The legacy of the space shuttle programme

The final launch of Nasa's space shuttle brings an end to 30 years of flights and a controversial space programme that will be remembered as much for its tragedies and failures as its successes.

When plans for the shuttle were drawn up half a century ago, the logic was clear enough: replace the one-shot rockets of the Apollo era with a reusable space bus and the business of spacefaring would become cheap, reliable and everyday. The reality was very different. The shuttle was never as reusable as hoped. Maintaining the fleet took months of arduous technical work and instead of flying once a week, the shuttle made on average fewer than five flights a year. Originally, the US space agency reckoned on carrying payloads into orbit aboard the shuttle for $1,500 (£938) per kg. The true cost was 40 times that, making the shuttle a far more expensive option than, say, an expendable Russian rocket. Hopes of cheap spaceflight quickly evaporated.

Nor was the shuttle particularly safe. Two accidents that destroyed Challenger in 1986 and Columbia in 2003 killed 14 astronauts and forced the agency to ground the remaining shuttles for more than five years in total. The final cost of the programme reached $192bn.

The failures of the shuttle could easily eclipse the programme's achievements. But aficionados point to a long list of triumphs. The shuttle hauled three of Nasa's four "great observatories" into orbit – the Hubble Space Telescope, the Compton Gamma Ray Observatory and the Chandra X-ray Observatory. When Hubble turned out to have blurred vision, a shuttle crew went back, took the telescope into their cargo bay, and manually fitted corrective optics. The mission was so successful the shuttle performed three more servicing missions that further extended the life of the telescope. Together, these observatories give us an unprecedented view of the heavens.

Several spacecraft hitched a ride into orbit on the shuttle before embarking on their onward journeys. The Galileo probe went to Jupiter, Magellan mapped Venus and the European Space Agency's Ulysses spacecraft conducted the first survey of the sun's environment.

Hundreds of small-scale lab experiments have run on the space shuttle, some valuable, some frivolous. When Coca-Cola flew its fizzy drinks on Challenger in 1985, Pepsico Inc got wind of it and grabbed a place too. The companies' experiments – ostensibly into taste in weightless conditions – were deemed a failure by the crew.

Other shuttle experiments looked at how materials, and even living organisms, behaved in the microgravity conditions of orbit. Did spiders spin webs, did seeds grow well, could fish still swim upright? (Answers: yes, sort of, no.) More valuable experiments revealed how weightlessness takes its toll on the body, causing debilitating muscle and bone wastage. With that knowledge, medics drew up training programmes to protect astronauts in orbit, and appreciated more than ever the risks of sending crews on lengthy missions to other planets.

But above all, the shuttle did the heavy lifting for the International Space Station. A controversial project, it has a decade to prove its worth as an orbiting science lab. With a price tag of $100bn, that is a tall order, but if nothing else, the station taught astronauts how to build complex structures in space. And that might reap dividends in future.