Q&A with Sara Seager, deputy director of science on NASA’s TESS mission (members only)

SpaceX has set the first launch of a “flight-proven” Falcon 9 rocket for Thursday evening after running the booster through a hold-down engine firing Monday at NASA’s Kennedy Space Center in Florida.

Citing schedule concerns over price benefits, Iridium announced Thursday it will launch its next 20 satellites on a pair of previously-flown Falcon 9 boosters from Vandenberg Air Force Base in California, beginning with a Dec. 22 mission.

Watch the NASA Television live coverage of Saturday’s predawn Falcon 9 launch that delivered the Dragon spacecraft into orbit.