Starting in March 2017, some of the Soyuz rockets that launch to the International Space Station will have just two crew members on board — instead of the typical three. The change is the result of Russia’s desire to reduce the number of cosmonauts that typically reside on the ISS. That means a few launches will be short one cosmonaut starting next year.

Typically, Soyuz launches alternate between two different types of crew configurations. Usually, one launch will include two Russian cosmonauts and a NASA astronaut, and then a couple months later a Soyuz will launch with one cosmonaut, one NASA astronaut, and a crew member from one of NASA’s international partners, such as the European Space Agency or the Japanese Aerospace Exploration Agency. These launches keep the average number of people on board the ISS to six, except during times when crews are rotated in and out.

A few launches will be short one cosmonaut starting next year

But moving forward, the launches that normally have two cosmonauts and one NASA astronaut will have just one cosmonaut instead. And as a result, the average six-member crew aboard the ISS will be reduced to five. NASA announced the updated crew assignments today, noting that only NASA astronaut Jack Fischer and cosmonaut Fyodor Yurchikhin would be launching to the station in March. Originally, that flight was supposed to include two Russian cosmonauts and NASA astronaut Mark Vande Hei.

News first circulated in August that Russia was considering reducing its crew complement on the ISS as a way of cutting costs and increasing efficiency. A smaller Russian crew aboard the station means that Roscosmos can cancel one of its planned Progress resupply missions next year. It’s also a potential way for the agency to make money. Russia has floated the idea of allowing other agencies to buy the vacant seats, to add another crew member or to carry more cargo to the ISS. However, NASA has not made any indication that it will buy the extra seats.

The move to a two-member Russian ISS crew is supposed to be temporary

The move to a two-member Russian ISS crew is supposed to be temporary, though. Roscosmos will like increase its crew to three after it launches a new segment to the station called the Multipurpose Laboratory Module, or MLM. The launch of the MLM has been delayed several years, but is expected to finally go to the station in late 2017 or early 2018. Once that module finally arrives, then Roscosmos will increase its crew size again, Sergei Krikalev, director of Russia’s human spaceflight program at Roscosmos, said at the International Astronautical Congress in Mexico this year.

If Russia does decide to go back to three crew members, then we could eventually see crews of seven aboard the ISS. NASA’s Commercial Crew partners — SpaceX and Boeing — are expected to start launching astronauts to the ISS on their own vehicles in 2018. And those spacecraft are required to carry up to four astronauts for NASA to the orbiting lab.