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. via NASA http://ift.tt/2rI8dMJ

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. via NASA http://ift.tt/2sE8SPl

NASA astronaut Jack Fischer tweeted this photograph from the International Space Station on June 3, 2017, writing, “Never had a corner office with a view, but I must admit, I like it… a lot! #SpaceRocks.” Fischer, a member of the 2009 astronaut class, has been living and working aboard the orbiting laboratory since April 20, 2017. via NASA http://ift.tt/2rQJJmL

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. via NASA http://ift.tt/2qUdTGt

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. via NASA http://ift.tt/2qUdTGt

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. via NASA http://ift.tt/2rEbNcK

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. via NASA http://ift.tt/2s25Hnd

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. via NASA http://ift.tt/2sitxbp

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. via NASA http://ift.tt/2rkVCyQ

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. via NASA http://ift.tt/2r7Hp9U