Q&A with George Ricker, principal investigator for the TESS mission (members only)

SpaceX test-fired a reused Falcon 9 booster Monday at NASA’s Kennedy Space Center in Florida, checking the rocket’s readiness for a planned liftoff Saturday with an Airbus-built commercial communications satellite.

SpaceX’s first full-size stainless steel Starship test vehicle stands some 164 feet tall and measures wider than the cabin of a Boeing 747 jumbo jet. If Elon Musk has his way, it will fly to an altitude of 65,000 feet before the end of the year.

The successful maiden flight of SpaceX’s Falcon Heavy rocket in February was enough for the U.S. Air Force to certify the huge booster to carry the military’s most precious cargo into orbit, beginning with the mid-2020 launch of a classified payload under a $130 million contract awarded last week.