The National Aeronautics and Space Administration (NASA) is the biggest and most well-known space agency in the world.

It currently has a 'Vision for Space Exploration'. It intends to carry out a series of missions, manned and with robots, to achieve new goals in space exploration. This will include a mission to the Moon with robots, no later than 2008, which will lay the groundwork for the future exploration of Mars.

In November 2004, the Swift spacecraft took off from Cape Canaveral. It is the first multi-wave observatory designed to study gamma ray burst science.

In July 2005, the probe Deep Impact fired a huge copper 'bullet' into the comet Temple1. Scientists studying the plume of debris that billowed from the comet's surface hope it will yield clues about the formation of the universe.

The robotic rovers Spirit and Opportunity have long exceeded their expected 90-day working lives and are still investigating the surface of Mars more than two years after they touched down in January 2004. And another probe, Mars Reconnaissance Orbiter, is due to arrive at the Red Planet in March 2006 to photograph and study the planet's surface for signs of water.

The spacecraft New Horizons blasted off in January 2006 on a 10-year mission to explore the ninth planet, Pluto. Some scientists argue that Pluto is not really a planet, but instead an icy object in a region of called the Kuiper Belt. It's hoped that the New Horizons probe, which runs on less electricity than a pair of common 100-watt light bulbs, will clear up the mystery. Once it finishes its work at Pluto, the craft will continue on a voyage to study the edge of our Solar System.