As final preparations are made for the Atlantis lift-off at the Kennedy Space Center, Channel 4 News Washington Correspondent Sarah Smith asks what Nasa's space shuttle programme has achieved?
It's not very often in America that you come across something that really deserves the epithet "awesome". But I am assured that watching a space shuttle launch really is one of those experiences.
Just arriving at the Kennedy Space Center is pretty exciting. Driving past buildings so huge they say that it rains inside. Watching the countdown clock ticking down. And across a large lake, a couple of miles away but still clearly visible, we can see the space shuttle Atlantis on the launching pad ready for her last-ever voyage.
The is always a palpable air of excitement when the countdown has begun to a shuttle launch - but this time you can tell it's tinged with regret, sadness and pessimism, for this launch will mark the end of the shuttle programme forever.
As soon as Atlantis finishes her mission and touches down in about two weeks' time, hundreds of people here will lose their jobs. And for those that stay on, it's a very uncertain future. They are not even sure where they are meant to be heading for next. They all want to shoot for Mars but right now there simply is not the funding to make that happen.
How can you have space programme without any space craft? The US government insists it can be done, but to get American astronauts into space they will have to buy seats on Russian Soyuz rockets.
What does it tell you about America's place in the world when they are having to hitch a ride with the Russians, whilst the Chinese are busy developing their own brand-new spaceship that will soon take them to the moon?
The space programme means a very great deal to American self-esteem. In the national cathedral in Washington DC they have a stained glass window depicting the Apollo moon landing. And it's a source of great national pride that it was America that built the engineering miracle that was the space shuttle. The craft that has become the iconic symbol of the space age.
What has it achieved?
So there is a great deal of concern that without an operating space programme generations of American children will not be inspired to become the scientists, technicians and engineers of the future, causing the country to fall further behind in technological development.
But after nearly $200bn and 134 launches so far, what did the shuttle actually give back to America or the rest of the world?
It certainly didn't fulfil its original mission to make space flight frequent, safe and cheap. The people who designed the very first space shuttle though it was going to take off almost every week, at a cost of about $1m a launch. In fact it's over $1bn every time they send one up, and it never took off more than nine times in one year - with one in every 67th mission ending in disaster.
Nasa proudly boasts that without the shuttle we wouldn't have the International Space Station (ISS) - but then struggles to explain what benefits have been brought to humanity by that huge laboratory in space. Just wait and see, they say - it's all about to start happening on board the ISS. And of course without the shuttle we wouldn't have the Hubble telescope and the amazing pictures that have helped to pinpoint the age of the universe and proved the existence of dark matter.
Read more: Space travel - the final frontier?
But is that really worth the combined cost of all the Apollo missions to the moon, the Manhattan project that built the first atom bomb and the digging of the Panama canal? And the loss of 14 lives in the Columbia and Challenger disasters?
The truth is that 30 years of the shuttle programme managed to make space travel look quite dull because they never went anywhere very exciting. They have circled the earth 20,830 times but they never ventured toward that elusive final frontier.
If Nasa hadn't spent so much money on the shuttle, who knows where they might have reached by now? Which far planet might have been touched by human hands? Or, more likely, by human-built robotic hands. We are learning far more from rovers and unmanned rockets shooting deeper into space that we have from all the combined shuttle missions.
The vehicle that has dominated the American space programme for decades has also kept them in a low earth orbit that has stopped them reaching further and deeper into outer space.
President Nixon promised that the space shuttle "will revolutionise transportation into near space by routinising it". In other words, it was meant to be boring!
The craft that takes off like a rocket and lands like a plane may have had pride of place on many a young boy's bedroom wall, but it didn't test the limits of human ingenuity or deep space travel.
Nasa may not know exactly what is coming next, but once they do start to reach for the stars once more, they may find a mission far more inspirational than the shuttle could ever aspire to be.
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