A model of the planned Dream Chaser mini-shuttle designed by Sierra Nevada Corp. is displayed in March 2014 for a news conference at NASA's Michoud Assembly Facility in New Orleans.
The main control room of the European Space Operation Center in Darmstadt, Germany, is pictured Friday during the controlled descent of the European Space Agency space probe Rosetta onto the surface of Comet 67P/Churyumov-Gerasimenko.
Daniel Roland/AFP/Getty Images
An illustration of Rosetta just before Friday's expected landing on the comet known as 67P/Churyumov-Gerasimenko. The final approach aims to be only at "walking speed," mission specialists say, but that's enough to tip the antenna away from Earth.
Elon Musk, CEO and CTO of SpaceX, introduces the Dragon V2 spaceship at the company's headquarters in Hawthorne, Calif., in May 2014. Musk predicted during an interview at the Code Conference in Southern California on June 1 that people would be on Mars in 2025.
Jae C. Hong/AP
Visitors stand beside a model of the Tiangong-1 space lab in 2010, at the 8th China International Aviation and Aerospace Exhibition in Zhuhai, China. The real Tiangong-1 was launched into space in 2011 and will be returning to Earth next year — with some observers speculating China has lost control over the spacecraft.