Final shuttle launch for Discovery: Was shuttle program worth it?
Feb. 24 will mark the last shuttle launch of Discovery, with the final flight of Endeavour to follow in April and – if there's enough money – Atlantis's last flight of the entire program in June. Here are five questions about what the shuttles have – and haven't – accomplished.
3. Why not keep them flying?
NASA can't afford it with the budgets and programs it has worked out with the president and Congress, especially those aimed at moving human explorers beyond low-Earth orbit.
In addition, according to former NASA administrator Michael Griffin, while technicians went over the orbiters with a fine-toothed comb to ensure they were ready to return to service after the Columbia accident in 2003, the fleet's accident rate through 2005 implied a 1-in-8 chance of losing another crew if the fleet's operations were extended.