U.S. human spaceflight and the road ahead

The USA first lofted a human into space in 1961. Within only a dozen years of that ride around the Earth by astronaut Alan Shepard, NASA landed 12 men on the moon and launched the Skylab space station.
The space shuttle era began in 1981, when shuttle Columbia launched from Cape Canaveral. Since then, the shuttle has lifted off 132 times, returning safely to Earth on all but two missions: Challenger's launch on Jan. 28, 1986, and Columbia's return flight on Feb. 1, 2003.
Three more shuttle missions are planned, one each for the remaining shuttles.
Discovery is due to launch Feb. 24 and go to the space station with a load of supplies and a storage cubicle. Endeavour is to launch April 19 and also go to the space station. It will carry more supplies and a multimillion-dollar physics experiment, the Alpha Magnetic Spectrometer.
NASA has a final flight set for June 28. Shuttle Atlantis will take supplies to the space station and return a faulty pump. But NASA does not have funding yet for the few hundred million dollars to pay for the mission.
The mission scheduled for April was to be commanded by astronaut Mark Kelly. But Kelly's wife, Rep. Gabrielle Giffords, D-Ariz., was critically wounded in a shooting this month, and it's not clear whether Kelly will fly his mission with her in rehabilitation.