One of the astronauts who was assigned to fly on the first crewed test launch of the CST-100 Starliner, won’t be flying on the mission due to some unstated medical reasons. NASA declared that astronaut Eric Boe won’t be flying on the mission and instead of him another astronaut E. Michael “Mike” Fincke will be flying for the Boeing CST-100 Starliner’s Crew Flight Test.

In 2018, Boe along with eight other astronauts was assigned on the inaugural mission for NASAs Commercial Crew Program. The Crew Flight Test has been scheduled to launch later in 2019. For this program, two private companies SpaceX and Boeing have been developing capsules that would transport astronauts back and forth from low Earth orbit, where the International Space Station (ISS) resides.

In fact, Boeing’s Starliner is a capsule that has been constructed in order to take passengers to the ISS.

NASA stated that even though Boe won’t be flying, yet he would remain with the mission as assistant to the chief for commercial crew at NASAs Johnson Space Center.

In their statement, NASA stated that Fincke is an expert and experienced replacement, as he have finished three space trips since he joined the astronaut corps in 1996. He has spent 382 days in space and accomplished nine spacewalks. He has flown on two Russian Soyuz rockets as well as Space Shuttle Endeavor.

Fincke would be joining astronauts Chris Ferguson from Boeing and Nicole Mann from NASA for the mission. NASA stated that Fincke’s training would start immediately along with Ferguson and Mann.

The Starliner’s Crew Flight Test would be the first staff launch of the spacecraft that is part of NASA’s Commercial Crew Program, a partnership with Boeing and SpaceX targeting to send humans to the International Space Station (ISS).

In case, the Starliner’s Crew Flight Test becomes a success, it would mark be the first time in history that NASA would be sending astronauts to space on systems that is owned, developed, tested and operated by private companies.