Watch SpaceX reuse its rocket on a NASA mission for the first time

SpaceX is set to launch two previously-flown vehicles on a NASA mission Friday morning out of Cape Canaveral Air Force station in Florida.

This mission is the first time NASA will launch its resupply mission to the International Space Station on a "flight proven" rocket booster. The first stage of the Falcon 9 rocket for this mission, Commercial Resupply Services 13 (CRS-13) was first launched and landed for NASA resupply mission CRS-11 in June this year.

NASA officials announced the CRS-13 would reuse a booster, saying in a press conference before the launch that the administration is "very comfortable that the risk posture on this vehicle is not significantly greater than a new booster."

This is only launch NASA has approved use of a previously launched rocket. Elon Musk's company demonstrated thorough readiness for the rocket after NASA participated "in a broad range" of date assessments and inspections of the Falcon 9.

The launch has been delayed multiples times from its original December 8 target, with Friday marking the last backup opportunity until December 25.