Leading Article: After Hubble, Nasa looks for a life raft

ASKED TO name three facts about their space programme, most Americans mention the landing on the Moon, the explosion of the Challenger space shuttle in 1986 and the failure of the dollars 1.5bn Hubble space telescope to work to specification. Ever since the discovery, shortly after its launch in 1990, that the primary mirror on the Hubble telescope had a manufacturing defect, Nasa has been the object of widespread derision.

Everybody enjoys watching a large and arrogant institution slip on a very visible banana skin. Nasa had sold the Hubble telescope as one of the greatest developments in astronomy since the findings of Galileo. It would see stars and galaxies a hundred times more clearly than was possible from Earth and reveal the secrets of black holes and quasars. Next July it was expected to observe fragments of a comet, some a mile across, crash into Jupiter.

None of this will happen unless the seven astronauts aboard the space shuttle Endeavour succeed over the next 10 days in installing equipment to compensate for defects in the telescope. For Nasa it is almost a last chance to rescue its reputation. The mood in America has set heavily against civil and military prestige projects, with their tradition of vast cost over-runs. This year has already seen the cancellation of the dollars 10bn super-collider, or particle accelerator, being built in Texas.

It would be a pity if Nasa were to go the same way. During the Cold War it was preferable to see American and Soviet missile technology used to send satellites into space than deployed to dispatch nuclear warheads into each other's territory. The aims of space exploration remain attractive. Nasa's budget is still small compared with the overall US defence budget. Exploring the stars looks a sensible way to spend money compared with the sums expended by the US Navy tracking a largely non-operational Soviet submarine fleet.

Now, at the moment of Nasa's deepest despair, its long-term future is looking more secure. For long its best card in winning support was competition with Soviet space exploration. The announcement this week that the US and Russia will build a joint space station again locks Nasa into a central goal of American foreign policy: this time to support the present government in Russia. Despite Hubble, Nasa seems likely to survive.