Clear eyes, full hearts. It might as well be a NASA catchphrase, as the space shuttle Endeavour touched down at the Kennedy Space Center in Florida this morning, completing its 25th and final mission (dubbed “STS-134″) and heralding the beginning of the end for over three decades of shuttle flight. Space shuttle Atlantis will carry the shuttle program into that good night when it launches into orbit one last time in mid-July this summer.
“It’s been a great morning at the Kennedy Space Center,” said Mike Leinbach, space shuttle launch director, in a NASA statement referring to Endeavour‘s touchdown at 2:34 a.m. Eastern time. The shuttle returned just shy of 16 days after launching on May 16th, and after making 248 orbits around the Earth—a journey of over 6.5 million miles.
(In Pictures on TIME.com: NASA Space Shuttle Endeavour Makes Its Final Landing)
Endeavour‘s mission was pretty cool. The shuttle delivered something called an Alpha Magnetic Spectrometer to the International Space Station. The AMS is a $2 billion particle physics experiment module—the “most sophisticated particle detector ever sent into space”—designed to scour cosmic rays for unusual matter. It’ll be looking for evidence of “dark matter,” the stuff astrophysicists believe balances out the cosmic “how much stuff in the universe is there, really” equation. It’ll also poke around for antimatter, of which there’s relatively little—apparently a serious problem for physics.
“What a great ending to this really wonderful mission,” said Bill Gerstenmaier, associate administrator for Space Operations, adding “They’re getting great data from their instrument [the AMS] on board the space station. It couldn’t have gone any better for this mission.”
And then there’s the part where Endeavour delivered tiny stamp-sized satellites designed, as I wrote last month, to “cling like barnacles to the ISS’s exterior, gathering data about the void and transmitting it realtime.” If all goes to plan, those micro-satellites could one day voyage to planets like Saturn, where they might rove through the planet’s atmosphere to amass information about its makeup firsthand.
(More on TIME.com: Tiny Stamp-Sized Satellites Carried by Endeavour into Space)
Endeavour‘s total lifetime in space amounted to 299 days, including 4,671 times around the planet for a total of nearly 123 million miles. That’s equivalent to roughly 257 trips to and from the Moon, or—at the nearest orbital points—nearly two voyages to and from Mars.
Next up: Atlantis, which NASA finished moving 3.4 miles from its Vehicle Assembly Building to Launch Pad 39A this morning. And then that’s it—the fleet’s off to museums, we pass the baton to Russia for trips to and from the ISS, and all eyes shift to NASA’s next projects, which include a capsule-style “space taxi” to get astronauts into orbit and back again, and a heavy lift rocket for crewed deep space exploration.