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.

NASA has selected three finalists for a new Explorer-class astrophysics satellite mission scheduled to launch by the end of 2020, and two of the proposals aim to fulfill similar goals to an X-ray telescope shelved after cost overruns in 2012.

With a view 100 times bigger than that of the Hubble Space Telescope, NASA’s Wide Field Infrared Survey Telescope (WFIRST) will aid researchers in their efforts to unravel the secrets of dark energy and dark matter, and explore the evolution of the cosmos. It also will discover new worlds outside our solar system and advance the search for worlds that could be suitable for life.