A fjord in southern Greenland, as seen during Operation IceBridge's last flight of the 2017 Arctic campaign, on May 12, 2017. This final full science flight, ICESat-2 South, was designed along the ground tracks of NASA’s upcoming ICESat-2, to fill in a gap in altimetry coverage of central southern Greenland. http://www.nasa.gov/sites/default/files/thumbnails/image/34485673501_af6e8f688c_o.jpg

A view of Earth from 36,000 nautical miles away as photographed from the Apollo 10 spacecraft during its trans-lunar journey toward the moon. While the Yucatan Peninsula is obscured by clouds, nearly all of Mexico north of the Isthmus of Tehuantepec can be clearly delineated. http://www.nasa.gov/sites/default/files/thumbnails/image/as10-34-5013-orig.jpg

A pair of CubeSats, with the Earth's limb in the background, moments after being ejected from a small satellite deployer outside of the International Space Station's Kibo laboratory module on Wednesday, May 16, 2017. Over a dozen CubeSats were ejected into Earth orbit this week to study Earth and space phenomena for the next one to two years. http://www.nasa.gov/sites/default/files/thumbnails/image/iss051e043291.jpg

The low angle of sunlight along the slim crescent of Saturn's moon Enceladus. http://www.nasa.gov/sites/default/files/thumbnails/image/pia21330-1041.jpg

This illustration depicts NASA's Mars 2020 rover on the surface of Mars. The mission, targeted for launch in July/August 2020, takes the next step by not only seeking signs of habitable conditions on Mars in the ancient past, but also searching for signs of past microbial life itself. http://www.nasa.gov/sites/default/files/thumbnails/image/pia21635.jpg

Astronaut Scott Carpenter walks to the launch site to begin the Mercury-Atlas 7 (MA-7) mission on May 24, 1962. Carpenter's Aurora 7 capsule lifted off aboard an Atlas rocket from Cape Canaveral, Florida, at 7:45 a.m. EST, May 24. Carpenter was the fourth American in space and second American to orbit Earth. http://www.nasa.gov/sites/default/files/thumbnails/image/s62-04044-orig.jpg

This sequence of enhanced-color images shows how quickly the viewing geometry changes for NASA’s Juno spacecraft as it swoops by Jupiter. The images were obtained by JunoCam. http://www.nasa.gov/sites/default/files/thumbnails/image/13-candy-1-new-fix.jpg

A new NASA mission, the Neutron Star Interior Composition Explorer (NICER), is headed for the International Space Station to observe one of the strangest observable objects in the universe. In this photo, NICER’s X-ray concentrator optics are inspected for dust and foreign object debris that could impair functionality once in space. http://www.nasa.gov/sites/default/files/thumbnails/image/34718447506_7ff2cfa1b2_o.jpg

On April 3, 2017, the student-controlled EarthKAM camera aboard the International Space Station captured this photograph of a favorite target -- the Grand Canyon -- from low Earth orbit. The camera has been aboard the orbiting outpost since the first space station expedition began in November 2000 and supports approximately four missions annually. http://www.nasa.gov/sites/default/files/thumbnails/image/ccfid_136341_2017094234803_image.jpg

Expedition 51 Flight Engineer Thomas Pesquet captured this nighttime photo of Florida from the International Space Station. Bright lights include the Miami-Fort Lauderdale area, and Orlando, with Cape Canaveral to the east, where launch preparations for SpaceX's next cargo mission are underway at NASA's Kennedy Space Center. http://www.nasa.gov/sites/default/files/thumbnails/image/32894787863_81394822de_o.jpg

The SpaceX Falcon 9 rocket, with the Dragon spacecraft onboard, is seen shortly after being raised vertical at Launch Complex 39A at NASA’s Kennedy Space Center in Cape Canaveral, Florida, Thursday, June 1, 2017. Liftoff is scheduled for 5:55 p.m EDT. http://www.nasa.gov/sites/default/files/thumbnails/image/34991387636_ccc9430d87_o.jpg

This observation from NASA's Mars Reconnaissance Orbiter show it is late summer in the Southern hemisphere, so the Sun is low in the sky and subtle topography is accentuated in orbital images. http://www.nasa.gov/sites/default/files/thumbnails/image/pia21636.jpg

The SpaceX Falcon 9 rocket, with the Dragon spacecraft onboard, launches from pad 39A at NASA’s Kennedy Space Center in Cape Canaveral, Florida, Saturday, June 3, 2017. http://www.nasa.gov/sites/default/files/thumbnails/image/34691015500_418541e0d8_o.jpg

From high above Saturn's northern hemisphere, NASA's Cassini spacecraft gazes over the planet's north pole, with its intriguing hexagon and bullseye-like central vortex. http://www.nasa.gov/sites/default/files/thumbnails/image/pia21331-1041.jpg

NASA astronaut Jack Fischer tweeted this photograph from the International Space Station on June 3, 2017, writing,

NASA's 2017 astronaut candidates take a group photo at Ellington Field near Johnson Space Center. Pictured are, front row, left to right, Zena Cardman, Jasmin Moghbeli, Robb Kulin, Jessica Watkins, Loral O'Hara; back row, left to right, Jonny Kim, Frank Rubio, Matthew Dominick, Warren Hoburg, Kayla Barron, Bob Hines, and Raja Chari. http://www.nasa.gov/sites/default/files/thumbnails/image/img_0524a.jpg

In biology, “symbiosis” refers to two organisms that live close to and interact with one another. Astronomers have long studied a class of stars – called symbiotic stars – that co-exist in a similar way. Astronomers are gaining a better understanding of how volatile this close stellar relationship can be. http://www.nasa.gov/sites/default/files/thumbnails/image/raquarii-aas-optical-xray.jpg

This image from NASA's Dawn spacecraft shows the northeastern rim of Urvara Crater on Ceres. http://www.nasa.gov/sites/default/files/thumbnails/image/pia21408-1041.jpg

On May 29, 2017, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured the data for this image of an ongoing phytoplankton bloom in the Black Sea. The image is a mosaic, composed from multiple satellite passes over the region. http://www.nasa.gov/sites/default/files/thumbnails/image/blacksea_amo_2017149_lrg.jpg

This artist illustration shows the thick ring of dust that can obscure the energetic processes that occur near the supermassive black hole of an active galactic nuclei. Researchers have found that the dust surrounding active, ravenous black holes is much more compact than previously thought. http://www.nasa.gov/sites/default/files/thumbnails/image/agn_fnl_lcook-1.jpg