Epps was set to become the first Black American crew member on the International Space Station in 2018, but the agency announced Thursday that she had been removed from the mission, according to The Verge.
The space agency has not disclosed its reasons for Epps removal from the team, but says she is being considered for future endeavors.
It's still unclear why, but plans for her June liftoff suddenly changed, and another astronaut was chosen in her place, NASA has announced.
Epps is returning to Houston from Russia, where she'd been training to fly with a German and Russian. Since completing her training she's worked on various NASA operations and further training while awaiting mission assignment. The seasoned aerospace engineer was on track to launch as part of Expedition 56/57 this summer. Each expedition's tour of duty typically lasts three months.
African-Americans have visited the space station, but Epps would have been the first to live there.
She was a technical intelligence officer for seven years, including deployment to Iraq, before NASA selected her as a member of its 2009 astronaut class.
"Before being selected as an astronaut, she spent more than nine months in Russian Federation supporting medical operations for space station crew members, including water survival training in the Ukraine, and served as the deputy lead for medical operations for NASA's Orion spacecraft".
A release from NASA said that Epps would be replaced by Serena Auñón-Chancellor who was originally scheduled to go to the ISS on Expedition 58/59.