A daily update by email. Science news, great photos, sky alerts.

The first-ever rendezvous and docking of Boeing’s Starliner with International Space Station is complete. It was Boeing’s 3rd attempt to dock Starliner with the ISS, and, during the docking procedure, a handful of hitches happened on the way to the successful completion of the main mission goal. The docking ring retracted and the docking claws locked into place Friday evening (May 20, 2022). Now astronauts aboard the ISS are ready to unload the capsule and continue testing Starliner’s systems. Another livestream of events will begin at 11:30 a.m. EDT (15:30 UTC) on Saturday. You can watch the live show in the video above, or go to NASA’s YouTube channel for the broadcast.

A workhorse Atlas V booster hoisted Starliner to space on Thursday (May 19).

Starliner is a reusable space capsule making this initial test flight without a live human crew. Before the launch, we were hearing phrases like “critical” and “high-stakes” attached to this mission. This mission – called the OFT-2 mission – marks Starliner’s entry into NASA’s growing stable of available crew capsules.

The craft is now berthed at the space station’s Harmony module, where it will undergo continued testing. The capsule is also carrying 500 pounds (227 kg) of NASA cargo and 300 pounds (135 kg) of Boeing cargo, which is ready to unload at the start of its five-to-ten-days stay on orbit.

During NASA’s post-launch press conference Thursday evening, NASA revealed a failure of two out of three orbital maneuvering attitude control (OMAC) thrusters in one of Starliner’s four rear-facing doghouses. The first OMAC thruster failed after a 1-second burn. When the onboard computer switched to a second thruster, it too failed after 25 seconds.

Starliner is equipped with 12 rear-facing OMAC thrusters total … so the mission proceeded.

Once at the space station, there was also a momentary partial failure of one of the capsule’s antennas, and Starliner also experienced a brief alignment problem as its onboard flight systems linked for the first time on orbit with the NASA Docking System (NDS), slightly delaying the first contact.

Both issues were resolved quickly, allowing Starliner’s operators to complete maneuvers within the scheduled time frame.

All times for the coverage schedule are in Eastern Daylight Time, which coordinates to UTC-4.

On Saturday, coverage of the opening of the OFT-2 hatch at the ISS starts at 11:30 a.m. EDT (15:30 UTC), followed by remarks on the OFT-2 arrival from the Expedition 67 crew.

See a full schedule of NASA TV programming at NASA Live.

NASA flight engineers onboard the ISS – Kjell Lindgren and Bob Hines – monitored the 3 1/2 hour automated approach of OFT-2 before docking the capsule.

On its website, Boeing describes Starliner like this:

Boeing’s Crew Space Transportation (CST)-100 Starliner spacecraft is being developed in collaboration with NASA’s Commercial Crew Program. The Starliner was designed to accommodate seven passengers, or a mix of crew and cargo, for missions to low-Earth orbit. For NASA service missions to the International Space Station, it will carry up to four NASA-sponsored crew members and time-critical scientific research. The Starliner has an innovative, weldless structure and is reusable up to 10 times with a six-month turnaround time. It also features wireless internet and tablet technology for crew interfaces.

The May 19 launch was Starliner’s third attempt to reach the International Space Station. The first attempt, OFT-1, failed when the onboard Mission Elapsed Time (MET) clock malfunctioned, causing a bad burn and a failure to make the correct orbital insertion for docking with the ISS.

The failure of OFT-1 came at the end of 2019, and Boeing engineers thought they were ready for another try in August of last year. That attempt never left the ground, as preflight testing revealed a set of stuck propulsion valves. According to a report by CNBC, Boeing intends to have the valve redesigned. For OFT-2, however, the company applied a quick fix they hope will keep the valves from failing again. From CNBC:

For this attempt, the company applied a sealant to the valves. But the fix is likely a temporary solution to the issue, which in August saw 13 of the 24 oxidizer valves that control Starliner’s movement in space get stuck after launch site humidity caused corrosion.

The news service Reuters reported on May 8 that Boeing and Aerojet Rocketdyne, which produced the faulty valves, have been at loggerheads over the cause of the failure, with each company pointing a finger at the other. From the Reuters report:

A team of Boeing and NASA engineers is in general agreement that the cause of the stuck valves involves a chemical reaction between propellant, aluminum materials and the intrusion of moisture from Starliner’s humid Florida launch site.

Aerojet engineers and lawyers see it differently, blaming a cleaning chemical that Boeing has used in ground tests, two of the sources said.

Timing of the clash with Aerojet Rocketdyne could not have come at a more inopportune moment for Boeing, according to Reuters:

The disagreement, which has not been reported before, comes at a time when Boeing already is scrambling to emerge from successive crises that have hobbled its jetliner business and drained cash.

Boeing has spent around $595 million from its own pockets to correct Starliner’s problems, leaving the company facing a shrinking profit margin. Development of Starliner was funded by a $6 billion award to Boeing from NASA’s Commercial Crew Program.

During the May 19 launch, the only hiccup was a slight overboost by the main Atlas lift vehicle, which commentators noted as a good thing, a sign of the craft’s hardiness and reliability. The overboost came at around the T-plus 8 minute mark. Main engine cutoff (MECO) was scheduled for T-plus 12 minutes, but was advanced to around 11 minutes 50 seconds to allow the second-stage Centaur to compensate for the overenthusiam of the Atlas. Centaur’s burn was clean.

Starliner’s separation from the Centaur vehicle was confirmed at T-plus 14 minutes 58 seconds, leaving Starliner to lift itself during the final orbital insertion burn at the 31-minute mark. Orientation of the craft was set by Mission Control Houston beginning at the 23-minute mark, leaving the Starliner on its final trajectory to the International Space Station. The brief reorientation went off without a hitch.

Coverage of the combined liftoff of United Launch Alliance Atlas V topped with the Centaur second stage and integrated Starliner was live via NASA TV and NASA’s YouTube channel. Both sources will also provide coverage of Saturday’s continuing OFT-2 activities, when NASA will broadcast coverage of the opening of the hatch by the current crew aboard the ISS.

On Thursday morning, Starliner was resting atop one of the most reliable rocket boosters ever manufactured, the United Launch Alliance Atlas V at Cape Canaveral Space Force Station, which is located adjacent to NASA’s main space flight complex, the Kennedy Space Center.

Photographer Greg Diesel Walck is covering the launch for EarthSky.

Bottom line: Boeing’s Starliner is at the International Space Station. Unloading of cargo is scheduled for 11:30 a.m. EDT (15:30 UTC) on Saturday, May 21, 2022. Watch the livestream in this post.