A setting sun and Earth's horizon are featured in this image photographed by an Expedition 13 crewmember on the International Space Station in 2006. NASA
Three full-disk color views of Jupiter's volcanic moon Io are seen by NASA's Galileo spacecraft camera. Comparisons of these images to those taken by the Voyager spacecraft 17 years ago has revealed many changes have occurred on Io. Since that time, about a dozen areas at least as large as the state of Connecticut have been resurfaced. NASA/JPL
This artist's animation shows the view from a hypothetical moon in orbit around the first known planet to reside in a tight-knit triple-star system. HD 188553 Ab is a gas giant planet, about 1.14 times the mass of Jupiter, with an orbital period of 3.3 days, discovered using the Keck I telescope atop Mauna Kea in Hawaii, and zips around a single star that is orbited by a nearby pair of pirouetting stars. Because the stars in this triple system are bunched together, sunsets on the planet - or on any moons that might exist around the planet - would be spectacular. NASA
The Space Shuttle Discovery, mated to NASA's 747 Shuttle Carrier Aircraft (SCA), takes to the air for its ferry flight back to the Kennedy Space Center in Florida in September 1994. NASA Dryden Flight Research Center
With its drag chute opened, orbiter Columbia is silhouetted against the brilliant xenon lights at the KSC Shuttle Landing Facility on March 12, 2002. Columbia landed at 4:33:09 a.m. EST with its crew of seven after a successful 11-day mission servicing the Hubble Space Telescope. NASA
T-38 trainer jets carrying the STS-103 crew arrive in formation above Kennedy Space Center's Shuttle Landing Facility in November 1999. The crew is here to take part in Terminal Countdown Demonstration Test activities this week. The TCDT provides the crew with emergency egress training, opportunities to inspect their mission payloads in the orbiter's payload bay, and simulated countdown exercises. NASA/Kennedy Space Center
In front of a fully-fueled ascent vehicle waiting to return them to Earth, the Mars crew salutes all of the people and nations of the world that made the journey possible in this 1997 artist's concept. These images were produced for NASA by John Frassanito and Associates with technical concepts by NASA's Exploration Office, Johnson Space Center. NASA/JSC/John Frassanito
Dramatically reflected by the waters of the extensive lagoonal sysem adjacent to Launch Pad A, the Space Shuttle, the world's first reusable space vehicle, is lighted by spotlights and the setting sun on the evening prior to Flight Readiness Firing of the orbiter Columbia's main engines on Feb. 19, 1981. The 20-second firing was a milestone procedure in flight preparation of the world's first reusable space vehicle. NASA
NASA's Constellation Program was planning on building a new spacecraft that to return humans to the moon and blaze a trail to Mars and beyond. This artist's rendering represents a concept of a cargo launch vehicle as the first and second stages separate in Earth orbit. President Obama canceled the Constellation program, effective with the 2011 fiscal year budget. NASA
Two kilometers above the lava flows of Mars' Tharsis Bulge region, a geologist collects samples from the eastern cliff at the base of Olympus Mons, the solar system's largest known shield volcano, in this artist's depiction. To better understand the evolution of the Arizona-sized volcano, the scientist investigates the layers of hardened lava that make up the massive feature. The block-like nature of the rock face, caused by columnar jointing, is similar to features on Earth, such as the Devil's Tower in Wyoming. NASA/Pat Rawlings/SAIC.
Cambodia's lost city of Mahendraparvata lay hidden beneath a canopy of dense vegetation. Airborne lasers produced a detailed map of a vast cityscape, including highways and previously undiscovered temples near Cambodia's prized Angkor Wat temples.
Kristen Gelineau, Associated Press /
June 18, 2013
Heng Sinith / AP / File
Cambodia's lost city has been found. Airborne laser technology uncovered a network of roadways and canals, illustrating a bustling ancient city linking Cambodia's famed Angkor Wat temple complex.