Final countdown: The space shuttle's last ever mission

Thirty years after the first blast-off, David Usborne reports from the Kennedy Space Centre, Florida, on the end of an era

Dotted across the sprawling campus that is the John F. Kennedy Space Centre in Florida are blue and white signs designed to get the thousands of workers here pepped up. "1 Days to Launch", they declared yesterday above an image of the NASA shuttle. But they might have read "1 Days to Pack up your Bags".

It is 30 years since the first shuttle, Columbia, lifted off from its pad here at Cape Canaveral and opened a new chapter in an American space romance that began a decade earlier with the Apollo flights. The mission about to be undertaken by the shuttle will be number 135 and the last. For the first time in half a century, the US will have no means on its own to fire humans to the stars.

The shuttle swansong will begin, of course, only when Florida's thundery weather allows. The launch is scheduled for this morning, US time. But as hundreds of thousands of onlookers swarmed to Florida's Space Coast last night, rain fell in chain-mail curtains and the forecast was ominous. Bad conditions, officials said, presented a 70 per cent chance of delaying today's lift-off until Saturday or Sunday.

Whenever it begins, the last flight of Atlantis will trigger bittersweet emotions here. Even for those tourists cramming the parks and shores to watch the white bird soar on its thick thread of smoke it will, as one NASA spokesman put it, be a "bucket-list" moment, never to be experienced again.

Already as the digital countdown directed from Mission Control in Houston ticked down, a sense of nostalgia was filling the press centre. Even reporters who have been covering launches for years weren't shy to have their pictures taken beside a vintage space suit brought into the filing centre for the occasion.

The Atlantis voyage – the cargo hold has been crammed with supplies to keep the International Space Station going for at least another year – marks the conclusion of a wind-down process started in 2004 when then President George Bush ordered the whole shuttle fleet retired. President Barack Obama inherited plans to replace it with the Constellation programme to return to the moon, but last year he ditched it.

For generations of Americans, NASA has been an acronym for national pride through frontier-breaking innovation and pre-eminence in the race to breach our planet's bounds. It was a race that was initially spurred by American competition with the Soviets in the depths of the Cold War. Some see irony – if not ignominy – in the reality that mothballing Atlantis will present. For the next several years, any American astronauts deployed to the Space Station will have to hitch a ride on the Russian Soyuz spacecraft.

"Right now, we are dependent upon Russia, and I do find that unseemly for the United States," Mike Griffin, a former NASA administrator, noted mournfully. "I find that unseemly in the extreme." And it is not just those "Days to" signs that will have to be taken away here at the Space Centre. Swathes of employees here – from engineers to welders and even to the guy who drives the huge crawler vehicle used to transport the shuttles from its towering hanger to the pad – will see their careers suddenly ended. A few months ago 17,000 people worked here; weeks after this mission only about 1,000 will remain.

NASA officials insist that America's space story is not over. The Obama blueprint for the agency envisages a future with deep-space exploration becoming the main focus, theoretically putting human footprints on Mars and asteroids, if not in this decade then hopefully by the mid-2020s (although getting to Mars may take 10 years longer). But to most Americans, this goal seems murky and undefined.

In the shorter term, NASA must adjust itself to getting help from private contractors to restore a direct link to the Space Station. A handful of companies, including SpaceX Boeing and Sierra Nevada, are developing space vehicles first to take cargo and then astronauts to the station on behalf of NASA, perhaps beginning as soon as 2015. NASA hopes some of their development work will happen here at Canaveral.

When Atlantis glides back to earth, NASA will celebrate a span of 30 years that saw tragedy with the explosion 73 seconds after lift-off of Challenger in January 1986 and the disintegration of Columbus upon re-entry in February 2003. The price tag for each NASA trip has averaged out at about $1.5 billion.

But the shuttles kept the thrill of space travel alive. It became commonplace to see astronauts weightlessly conducting experiments in the dark ink of space or chatting to school children from their living quarters via satellite. One astronaut played his saxophone for us. Senator John Glenn, one of the original Mercury astronauts, rode a shuttle back to space aged 77 in 1998. Perhaps most importantly, it was a shuttle that deployed the Hubble Telescope, giving us sparkling new glimpses into our solar system.

Yet when this mission is over, NASA will be like a spacecraft without proper instruments, fishtailing its way forward to a place not yet properly identified and with money that may never be available to it.