2. Build A Space Shuttle
When it comes to ambition, there is one challenge which trumps all others hands down. Also in series 9, and with a large dose of help from the United Kingdom Rocketry Association, James May and Richard Hammond had the enviable challenge of converting a car into a reusable space craft. Naturally their starting point was the Reliant Robin (because it's relatively light and pointy), and set about building a replica of NASA's very own space shuttle, complete with separating booster rockets. It didn't actually have to go into space, just prove that it was possible (with emphasis placed on the 'reusable'. It's fair to say that nothing since has come close to this challenge, as what they constructed was the largest and most powerful non-commercial rocket in Europe. Of course, this being Top Gear, there were a few cheap and obvious gags to entertain people between the rocket science and wind tunnels, Hammond 'flying' a remote control plane into a window for example, but the actual work that must have gone into such a project is surely mind boggling to the likes of the average viewer. As should be expected with a task as ambitious as this, hopes and expectations were rather high. For all their acting in other challenges, the trepidation on the faces of May and Hammond was no doubt what they were truly experiencing before take off, not to mention their sheer delight during the shuttle's time in the air. The final results of all the hard work were just spectacular. Lift off was nothing less than phenomenal, and the twin boosters detached perfectly. As with so many other dreams however, perfection would be denied thanks to just a small matter of the shuttle not detaching from the main rocket. As the main fuel tank fell back down to earth, it dragged the Robin with it, landing rather unceremoniously with a rather large explosion. Who knows how well the shuttle would have flown solo, but considering how preposterous the idea must have sounded in the first place, this is a small shame considering how much was achieved prior to the simple act of explosive bolts not exploding. For all the ambition of building a space shuttle however, no amount of achievements can deny the fact that the UK Rocketry Association did all the actual work. Hammond and May were pretty much only there as presenters, and Clarkson wasn't even there at all.