Snapshots from Atlas 5 launch

The 330-foot tall mobile service tower is rolled away from the United Launch Alliance Delta 4 rocket at Cape Canaveral’s pad 37B in the hours before the scheduled liftoff on Aug. 19.

The next-to-last Delta 2 rocket is being stacked at its California launch site to take flight in January to put a civilian weather satellite into polar orbit.

In another first on Mars, an instrument inside NASA’s Perseverance rover has made oxygen out of carbon dioxide sucked in from the planet’s atmosphere, officials said Wednesday. The technology could help future astronauts “live off the land” by generating their own rocket fuel and breathing air.