The Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, shown in an artist's rendering, will measure tiny fluctuations in Earth's gravitational field to show how water moves around the planet.
This is an artist's concept of a plume of water vapor thought to be ejected off of the frigid, icy surface of the Jovian moon Europa, located 500 million miles from the sun.
NASA, ESA, and K. Retherford
The Atlas V rocket carrying the Mars InSight lander launches from Vandenberg Air Force Base, as seen from the San Gabriel Mountains more than 100 miles away, on Saturday morning. The InSight probe is the first NASA lander designed entirely to study the deep interior structure of Mars.
David McNew/Getty Images
An artist's rendition of NASA's InSight lander, which is expected to launch on Saturday morning. InSight will monitor the Red Planet's seismic activity and internal temperature.
Ellen Stofan saw her first rocket launch when she was 4 years old. Now, more than 50 years later, she's director of the National Air and Space Museum — the first woman to hold the position.
Amanda Edwards/Getty Images for Discovery
A NASA/ESA Hubble Space Telescope image of the Lagoon Nebula, which is about 4,000 light-years away. It was taken by Hubble's Wide Field Camera 3 in February. The image was released to celebrate the 28th anniversary of Hubble.
NASA, ESA, STScI
A SpaceX Falcon 9 rocket transporting the TESS satellite lifts off at the Cape Canaveral Air Force Station in Florida on Wednesday. The satellite will scan nearly the entire sky for alien worlds.