SpaceX is preparing to launch their 21st contracted Cargo resupply flight to the International Space Station (ISS), marking the first flight of Cargo Dragon 2, the company’s new and upgraded un-crewed cargo spacecraft.
The Commercial Resupply Services-21 (CRS-21) mission is scheduled to lift off from Launch Complex-39A (LC-39A) at the Kennedy Space Center on 6 December 2020 at 11:17am EST ahead of an approximately 30 day mission to the ISS, resupplying the seven member Expedition 64 crew.
The Falcon 9 first stage booster set to loft the spacecraft into space will be B1058, which has successfully flown three prior flights including the launch of SpaceX Demo-2 earlier this year (the first crewed test flight of SpaceX’s Crew Dragon spacecraft), ANASIS-II for South Korea, and an October Starlink mission.
B1058 and Dragon capsule C208, the first purpose-built Cargo Dragon 2 capsule, were rolled out to LC-39A on 2 December via SpaceX’s horizontal crawler-transporter vehicle, following which the rocket was moved upright and into launch position.
On 4. December, the rocket performed a routine static fire test, certifying it for flight.
Although the flight had remained on track for a launch attempt on 5 December, weather conditions in the recovery zone forced a scrub hours before liftoff. The 6 December attempt has more favorable weather conditions for both recovery and launch.
SpaceX has completed 20 cargo Dragon missions to and from the space station. The company has delivered over 95,000 pounds of supplies and returned 75,000 pounds. "Cargo resupply from U.S. companies ensures a national capability to deliver critical science research to the space station, significantly increasing NASA's ability to conduct new investigations at the only laboratory in space," the agency wrote in a press release.
The CRS-21 mission will be the first resupply mission that will utilize SpaceX's upgraded version of the cargo Dragon capsule, that is capable of carrying 50% more payload mass. This week NASA announced it targets to conduct the mission no earlier than December. A Falcon 9 rocket carrying Dragon will liftoff from Launch Complex 39A at NASA’s Kennedy Space Center in Florida.
The Dragon capsule will carry a variety of equipment on the upcoming flight. "On October 10, teams moved the Nanoracks Bishop Airlock to SpaceX’s processing facility at NASA’s Kennedy Space Center [...] Two days later, it was packed in the Dragon spacecraft’s trunk for its ride to the orbiting laboratory," the agency shared. The Nanoracks Bishop Airlock is already aboard the Dragon capsule's unpressurized trunk, ready to be delivered (pictured below). An airlock is a segment that is used like a airtight door to safely transfer cargo between the inside and outside of ISS.