Months before launch, NASA has updated the crew that will go on board the Boeing CST-100 Starliner's manned flight test later this year.

Astronaut E. Michael "Mike" Fincke will be replacing Eric Boe who, according to the U.S. space agency, is unable to fly due to medical reasons. Instead, Boe will replace Fincke as the assistant to the chief for the commercial crew at the Johnson Space Center in Houston.

Updated Crew Assignment

This will be Fincke's fourth trip to space. Prior to the assignment, the former Air Force colonel served as a flight engineer, a science officer, and a commander of the crew onboard the International Space Station. So far, he has spent a total of 382 days in space since joining the astronaut corps in 1996, with a record of nine spacewalks.

NASA revealed that as assistant to the chief for commercial crew, Fincke has also worked closely with both Boeing and SpaceX — the two private companies that have been developing the capsules that will ferry astronauts to and from the ISS as part of NASA's Commercial Crew Program.

Fincke will be joining astronauts Nicole Aunapu Mann and Chris Ferguson, who were both assigned to the mission in 2018, onboard the Boeing CST-100 Starliner. He will immediately begin training for the flight scheduled later this year.

The Boeing CST-100 Starliner's Crewed Test Flight

The upcoming crewed test flight will be the first for Boeing CST-100 Starliner to be launched with humans onboard. However, before that happens, NASA will ensure that the new spacecraft is safe and ready for operational missions by first performing an unmanned orbital flight test in March. If everything goes according to plan, the new spacecraft will launch astronauts Fincke, Mann, and Ferguson to the ISS in August 2019.

Meanwhile, SpaceX's Crew Dragon capsule, which was also developed as part of the Commercial Crew Program, will ferry NASA astronauts, namely Bob Behnken and Doug Hurley, also later this year.

Since the Space Shuttle Program ended, the United States has been relying on Russia's Soyuz rockets to carry astronauts to the ISS. However, NASA's contract with Roscosmos is expected to expire in November 2019.

NASA Johnson | Flickr