Shuttle Glow Experiment-4 (GLO-4) MISSION UPDATE
GLO-4 PRESSURE GAUGE WORKING SPECTACULARLY!
GLO flight controllers are ecstatic about the data collected from the GLO-4 Pressure Gauge, which is being flown for the first time.
The GLO-4 experiment is designed to study, among other things, the Orbiter environment. To that end, a Redhead style magnetron cold cathode pressure gauge was added to the suite of instruments for STS-74. This gauge is mounted in Bay 5 on the port side wall such that the gauge is pointed straight out of the bay and the end of the gauge is even with the sill of the cargo bay.
Gas enters the gauge from all directions. The source of the gases that make up the local environment around the Shuttle come from many sources. The background atmospheric pressure at the Orbiter attitudes is about 1 X 10-3 TORR. The outgassing from all of the tiles and blankets that shroud the shuttle and its payloads contributes significantly and brings the pressure up to about 1 x 10-7 Torr. The thrusters and OMS engines add another two orders of magnitudes to the pressure and bring the total up to about 1x10-5 Torr when they fire.
GLO is also observing the gas cloud around the MIR space station. There have been several significant pressure events that are associated with activities on MIR. The figure below shows the pressure during two minutes of the MIR PIC test at 03/21:02 MET. The figure shows two of ten groups of 100 ms pulses. This data is of superb quality and will be applied to our existing knowledge of the interaction between the spacecraft environment and the atmospheric environment.
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HYPERSPECTRAL IMAGES REVEAL ATMOSPHERIC STRUCTURE!
GLO flight controllers obtained the following hyperspectral image of atmospheric clouds during a previous Earth Limb observation.
The above figure shows the brightness of the 6300 atomic oxygen emission as a function of horizontal distance and tangent height.
The University of Arizona Lunar Planetary Laboratory and Hanscom Air Force Base Phillips Laboratory teams continue to debunk the idea that the Shuttle is a poor platform for performing "optical" science observations. (GLO spectrographs can detect emissions from far UV to near IR).
When asked about the perception that optical science is not possible from the shuttle, Dr. Broadfoot, of the University of Arizona Lunar Planetary Laboratory replied: "That's silly!"
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FROM EARLIER IN THE MISSION
The GLO-4 constitutes the third shuttle flight for GLO in the last 9 months!
The University of Arizona team has already collected one crew sleep period worth of Earth limb data; ie, far UV, visible, and near IR data. More data collection is scheduled for tonight's crew sleep period as well!
Stay tuned to this space for more info as the mission progress's.
This page last updated November 17, 1995, 1:00 PM est.
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