Live from launch pad 39A (members only)

George Ricker, an astronomer and pioneer in space imaging sensor ships at MIT, leads the science team for NASA’s Transiting Exoplanet Survey Satellite.

Launch of a SpaceX Falcon 9 rocket carrying a Dragon cargo ship loaded with more than 5,100 pounds of equipment and supplies bound for the International Space Station was called off Tuesday less than two minutes before liftoff because of apparent problems with the second stage engine steering system.

A Falcon 9 rocket and 60 more Starlink internet satellites set for launch early Sunday at Cape Canaveral will mark the first time SpaceX has flown a first stage 10 times, reaching a milestone that the company once said could be a limit for reusing boosters. Now SpaceX plans to keep flying reused rockets on Starlink missions until one fails.