Watch a 4K video replay of the Falcon 9 static fire (members only)

SpaceX has delayed the launch of the SES 12 commercial communications satellite from Cape Canaveral until Monday to conduct additional tests on the Falcon 9 rocket’s second stage, officials said Thursday.

Spaceflight Industries has booked reservations for two commercial rideshare missions on Arianespace’s Vega rocket, officials announced Tuesday, beginning with a proof-of-concept flight in early 2019 of a new Italian-built multi-payload dispenser tailored to accommodate small satellites and CubeSats seeking a ride into orbit.

A Falcon 9 booster that flew into space last year is set to launch again Thursday from Florida’s Space Coast with an SES communications satellite on a historic mission that could make major strides in validating SpaceX’s audacious goal of recovering and reusing launchers, an achievement the company says will revolutionize the rocket business. Liftoff is set for 6:27 p.m. EDT (2227 GMT).