In a slew of firsts for NASA and SpaceX, CRS-21 marked the first time in history a new spacecraft has debuted on a flight-proven rocket, the first time SpaceX has flown an orbital mission for NASA on a twice or thrice-flown Falcon 9 booster, and the first time SpaceX has flown an orbital mission for NASA on a booster with non-NASA flights in its history.The Cargo Dragon 2 craft is a big improvement over the first version that was the first mission SpaceX undertook for NASA. Ars Technica reports:
Even further, still, SpaceX managed to turn Falcon 9 booster B1058 around for CRS-21 – satisfying NASA’s strict standards – in just 61 days, making it the third fastest Falcon booster turnaround ever. In other words, SpaceX’s successful CRS-21 launch has simultaneously demonstrated that a booster good enough for Starlink is good enough for NASA and that even rapid Falcon refurbishment is up to NASA’s standards. With an average turnaround of ~60 days, a single Falcon 9 booster could feasibly support five annual Dragon launches.
Compared to the first SpaceX cargo vehicle, Cargo Dragon 2 features a dozen powered lockers for science experiments, twice as many as previously flown. It is also designed to be recovered and readied for repeat flights more quickly than its predecessor, and the vehicle has the capability to autonomously dock with the station, rather than needing to be grabbed by a robotic arm and attached to a port.Cargo Dragon 2 is a modified version of the Crew Dragon used for manned launches; the cargo version lacks every system dedicated to human flight. There are no seats, no cockpit controls, and no life support system. The vehicle doesn't have the abort system that's required as an emergency escape system if a problem occurs during launch.
SpaceX points out that when the Cargo Dragon autonomously docks with the ISS, currently set for tomorrow at 1:30 PM EST, there will be two Dragon spacecraft docked at the ISS (the Crew Dragon capsule named Resilience by the crew of four is currently docked there) and that there will very likely be at least one Dragon docked at the ISS from now on. This calls for a larger number of launches than they have been doing for NASA this year.
Following on the heels of Crew Dragon’s second astronaut flight and operational launch debut, Crew-1 and Cargo Dragon’s CRS-21 resupply run also represent the quickest back-to-back Dragon launches in SpaceX’s history by several months. According to SpaceX comments and NASA schedules, the company’s 2021 manifest will be at least as packed with Dragon launches as 2020, packing another five (and maybe even six) orbital missions into a single year.
To achieve that ambitious manifest (potentially as many Dragon missions as ULA launches in all of 2020, for example), SpaceX and NASA will have to rely more heavily than ever on reusability. Thankfully, CRS-21 has already expanded the envelope of NASA-approved Falcon 9 booster reuse.
The CRS-21 mission lifts off Sunday Morning - SpaceX Photo