Studies of H2O sources by means of a very- long-baseline interferometer
Water sources associated with W3, Orion Nebula, W49 and VY Canis Majoris observed with coherent interferometers having long baseline
Burke, B. F.↗
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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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Very Long Baseline Interferometer /VLBI/ experiments using ATS-3 and ATS-5 satellites
Very Long Baseline Interferometer experiments using ATS 3 and ATS 5 satellites
Ramasastry, J.↗
Very Long Baseline Interferometer /VLBI/ experiments using ATS satellites - Test plan
Test plans for conducting very long baseline interferometer experiments using Applications Technology Satellites 3 and 5
Michelini, R. D.↗
Very long baseline interferometry of Jupiter at 18 MHz
Very long baseline interferometry /VLBI/ of Jupiter decametric bursts at HF
Block, W. F.↗
Atmospheric effects in very long baseline interferometry
Ionospheric and tropospheric effects on differential phase path in very long baseline interferometry, using ray tracing computer program
Grossi, M. D.↗
Very long baseline interferometry
Some astronomical results, obtained by very long baseline interferometry, on quasi-stellar sources are reported. Data cover variations in optical luminosity, radio brightness variations, and observations of quasi-stellar nuclei.
Clark, T.↗
Inertial subsystem functional and design requirements for the orbiter (Phase B extension baseline)
The design requirements use the Phase B extension baseline system definition. This means that a GNC computer is specified for all command control functions instead of a central computer communicating with the ISS through a databus. Forced air cooling is used instead of cold plate cooling.
Flanders, J. H.↗
Tracking of the ATS-3 synchronous satellite by the Very Long Baseline Interferometer (VLBI) technique
During 1971, a series of very long baseline interferometer observations were made of the C-band (6 cm) radio signals from the ATS-3 communications satellite which is in a synchronous, near-equatorial orbit. The first series of observations were conducted during May-June 1971 from Rosman, North Carolina (NASA/ATS Station 85' dish) and Mojave, California (NASA/ATS Station, 40' dish). The second series of observations were conducted during August-September, 1971 from Rosman, North Carolina (NASA/ATS Station, 85' dish), Owens Valley, California (Cal Tech, 130' dish) and Agassiz, Massachusetts (SAO Agassiz Radio Observatory, 84' dish). The ATS-3 Spacecraft position was determined with a precision of 70-100 meters and its velocity with a precision of less than a mm/sec. The ATS-3 orbital elements were computed using the GEODYN program and the derived values are consistent with those derived from conventional tracking data.
Ramasastry, J.↗
An investigation of the landing characteristics of the NASA-MSC August 1969 baseline orbiter configuration in ground effect
A 0.05 scale model of the NASA-MSC August 1969 baseline shuttle craft was tested in Texas A&M University's 7- x 10-foot low speed wind tunnel facility. The purpose of the test was to determine the landing aerodynamic characteristics of the shuttle craft vehicle in ground effect and to evaluate control surface hinge moments experienced in the cruise and landing operational phases of flight. Analysis of the final data will allow evaluation of vehicle flight stability in ground effect and estimation of vehicle control surface power system requirements.
Chambliss, E. B.↗
Summary of engine design and analytical studies to mature the 1137400E engine baseline
Activities in packaging components into integral module arrangements compatible with engine design requirements for the 1137400E flight engine baseline are summarized along with the applied mechanics and thermal analysis. Revisions to drawings, configurations, and support structures are discussed.
Kleinert, D. E.↗
Very long baseline interferometry
S-band stations with dual tracking capability have been used to gather double differential very long baseline interferometry data on Apollo 16 and Apollo 17. This was accomplished by simultaneously receiving both monochromatic radio signal emissions at each of two separated receiving stations, transmitting these data to a central processing facility, and calculating the differences between Doppler angular rates to determine the motion of the lunar roving vehicle.
Salzberg, I. M.↗
Aerodynamic investigations on a 0.004 scale model MCR 0074 baseline space shuttle launch vehicle at Mach numbers between 0.6 and 4.96
A test of a 0.004-scale MCR 0074 Baseline Launch Configuration Space Shuttle model was conducted in the NASA-MSFC 14 x 14-inch Trisonic Wind Tunnel (MSFC TWT 566). The objective of the test was to determine the effects of model parametric variations on aerodynamic static stability characteristics over a Mach number range from 0.6 to 4.96. Angles-of-attack from minus 10 deg to plus 10 deg at 0 deg sideslip and angles-of-sideslip from minus 10 deg to plus 10 deg at minus 5 deg, 0 deg, and plus 5 deg angle-of-attack were investigated. The basic configuration investigated was the integrated vehicle consisting of the orbiter, and external tank, and two solid rocket boosters. It was designated 03T9S3.
Ramsey, P.↗
Shuttle mission simulator baseline definition report, volume 2
The baseline definition report for the space shuttle mission simulator is presented. The subjects discussed are: (1) the general configurations, (2) motion base crew station, (3) instructor operator station complex, (4) display devices, (5) electromagnetic compatibility, (6) external interface equipment, (7) data conversion equipment, (8) fixed base crew station equipment, and (9) computer complex. Block diagrams of the supporting subsystems are provided.
Dahlberg, A. W.↗
Meter-wavelength observations of pulsars using very long baseline interferometry
The results of an investigation of the angular structure imposed on pulsar radiation due to scattering in the interstellar medium are presented. The technique of very-long-baseline interferometry was used to obtain the necessary high angular resolution. The interferometers formed by the Arecibo, NRAO, and Sugar Grove telescopes were used at radio frequencies of 196, 111, and 74 MHz during seven separate observing sessions between November 1971 and February 1973. A crude visibility function for the Crab nebular pulsar was obtained along with the correlated pulse profile. The technique of differential fringe phase was used to show that the pulsar and the compact source in the Crab nebula are coincident to within 0.001 arcsec which corresponds to aproximately 2 a.u. at the distance to the nebula. The ratio of pulsing to total flux, and the fringe visibility of the time-averaged pulsing flux are also discussed, and apparent angular sizes of the pulsars were measured.
Vandenberg, N. R.↗
Lunar baselines and libration from differential VLBI observations of ALSEPs
Differential very-long-baseline interferometric observations of signals from Apollo Lunar Surface Experiment Package telemetry transmitters will yield the relative projected positions of the transmitters with uncertainty of only 1-3 m, set mainly by uncertainty of the lunar ephemeris. Noise and systematic instrumental errors which in the past affected similar observations have been reduced to the equivalent of a few centimeters on the lunar surface by the development of a new type of differential receiver. Continued observations should yield a determination of the motion of the moon about its center of mass with uncertainty less than 1 sec of selenocentric arc. Improvements (by other means) in our knowledge of the moon's orbital motion would allow a further order-of-magnitude refinement in the libration and relative position results obtainable by differential VLBI.
Counselman, C. C., III↗
Space Shuttle - The new baseline
Recent design alterations and refinements in the Space Shuttle program are considered with particular attention to the present baseline Shuttle configurations, performance characteristics, mission profiles, and flight and ground operations. Hardware and software development and testing, propulsion systems, entry trajectory events, and payload capability are covered. The refined Space Shuttle system design is characterized as one reflecting firm technical and economic considerations. Systems development is well under way, with all major contractors progressing on schedule.
Malkin, M. S.↗
Extragalactic radio sources - Accurate positions from very-long-baseline interferometry observations
Relative positions for 12 extragalactic radio sources have been determined via wide-band very-long-baseline interferometry (wavelength of about 3.8 cm). The standard error, based on consistency between results from widely separated periods of observation, appears to be no more than 0.1 sec for each coordinate of the seven sources that were well observed during two or more periods. The uncertainties in the coordinates determined for the other five sources are larger, but in no case exceed 0.5 sec.
Rogers, A. E. E.↗
Precision timing and Very Long Baseline Interferometry (VLBI)
The use of very long baseline interferometry (VLBI) for investigating small angular features in galactic and extragalactic radio sources is discussed. Mathematical models are developed to describe the operation of an interferometer and to show the variations in the resultant fringe frequency. The types of sources to which the interferometer will respond are identified.
Clark, T. A.↗