New US Spacecraft: First US Space Lifeboat in 40 Years

The next generation of American spacecraft designed to carry people into low-Earth orbit will be required to function as a lifeboat for the International Space Station for up to seven months.

This service has not been provided by an American spacecraft since an Apollo command module remained docked to Skylab for about three months from 1973 to '74.

Like a lifeboat on a cruise ship, the spacecraft is not expected to be called into service to quickly evacuate people but it has to be ready for that job just in case.

Right now, the lifeboat function on the space station is served by requiring a pair of Russian Soyuz Zvezda spacecraft to be docked at all times.

Sierra Nevada Dream Chaser

Each Soyuz Zvezda module holds three people. So with two docked, there can be six people working on the station at any one time.

The crew drops to three when one Soyuz spacecraft leaves and before another arrives during a procedure called an indirect handover.

The situations when the craft will be needed are not only hypothetical.

There have been occasions on the International Space Station when the crew members took refuge in the Soyuz Zvezda module because space debris was passing near the station.

Space Station with Shuttle and ATV Docked

CCP gave aerospace companies a list of requirements their spacecraft need to meet during NASA's certification process for use as in-orbit lifeboats, Scott Thurston, deputy manager of CCP's Spacecraft Office said.

Boeing, Sierra Nevada Corporation and SpaceX are working in partnership with NASA on spacecraft designs that meet these criteria under their Commercial Crew Integrated Capability agreements.

Thurston said each company is coming up with its own novel solutions for the best way to meet the needs of a spacecraft that docks with the station and then stays in orbit for seven months.

"There's no rock left unturned," Thurston said. "Some have started out with very extravagant environmental control and life support systems and as they're doing their studies, they're slowly figuring out exactly what they need and what they don't need."

With a new American spacecraft also offering another four to seven seats, the station can host more astronauts than its current complement of six. That means more science on the station since more people would be available for research duties.