Delayed SpaceX Launch, How Long Can Space Station Go Without Resupply?

This week alone, SpaceX postponed its resupply mission to the International Space Station twice, with the launch next window opening Friday morning at the Kennedy Space Center in Florida. The company has a contract with NASA to conduct the resupply missions to the station and this delivery will mark the 6th this year.

Before this week, the launch was originally targeted for early December. Now that the month is almost half over, and the resupply has yet to happen, the question of whether the six astronauts on the station have everything they need. The short answer is yes.

"We keep the station well stocked," acting NASA Press Secretary, Stephanie Schierholz, told International Business Times, "Typically we keep enough supplies on board for about six months."

The station got its last resupply delivery in November from an Orbital ATK launch so it’s currently in good shape in terms of supplies. In addition to the SpaceX and Orbital ATK supply launches to the station, there have been three Russian Progress resupplies this year as well, said Schierholz.

Aside from the supply stock, the SpaceX launch to the station doesn’t really change much of what goes on on the station. The SpaceX launches actually don’t impact the crew rotation because those rotations are prioritized over the SpaceX launches.

Three astronauts are currently scheduled to leave the ISS at 12:14 a.m. EST Thursday. A few days after NASA’s Randy Bresnik, the European Space Agency’s Paolo Nespoli, and Roscosmos astronaut Sergey Ryazanskiy leave the station and return home, three more astronauts will launch to the station. The three new Expedition 54-55 astronauts are scheduled to launch Sunday and should dock at the station around 3 a.m. Tuesday morning EST.

This launch is the reason that if SpaceX doesn’t launch on Friday, the company will have to wait a while to launch. "By the time the crew would be in a position to handle the arrival of Dragon and the science onboard, we will be in what’s called a beta angle cutout, during which time we do not launch spacecraft because of the angle of the sun and subsequent heating and power generation on the station," Schierholz told IBT.

The only other thing that the delayed delivery could potentially impact would be the science both on board the station and inside the payload that has yet to launch. There’s near constant turnover of the experiments going on at the ISS, so when a launch is delayed so is some science.

"Sometimes an experiment or part of it may need to be refreshed in between launch attempts, but that is something NASA works closely with all the researchers [on]," Schierholz said. When this happens, NASA works closely with the scientists to make any adjustments necessary. The SpaceX launch is tentatively scheduled for Friday morning. Currently the company is "Taking additional time for the team to conduct full inspections and cleanings due to detection of particles in 2nd stage fuel system," according to a tweet from SpaceX.

The return of astronauts Bresnik, Nespoli, and Ryazanskiy, to Earth, the SpaceX launch, as well as the launch of the three new astronauts to the station on Sunday will all be broadcast live on NASA’s website and YouTube channel. Check the updated schedule here.