The other two shuttles -- Challenger and Columbia -- did not make it back to Earth after accidents that killed their entire crews.
9. SpaceX gets to the space station, and back
No NASA shuttles flew in 2012, but a private company called SpaceX successfully sent almost 900 pounds of cargo to the international space station in its first official mission in October. The Dragon capsule came back with nearly 1,700 pounds of freight. This was only months after the SpaceX demonstration flight in May.
NASA and SpaceX have a contract for a dozen flights to the space station, and the October trip was just the first.
SpaceX isn't the only player in this commercial spaceflight arena. Virgin Galactic, Sir Richard Branson's private spaceflight company, recently completed a high-altitude test. Orbital Sciences is also under contract with NASA, and will also launch a demonstration flight.
10. Baby's DNA constructed before birth
For the first time, researchers at the University of Washington were able to construct a near-total genome sequence of a fetus, using a blood sample from the mother and saliva from the father.
The study suggested this method could be used to detect thousands of genetic diseases in children while they are still in the fetal stage. In the long run, it could help scientists derive new insights about genetic diseases.
Right now, this sequencing costs in the neighborhood of $50,000, but given how rapidly the price of genetic testing is falling, the process may become less expensive over time. Of course, it also raises ethical issues about selecting certain desirable traits in children. For right now, however, the technology is still in its early stages.
What were your favorite science stories this year? Share them in the comments.