Booster Concerns

When Columbia reached orbit on the evening of 19 November 1996, the ORFEUS-SPAS-2 deployment was the first major objective on the crew's agenda, scheduled to take place seven hours into the STS-80 mission. The launch itself was three weeks overdue. Firstly, problems had surfaced earlier that year with a new-specification adhesive on the SRBs, which engineers suspected was partially to blame for field-joint damage experienced during the STS-78 ascent. That had led to the postponement of Atlantis' STS-79 flight and the replacement of her set of SRBs with those previously earmarked for STS-80.

Additionally, preparations at KSC in anticipation of Hurricane Fran had forced managers to delay the launch from 31 October until 8 November and later the 11th. Otherwise, readying Columbia herself for her 21st trip into space was proceeding well: the only minor problem, on 7 October, was the need to replace two of her flight deck windows after an engineering analysis determined that windows with a high number of flights could tend to fracture more easily. One of the windows had been in space eight times previously, the other seven.

Elsewhere, the primary payloads for STS-80 - ORFEUS-SPAS-2 and the Wake Shield Facility - were transferred to Pad 39B on 11 October and installed on board Columbia when she arrived a few days later. Then, on 28 October NASA managers opted to postpone the launch by at least an additional week beyond 11 November to allow engineers time to better understand an issue regarding erosion of one of the SRB nozzles during STS-79's ascent in September.

The concern surrounded insulating material, which had experienced higher-than-normal 'grooving' erosion in the nozzle's 'throat' area. Although this presented no safety-of-flight issue, it was decided to evaluate and clear the issue before committing Columbia to flight. ''Our decision to defer setting a launch date allows the team time to ensure the RSRM nozzles are safe to fly,'' said Shuttle manager Tommy Holloway. ''We will take whatever time is necessary to understand the phenomenon seen on the STS-79 boosters before we proceed with the STS-80 launch.''

Ultimately, after agreeing on a new target date of 15 November, he told journalists: ''Everyone involved with the investigation of this issue has been doing a superb job and it appears that the effort is nearing a point where it will provide us with a good understanding of the phenomenon. However, this additional week will ensure that the final portions of the investigation are not rushed, and it will allow those involved to organise and present their data in the best way possible as they draw their conclusion.''

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