Twenty-five years have passed since the Hubble Space Telescope was launched into orbit.
NASA said that after retiring, Kelly, 52, will still work on ongoing research related to his time in space.
Brilliant celestial systems light-years away from us.
Known black holes in galaxies near and far.
Top images from space in 2015.
Scientists have found the first evidence that briny water flowed on the surface of Mars raising the possibility that the planet...
A planet remarkably similar to Earth has been discovered in a "habitable zone" around a distant sun-like star.
NASA's New Horizons spacecraft is poised to become the first probe to visit distant Pluto.
The U.S. stepped into the void in 1965, when Ed White became the first American astronaut to perform a...
The US space shuttle Discovery was approaching the International Space Station Saturday as part of its final odyssey into orbit, carrying...