This year we could have witnessed a Christmas-time shuttle flight as November’s STS-133 mission had been re-scheduled to 17 December, but once again Discovery’s final flight has been postponed, this time to February. Sinead McNicholl has the details.
Originally Discovery had been set to launch on 1 November, but this was delayed when fatigue cracks were found in the structure of its External Tank. The next launch opportunity presented itself on 17 December raising the prospect of a festive flight. However engineers wanted to fully understand what has caused the cracks before rescheduling. Their concern was that cracks could spread on ascent, possibly leading to the Tank’s destruction. In this worst case scenario, debris could strike the body of Discovery, something similar happened to the ill-fated Columbia in 2003 resulting in its destruction during re-entry, tragically killing all onboard.
The flight is now scheduled for 3 February 2011. This may seem quite a long time in the future but missions to the ISS are only possible in periods when the station’s orbit carries it near or over the Florida launch site. There is a nice description of the complexities of Shuttle launch windows in the Smithsonian’a Air and Space magazine site. STS-133 will be the 35th Shuttle mission to the ISS and will deliver the EXPRESS Logistics Carrier 4 and Permanent Multi-Purpose Module to the station.
A little bit of trivia is that Discovery has actually made the only shuttle-era Christmas time flight to date, this was STS-103, a mission to repair the Hubble Space Telescope in 1999.
Keep an ear out for developments on Discovery’s launch date. You can see a fascinating 45 minute long documentary on Shuttle launches by clicking on this link.