Snapshots from Atlas 5 launch

The 900-ton suspended platform of Puerto Rico’s famed Arecibo Observatory collapsed Tuesday after cable failures, crashing into the radio telescope’s iconic dish and shattering a research instrument used to study pulsars, galaxies, planets, and asteroids that might threaten Earth.

Ground crews at Vandenberg Air Force Base in California retracted a mobile gantry away from the Delta 2 rocket Monday afternoon, revealing the 128-foot-tall (39-meter) booster on its launch pad awaiting liftoff with a new polar-orbiting weather observatory.

Follow the Atlas 5 rocket’s ascent from Cape Canaveral’s Complex 41 launch pad to send NASA’s OSIRIS-REx on an interplanetary trajectory to intercept Asteroid Bennu and bring back a pristine sample. Launch is scheduled for Thursday at 7:05 p.m. EDT (2305 GMT).