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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 145 records · Page 8
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NASA NTRS1975

Scout fourth stage attitude and velocity control (AVC) system feasibility study

The feasibility of incorporating a guidance system in the Scout fourth stage to achieve a significant improvement in expected payload delivery accuracy is studied. The technical investigations included the determination of the AVC equipment performance requirements, establishment of qualification and acceptance test levels, generation of layouts illustrating design approaches for the upper D and payload transition sections to incorporate the hardware, and the preparation of a vendor bid package. Correction concepts, utilizing inertial velocity and attitude, were identified and evaluated. Fourth stage attitude adjustments as determined from inertial velocity variation through the first three stages and a final velocity correction based upon the measured in-plane component errors at injection were employed. Results show radical reductions in apogee-perigee deviations.

Byars, L. B.↗
NASA NTRS1974

Atmosphere Explorer orbit adjust propulsion system

The Atmosphere Explorer-C (AE-C) spacecraft was launched into a highly elliptical orbit by a two-stage Delta 1900 vehicle on December 15, 1973. Its mission is to observe and study phenomena in the earth's atmosphere at altitudes between 150 and 4000 kilometers with several excursions down to 130 kilometers. An Orbit Adjust Propulsion System (OAPS) is included on the spacecraft in order (1) to perform low perigee maneuvers at 130 to 150 kilometers; (2) to periodically restore apogee in order to offset the effect of aerodynamic drag at perigee; and (3) to provide the capability for occasional large attitude maneuvers. This paper describes the configuration of the OAPS and the design characteristics of its individual components. Special emphasis is placed on the valving arrangement, which provides a means of adjusting the center-of-mass of the spacecraft through control of the distribution and usage of the propellant within the system.

Woodruff, W. L.↗
NASA NTRS1974

Initial observations of magnetospheric boundaries by Explorer 45 /S3/

Attention is given to the nature of the inner edge of the proton ring current and its relationship to the plasmapause, the observation of the magnetopause during the large event of Aug. 4, 1972, and the observation of the electron plasma sheet at the apogee of Explorer 45. Two features in the interaction region between the inner edge of the proton ring current and the plasmapause are discussed.

Fritz, T. A.↗
NASA NTRS1975

Substorm-associated reconfiguration of the dusk side equatorial magnetosphere - A possible source mechanism for isolated plasma regions

A rapid reconfiguration of the dusk side magnetosphere was observed near the magnetic equator by particle and field experiments aboard Explorer 45 at 1715 UT on June 17, 1972. Following the onset of an 800-gamma negative bay in the auroral zone, Explorer 45, inbound at 1700 MLT and L about 5, observed a sharp dropout of outer zone electrons. Simultaneously, the plasma density dropped from a level typical of the plasmasphere to one typical of the ion trough, and plasma sheet proton fluxes increased, producing a 100-gamma depression in B, in a shift to a taillike configuration. Outer zone electrons with pitch angles near 45 deg returned with delay times consistent with injection near midnight at the time of dropout and eastward drift to the dusk meridian. Approximately 45 min after the reconfiguration, the satellite reentered the plasmasphere, and the electron fluxes returned to previous levels. In the next orbit, approximately 6 hours later, a region of isolated plasma was detected near apogee at 1400 MLT. There is therefore circumstantial evidence that the type of magnetospheric reconfiguration observed here is responsible for the detachment of regions of cold plasma from the plasmasphere.

Barfield, J. N.↗
NASA NTRS1975

Drag coefficients for astronomical observatory satellites

The first experimental European communications satellite Symphonie is a geostationary satellite. The satellite is designed and built in a joint project by French and German aerospace firms. A description is given of the basic technical concept of the satellite. The apogee motor is discussed along with the satellite stabilization system. The stabilization system provides a three-axis positional stabilization and an orbital stabilization. Attention is given to the spin stabilization phase, the sensors employed, the approache used for orbital correction maneuvers, and the conduction of simulation tests on the ground.

Williams, R. R.↗
NASA NTRS1975

Auroral electrons and the optical emissions of nitrogen

Simultaneous rocket measurements of the auroral electron flux and the optical emissions of N2 give a consistent picture of electron impact excitation in an aurora. The electron data show that the incident auroral electrons are nearly monoenergetic with energy about 25 keV. The overall shape of the observed low-energy electron spectrum is in good agreement with other recent observations and also with recent theoretical models, although there is some disagreement with the models in the value of the power law slope above 20 eV. A discussion of the secondary electron spectrum obtained near apogee shows that a single power law cannot accurately describe the secondary electron spectrum in the energy range from 3 to 85 eV. About 40% of the N2(+) 1NG (0,0) band emission at 3914 A is excited by electrons with energy below 85 eV.

Feldman, P. D.↗
NASA NTRS1975

Protons as the prime contributors to storm time ring current

Following a large sudden commencement on June 17, 1972, a large magnetic storm evolved, with a well-developed main phase and recovery phase. Explorer 45 (S3-A), with its apogee near 16 hours local time in June, measured the equatorial particle populations and magnetic field throughout this period. By use of data obtained during the symmetric recovery phase it is shown that through a series of self-consistent calculations, the measured protons, with energies from 1 to 872 keV, can account for almost all of the observed ring current magnetic effects within the limits of experimental uncertainties. This enables us to set an upper limit to the heavy ion contribution to the storm time ring current of a few percent of the proton contribution.

Berko, F. W.↗
NASA NTRS1975

The LAGEOS system

The LAGEOS system is defined and its rationale is developed. Key features of the baseline system specified included a circular orbit at 5900 km altitude and an inclination of 110 deg, and a satellite 60 cm in diameter weighing some 385 kg and mounting 440 retroreflectors, each having a diameter of 3.8 cm, leaving 30% of the spherical surface available for reflecting sunlight diffusely to facilitate tracking by Baker-Nunn cameras. The satellite weight was increased to 411 kg in the actual design through the addition of a 4th-stage apogee-kick motor. The number and diameter of the retroreflectors are now 426 and 3.81 cm, respectively. The net effect of these partially compensating changes is not significant. The diffusely reflecting area was increased to 47% of the satellite surface.

Siry, J. W.↗
NASA NTRS1975

SENS-5D trajectory and wind-sensitivity calculations for unguided rockets

A computational procedure is described which numerically integrates the equations of motion of an unguided rocket. Three translational and two angular (roll discarded) degrees of freedom are integrated through the final burnout; and then, through impact, only three translational motions are considered. Input to the routine is: initial time, altitude and velocity, vehicle characteristics, and other defined options. Input format has a wide range of flexibility for special calculations. Output is geared mainly to the wind-weighting procedure, and includes summary of trajectory at burnout, apogee and impact, summary of spent-stage trajectories, detailed position and vehicle data, unit-wind effects for head, tail and cross winds, coriolis deflections, range derivative, and the sensitivity curves (the so called F(Z) and DF(Z) curves). The numerical integration procedure is a fourth-order, modified Adams-Bashforth Predictor-Corrector method. This method is supplemented by a fourth-order Runge-Kutta method to start the integration at t=0 and whenever error criteria demand a change in step size.

Singh, R. P.↗
NASA NTRS1976

University of Utah four-channel pulse-to-pulse commutated SUPER-LOKI rocket meteorological parachutesonde (electronics)

The electronics and temperature sensing units of the pulse-to-pulse rocketsonde are described. The sonde is designed for the 2 1/8-inch dart of the SUPER-LOKI meteorological rocket. In flight, the sonde descends by parachute from rocket apogees of about 75 kilometers. As the sonde descends, it transmits air temperature data back to ground radio receiving stations.

Atwood, K. W.↗
NASA NTRS1975

Circular earth orbits attainable with fixed two-impulse expendable tug

The performance of solid rocket motors in expendable stages as an alternative concept for Shuttle interim upper stage applications is assessed from the standpoint of mission flexibility. The system comprises two stages and a payload, released from a circular Shuttle orbit at 160 naut miles altitude. The stages are sized to deliver a given payload mass to synchronous equatorial orbit. Only nonreturn missions are considered. A parametric sweep was made with small increments of pitch and yaw to compute the possible transfer orbits with an apogee greater than 160 naut miles. At several points on each transfer orbit the possibility of attaining a circular orbit with the second burn impulse of 6000 fps was assessed. Constraints on the vertical component of the second impulse and on the total velocity after firing determine the pitch angle for second burn. Results indicate a fixed two-impulse system designed to place a payload into synchronous equatorial orbit from the Shuttle orbit can deliver the payload mass into any lower circular orbit at any inclination within about 30 deg of the Shuttle orbit. The only apparent disadvantage of the system is an inability to achieve circular orbits above geosynchronous altitudes with the design payload.

Porter, R. F.↗
NASA NTRS1976

Rocket and ground-based measurements of the dayside magnetospheric cleft from Cape Parry, N.W.T.

On Dec. 6, 1974, a Black Brant VD rocket was launched from Cape Parry, N.W.T., into the dayside magnetospheric cleft. The prime launch criterion was the detection of 6300-A emission by two ground-based scanning photometers, but support was provided by two ionosondes. The payload passed through a narrow region of soft electron precipitation, a broader region of enhanced electron densities, and a similarly broad region of O I 5577-A and 6300-A emission. At apogee (236 km), the payload had not penetrated into the 5200-A emission, which had a very sharp equatorward boundary and extended far into the polar cap, presumably as a result of antisunward convection.

Shepherd, G. G.↗
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 NTRS1976

The Nike-Black Brant V development program

The Nike-Black Brant V represents a combined U.S.-Canadian program to achieve a 40 percent increase in apogee performance over that of the unboosted BBV, with minimum component modification and no meaningful increase in flight environment levels. The process of achieving these objectives is described, in particular optimization of sustainer coast period and roll history, and the techniques used to ensure good stage separation. Details of the structural test program and subsequent successful vehicle proving flight are provided. Basic performance data are preented, with an indication of the further potential offered by Terrier boost.

Sevier, H.↗
NASA NTRS1975

International Ultraviolet Explorer (IUE) satellite mission analysis

The results are presented of the mission analysis performed by Computer Sciences Corporation (CSC) in support of the International Ultraviolet Explorer (IUE) satellite. The launch window is open for three separate periods (for a total time of 7 months) during the year extending from July 20, 1977, to July 20, 1978. The synchronous orbit shadow constraint limits the launch window to approximately 88 minutes per day. Apogee boost motor fuel was computed to be 455 pounds (206 kilograms) and on-station weight was 931 pounds (422 kilograms). The target orbit is elliptical synchronous, with eccentricity 0.272 and 24 hour period.

Cook, R. A.↗
NASA NTRS1977

Satellite situation report, volume 17, no. 1

Space objects in orbit as well as those which decayed during the reporting period are listed. Data provided include international designation and catalog number, nation of source, launch date, and inclination, apogee and perigee. Transmitting frequencies for satellites being monitored by NASA space flight tracking and data network are given.

Source record↗
NASA NTRS1977

Satellite situation report, volume 17, no. 2

Space objects in orbit are listed as well as those which decayed during the reporting period. Data provided include international designation and catalog number, nation of source, launch date, and inclination, apogee and perigee. Transmitting frequencies for satellites being monitored by NASA space flight tracking and data network are given.

Source record↗
NASA NTRS1977

Satellite situation report, volume 17, no. 4

Space objects in orbit are listed as well as those which decayed during this reporting period. Data provided include international designation and catalog number, nation of source, launch date, inclination, apogee and perigee. Transmitting frequencies for satellites being monitored by NASA space flight tracking and data network are given.

Source record↗