In the wee hours of Thursday morning, a pair of astronauts are scheduled to launch to the International Space Station on a Russian Soyuz rocket. NASA astronaut Jack Fischer and Russian cosmonaut Fyodor Yurchikhin are on the docket for this flight, scheduled for take off at 3:13AM ET from Baikonur, Kazakhstan. Once they arrive at the station, they’ll join the three astronauts already living in the orbiting lab and will become part of Expedition 51.
This is the first crewed launch in years that will only include two passengers, as Soyuz rockets always go to the station with a crew of three. The reason for the vacant seat has to do with Russia’s desire to reduce the number of cosmonauts on the station this year. Russia’s Federal Agency, or Roscosmos, typically has three people on the station, while two NASA astronauts and a crew member from another international space agency bring the total ISS population to six. But by reducing its crew complement to two, Roscosmos hopes to save money by launching fewer resupply missions and increasing efficiency. The move is supposed to last until Roscosmos sends up its long-delayed Multipurpose Laboratory Module, which is slated to go up at the end of the year or early next.
So after this launch, only five people will be on the station instead of the usual six. But NASA is using this change to make a few changes of its own. The space agency decided to keep current ISS resident Peggy Whitson on the station an extra three months. That means Whitson — who is already about to set a record for most cumulative time in space by a US astronaut — will spend around nine months on the ISS instead of six. And she’ll also stick around once her fellow two crew members leave in June and another trio of astronauts come to the station in July. At that point, the station will have six residents again and more NASA crew members than usual.
After Fischer and Yurchikhin get off the ground tomorrow, they’re set to rendezvous with the station about six hours later at 9:23AM ET. Their boarding will pave the way for another vehicle to then hook up with the ISS too. NASA’s commercial partner Orbital ATK launched a Cygnus cargo capsule filled with more than 7,600 pounds of supplies into orbit yesterday. But the capsule is hanging out in space so that Fischer and Yurchikhin can get to the station first. Then the Cygnus will arrive early Saturday and astronauts will use the station’s Canadian robotic arm to grab the capsule and attach it to the ISS.
If you happen to be in a good viewing time zone or just plan on pulling an all-nighter you can watch NASA’s coverage of tomorrow’s launch starting at 2:15AM ET. NASA also plans to cover the Soyuz docking starting at 8:30AM ET as well as hatch opening and astronaut arrival at 10:45AM ET.