Astronomy Picture of the Day

Explanation: The booster has landed. Spaceflight took a step toward the less expensive last week when the first stage of a Falcon 9 rocket set down on a landing pad not far from its Florida launch. Previously, most rocket stages remained unrecovered -- with the significant exception of the Space Shuttles landing on a runway and their solid rocket boosters being fished back from the sea. The landing occurred while the Falcon 9 second stage continued up to launch several communications satellites into low Earth orbit. The controlled landing, produced by SpaceX, was the first of its kind, but followed a booster landing last month by Blue Origin that did not involve launching satellites. Boeing and SpaceX were selected last year by NASA to launch future astronauts to the International Space Station. The pictured rocket booster will be analyzed for wear and reusability, but then is scheduled to be retired.