Survey of GLO Flight Data


The orbit of STS-53 was very near the terminator, so many observations of sunrise and sunset were possible. Because the Shuttle attitude was predominantly bay towards the Earth, altitude profiling along the slit was usually not possible. In order to obtain altitude information, the instrument scan platform was continually stepped through a series of elevations during the observation. Orbit inclination was 57°.

Spectrographs B - E were working. Grating efficiency was very poor in the E spectrograph between about 1300Å to 1500Å.

There was almost no imaging data on this flight because of software problems.


STS-63 was launched in the middle of the night, so the northward pass as well as the maximum northward excursion of each orbit were in the night, while the southward pass and maximum southern excursion of the orbit were daylit. The STS-63 orbit was inclined at 51.6° to the equatorial plane to rendezvous with the MIR Space Staion.

The image intensifier tube on spectrograph C failed on MET day 2. The optics of spectrograph E shifted during launch, so the spectrum from 1150Å to 2000Å was out of focus.

The on-board tape recorder failed, so we were only able to take data at the full rate when the orbiter was in communication with the ground through the ku band. The orbiter was in LOS (Loss of Signal) for roughly 20 percent of the time. After MET day 2, data was taken at a reduced rate during LOS periods and stored in memory until the ku band was restored to us.


STS-69 orbited the Earth at an inclination of 28.5°. We were able to track on the airglow layer at night for most of the mission, allowing us to compensate for the Shuttle attitude limit cycle. A number of stars were observed during inertial holds for occultation experiments and calibration purposes.

There is a 60 hour period during which GLO was making continuous limb observations. The period starts at MET 4/06:04.

On STS-69, the D spectrograph did not work. The optics shifted in the E spectrograph, so the full altitude range is not available in the 1150Å to 2000Å spectral image.


STS-74 was a MIR docking mission, so the orbit inclination was again 51.6°. There were several observations of star occultations.

All spectrograph and imager detectors were working on this mission.

There were problems with the tracking which are still being analyzed. There was no night limb tracking, and during the day tracking worked only on a few passes.

A very noisy low-rate communications channel made commanding difficult on this flight.

o Last Updated: 05 February, 1996

This page is maintained by:
Jesus A. Ramirez