Weather permitting, the American experiment with a reusable space craft opened its final chapter at precisely 3.26am this morning.
We know where this last voyage of Atlantis is headed - to the International Space Station. What we don't know is where manned space travel will go once this mission ends.
For over three decades the National Aeronautics and Space Administration, Nasa, has been synonymous with discovery and human triumph. The shuttle's mothballing means the end of one great ride.
Yet for all the teary-eyed reflection, the shuttle is indeed a hulk of metal whose time has clearly come. Each shuttle mission was exorbitantly expensive and time-consuming, resulting in far fewer shuttle missions each year than originally promised. And remember the two accidents in 1986 and 2003 that took the lives of 14 astronauts.
The future of manned space travel will, in the short term, become a Russian monopoly. Over time, private investors and entrepreneurs may also sling people towards the heavens for a hefty price. More ambitious missions, like sending people on a one way trip to colonise Mars, now seem a very long way off indeed.
The best we might hope for is renewed international cooperation on projects like the space station. No matter what the future holds, though, the explorer in all of us will feel a sense of loss when Atlantis touches down and Houston signs off for a final time.
