SpaceX's next astronaut mission for NASA has been pushed back to Halloween

• NASA announced on Friday that its next mission with SpaceX won't launch until late October at the earliest.
• That mission, called Crew-1, will ferry four astronauts to the space station and back.
• It was initially slated to launch as early as this month, but the delay better accommodates the timelines of other astronauts going to and from the ISS, NASA said.

SpaceX and NASA will launch their next batch of astronauts to the International Space Station on Halloween, the agency announced Monday.

The Crew-1 mission plan now calls for it to launch at 2:40 a.m. ET on October 31. That's a delay: The mission was originally slated to launch as early as late September.

Crew-1 is technically SpaceX's first official, contracted astronaut mission for NASA, since the one it recently completed was a demonstration. The successful completion of that test, called Demo-2, paved the way for at least six more planned ISS missions as part of NASA's Commercial Crew Program.

Monday's announcement was not the first indication from NASA that the launch timeline had been revised — the agency previously said mission would start "no earlier than October 23." The change enables the agency to better coordinate with the schedules of other cosmonauts and astronauts going to and from the ISS. That includes the next crew members expected to launch: NASA astronaut Kate Rubins and Russian cosmonauts Sergey Ryzhikov and Sergey Kud-Sverchkov. They're slated to blast off on a Russian Soyuz rocket on October 14.

The Crew-1 mission will also wait for NASA astronaut Chris Cassidy and cosmonauts Anatoly Ivanishin and Ivan Vagner to return to Earth from the station, which they plan to do on October 22.

The new timeline allows the Crew-1 astronauts' stay on the ISS to intersect with that of the members of the Crew-2 mission after them, which is scheduled for spring.

Additionally, the delay gives NASA and Roscosmos, Russia's space agency, more time to conduct additional testing on a leak in the space station's Zvezda Service Module. That module provides the Russian side of the station with life support, like oxygen and drinkable water, and hosts its sleeping quarters, dining room, and bathroom.

The leak was first detected in September 2019 but the rate of airflow has increased in recent months. It doesn't yet pose any danger to crew members, according to NASA. The station always leaks some air, and that gets replaced by pressurized tanks full of nitrogen and oxygen. But the leak could pose a risk if it gets bigger, since those tanks might not be able to replace the lost air quickly enough.

Meet the Crew-1 crew

Crew-1 includes NASA astronauts Shannon Walker, Mike Hopkins, and Victor Glover, as well as Japan Aerospace Exploration Agency astronaut Soichi Noguchi. Hopkins is slated to be the mission's commander, Glover the pilot, and Walker and Noguchi mission specialists.

Of the crew members, Glover is the only one who hasn't been in space before, but he has logged more than 3,000 hours of flying experience. Noguchi is the most experienced member of the team: He has flown on Russia's Soyuz capsule and the US Space Shuttle.

The team plans to stay on the ISS for the standard six months, during which they'll conduct space walks, do science experiments, and work on regular station maintenance.

By partnering with SpaceX, NASA has reduced its reliance on Russian Soyuz spacecraft, which have recently cost up to $90 million per seat. Before the Demo-2 mission, NASA hadn't been able to launch its own astronauts on American rockets or spacecraft since 2011, when it ended the space-shuttle program. A seat on a SpaceX capsule is projected to cost $55 million, though that figure does not include the funding NASA gave the company to develop its new Crew Dragon spaceship in the first place.

Through its Commercial Crew Program, NASA is also funding the development of a new spaceship from Boeing. The company has launched one uncrewed test mission of that capsule, called Starliner, but it hit technical difficulties and was unable to dock with the space station as planned. Boeing plans to launch a follow-up Starliner demo in December.