NASA SpaceX CRS-21 commercial cargo resupply mission to the ISS will attempt to launch on Saturday 12-5-2020 at 11:39 AM EST or 8:39 AM PST or 16:39 UTC from launch complex 39A Cape Canaveral Florida.

This will be the first mission for the upgraded cargo Dragon 2 spacecraft and SpaceX first flight under the new CRS-2 contract with NASA. Including the previous cargo Dragon 1 spacecrafts this marks the 21st mission to the ISS by SpaceX.

Another first will be the a splash down in the Atlantic ocean for cargo Dragon 2. This will also mark the first time the crew access arm at LC-39A will be used for late load cargo into the capsule. Once cargo Dragon 2 is docked at the ISS it will make for two SpaceX Dragon crafts at the ISS. It is estimated that cargo Dragon will stay at the ISS for one month while crew Dragon will stay for six months.

Weather is an issue on Saturday with 60% No Go due to an expected cold front to arrive near launch time. The three main weather violations of concern are cumulus cloud rule, thick cloud rule and flight through precipitation including potential issues in the booster recovery area too. The Sunday forecast is much better with only 20% No Go for launch.

First stage booster being used for this mission B-1058.4 which will be it’s 4th flight to outer space. It previously flew on Crew Demo-2, ANASIS 2 and Starlink 13 with two landings on drone ship OCISLY and one landing on JRTI.

The cargo Dragon 2 vehicle is identical to crew Dragon but lacks the Super Draco thrusters, seats, plumbing and fuel for Super Draco and limited life support systems because humans are not on board. It can also dock itself to the ISS instead of being berthed and can carry 50% more science payloads than the original cargo Dragon vehicle.

Article and Photos Credit: Scott Schilke for &