SHUTTLE FLEET GROUNDED

NASA suspended all Shuttle flights on June 25, 2002 as a result of small cracks, between 2.5 mm and 7.62 mm in length, being found in the metal liners used to direct liquid hydrogen flow inside the Space Shuttle Main Engine (SSME) propellant lines on Atlantis, on July 11. Three cracks were subsequently found on Columbia’s No. 2 SSME and Atlantis’ and Discovery’s No. 1 SSMEs. One crack was found in the No. 1 and No. 2 SSMEs on Endeavour. Investigation showed that the cracks were most likely caused by bad welding, rather than age, or wear and tear. The entire Shuttle fleet was grounded as a safety measure while an investigation and replacement work was undertaken. The principal concern was that small pieces of metal might be ingested into an engine during a launch. Inspection of the five orbiters was expected to take the remainder of July. With no spare pipe liners in stock, repair would take at least 7 weeks. Replacement would require new liners to be manufactured, a task requiring several months.

In this same period, a mechanical fault was discovered in the bearings inside the hydraulic jacks that maintained the Mobile Launch Platform in the horizontal position during the Shuttle’s rollout to the launch pad. Fifteen cracks were discovered in Crawler-1 and a further 13 in Crawler-2. All 16 jacks on the two Crawler Transporters were replaced.

When the Expedition-5 crew were informed that their occupation of ISS had been extended for one month, Bursch wrote,

“We just got news that our Shuttle flight home has been delayed… That should send us over the six-month mark and we should break Shannon Lucid’s U. S. record of 188 continuous days in space. That feels nice to be able to share in a record… but I sure do miss my family.’’

Meanwhile, NASA’s own inspectors criticised the Administration for not thoroughly checking on United Space Alliance, the private contractor that serviced the Shuttles and prepared them for launch. NASA had announced that the estimated risk of a catastrophic failure of a Shuttle had risen from 1: 78 in 1986, the year STS-51L was lost, to 1: 55 in July 2002.

With all of this going on, STS-107, the “Freestar’’ solo science flight planned for launch on July 19,2002 was grounded indefinitely, but was expected to be launched at the end of the year. This 16-day flight, with a crew of 7, would carry the new SpaceHab Research Double Module, loaded with more than 80 experiments. The mission was designed to answer the criticism that ISS was not performing sufficient science. However, on the resumption of flights it was decided that STS-107 would not now be launched until after STS-112 and STS-113 had flown to ISS, delivering the Starboard-1 (S-1) and Port-1 (P-1) ITS segments, respectively, which would slip STS-107 to January 2003.