Washington D.C: NASA and Boeing have announced that test flights of the company’s CST-100 Starliner commercial crew vehicle would begin operational missions to the International Space Station (ISS) at the end of 2021.

NASA said that before that happens, it has scheduled a second uncrewed test flight, known as Orbital Flight Test (OFT) 2, for no earlier than December this year.

Teams from Boeing are well into final assembly of the crew and service modules that will fly OFT-2 to the space station.

OFT-2 will fly a new, reusable Starliner crew module providing additional on-orbit experience for the operational teams prior to flying missions with astronauts.

For Boeing’s Commercial Crew missions, the Starliner spacecraft will launch atop a United Launch Alliance Atlas V rocket, the US space agency said on Friday.

“Boeing also remains focused on incorporating the recommendations from the joint NASA-Boeing Independent Review Team with almost 75 percent of the 80 proposed actions implemented,” it said.

The independent team was formed to review anomalies experienced during OFT, which led to Starliner not reaching its planned orbit or docking to station as planned, and to provide recommendations to ensure a robust design for future missions.

Following a successful OFT-2, Boeing will focus full attention on preparations for its final flight test with astronauts and is already completing work on the Crew Flight Test spacecraft in parallel.

The CFT crew members are Boeing astronaut Chris Ferguson and NASA astronauts Mike Fincke and Nicole Mann. NASA astronauts Sunita Williams, Josh Cassada and Jeanette Epps are crew members of the Starliner-1 mission.

Cassada and Williams were both selected for the mission in August 2018, and NASA announced Epps’ assignment on August 25.