This view from NASA’s Cassini spacecraft shows a wave structure in Saturn’s rings known as the Janus 2:1 spiral density wave. via NASA http://ift.tt/2gKui8n

The combination of morphological and topographic information from stereo images from NASA’s Mars Reconnaissance Orbiter. via NASA http://ift.tt/2xOVHxu

Expedition 53 crew members: Joe Acaba of NASA, left, Alexander Misurkin of Roscosmos, center, and Mark Vande Hei of NASA answer questions from the press outside the Soyuz simulator ahead of their Soyuz qualification exams, Thursday, Aug. 31, 2017 at the Gagarin Cosmonaut Training Center (GCTC) in Star City, Russia. via NASA http://ift.tt/2wHF3zZ

The Voyager 1 aboard the Titan III/Centaur lifted off on September 5, 1977, joining its sister spacecraft, the Voyager 2, on a mission to the outer planets. via NASA http://ift.tt/2gJoEad

MCG+01-38-005 (below) is a special kind of megamaser; the galaxy’s active galactic nucleus pumps out huge amounts of energy, stimulating clouds of surrounding water. via NASA http://ift.tt/2epVgS0

NASA engineers closed a summer of successful hot fire testing Aug. 30 for flight controllers on RS-25 engines that will help power the new Space Launch System (SLS) rocket being built to carry astronauts to deep-space destinations, including Mars. via NASA http://ift.tt/2xyYAm6

NASA’s Operation IceBridge is flying its summer Arctic land ice campaign in Greenland, continuing its measurements of the Greenland Ice Sheet and its outlet glaciers. This photograph from the mission was taken on Aug. 29, 2017, from 28,000 feet, looking north while surveying Nioghalvfjerdsbrae (79 N) Glacier in northeast Greenland. via NASA http://ift.tt/2x5KGKi

Gemini V command pilot Gordon Cooper (right) and Charles “Pete” Conrad, pilot, walk across the deck of the aircraft carrier USS Lake Champlain following their spacecraft’s recovery from the ocean on Aug. 29, 1965. The eight-day Gemini V endurance mission doubled America’s spaceflight record set two months earlier. via NASA http://ift.tt/2x1awPF

A NASA F-18 jet takes off from the agency’s Shuttle Landing Facility at NASA’s Kennedy Space Center in Florida on Aug. 23, 2017. The F-18 jets fly at supersonic speeds while agency researchers measure the effects of low-altitude turbulence caused by sonic booms, part of NASA’s Sonic Booms in Atmospheric Turbulence, or SonicBAT II Program. via NASA http://ift.tt/2xGKj62

On August 25, 2017, NASA astronaut Jack Fischer photographed Hurricane Harvey from the cupola module aboard the International Space Station as it intensified on its way toward the Texas coast. The Expedition 52 crew on the station has been tracking this storm for the past two days and capturing Earth observation photographs and videos. via NASA http://ift.tt/2wOiueR