Live coverage: Rosetta’s final hours

Europe’s Sentinel 3A satellite, designed for real-time surveys of the world’s oceans, ice sheets, lakes and rivers, is attached to a decommissioned Russian nuclear missile for launch Tuesday. These photos show the spacecraft’s final prelaunch preparations.

NASA’s InSight spacecraft plunged into the rarefied atmosphere of Mars at a speed of more than 12,000 mph Monday and braked to a gentle touchdown, setting the stage for a two-year surface mission to probe the planet’s deep interior.

A $150 million cost overrun and two-year launch delay for NASA’s InSight Mars mission could mean fewer opportunities for new planetary science missions in the next few years, but the head of the agency’s science division said this week NASA will still approve development of at least one new solar system probe in December.