Unlucky Delays Mean ISS Astronauts Could Return to Earth Before Their Replacements Arrive

Unlucky Delays Mean ISS Astronauts Could Return to Earth Before Their Replacements Arrive
The (eventual) replacements: NASA's SpaceX Crew-3, from left: Matthias Maurer, Tom Marshburn, Raja Chari, and Kayla Barron. (Photo: SpaceX)

The International Space Station could be emptier than usual next week, should NASA decide to send four astronauts home prior to the arrival of the SpaceX Crew-3 mission.

I hope astronauts are a patient bunch, because it’s taking a while for the SpaceX Crew-3 mission to get off the ground. Launch of the brand new Endurance Crew Dragon capsule was supposed to happen on October 31, but ongoing weather problems and a minor medical issue involving a crewmember has resulted in a series of delays. Meanwhile, back at the orbital ranch known as the International Space Station, the Crew-2 team is preparing to return home. The lingering question right now is, will Crew-3 launch before or after Crew-2 says au revoir to the ISS?

“These are dynamic and complex decisions that change day by day,” Steve Stich, manager of NASA’s Commercial Crew Program, said in a statement. “The weather in November can be especially challenging, so our goal is to move forward on the plan with the highest probability of mission assurance and crew safety.”

All dressed up but nowhere to go: A SpaceX Falcon 9 rocket on the launchpad, as photographed on October 27, 2021.  (Photo: NASA/Joel Kowsky) All dressed up but nowhere to go: A SpaceX Falcon 9 rocket on the launchpad, as photographed on October 27, 2021. (Photo: NASA/Joel Kowsky)

Allow me to present to you the situation as it exists right now.

Crew-2, consisting of NASA astronauts Shane Kimbrough and Megan McArthur, JAXA astronaut Akihiko Hoshide, and ESA astronaut Thomas Pesquet, could leave the ISS as early at 1:05 p.m. EDT on Sunday, November 7. They could also leave the next day, should the situation warrant. Departure of Crew-2 is dependent on several factors, including the readiness of the Crew Dragon capsule and recovery teams, along with favourable weather and ocean conditions (parachute-assisted splashdown is expected off the Florida coast).

Should Crew-2 leave before Crew-3 arrives, that would leave just three Expedition 66 crew members aboard the ISS: Roscosmos cosmonauts Anton Shkaplerov and Pyotr Dubrov and NASA astronaut Mark Vande Hei. If Crew-2 can’t leave the ISS on either Sunday or Monday (for whatever reason), that would set the stage for the launch of Crew-3 on Monday, November 8, at 9:51 p.m. EDT.

A launch window for Crew-3 exists for November 6 and 7, but NASA and SpaceX have chosen to forgo these dates on account of expected poor weather. Specific concerns have to do with high winds at the launch pad, the presence of cumulus clouds, risk of lightning, and unfavourable conditions down range should an in-flight abort be necessary.

Frustratingly, weather predictions for November 8 also do not look good. At the same time, NASA is still monitoring that minor (and undisclosed) medical issue involving one of the Crew-3 astronauts. The Crew-3 team consists of NASA astronauts Raja Chari, Tom Marshburn, and Kayla Barron, and ESA astronaut Matthias Maurer.

“Mission teams will make a final decision on whether to prioritise Crew-3’s launch or Crew-2’s return in the coming days based on the likelihood of favourable conditions for a Crew Dragon splashdown or Crew Dragon launch,” NASA says. “NASA and SpaceX also are reviewing the time needed between launch or return operations.

Crew-2 launched on April 23 and arrived at the ISS the following day. Their Crew Dragon, Endeavour, has been in space for 195 days. That’s significant, because NASA has a requirement stating that the SpaceX capsule must be capable of staying in orbit for 210 days. “Additional analysis could allow the spacecraft to remain in orbit for longer, if necessary,” according to NASA.

Eventually — we think — the Crew-3 mission will launch. Once in space, the crew can sit back and relax, and even use the toilets with reckless abandon. For you see, Endurance has been fitted with upgraded toilets, which means the crew doesn’t have to worry about spilling their urine all over the place. The same cannot be said for the Crew-2 astronauts, as Endeavour’s toilet is still in the old configuration. Thankfully that shouldn’t pose a problem given the quick journey home.