Boeing Starliner: Timeline, testing, and specs for SpaceX competitor

As the private spaceflight industry continues its rapid evolution, NASA has stopped sending astronauts to the International Space Station, opting to contract private companies to make the 200-mile journey to the ISS.

Only two companies have so far secured NASA Commercial Crew Program contracts: SpaceX and Boeing. While SpaceX launched a third crew of astronauts to the ISS aboard its Crew Dragon module on April 23, (and before that the Crew-1 and Demo-2 missions) Boeing is still testing its CST-100 Starliner reusable crew module.

NASA first signed Boeing onto its commercial crew program in 2010 with an $18 million award, which furthered initial development of the spacecraft.

Four years later, in 2014, Boeing won a $4.2 billion NASA contract to build and fly the Starliner. The contract includes two uncrewed test flights and six crewed missions to the ISS. SpaceX’s contract was significantly less, $2.6 billion, for essentially doing the same job.

But Boeing is getting closer to sending astronauts to the ISS. The company expects to conduct its second uncrewed test flight in August or September 2021, and then crewed flights shortly after.

What is the Starliner module?

Boeing’s Starliner is a crew capsule, meant to transport up to seven astronauts to the ISS, and measures 16.5 feet tall with a diameter of 15 feet. Between the crew module and service module (which holds flight instruments and equipment), the Starliner has 60 rocket thrusters and four engines to abort launch in case of emergency.

The capsule is designed to be launched on top of a United Launch Alliance Atlas V rocket, which brings the module into orbit. It’s made to autonomously dock with the space station.

When the capsule returns to Earth with its crew, the Starliner is meant to return to land. Three parachutes deploy after the capsule has entered the atmosphere to slow the Starliner’s descent, and six inflatable airbags soften the landing. Boeing has planned five landing sites in the western United States, according to the company. This is a different approach from SpaceX’s Crew Dragon capsules, which land in the Gulf of Mexico and need to be retrieved.

The Starliner capsule also harvests solar energy to power itself. Each spacecraft is outfitted with more than 3,500 solar panels, which generate 2,900 watts of electricity, according to NASA. The panels are part of the module’s micrometeoroid debris shield.

Boeing has made three Starliner capsules, named Spacecraft 1 through 3. Only Spacecraft 2 and 3 will be used in orbital flight, according to the company.

Has the Boeing Starliner been tested?

Two Starliner capsules have been tested as of May 2021.

Spacecraft 1 was used to test the equipment for aborting a launch in November 2019, and the capsule’s thrusters successfully flew one mile up and one mile north, before the capsule landed safely.

Shortly after, Spacecraft 3 launched for Starliner’s first orbital flight in December 2019, when it ascended to a 155-mile orbit and circled the Earth 33 times before softly landing in New Mexico’s White Sands Space Harbor. The test lasted for two days.

However, that wasn’t the plan. The test was originally slated to last eight days in orbit, including docking with the ISS. But about 90 minutes after launch, NASA announced that due to a timing issue, the capsule burned too much fuel and wouldn’t make it to the space station after all.

After the capsule landed, NASA launched an investigation and identified 80 bugs that Boeing would have to fix.

NASA called the test a “high visibility close call,” and noted that the spacecraft could have been lost twice during the flight. The second uncrewed orbital flight will use the unflown Spacecraft 2 module.

When will Boeing Starliner fly next?

Boeing announced on April 17 that it is now targeting August or September 2021 for the second uncrewed orbital test. It’s done making physical modifications to the spacecraft, and is now completing all of the software fixes suggested by NASA following the investigation.

If conditions allow, the module will actually be ready to fly by May, Boeing said. But it's launch timeline is limited by whether the space station has an open dock, and rocket availability.

The company is also working on the Crewed Flight Test, in anticipation of a successful second uncrewed test. Since the test capsules for crewed and uncrewed missions are nearly identical, Boeing astronauts have begun climbing into the capsule to test life support and communications equipment.