SpaceX plans to launch a mission to resupply the ISS today, but that flight has been scrubbed. The launch attempt was meant to happen on Saturday, December 5, but weather conditions forced the launch to be scrubbed hours before liftoff. SpaceX has a backup launch window at 1117 EST on December 6 if weather conditions are more favorable at the lift off site and the location where the Falcon 9 first stage will land.
This mission is called Commercial Resupply Services-21 and will launch from the Launch Complex-39A at Kennedy Space Center. The mission is notable for being the first flight of the Cargo Dragon 2 upgraded spacecraft.
Once launched, when the CRS-21 mission arrives at the ISS, it will spend 30 days there delivering supplies for the seven-member Expedition 64 crew. SpaceX is using a Falcon 9 first stage booster that has flown three flights previously; it’s called B1058. Those other flights included launching the Demo-2 flight earlier this year, the first crewed flight test of the Crew Dragon spacecraft, and the South Korean ANASIS-II mission. It also put Starlink satellites into orbit in October.
The Falcon 9 booster and the Cargo Dragon 2 capsule were placed on the launchpad on December 2. The rocket performed a routine static fire test on December 4, achieving its certification for flight. There appear to be no issues with the rocket or capsule.
The launch delay was due to the weather. If the rocket can make its backup launch window tomorrow, it will reach the ISS on December 7 at 1330 EST. Due to the mass of the Cargo Dragon 2 capsule, the Falcon 9 won’t be able to return to the launch site for landing and will instead land on a drone ship in the Atlantic.