After decades of amazing discoveries, spacecraft Cassini embarks on its final - and most daring - mission: a dive below Saturn's rings.
Since it explored Pluto in 2015, the New Horizons spacecraft has been zooming toward NASA's most distant target yet. Join the mission team as the probe attempts to fly by Ultima Thule, an object 4 billion miles from Earth.
NASA launches its most ambitious hunt for traces of life on Mars, landing a car-sized rover in a rocky, ancient river delta. The rover will stow samples for possible return to Earth and test technology that may pave the way for human travel to Mars.
