The National Aeronautics and Space Administration (NASA) was established 50 years ago today by the aptly named National Aeronautics and Space Act.

NASA began operations on October 1, 1958, with a staff of 80 spread among four laboratories. The agency now consists of 15 facilities that employed more than 17,000 people in 2006, according to Best Places to Work.

The agency's mission statement since 2006 has been "to pioneer the future in space exploration, scientific discovery and aeronautics research."

After the early tragedy of Apollo 1, in which three astronauts died in a fire on the launch pad when the hatch door wouldn't open, the Apollo program made six successful moon landings in 1969 and the 1970s.

NASA's recent history has been marred, however, by the losses of two Shuttles—Challenger in 1986 and Columbia in 2003—and their 14 astronauts.

Faced with shrinking budgets during the 1990s, the agency under administrator Dan Golden adopted the mantra of "faster, better, cheaper," focusing on smaller robotic missions to Mars.

Coincidentally or not, NASA lost two craft in 1999: Mars Climate Orbiter and Mars Polar Lander. It followed up in 2003, however, with the Mars Rovers Spirit and Opportunity, which are still active, their missions having been extended multiple times.

Riding on the Spirit rover's successful landing, President Bush announced in January 2004 that NASA's new goal would be returning astronauts to the moon by 2020 to establish a waystation for a manned mission to Mars.

To meet that goal, the agency plans to retire the aging space shuttle fleet in 2010 and replace it with the more Apollo-like Orion craft, part of the Constellation Program, by 2015.

Uncertain budgets continue to plague the agency. Alan Stern, NASA's Associate Administrator for the Science Mission Directorate resigned in March after less than a year on the job following attempts to bring the Mars program budget under control by cutting funding for the rovers and the Mars Odyssey orbiter.

A recently leaked internal NASA report showed that at current funding levels the agency would be unable to meet its internal goal of launching Orion early, in the summer of 2013.

One way NASA has attempted to cut cost is by establishing a series of prizes for private groups to develop the technology the agency needs, such as a lunar lander vehicle and better spacesuit gloves.

Private groups have also begun working on spaceflight independently of NASA. Microsoft co-founder Paul Allen and aerospace engineer Burt Rutan's company Scaled Composites won the $10 million Ansari X PRIZE in 2004 for reaching an altitude of 100 kilometers twice in two weeks with its spaceplane SpaceShipOne.

Rutan and Sir Richard Branson are currently working on a space tourist craft, SpaceShipTwo. (Its mothership, the White Knight Two was unveiled yesterday in the Mojave Desert.)

NASA has drawn fire for focusing on space exploration at the expense of ignoring threats to the home planet such as climate change and asteroid strikes.

In 2006 the phrase "to understand and protect our home planet" was quietly struck from the agency's mission statement after four years. NASA said the deletion was in accordance with the President's vision of going back to the moon.