New, American-made spacecraft flying to the International Space Station will play a big role in bringing resident crews back home to Earth, but their missions also include the ability to provide the orbiting laboratory with a temporary shelter in case of an emergency in space, or even a safe ride back to Earth with short notice.
The scenarios that would call for the spacecraft to operate as space-borne lifeboats have not occurred on the International Space Station before, but mission planners have long made sure they are prepared. An electrical issue or ammonia leak on the space station could call for astronauts to shelter inside a Commercial Crew Program spacecraft long enough to correct the problem.
A medical emergency requiring surgery on an astronaut would be a case demanding immediate evacuation from orbit to Earth, something the spacecraft supporting NASA missions would be equipped to handle. The Soyuz spacecraft handle the lifeboat capability needs for the station’s current crews.
The need for a quick departure is more than a luxury for the space station. Every person on the orbiting complex has a specific emergency seat assigned throughout their mission that they have to get to if the need arises. Because there are limits to how many seats are available at a time, there also is a limit to how many residents can live and work there.
What does it mean for a spacecraft to be capable of serving as a lifeboat? As with all the needs for the new spacecraft, NASA outlined a list of requirements for designers to meet. For the most part, it means the spacecraft can be powered on quickly while docked to the station, even if it has been dormant for weeks or a couple of months. From air circulation fans to life support systems to thrusters, the spacecraft’s systems will be designed to engage in minutes.
“Some systems will take longer to bring online, but the idea is to have spacecraft that astronauts can get into quickly for survival and then use to pull away from the station and come home if that is needed,” said Kathy Lueders, manager of NASA’s Commercial Crew Program. “Defining exactly what that means, and what the companies can do to make it real was the hard part. That’s why we took a teamwork approach from the start and why we’ve treated this as a partnership.”
Boeing and SpaceX, each working on their own crew-capable spacecraft — the CST-100 Starliner and Crew Dragon, respectively — are testing their systems thoroughly on Earth before they undergo evaluation in orbit without a crew aboard, and then on a short mission with astronauts. Their performances in space – without an actual emergency – are to be considered carefully before NASA certifies the companies to fly operational missions, which could see a spacecraft docked to the station for months at a time.