Selected as a NASA astronaut candidate in 1996, Fincke was first assigned to the International Space Station Capsule Communicator (CAPCOM) arena at the Johnson Space Center and also served as a Crew Test Support Team member in Russian Federation for Expeditions 4 and 6.
"NASA astronaut Eric Boe played an instrumental role in the development of Boeing's CST-100 Starliner, first as a member of the Commercial Crew Program's astronaut cadre and then during his assignment on the Crew Flight Test", the Boeing spokesperson said.
Boeing astronaut Chris Ferguson, who commanded the final space shuttle flight in 2011 before leaving NASA, said it would have been "an honor" to fly with Boe again to the space station.
Astronaut E. Michael "Mike" Fincke will be replacing Eric Boe who, according to the USA space agency, is unable to fly due to medical reasons.
In its statement, NASA said only that Boe would no longer be able to fly on the Starliner test flight "due to medical reasons".
If successful, Boeing's Starliner and SpaceX's Crew Dragon, reportedly due to make its first launch - unmanned - on February 9, will mark the first time in history NASA has sent astronauts to space on systems "owned, built, tested and operated by private companies". Taking his seat will be Mike Fincke, a former space station commander. Fincke's time in space now adds up to 382 days, with nine spacewalks performed. He was part of the 2000 NASA astronaut class. Boe piloted both Endeavour and the final mission of Discovery in 2011. During that mission, Fincke broke the previous USA record for longest time in space. They had been on the same shuttle flight in 2008 throughout station building.
Fincke has amassed a total of 381 days 15 hours 11 minutes in space and has 48 hours 37 minutes of spacewalk experience to his name. For Boeing, those names were Eric Boe and Christopher Ferguson, both shuttle missions veterans, accompanied by rookie Nicole Aunapu Mann. However, NASA's contract with Roscosmos is expected to expire in November 2019.