The launch of NASA’s twin GRAIL spacecraft

NASA’s Kepler planet-finder began its mission to discover Earth-like worlds orbiting other stars in the galaxy today in 2009, successfully launching aboard a Delta 2 rocket from Cape Canaveral.

When the first Delta 2 rocket took off on Valentine’s Day 1989, ideas like navigating by smartphone and driving robots on Mars were science fiction. More than 150 launches over the last 30 years helped change all that.

The satellite awaiting launch early Saturday from California aboard the final flight of the venerable Delta 2 rocket should allow scientists to more precisely track changes in our planet’s ice sheets, using six green laser beams to chart the height and slope of polar ice and glaciers, providing a key input into climate change research.