Bittersweet Mission

In terms of its microgravity research, STS-75 had been a superb success, hampered only by the tether breakage which lost almost a day of valuable electrodynamic measurements. Nevertheless, the reflight of the unusual satellite did demonstrate the concept of powering spacecraft using conducting tethers and, undoubtedly, will be returned to at some point in the future. Columbia's landing, extended a day to 8 March, was postponed 24 hours due to a forecast of low clouds and the chance of rain and gusty winds. ''Conditions are marginal for Friday [8th], worse for Saturday [9th],'' was KSC spokesman George Diller's summing-up of the situation.

Although weather was acceptable in California for a landing at Edwards, NASA managers - aware that Columbia had another mission booked for late June -decided to hold out for conditions to improve in Florida. A cold front passed through the spaceport on 7 March and was expected to become stationary over the Caribbean by the 9th, perhaps leading to an upper-level low-pressure system that

A bittersweet mission 265

In-flight crew portrait. Front row (left to right) are Franklin Chang-Diaz, Andy Allen and Jeff Hoffman and back row are Maurizio Cheli, Claude Nicollier, Scott Horowitz and Umberto Guidoni.

could cause clouds and showers. Fortunately, weather on 9 March turned out to be acceptable and Allen and Horowitz brought Columbia safely onto Runway 33 at 1:58:21 pm.

''All right!'' yelled the seven-man crew at the instant of wheels-stop, to which Mission Control responded simply: ''We copy your elation!''

Meanwhile, the review panel charged with investigating the cause of the TSS-1R tether breakage was established on 26 February. ''Given the public investment in the tethered satellite, it is important that we find out what went wrong,'' said NASA's Associate Administrator for the Office of Space Flight, Wil Trafton. ''To do any less would be a disservice to the American and Italian people.'' Ultimately, by the time its report appeared in May 1996, the panel blamed a defect in the tether insulation within the Shuttle's payload bay. This had apparently caused a local electrical discharge, which led to the breakage.

0 0

Post a comment