Barium releases at altitudes between 200 and 1000 kilometers - A joint Max-Planck-Institut-NASA experiment
Barium releases from Javelin and Nike-Tomahawk sounding rockets for ion cloud study of earth electric and magnetic fields
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Barium releases from Javelin and Nike-Tomahawk sounding rockets for ion cloud study of earth electric and magnetic fields
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Summary plots are presented for the time histories and power spectral density analyses of vibration and acceleration on the spacecraft from the Titan Centaur launchings carrying the Viking dynamic simulator and the two Viking spacecraft (TC-1, TC-3 and TC-4).
Power spectral density plots and associated time history plots are presented for the Titan-Centaur launch carrying the Viking dynamic simulator.
Power spectral density plots and associated time history plots are presented for the Titan-Centaur launch carrying the Viking A spacecraft.
Power spectral density plots and associated time history plots are presented for the Titan-Centaur launch carrying the Viking B spacecraft.
A method for calculating the flow about airfoils up to and beyond the stall is described. It is an iterative procedure between potential flow and boundary layer solutions. The separated region is modeled in the potential flow analysis using free vortex sheets which require an inner iteration to establish their shapes. The free vortex sheet length is an important parameter in the potential flow calculation. Results so far indicate a possible correlation between wake length and airfoil thickness/chord ratio. Calculated and experimental results are compared for a series of airfoils.
The thickness of the upper surface of 64 airfoils was increased from the leading edge to the position of maximum thickness. The modifications were generated using a numerical optimization routine coupled with an aerodynamic analysis code. The type of modification presented can be used for aircraft design or for the retrofit of current aircraft to improve the stall characteristics and climb performance. The coordinates of the modified airfoils are presented with plots of the forward 45% of the profiles and pressure distributions for both the modified and unmodified sections at an angle of attack of 14 degrees.
Technology and procedures designed for replacing a faulty attitude control module and scientific instruments on the only orbiting solar observatory are described. The rationale for the repair mission is given and the operations of the flight support system within the cargo bay of the space shuttle are discussed. The use of the manned maneuvering unit in capturing the satellite and of the remote manipulator arm in berthing it are discussed, as well as the space tools to be used for repair operations. The space crew and their responsibilities are identified.
Using NASA's Tracking and Data Relay Satellite as a communications link, astronomers are able to receive scans from the Solar Maximum Mission (SMM) satellite immediately and regularly at the Goddard Space Flight Center. This major operational improvement permits the examination of SMM imagery and spectra as they arrive, as well as the formulation of future observational sequences on the basis of the solar activity in progress. Attention is given to aspects of the sun that change in the course of the 11-year sunspot cycle's movement from maximum to minimum. Proof has been obtained by means of SMM for the near-simultaneity of X-ray and UV bursts at flare onset.
Langley, in the late nineteenth century, attempted to measure solar irradiance over an extended period of time in order to detect changes. The problem with this and other early attempts was that ground based measurements are not sufficiently accurate to measure solar irradiance fluctuations, which are on the order of 0.1%. It was not until the Active Cavity Radiometer Irradiance Monitor (ACRIM) experiment on the NASA Solar Maximum Mission (SMM) was launched in 1980 that continuous data with precision 0.1% was available.
Terrestrial climatic effects associated with solar variability have been proposed for at least a century, but could not be assessed quantitatively owing to observational uncertainities in solar flux variations. Measurements from 1980 to 1984 by the Active Cavity Radiometer Irradiance Monitor (ACRIM), capable of resolving fluctuations above the sensible atmosphere less than 0.1% of the solar constant, permit direct albeit preliminary assessments of solar forcing effects on global temperatures during this period. The global temperature response to ACRIM-measured fluctuations was computed from 1980 to 1985 using the NYU transient climate model including thermal inertia effects of the world ocean; and compared the results with observations of recent temperature trends. Monthly mean ACRIM-driven global surface temperature fluctuations computed with the climate model are an order of magnitude smaller, of order 0.01 C. In constrast, global mean surface temperature observations indicate an approx. 0.1 C increase during this period. Solar variability is therefore likely to have been a minor factor in global climate change during this period compared with variations in atmospheric albedo, greenhouse gases and internal self-inducedoscillations. It was not possible to extend the applicability of the measured flux variations to longer periods since a possible correlation of luminosity with solar annual activity is not supported by statistical analysis. The continuous monitoring of solar flux by satellite-based instruments over timescales of 20 years or more comparable to timescales for thermal relaxation of the oceans and of the solar cycle itself is needed to resolve the question of long-term solar variation effects on climate.
The Solar Maximum Satellite was launched on February 14, 1980. Problems with the Main Electronics Box (MEB) were experienced in the period July 10 to September 30, 1980. Failure occurred in the October to November time frame. Replacement of the Main Electronic Box (MEB) was performed in April 1984. The failed original MEB was returned to Earth and offered an opportunity to study some electronic parts which had spent 50 months in the natural radiation environment of a low Earth orbit (LEO) spacecraft. Spare parts were annealed at ambient temperatures on the ground. Dose rate effects between the flight and laboratory environments were compared.
Several samples of Kapton and Teflon which was exposed to solar radiation were examined. The samples represent material behavior in near Earth space. Clues to the identity of erosive processes and the responsible species were searched for. Interest centered around oxygen atoms which are ubiquitous at these altitudes and are known to erode some metal surfaces. Three diagnostic methods were employed: optical microscopy, scanning electron microscopy, and fourier transform infrared spectroscopy. Two types of simulation were used: a flow containing low energy oxygen atoms and bombardment with 3000 volt Ar ions. Results and conclusions are presented.
A Solar Maximum satellite was retrieved and repaired after being subjected for four years and 55 days to impacts by micrometeorites and Earth-orbiting space debris. The chemical variety and physical condition of particles associated with two particular impact structures in the insulation blanket of the main electronics box are studied. A scanning electron microscope equipped with an energy dispersive X ray analyzer was used to determine morphology and chemistry of impacted areas and associated particles. Some details are discussed.
The thermal insulation of the Solar Maximum Mission launched on 14 February 1980 which consisted of 17 layers of alumized Kapton offers an excellent opportunity to obtain chemistry of impacting particles. To date, approximately 0.7 sq. met. of the insulation and 0.05 sq. met. of the aluminum louvers have been mapped by optical microscope for crater diameters larger than 40 microns. Atomic oxygen has eroded up to 20 microns of the exposed Kapton surfaces removing the older and smaller craters. The crater size distribution found on 3 different Kapton surfaces is shown. About 250 chemical spectra were recorded of particles observed in or around impact pits or in the debris pattern found on the second layer beneath impact holes in the outer layer. The debris populations are listed and discussed.
An outline as of February, 1986 is briefly described of a Japanese plan to construct a large radio heliograph in the next solar maximum. The principal performance specifications of the heliograph are 10 arsec by 10 arcsec x SEC(Zenith Distance) spatial resolution, 1 arc degree by 1 arc degree field of view, 1-sec temporal resolution, and six hour coverage of observing time. It will be operated at 17 GHz with possible other frequency of 35GHz.
A Mach-Zehnder interferometer is used for optical flow measurements in a transonic wind tunnel. Holographic interferograms are reconstructed by illumination with a He-Ne-laser and viewed by a video camera through wide angle optics. This setup was used for investigating industrial double exposure holograms of truck tires in order to develop methods of automatic recognition of certain manufacturing faults. Automatic input is achieved by a transient recorder digitizing the output of a TV camera and transferring the digitized data to a PDP11-34. Interest centered around sequences of interferograms showing the interaction of vortices with a profile and subsequent emission of sound generated by this process. The objective is the extraction of quantitative data which relates to the emission of noise.