Security concerns have prompted NASA not to use the Ben Geurir airport in Morocco as the prime site for a transatlantic abort landing (TAL) for the Space Shuttle return-to-flight mission, STS 114 Discovery, scheduled for launch no earlier than 14 May.

Ben Geurir is being replaced indefinitely by Istres-le-Tube, north west of Marseilles, France, as a result of terrorist fears. One of the largest military bases in Europe, Istres-le-Tube was earmarked as a potential TAL site in 2000. A transatlantic abort has not yet been used on any of the 112 Shuttle missions.

Once a Shuttle has launched, there are no abort modes for any type of solid rocket booster (SRB) failure during the first 120s. After SRB separation, there are two options: a contingency abort to get down safely anywhere on sea or land, preferably at an airport such as Bermuda; and the more challenging return to launch site (RTLS) abort.

The next option is a TAL. Either an RTLS or TAL can be made in the 3-4min after launch. The final option is an abort to orbit, which was activated once, on the STS 51F Challenger mission in 1985, when one engine failed. The TAL also provides abort options in the event of a major systems failure such as cabin depressurisation.


Source: Flight International