On this day in 1977, NASA’s Voyager 2 spacecraft, the first Voyager spacecraft to launch, departed on a journey that would take it to Jupiter, Saturn, Uranus and Neptune and beyond.

Observations by NASA’s Curiosity Rover indicate Mars’ Mount Sharp was built by sediments deposited in a large lake bed over tens of millions of years, challenging the notion that warm and wet conditions were transient, local, or only underground on the Red Planet.

Mission controllers are trying to diagnose a problem that put NASA’s Kepler planet-hunting observatory in emergency mode nearly 75 million miles from Earth this week.