Boeing’s Starliner successfully docks to the International Space Station for the first time

Tonight, Boeing’s new passenger spacecraft, the CST-100 Starliner, successfully docked itself at the International Space Station — demonstrating that the vehicle could potentially take people to the ISS in the future. It’s a crucial possibility that Starliner has finally validated in space after years of delays and failures.

Starliner is in the midst of an important test flight for NASA, called OFT-2, for Orbital Flight Test-2. Developed by Boeing for NASA’s Commercial Crew Program, the capsule is designed to transport NASA astronauts to and from the space station. But before anyone climbs aboard, NASA ordered Boeing to conduct an unmanned flight demonstration of Starliner to show that the capsule can achieve all the key milestones it needs to reach when carrying passengers.

Boeing has so far struggled to demonstrate Starliner’s capability. This mission is called OFT-2 because it is technically a repeat of a mission Boeing attempted in 2019 called OFT. During that flight, Starliner was launched to space as planned, but a software glitch prevented the capsule from entering the proper orbit necessary to reach its rendezvous with the ISS. Boeing had to bring the vehicle home early, and the company never demonstrated that Starliner was capable of docking at the ISS.

Now, about two and a half years later, Starliner has finally shown what it was designed for. Using an array of sensors, the capsule autonomously guided itself to an open docking port on the space station. “The Boeing Starliner spacecraft completes its historic first docking with the International Space Station, opening a new access route for crews to the orbiting laboratory,” said Steve Siceloff, a communications representative for Boeing, during the docking livestream. Docking took place just over an hour behind schedule due to some issues with Starliner’s graphics and docking ring, which were resolved prior to docking.

Starliner docked to the International Space Station
Image: NASA TV

There was some concern about Starliner’s ability to dock at the space station after Boeing revealed some problems with the capsule’s thrusters yesterday. At 6:54 PM ET, Starliner successfully launched into space atop an Atlas V rocket built and operated by the United Launch Alliance. Once Starliner separated from the Atlas V, it had to fire its own thrusters to steer itself into orbit to reach the space station. However, after that maneuver took place, Boeing and NASA revealed that two of the 12 thrusters Starliner uses for the procedure failed and cut off prematurely. The capsule’s flight control system was able to kick in and be diverted to a working thruster, helping to put Starliner into stable orbit.

Ultimately, NASA and Boeing argued that the issue should not affect the rest of Starliner’s mission. “There’s really no need to fix them,” Steve Stich, NASA’s program manager for the Commercial Crew Program, said at a post-flight press conference. “But I know what the teams will do, and what we always do is we’re going to look at the data and try to understand what happened.” Today, Boeing revealed that a drop in chamber pressure had caused the early thruster shutdown, but that system behaved normally during subsequent thruster burns. And with layoffs on the spacecraft, the problem poses “no risk to the rest of the flight test,” Boeing said.

Boeing also noted today that the Starliner team is investigating an odd behavior of a “thermal cooling loop,” but said temperatures on the spacecraft are stable.

Now that Starliner is docked to the space station, it will hang around for the next four to five days. Tomorrow morning, the astronauts already aboard the ISS will open the hatch to the vehicle and retrieve some of the cargo that is inside. Also in Starliner is a mannequin named Rosie the Rocketeer, who simulates what it would be like for a human to ride in the vehicle.

After its short stay on the ISS, Starliner will detach from the ISS and distance itself from the station before returning home. The capsule will use its thrusters to move itself out of orbit and set course for Earth. The two thrusters that failed are of the same kind used for this deorbit maneuver, but NASA and Boeing seemed unconcerned. “We just need to see if we can get the thrusters back,” Stich said. He also noted that the working thrusters can be used and that Boeing has the option of using a different set of thrusters to complete the task if necessary. “So there’s plenty of redundancy in the spacecraft.”

For now, the Starliner team is celebrating their big milestone. “Today marks a great milestone toward providing additional commercial access to low Earth orbit, supporting the ISS and enabling NASA’s goal of bringing humans to the Moon and eventually Mars,” said NASA astronaut Bob Hines, currently aboard the space station, after docking. “Great achievements in manned spaceflight are long remembered by history. Today will be no different.”


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