realtime - 23/10/2005 11:44 PMThought some of you out there might like to see these. Back when there were more than two (or is that one) companies bidding on contracts.http://www.astronautix.com/lvfam/shuosals.htm
In late 1969 the USAF had indicated a preference for all-aluminium structures in the shuttle due to a titanium shortage. This requirement forced a move to non-metallic thermal protection systems, which at the time it was thought would weigh 15% less but cost 300% more. Thermal protection shingles for a titanium structure would weigh 2300 to 4500 kg less, but an aluminium structure would weight about 1800 kg more - meaning there was no essential weight difference between the two approaches. Therefore at the aluminium structure was accepted as a specification requirement. In retrospect it could hardly have been necessary to apply this requirement on a project where only a few flight vehicles were be built. It made the shuttle much more vulnerable to any breach of heat shield integrity and would lead to the death of the Columbia crew 35 years later. The resulting need for a non-metallic thermal protection system would also have enormous cost and schedule consequences for the actual program.
realtime - 24/10/2005 12:24 AMThere's plenty of food for thought in there. An interesting bit of analysis at the end of this discussion on TPS:QuoteIn late 1969 the USAF had indicated a preference for all-aluminium structures in the shuttle due to a titanium shortage. This requirement forced a move to non-metallic thermal protection systems, which at the time it was thought would weigh 15% less but cost 300% more. Thermal protection shingles for a titanium structure would weigh 2300 to 4500 kg less, but an aluminium structure would weight about 1800 kg more - meaning there was no essential weight difference between the two approaches. Therefore at the aluminium structure was accepted as a specification requirement. In retrospect it could hardly have been necessary to apply this requirement on a project where only a few flight vehicles were be built. It made the shuttle much more vulnerable to any breach of heat shield integrity and would lead to the death of the Columbia crew 35 years later. The resulting need for a non-metallic thermal protection system would also have enormous cost and schedule consequences for the actual program.The man has a talent for understatement...http://www.astronautix.com/lvs/shur134g.htm
FransonUK - 24/10/2005 2:18 PMMost of those ships look like lifting bodies (and very cool too). Why did NASA go with wings in the end?
realtime - 24/10/2005 6:22 PMQuoteFransonUK - 24/10/2005 2:18 PMMost of those ships look like lifting bodies (and very cool too). Why did NASA go with wings in the end?USAF wanted the cross-range capability afforded by wings, and NASA needed the USAF to fund Shuttle. Then USAF lofted one military payload and decided they'd be better off with their own systems.Picky, picky.