NASA plans to conduct two reviews before deciding how it will safely return two astronauts stranded in space, according to the agency's update on Tuesday.

The agency will conduct a Program Control Board Review and an Agency Flight Readiness Review before making its decision by the end of August.

Astronauts Butch Wilmore and Suni Williams arrived at the International Space Station (ISS) on June 6 aboard the Boeing Starliner after lifting off on June 5 from the Cape Canaveral Space Force Station in Florida.

During Starliner's flight to the space station, engineers noticed some of the spacecraft's thrusters did not perform as expected and several leaks in Starliner's helium system were observed.

Engineering teams at NASA and Boeing have conducted several thruster tests and in-depth data reviews to better understand the spacecraft.

NASA continues to evaluate all options as it learns more about Starliner's propulsion system.

Wilmore and Williams may return home aboard Starliner, or they could come back as part of the agency's SpaceX Crew-9 mission early next year, according to NASA.

The astronauts were originally scheduled to stay at the ISS for eight days.