Artist's concept illustrating Kepler-16b.

Artist's concept of the Gamma-Ray Large Area Space Telescope, or GLAST.

Artist's concept of Jovian Trojans asteroids.

Artist's concept of NASA's MAVEN spacecraft.

Artist's concept illustrating the two Saturn-sized planets discovered by the Kepler mission.

Artist concept of NanoSail-D in space.

Artist's concept of the Kepler-16 system.

Artist's concept of the Lunar Reconnaissance Orbiter.

Artist's rendering of future space exploration missions.

Artist's concept of the Lunar Reconnaissance Orbiter.

Artist's rendering of future space exploration missions.

Artist's rendering of future space exploration missions.

Artist's concept of a Utahraptor.

Artist's concept of a solar storm.

Artist's concept of an alien planet.

Artist's concept of an astronaut falling towards a black hole in outer space.

Artist's concept of a terrestrial planet.

Artist's concept of a terrestrial planet.

Artist's concept of the Deep Space Vehicle mated with an Extended Stay Module.

Artist's concept of an astronaut floating in outer space by a water covered planet.

Artist's concept of a Hypergiant Star.

Artist's concept of a protoplanetary disk.

Artist's concept of an extraterrestrial planet.

Artist's concept of an extraterrestrial planet.

Artist's concept of Space Interferometry Mission.