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Clifton, K. S.

Publications and source records attributed to Clifton, K. S..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Space station particulate contamination environment

The origin of particulate contamination on the Space Station will mostly be from pre-launch operations. The adherence and subsequent release of these particles during space flight are discussed. Particle size, release velocity, and release direction are important in determining particle behavior in the vicinity of the vehicle. The particulate environment at the principal science instrument locations is compared to the space shuttle bay environment. Recommendations for possibly decreasing the particulate contamination are presented.

Miller, E. R.↗
NASA NTRS1986

A digital imaging photometry system for cometary data acquisition

This report describes a digital imaging photometry system developed in the Space Science Laboratory at the Marshall Space Flight center. The photometric system used for cometary data acquisition is based on an intensified secondary electron conduction (ISEC) vidicon coupled to a versatile data acquisition system which allows real-time interactive operation. Field tests on the Orion and Rosette nebulas indicate a limiting magnitude of approximately m sub v = 14 over the 40 arcmin field-of-view. Observations were conducted of Comet Giacobini-Zinner in August 1985. The resulting data are discussed in relation to the capabilities of the digital analysis system. The development program concluded on August 31, 1985.

Clifton, K. S.↗
NASA NTRS1986

STS-9 Shuttle grow - Ram angle effect and absolute intensities

Visible imagery from Space Shuttle mission STS-9 (Spacelab 1) has been analyzed for the ram angle effect and the absolute intensity of glow. The data are compared with earlier measurements and the anomalous high intensities at large ram angles are confirmed. Absolute intensities of the ram glow on the shuttle tile, at 6563 A, are observed to be about 20 times more intense than those measured on the AE-E spacecraft. Implications of these observations for an existing theory of glow involving NO2 are presented.

Swenson, G. R.↗
NASA NTRS1985

Ram vehicle glow spectrum - Implication of NO2 recombination continuum

An experiment was operated on several Space Shuttle missions to provide spatial and spectral distributions of a ram glow associated with the Orbiter. The most recent data featured resolved spectrum and imagery of the glow with spectroscopic resolution of 34 A FWHM between 4000 and 8000 A. The spectrum of the glow on the Shuttle tail pod could be clearly separated from spectrum of the reflected light from the Orbiter. Analysis and comparison have been performed which strongly suggest the emission originates from recombination continuum of NO2. Both fast recombination (high temperature) and the spectral dependence in lifetime can describe the spectral difference. If the recombined NO2 retains 25 percent of the kinetic energy of the ram OI, the thickness of the glow layer can be explained by the lifetime of NO2 (2B1) recombination emission.

Swenson, G. R.↗
NASA NTRS1985

Space vehicle glow measurements on STS 41-D

A flight experiment using a hand-held, image-intensified spectrographic camera was performed on mission 41-D. The instrument enabled the photographic documentation of the position of the spectral slit on the image to be subjected to spectrographic analysis. Because of this instrument feature, the spectrum of the glow on the Shuttle tail pod could be clearly separated from spectrum of the scattered light from the Orbiter. From the measurements it is clear that the spectrum of the glow is a continuum in the passband of the instrument between 4200 A and 8000 A. The measured spectral resolution of the instrument was 35 A. The scattered light from the Orbiter surfaces distinctly show the components of the earth's airglow at 5577 A and 7620 A. On the same flight material samples were also carried by the Orbiter attached to the Remote Manipulating System arm. These samples were representative of the material overcoatings used on the space telescope. The altitude of the 41-D flight was 290 km, instead of the 220 km which was originally planned for this experiment. The signal to noise ratio in the material glow discrimination experiment was quite low. This made it difficult to draw strong conclusions regarding the glow propensity of the materials. Nevertheless it was clear that polyethylene produces a very weak glow, while most black overcoating materials produce significant glow. MgF2 was also found to produce a relatively intense glow.

Mende, S. B.↗
NASA NTRS1984

Atmospheric emissions photometric imaging experiment

The atmospheric emissions photometric imaging experiment was flown on Spacelab 1 to study faint natural and artificial atmospheric emission phenomena. The instrument imaged optical emission in the region 2000 to 7500 angstroms with a television system consisting of two optical channels, one wide-angle and one telephoto. A third optical channel imaged onto the photocathode of a microchannel plate photomultiplier tube that has 100 discrete anodes. A hand-held image intensifier camera with an objective grating permitted spectral analysis of the earth's airglow and the Shuttle glow. Preliminary data show magnesium ion emission features in the lower ionosphere as well as the spacecraft glow spectrum.

Mende, S. B.↗
NASA NTRS1983

Camera/photometer results

Camera/photometer systems have been constructed for analyzing particulate contamination on STS-2. The systems contained two 16-mm photographic cameras to make stereoscopic observation of contaminant particles and the background. During the STS-2 mission, 102 photographic exposures were obtained under conditions suitable for recording particulate contamination. Attention is given to a breakdown of STS-2 camera/photometer data with the number of particles observed per frame, a correlation of observed contamination with mission elapsed time broken into 5-hr segments, and a correlation of observed contamination with onboard spacecraft events.

Clifton, K. S.↗
NASA NTRS1982

Spacelab mission 2: Experimental descriptions

The second Spacelab Mission and the 12 multidisciplinary experiments selected to fly on board are described. These experiments include the following: vitamin D metabolities and bone demineralization; interaction of oxygen and gravity influenced lignification; ejectable plasma diagnostics package; plasma depletion experiments for ionospheric and radio astronomical studies; small helium cooled IR telescope; elemental composition and energy spectra of cosmic ray nuclei; hard X-ray imaging of clusters of galaxies and other extended X-ray sources; solar magnetic and velocity field measurement system; solar coronal helium abundance Spacelab experiment; solar UV high resolution telescope and spectroraph; solar UV spectral irradiance monitor; and properties of superfluid helium in zero-G.

Clifton, K. S.↗
NASA NTRS1980

Atmospheric Emission Photometric Imaging on Spacelab (AEPI)

Two parallel detector systems are used for atmospheric emission photometric emission. The top system is a TV system using the image intensified S.E.C. tube as the detector. The bottom system, the photon counting array (P.C.A.), uses a microchannel plate intensified anode array tube and is equivalent to a 100 channel photomultiplier. For the television, the filters are selected by means of a filter wheel set. The field of view of the is interchangeable between 20 and 6 degrees, by means of a moveable prism. The quartz window mu channel plate intensifier is fiber optically coupled to a 40-25 demagnifying tube which is in turn coupled to the S.E.C. tube. The PCA channel has a fixed field of view of 4 deg and a remote control interchangeable photometric converter optics which converts the imaging array into a multichannel photometer. The mu channel plate array tube amplifies the photons into detectable counts for the PCA electronics. The entire system is pointed by a two axis gimbal. The flight equipment to be acquired consists of a gyro package and an interactive flight control unit panel. The gyro package is necessary because of the inadequate attitude reference supplied by the current Spacelab systems.

Mende, S. B.↗
NASA NTRS1980

Low-light-level television measurements of lightning

Nighttime observations of lightning were conducted using a low-light-level television system at the Langmuir Laboratory for Atmospheric Research in New Mexico. The number of strokes per flash, the interstroke intervals, and flash durations of cloud-to-ground activity were measured for storms ranging from 50 to 200 km away from the observation site. The flash frequency was also obtained for a severe storm system at a distance of 320 km. Some comparisons of the data are made with results obtained from previous television and photographic lightning observations.

Clifton, K. S.↗
NASA NTRS1979

Video detection and analysis techniques of transient astronomical phenomena

Low-light-level television systems have been utilized to gain information on meteors, aurorae, and other faint, transient astronomical phenomena. Such phenomena change not only their position as a function of time, but also their photometric and spectral characteristics in as little as 1/60 second, thus requiring unique methods of analysis. Data observed with television systems and recorded on video tape have been analyzed with a system utilizing both analog and digital techniques. Both off-the-shelf equipment and inhouse developments are used to isolate sequences of moving images and to store them in a form suitable for photometric and spectral reduction. Current emphasis of the analysis effort is directed at the measurement of the first-order emission lines of meteor spectra, the results of which will yield important compositional information concerning the nature of the impinging meteoroid.

Clifton, K. S.↗
NASA NTRS1979

Video techniques in comet-debris studies

The paper describes techniques for examining comets and meteors. Data was obtained on four nights around the peak of the Geminid shower, using SEC Vidicon equipment at Mount Hopkins Observatory in Arizona at a latitude of 31 deg 41.9 north, longitude 110 deg 52.7 west, and 2320 meters above sea level. The TV employed, was mated to an f/0.75 lens of 105 mm focal length, and agove the lens a transmission diffraction grating was fixed with 300 lines/mm. Attention is given to the calibration curve of the seven-pixer means and to the contour lines drawn by the Image Data Processing System (IDAPS).

Millman, P. M.↗
NASA NTRS1978

Monitoring of particulate contamination and background brightness from IECM based instrumentation

Of particular concern to the astronomical community is the effect of Shuttle Transportation System induced contamination in the form of individual particles and general background on astronomical experiments. In an effort to investigate this problem, two camera/photometers in the Induced Environment Contamination Monitor (IECM) will be used to determine the size and velocity distribution of contaminant particles, their origin, and the extent of sunlit background brightness resulting from spacecraft contamination. The cameras will operate synchronously as a stereo pair to make continuous photographic measurements throughout the missions.

Clifton, K. S.↗
NASA NTRS1976

Science demonstrations

Three demonstrations of scientific concepts concerning liquids were performed during the Apollo-Soyuz Test Project mission. Chemical foaming, spreading of liquids, and capillary wicking were the subjects of each demonstration photographed in space. The results clearly illustrated the basic principles, and films suitable for educational uses are now available from the first author.

Snyder, R. S.↗
NASA NTRS1975

SEC Vidicon spectra of Geminid meteors, 1972

The SEC Vidicon, a low light level closed circuit television system, was used to obtain 137 spectrographic records of meteors at Mt. Hopkins, Arizona, during the Geminid meteor shower in December 1972. Seven of the best Geminid meteor spectra are studied here in detail. The near infrared, out to wavelengths near 9000 A, is recorded for the first time for Geminids. The spectra, in general, exhibit the elements previously found in photographic records of this shower but show a surprising frequency of occurrence of the forbidden green line of O I at 5577 A. This line is normally absent from meteors moving as slowly as the Geminids (36 km/sec) and its presence in these records may be due to the added sensitivity available with the SEC Vidicon. The average green line duration in Geminid meteors with a luminosity near zero absolute visual magnitude is 0.73 sec at a mean height of 95 km, 11 km lower than the green line peak in Perseid meteors of the same luminosity.

Millman, P. M.↗