Stories by SPACE.com

John L. Callas, the project manager for the space agency's Mars Exploration Rover mission, explores the rovers' endurance well beyond their original 90-day mission

The European Space Agency's probe was successfully awoken from hibernation Monday and will begin preparations  to explore a comet

A mission consisting of a 180-day cruise to Mars, a 500-day stay on the Red Planet and a 180-day return flight to Earth could expose astronauts to a cumulative radiation dose of about 1.01 sieverts

The images show startling detail of the increasingly bright ISON on November 14, when the comet entered full outburst mode

With a density nearly identical to that of our planet, the exoplanet Kepler 78 b is just 20 percent wider and about 80 percent more massive than Earth

"Hair" is a term among physicists as a stand-in for any other measure needed to describe a black hole other than its mass, its angular momentum and its electric charge

The moon will darken slightly as it passes through the outer edges of Earth's shadow. The event is best viewed in the eastern half of the U.S.

Although the two bodies have significant differences, researchers point to surprising similarities in their topographical evolution

The team is currently making sure the hardware is safe and has until December 7 to get the probe off the ground, after which point it would have to wait 26 months for another favorable alignment of Earth and Mars

NASA will continue operations in Mission Control to protect the lives of the six crew members in orbit and the safety and security of the space station

The strongest of these bright arms reaches out from the center of the Coma Cluster toward a small subgroup of galaxies, called NGC 4911, about 2.1 million light-years away

Cygnus is the second commercial spacecraft to launch toward the space station for NASA. The first private spaceship to visit the ISS was SpaceX's robotic Dragon space capsule

Although we associate the Harvest Moon with autumn, this year's version is actually the last full moon of the summer season

The robot will likely employ this "autonav" capability more and more as it continues the long trek toward the base of Mars' huge Mount Sharp

NASA announced that it will stand down on attempts to recover the exoplanet-hunting Kepler spacecraft, but might find other science uses for it

Every August, just when many people go vacationing in areas where skies tend to be darker, the best known meteor shower makes its appearance

As the space agency's Curiosity rover celebrates one year on Mars, preparations are under way for the launch later this year of NASA's next Red Planet mission, called MAVEN

The big bang should have distributed matter evenly throughout the universe. So why is there a big dense spot?

Scientists are now reviewing hundreds of asteroid-retrieval mission suggestions submitted by private companies, non-profit groups and international organizations

The damaged Kepler spacecraft's operating capability is much lower than expected, officials say

Amateur stargazers can see a rainbow of star colors in the night sky this summer

The newly discovered moon is the 14th in Neptune's orbit

A "lot of water" inside an astronaut's helmet cut a spacewalk short on Tuesday

Even with the loss of its precision pointing ability, Kepler can still search for exoplanets, scientists say