossed the equator, at which time descending and ascending portions of the orbit stretched symmetrically over the Southern and Northern Hemispheres. The open-source neutral mass spectrometer (OSS) on board AE-D measured helium densities between the perigee (about 150 km) and altitudes of 650 km. During the time the perigee was at the equator, altitudes above approximately 550 km were located north and south at latitudes greater than 50-deg. Helium showed, in the winter hemisphere, densities that were a factor of 20 higher than at corresponding altitudes and latitudes in the Southern (summer) Hemisphere. Absolute densities of helium agree well with previous measurements.

Mauersberger, K.↗
NASA NTRS1976

Determination of exospheric neutral gas temperatures

The Atmosphere Explorer satellites (AE-C, -D, and -E) were initially placed into highly elliptical orbits with perigees around 140 km and apogees of 4000 km. As a result of such an orbital geometry, measurements of neutral constituents at high altitudes represent mainly vertical changes in densities. The influence of horizontal density gradients on measurements above 400 km is small. Under geomagnetically quiet conditions, the density profiles can be used to derive scale-height temperatures of the exosphere. The open-source neutral mass spectrometer (OSS) flown on all three AE-satellites measured neutral constituents such as N2, O, and N well above 400 km. The temperatures derived from scale heights show a good agreement among the constituents and the expected close correlation with the F10.7-cm solar flux. Satellites with highly elliptical orbits provide the opportunity to measure simultaneously both densities and temperatures.

Mauersberger, K.↗
NASA NTRS1977

Empirical model of atomic nitrogen in the upper thermosphere

Atomic nitrogen number densities in the upper thermosphere measured by the open source neutral mass spectrometer (OSS) on Atmosphere Explorer-C during 1974 and part of 1975 have been used to construct a global empirical model at an altitude of 375 km based on a spherical harmonic expansion. The most evident features of the model are large diurnal and seasonal variations of atomic nitrogen and only a moderate and latitude-dependent density increase during periods of geomagnetic activity. Maximum and minimum N number densities at 375 km for periods of low solar activity are 3.6 x 10 to the 6th/cu cm at 1500 LST (local solar time) and low latitude in the summer hemisphere and 1.5 x 10 to the 5th/cu cm at 0200 LST at mid-latitudes in the winter hemisphere.

Engebretson, M. J.↗
NASA NTRS1977

Mass spectrometric measurement of thermospheric wind

The open source neutral mass spectrometer (OSS) on the Atmosphere Explorer C satellite was periodically operated in an experimental 'fly-through' mode. When the satellite is spinning, the signal from this mode displays a sharp maximum that occurs when the instrument source faces directly into the oncoming gas. Thus the location of this maximum is sensitive to neutral wind components in the spin plane. Twenty-two spinning fly-through orbits were analyzed to determine vertical wind magnitudes in the altitude range 160-250 km. Large (up to 65 m/s) magnitudes were detected in the early morning sector of the auroral zone.

Knutson, J. R.↗
NASA NTRS1979

Tables of thermospheric temperature, density and composition derived from satellite and ground based measurements. Volume 1: Ap=4

The tables contain the neutral temperature, neutral densities for N2, O2, O, Ar, He and H, mean molecular weight, and total mass density as predicted by the Mass Spectrometer and Incoherent Scatter empirical thermosphere model for selected altitudes, latitudes, local times, days and other geophysical conditions. The model is based on a least squares fit to density data from mass spectrometers on five satellites and temperature data from four incoherent scatter stations, providing coverage for most of solar sunspot cycle 20. Included in the model data base are longitudinally average N3, He, and O densities from the OGO-6 mass spectrometer longitudinally average N2, He, O and Ar densities from the AEROS-A (NATE) mass spectrometer the N2, He, O, and Ar densities from the San Marco 3 mass spectrometer the N2 densities from the AE-B mass spectrometer and the N2, He, O, and Ar densities from the AE-C (OSS, NACE, NATE) mass spectrometers. The O2 and H densities are inferred using ion mass spectrometer data from AE-C (BIMS). Neutral exospheric temperature data are included from Arecibo, St. Santin, Millstone Hill and Jicamarca.

Hedin, A. E.↗
NASA NTRS1980

Mixed mode missions - Designing payloads to match flight opportunities

Shuttle missions have usually been viewed as being devoted to a single mission mode. But full utilization of the STS capabilities as a platform for space research dictates a flexible strategy toward payload integration and mission design. Simple interfaces, single disciplines, and large design and resource margins point the way toward larger payload integration and operation costs. Payloads for early missions (i.e., OSTA-1, OSS-1, and MEA) are used as illustrations to support this argument. The implications of this approach for future NASA plans as well as for new STS operational concepts are considered.

Noblitt, B. G.↗
NASA NTRS1973

Final Environmental Impact Statement for National Aeronautics and Space Administration Office of Space Science: Sounding Rocket Program

The NASA OSS Sounding Rocket Program is responsible for the launch of approximately 80 science and applications payloads per year. These launches are for NASA programs and those of other U.S. government agencies private industry, universities, foreign countries, and international organizations. NASA launches occur or have occurred from 34 launch sites located throughout the world. Nine of these receive substantial use. Payloads launched by this program contribute in a variety of ways to the control and betterment of the environment (e.g., solar studies). Environmental effects caused by the research vehicles are limited in extent, duration, and intensity and are considered insignificant. There are no short-term alternatives to the current family of sounding rocket vehicles. The possibilities for changes in the family including new stage and sounding rocket developments, are continuously reviewed. Although measurements using high-altitude aircraft and balloons are possible at lower altitudes and using satellites at much higher altitudes, the specific region of the atmosphere between about 40 and 200 km cannot be reached in any other way. Sounding rockets can be launched simultaneously from several points and can be used in response to time-related phenomena.

Source record↗
NASA NTRS1980

Radio astronomy

The activities of the Deep Space Network in support of radio and radar astronomy operations during July and August 1980 are reported. A brief update on the OSS-sponsored planetary radio astronomy experiment is provided. Also included are two updates, one each from Spain and Australia on current host country activities.

Taylor, R. M.↗
NASA NTRS1981

Thermal protection systems for equipment pallets to be launched in Shuttle Orbiter

The thermal insulation for the OSS-1 Orbiter pallet is described and a design concept for future pallets is presented consisting of two independent thermal zones and new thermal insulation approaches. The application of these concepts is expected to reduce the effort required to integrate the payloads to their pallets and thereby reduce dollar costs and shorten time schedules. A stand-off insulation also is described for certain pallet areas to enclose the cabling and fluid lines in a controlled temperature environment. Methods for interfacing the payload and pallet insulations are presented and a number of areas are identified where the introduction of standards in the fabrication of thermal insulation can yield further savings.

Ruccia, F. E.↗
NASA NTRS1982

Early experiments in charged particle beams from the Space Shuttle

Characteristics of studies on board the Shuttle involving the interaction of particle beams with the atmosphere and the ionosphere, and the effects of the beams on the electrical potential of the platform, are discussed. Noting that the Shuttle allows greater weight and power demands by scientific payloads than previous satellite launches, the OSS-1 Vehicle Charging and Potential experiment and the Spacelab 1 Particle Accelerator and Phenomena Induced by Charged Particle Beams are described. Instrumentation details are provided, including charge and current probes, the Spherical Retarding Potential Analyzer, the Fast Pulse Electron Generator, and digital control and interface units. The SEPAC equipment, which comprises an electron beam accelerator, and MPD plasma jet, and diagnostic units are detailed, and operating procedures and experiment objectives are outlined.

Raitt, W. J.↗
NASA NTRS1982

U.S. mission plans for Spacelab

Mission configurations, instrumentation, and objectives for Spacelab sorties on board the Shuttle beginning in Sept. 1983 are reviewed. The first two flights will serve to verify the Spacelab systems and will be followed by operational status, including the fifth flight, which will be a reimbursible venture. Scientific investigations in the fields of atmospheric physics and environmental observation, space plasma physics, astronomy and solar physics, materials processing, and life sciences will be performed using the habitable long module, instrument pallets, and/or an instrument igloo mounted in the payload bay. Instrumentation, such as the imaging spectrometric observatory, which was developed in the U.S., will originate in either the U.S. or Europe. Details of the first four Spacelab flights are presented, noting that the OSS-3 through -7 missions will feature the first time that entire NASA payloads have returned to space.

Sander, M. J.↗
NASA NTRS1982

Astronomical facilities for Spacelab

Three significant Spacelab facilities which are being developed, or planned by NASA will use the 1-2 week observational capability for attached payloads on Shuttle to carry out advanced astronomical observations in the ultraviolet visible, and infrared spectral regions during the decade of the 1980s. The three facilities are expected to evolve in capability over several Shuttle flights with a final objective of protracted observational capability from a permanent facility in space with periodic servicing and/or retrieval. The three facilities are the Office of Space Science package (OSS-3/7), the Solar Optical Telescope (SOT), and the Shuttle Infrared Telescope Facility (SIRTF). The scientific and technical objectives of these astronomical facilities include both their current and projected capabilities, their use of the manned Shuttle, and their eventual disposition to a long-term facility. International aspects of the missions, including General Investigator programs, are also being planned.

Reeves, E. M.↗
NASA NTRS1983

Payload missions integration

Payload mission integration is summarized. Activities and achievements for Spacelab OSTA and OSS are discussed.

Source record↗
NASA NTRS1983

Test for contamination of MgF2 - coated mirrors

Graphs show preflight and postflight reflectivities in percent for exposed and covered mirrors carried on the OSS-1 payload pallet during STS-3. No changes greater than 1.8 sigma were observed except for a fingerprint. Weak evidence for degradation at 1216 A and 1600 A was found in several samples. There was no difference between flight mirrors and control mirrors. Covered samples suffered more than samples exposed to the Sun, but the differences are barely significant. The exposed side of the flight mirrors were somewhat dusty. No evidence was found for permanent solar-induced or shuttle-induced deterioration. There also was no evidence on oil-pumped vacuum versus oil-free vacuum during coating.

Bunner, A. N.↗
NASA NTRS1983

Vehicle charging and potential on the STS-3 mission

An electron gun with fast pulse capability was used in the vehicle charging and potential experiment carried on the OSS-1 pallet to study dielectric charging, return current mechanisms, and the techniques required to manage the electrical charging of the orbiter. Return currents and charging of the dielectrics were measured during electron beam emission and plasma characteristics in the payload bay were determined in the absence of electron beam emission. The fast pulse electron generator, charge current probes, spherical retarding potential analyzer, and the digital control interface unit which comprise the experiment are described. Results show that the thrusters produce disturbances which are variable in character and magnitude. Strong ram/wake effects were seen in the ion densities in the bay. Vehicle potentials are variable with respect to the plasma and depend upon location on the vehicle relative to the main engine nozzles, the vehicle attitude, and the direction of the geomagnetic field.

Williamson, R.↗
NASA NTRS1983

STS-3/OSS-1 Plasma Diagnostics Package (PDP) measurements of the temperature pressure and plasma

Designed to withstand the thermal extremes of the STS-3 mission through the use of heaters and thermal blankets, the plasma diagnostics package sat on the release/engagement mechanism on the OSS-1 payload pallet without a coldplate and was attached to the RMS for two extended periods. Plots show temperature versus mission elapsed time for two temperature sensors. Pressure in the range of 10 to the -3 power torr and 10 to the -7 power torr, measured 3 inches from the skin of the package is plotted against GMT during the mission. The most distinctive feature of the pressure profile is the modulation at the obit period. It was found that pressure peaks when the atmospheric gas is rammed into the cargo bay. Electric and magnetic noise spectra and time variability due to orbiter systems, UHF and S-band transmitter field strengths, and measurements of the ion spectra obtained both in the cargo bay and during experiments are plotted.

Shawhan, S. D.↗
NASA NTRS1983

Results of thermal environment measurements on the thermal cannister experiment and get away special enclosure

Because the OSS-1 pallet contained a variety of instruments with irregular surface geometry and properties which limited predictability, the total absorbed flux on thermal canister radiators was measured to determine heat rejection capability. The instrumentation and sensor cup design and locations for the thermal canister experiment are illustrated. Graphs show flux sensor history in hot and coal orbits. Kapton erosion is also considered. Results show that the flux levels measured in all STS attitudes are higher than predictions. In cold and moderate attitudes, flight results are a factor of two to three higher than predicts. In hot attitude, much better agreement occurred. It is concluded that in cold or moderate attitudes other sources may be contributing to added inputs (albedo, Earth shine, shuttle background). In hot attitude, smaller differences could be attributed to coatings assumptions or calculation uncertainty.

Ollendorf, S.↗
NASA NTRS1982

A solar flare X-ray polarimeter for the Space Shuttle

An instrument has recently been built and tested which is designed to measure the polarization of the hard (5-30 keV) X-ray emission from solar flares, and thereby to investigate the energy release mechanism and constrain flare models. In particular, these measurements will help to determine whether hard X-ray bursts are produced by nonthermal or by thermal electrons. The polarimeter makes use of the angular dependence of Thomson scattering from targets of metallic lithium. It has an energy resolution of a few keV, a time resolution of 5 s, and sufficient sensitivity to measure polarization levels (3 sigma) of a few percent in about 10 s for a moderate strength solar flare. The instrumental polarization has been directly measured and found to be within the design goal of approximately 1%. This polarimeter is scheduled to be flown as part of the OSS-1 pallet on an early Space Shuttle mission.

Lemen, J. R.↗