Q&A with Steve Clarke, deputy associate administrator for exploration in NASA’s science division (members only)

Virgin Galactic’s commercial SpaceShipTwo rocket plane made its highest and fastest flight to date Thursday, moving the company’s space tourism ambitions closer to reality more than three years after a fatal accident suspended powered test flights.

For the second day running, computers automatically aborted a Falcon 9 launch countdown Monday at NASA’s Kennedy Space Center in Florida in the final seconds before liftoff with the Intelsat 35e communications satellite.

A SpaceX Dragon supply ship departed the International Space Station and returned to Earth Tuesday to conclude its third round-trip flight to the orbiting research outpost, bringing home a spacesuit, mice and and numerous experiments.