For the first time, Boeing’s Starliner spacecraft docks with the International Space Station

Boeing’s Starliner capsule docked with the International Space Station on Friday night (May 20), marking a major step forward in the company’s drive to transport NASA astronauts to and from space.

On Thursday evening (May 19), Starliner launched atop a United Launch Alliance Atlas V rocket, beginning a critical uncrewed mission to the station known as Orbital Flight Test 2. (OFT-2). Starliner began zeroing in on the ISS some 22 hours later, completing a sequence of fly-arounds, approaches, and retreats to show its rendezvous ability.

Starliner finally connected with the station at 8:28 p.m. EDT (0028 GMT on May 21) today, docking at the station’s forward-facing port of its Harmony node. When the Boeing spacecraft and station collided in orbit, they were around 270 miles above the South Indian Ocean.

After docking, NASA astronaut Robert Hines radioed Mission Control from the station, saying, “Starliner is looking beautiful on the front of the space station.”

A delayed docking

The docking took place nearly an hour later than anticipated.

NASA and Boeing planned to dock Starliner to the station at 7:10 p.m. EDT (2310 GMT), but postponed it first to allow for improved illumination and communications, then again to reset the space capsule’s NASA Docking System, or NDS, when a slight issue was discovered. That reset was successful, and Starliner was able to connect to its docking port without difficulty.

After the docking, Kathy Lueders, NASA’s assistant administrator for space operations, told reporters, “The last few hours have been excruciating, you know, seeng that spacecraft just out of reach of [the] ISS.” “This is a really critical demonstration mission and it was important for us to get that demo data and get the learning from each of the steps along the way, and really put the vehicle through its paces.”

Sometimes, Lueders added, “that journey takes a little bit longer,” but for now, seeing “that vehicle docked now to the ISS is just phenomenal.”

The docking success of Starliner was the greatest birthday present for Steve Stitch, NASA’s Commercial Crew Program manager. Before Starliner arrived at the space station, NASA and Boeing celebrated his 57th birthday with a slice of cake.

“You know, I’ve had an incredible 24 hours,” Stitch remarked of witnessing Starliner launch and eventually dock at the space station, although an hour late. “I had to wait a little longer for my birthday present. It was worth the wait.”

Starliner’s long road to ISS

Boeing had inked a multibillion-dollar NASA deal in 2014 to shuttle astronauts to and from the International Space Station using Starliner. Today’s docking demonstrated that the capsule can make it to the orbiting lab, which it had previously failed to achieve.

In a post-docking news teleconference, Mark Nappi, Boeing’s vice president and programme manager for the company’s Commercial Crew Program, said, “It was really something to watch.” “It was really nail-biting watching that vehicle sit out there for a little while until it was time to come in.”

The initial OFT, which launched in December 2019, was cut short due to a series of technical issues that left Starliner stranded in an orbit too low for an ISS rendezvous. And while OFT-2 was intended to launch last summer, prelaunch inspections found that 13 of the 24 oxidizer valves in Starliner’s propulsion system were jammed. It took roughly eight months to figure out what was causing the problem and how to fix it.

OFT-2 hasn’t gone off without a hitch, either. During the key orbital insertion burn 31 minutes after liftoff, one of Starliner’s thrusters failed, NASA and Boeing officials revealed during a post-launch news conference on Thursday night.

To compensate, the backup thruster ignited but failed to complete the burn. Starliner was able to enter into the proper orbit for an ISS rendezvous after a tertiary backup thruster activated. According to NASA officials, the backup-to-a-backup thruster operated successfully during a later Starliner engine burn on Thursday night.

“The system is designed to be redundant, and it performed like it was supposed to. Now the team is working the ‘why’ as to why we had those anomalies occur,” Mark Nappi, vice president and program manager for Boeing’s commercial crew program, said during the news conference.

Boeing executives said in an emailed statement this afternoon that mission team members have now determined that the two thruster failures were caused by a drop in chamber pressure. The thruster system “operated normally during all of the propulsion system demonstrations, and with redundancies in place, does not pose a risk to the rest of the flight test,” according to the statement.

Before approaching the ISS, Starliner passed a number of tests, including abort manoeuvres and a test of its Vision-based, Electro-Optical Sensor Tracking Assembly (VESTA) system, which it used to lock onto the orbiting lab, according to the statement.

“Flight control teams continue to learn more about the vehicle and about how it is operating in space, and it continues to perform well as it makes its way toward the station,” Boeing representatives said in the statement. “The Guidance, Navigation and Control (GN&C) systems are performing nominally. Flight software is executing as designed. Power generation is positive.”

Although the researchers discovered some unexpected behaviour in a “thermal cooling loop,” Starliner was able to maintain a constant temperature, according to the release.

The Starliner’s Journey

Starliner has arrived at the International Space Station, where it will remain for four or five days before departing for a landing in the western United States. If the capsule passes its final tests, it might be allowed to transport NASA astronauts to the station by the end of the year.

“Today marks a great milestone, providing additional commercial access to low Earth orbit, sustaining the ISS and enabling NASA’s goal of returning humans to the moon and, eventually, to Mars,” NASA astronaut Hines informed Mission Control from the station. History will remember great achievements in human spaceflight for a long time. Today will be no exception.

Speaking of OFT-2 milestones, the next one to watch is the hatches between Starliner and the ISS opening, which will allow the astronauts now stationed on the orbiting lab to float onboard the newcomer. On Saturday at 11:45 a.m. EDT (1545 GMT), this is expected to happen (May 21). NASA’s coverage will begin at 11:30 a.m. EDT and will be available live on Space.com (1530 GMT).

NASA has a commercial crew contract with Boeing, but it also has one with SpaceX, which the agency inked in 2014. Elon Musk’s business has previously successfully launched four operational crewed missions to the International Space Station for NASA. After ferrying its crew to the station in April, one of the Crew Dragons is currently moored at the station.

“Our goal was to have two redundant crew transportation systems,” Stitch said of NASA’s Commercial Crew Program, which he said became a reality when Starliner arrived at the station, where a Crew Dragon was already docked.

He stated, “It was just a great day to see that.”