Celeste Biever, deputy news editor
(Image: Mark Wilson/Getty)
And then there was one. Now that NASA's space shuttle Endeavour is successfully in orbit around Earth, you only have one more chance to watch a shuttle take off live. The flight is the last ever for Endeavour and the second-to-last of any space shuttle, as NASA winds down the programme that it began in 1981.
Endeavour was scheduled to take off on 29 April but that launch was called off at the last minute when heaters for hydrazine fuel - used to power the movement of the shuttle's wing flaps and landing gear - stopped working.
It wasn't until today at 0856 Eastern Standard Time that Endeavour finally took off on its planned 16-day mission. Nine minutes later and NASA's launch blog announced the launch had been a success: "Main engine cutoff and Endeavour is in orbit!"
On board is a massive cosmic-ray detector called the Alpha Magnetic Spectrometer, which Endeavour will deposit at the International Space Station. The 6.9-tonne leviathan is expected to turn up clues in the hunt for mysterious dark matter and antimatter.
That's not all. Endeavour is also carrying the first cephalopods to enter space. These baby bobtail squid (Euprymna scolopes) could help us understand how "good" bacteria behave in microgravity.
The mission has also received widespread media attention because its commander, Mark Kelly, is married to US congresswoman Gabrielle Giffords, who is recovering from an assassination attempt in January.
The flight may also provide the opportunity for ordinary people to pose questions to astronauts mid-flight. A PBS journalist is due to interview the shuttle crew as they hurtle around the Earth, and pose a selection of questions from ordinary people too. Two weeks ago, we submitted our own questions to the PBS site.
The final shuttle to fly will be Atlantis, which NASA aims to launch on 28 June.
If you missed it, the launch of Endeavour can be viewed here.