Rupert Cornwell: Nasa embarks on a voyage into the unknown

If you have tears, space enthusiasts, prepare to shed them soon. At 11.57am on 16 September, weather and last-minute technical glitches permitting, the shuttle Discovery will blast off into the skies over Florida and head for the international space station – and an era will end. Discovery's mission will the 134th and last of a series that began in 1981. What next for the space agency Nasa and the entire US space programme? No one really knows.

Last week, Barack Obama went to the Kennedy Space Center to give his version of the answer. The President did his best. He set a target of getting to an asteroid by 2025, and sending a man to Mars some 10 years after that. "I am 100 per cent committed to the mission of Nasa and its future," he proclaimed, only increasing suspicion that the opposite was the case.

Some trusting souls compared his words to the historic address by JFK in 1961, pledging to put a man on the Moon by the end of that decade. And there were superficial similarities. Both were young presidents, whose elections had broken new ground. Both symbolised a break with the past. Both had a remarkable capacity to inspire.

But the parallels end there. You sensed that Obama's heart was not in it; that for one of his pragmatic bent, the problems of the here and now – of nuclear proliferation, colossal financial deficits and climate change on the planet on which we humans are fated to live for the coming centuries – far eclipsed in importance the possibility of a manned spacecraft getting to Mars.

To be fair, Obama is not the first president to be ambivalent on the subject. In January 2004, less than a year after the Columbia explosion – which, in retrospect, sealed the fate of the shuttle programme – his predecessor unveiled a grandiose plan for a permanent US base on the Moon by 2020, where rockets would be assembled to explore the solar system. Thereafter, George W Bush barely mentioned the subject. In that sense Obama was merely delivering the coup de grâce.

His enemies demonise him as a "socialist", bent solely on expanding government. With Nasa, however, he's doing the opposite. A return to the Moon is out; been there, done that, Obama argued, after his 2011 budget scrapped the hugely expensive Constellation programme. At the Kennedy Center he gave a little ground, proposing that Orion, the Constellation's capsule, should not be jettisoned after all, but reconfigured as an emergency rescue craft for the space station.

But this, like his announcement of $40m (£26m) to retrain Florida space workers who will lose their jobs, seemed primarily aimed at protecting his party in an unemployment-ravaged state, where Democrats will be fighting for their political lives in November's mid-term elections.

The most striking part of the Obama plan is its reliance on the private sector. And the emphasis is not on giant established contractors such as Boeing and Lockheed, but on smaller, nimbler companies that would build what amount to taxis to carry astronauts to the space station. The White House argues this would create enough jobs to compensate those lost by traditional Nasa suppliers.

Obama may be right. But his thinking reflects a deeper problem. The fact is that space no longer captures the public imagination, nor generates the public fear, it once did. When JFK committed America to putting a man on the Moon inside 10 years, he was preaching to the converted. The country was in a state of shock, bested in a strategic area by a supposedly weaker communist foe that had first stunned the US with Sputnik and then sent Yuri Gagarin. Kennedy was able to present space not just as a challenge to national pride, but as the site of the next, perhaps the decisive, Cold War battle.

Obama's bold targets are much further off, a quarter century or more. In the meantime, with the shuttle retired, there is the affront to national pride of US astronauts having to hitch rides on the Russian Soyuz rockets to reach the space station (at $50m a seat). Only in 2015 will Nasa start serious development of a new heavy-lift rocket as a workhorse for its future operations. By then China's aggressive space programme could be on the verge of an advanced spacecraft of its own, complete with orbiting refuelling systems.

But none of this greatly alarms the average citizen. Space is an infant industry – although, in Florida, it is a mature one too. For financial reasons alone, major new manned ventures may well be shared. Despite the loss of two craft and more than a dozen lives, the shuttles have become routine. Space, these days, means missile defence and satellite systems, in which Americans assume, rightly or wrongly, that their country reigns supreme.

Not until man sets foot on Mars will there be that sense of "frontier" engendered by the 1969 Moon landing. The Challenger and Columbia explosions were immense and unforgettable tragedies. But they did not have the protracted human drama of Apollo 13, with its catchphrase "Houston, we've had a problem", and whose improbably happy ending came exactly 40 years ago this weekend.

Today everything seems an anti-climax. Apollo 13's commander was Jim Lovell who – along with Neil Armstrong and Gene Cernan, the first and last men to walk on the Moon – has just issued a statement accusing the Obama administration of condemning the US to "second-, even third-rank stature". These strictures may be an exaggeration. More important, they will change nothing. Space travel has lost its glamour. For the public, if not for the enthusiasts, the thrill is gone.