Leading article: Spectacular - and pointless

Now that the Discovery shuttle has safely returned to Earth, it is worth asking the question: what did it achieve? Nasa says that the launch of the 114th shuttle mission was a dramatic display of smoke, fire and sound which honoured the memory of the seven astronauts who lost their lives more than two years ago when the shuttle Columbia fell apart on re-entry.

Strong words, but the reality, of course, is a little more prosaic. Apart from delivering supplies to the International Space Station, Discovery 's principal activities were to carry out three space walks. One of these was to fix a new platform into its position on the space station, and the other two involved sending astronauts out to check and mend the shuttle itself as a result of its being hit by flying debris from its fuel tank on launch.

Indeed, one of the most abiding memories of the mission was the rather ludicrous image of an astronaut removing a sliver of grouting from between the tiles on the underside of the shuttle's heat shield. It was enough to draw the sympathies of any DIY decorator tackling a leaky old shower.

Nevertheless, the sight of the shuttle coming into land in complete darkness yesterday morning at the Edwards air force base in California was indeed a spectacular display of technological prowess. It took less than 10 minutes to cover 80 miles of its descent, landing perfectly on the runway without hitch.

There is no doubt that the shuttle - the first and so far the only reuseable manned spacecraft - was an amazing technological leap in space exploration, but one that has now past its best. It is also incredibly expensive, mainly because of the multiple fail-safe systems that have to be built in to its design to minimise the inevitable risks to the seven lives on board.

Yet further shuttle missions have been mothballed until the recurring problem with floating debris from the fuel tank has been resolved. So now that Nasa has shown that it can return to manned space missions, albeit in a truncated way, it is perhaps advisable to reconsider why we are sending people there in the first place.

As this newspaper has argued before, robotic technology can do most if not all of the things that humans can do in space. And whatever it is they are still incapable of doing could be done if the appropriate research was carried out to build even better robots.

It is not longer justifiable to send humans into space because they make good television pictures. There needs to be real benefits, and it is no longer evident that these benefits are worth the money - and the risk.