Q&A with Keith Gendreau, principal investigator of the first X-ray space communications experiment (members only)

A Blagovest communications spacecraft lifted off Monday aboard a Proton rocket to complete a network of four relay satellites in geostationary orbit for the Russian military. The Proton rocket’s Breeze M upper stage successfully delivered the Blagovest spacecraft to its intended orbit nine hours later.

Liftoff of a previously-flown Falcon 9 rocket is set for 6:27 p.m. EDT (2227 GMT) Thursday from NASA’s Kennedy Space Center in Florida, the first time SpaceX has reused one of its first stage boosters on a second mission. Ground crews face a tight timeline to ready the rocket and the SES 10 communications satellite in time for a Thursday launch attempt.

These photos show NASA’s Transiting Exoplanet Survey Satellite undergoing preparations for launch at the Kennedy Space Center in Florida.