Q&A with Martin Halliwell, chief technology officer at SES

SpaceX test-fired a Falcon 9 rocket at Cape Canaveral on Saturday in a pre-flight checkout designed to verify the launcher’s engines are ready to loft a U.S. military GPS navigation satellite into orbit Nov. 5. An engine problem forced SpaceX to abort a launch attempt in early October.

Liftoff of the Starlink 9-5 mission from Space Launch Complex 4 East (SLC-4E) happened at 1:48 a.m. PDT (4:48 a.m. EDT, 0848 UTC). This was the second of two back-to-back overnight launches.

Following the same timeline as they will on launch day, NASA astronauts Doug Hurley and Bob Behnken put on their SpaceX flight suits and strapped inside SpaceX’s Crew Dragon spacecraft Saturday at the Kennedy Space Center in Florida.