Great Barrier Reef Near Whitsunday Islands

An astronaut aboard the International Space Station used a powerful lens to photograph these three reefs in Australia’s Great Barrier Reef on Oct. 12, 2015. Reefs are easy to spot from space because the iridescent blues of shallow lagoons contrast sharply with the dark blues of deep water.

Portland Sunrise

Scott Kelly's Post-Flight Visit to Washington

Former NASA astronaut Scott Kelly speaks about his historic mission aboard the International Space Station during an event at the United States Capitol Visitor Center, Wednesday, May 25, 2016, in Washington.

Hubble's Sharpest View of the Orion Nebula

Chasma Boreale and North Polar Ice Cap of Mars

Mars has bright polar caps of ice that are easily visible from telescopes on Earth. A seasonal cover of carbon-dioxide ice and snow is observed to advance and retreat over the poles during the Martian year. Scientists using radar data have found a record of the most recent Martian ice age recorded in the north polar ice cap.

NASA's OSIRIS-REx Spacecraft Prepared for Mission to an Asteroid

NASA's OSIRIS-REx spacecraft is revealed after its protective cover is removed inside the Payload Hazardous Servicing Facility at Kennedy Space Center, on May 21, 2016. OSIRIS-REx, targeted for a Sept. 8 launch, will be the first U.S. mission to sample an asteroid, retrieve at least two ounces of surface material and return it to Earth for study.

Ben Bullen