STS-135: The final space shuttle landing

SpaceX’s first Falcon Heavy launch for the U.S. Air Force took a major step closer to liftoff with a hold-down engine firing Wednesday night at launch pad 39A at NASA’s Kennedy Space Center in Florida. Liftoff with a cluster of experimental satellites and weather monitoring craft is set for June 24.

Sixty years ago Monday, a 27-year-old Russian test pilot named Yuri Gagarin strapped into a Vostok capsule in Central Asia and rode into orbit atop a launcher derived from a Soviet nuclear missile, becoming the first human to travel into the void of space. Twenty years later, in 1981, the era of reusable spacecraft dawned with the first launch of NASA’s space shuttle.

The Atlas 5 countdown leading up to Friday’s early morning liftoff from Cape Canaveral with Boeing’s Starliner crew capsule will be several hours longer than usual.