Update: Saturday, June 1

The Starliner launch has been scrubbed yet again. The countdown clock was stopped just minutes before launch by an automatic hold. Details are forthcoming. The next launch opportunity is Sunday, but it’s unclear if another launch will be attempted.

Original story

After many delays and much fanfare, Boeing Starliner did not launch on Monday, May 6.

Nor did it launch on the next scheduled date, Friday, May 17.

The scheduled launch date is now Saturday, June 1, at 12:25 p.m. ET—and it’s looking like this one will finally stick. If Starliner isn’t able to launch on June 1, there are backup dates on June 2, 5, and 6.

NASA will livestream the launch of the crewed spacecraft on its YouTube channel as well as on NASA TV.

What went wrong during previous launch attempts?

The past few weeks have been turbulent ones, with a few issues that needed to be dealt with. The initial launch attempt on May 6 was going pretty smoothly. But two hours before liftoff, the launch was scrubbed due to an off-seat pressure valve on the second stage of the Atlas V rocket.

It pushed the valve beyond its lifetime rated limit, so the United Launch Alliance determined that it needed to be replaced.

However, while NASA had the spacecraft back in its assembly building, engineers decided to take a closer look at another issue that had surfaced after the scrub: a helium leak on the service module of the Boeing Starliner spacecraft.

Starliner uses helium to push propellant to its thrusters, and engineers wanted to monitor the leak and find its source. They discovered it was due to a faulty seal and have determined it won’t affect the mission. They will continue to monitor it, but not fix it.

There was another issue as well: While taking a close look at the helium leak, the team decided to review the propulsion system for Starliner one more time to ensure they hadn’t missed anything.

They uncovered a redundancy issue: Basically, Starliner has three different combinations of thrusters that it can fire to initiate the deorbit burn and return to Earth. But there was a 0.77% chance that a specific combination of thruster failures could lead to Starliner not being able to initiate that burn. Engineers wanted to work through that scenario before launch.

They’ve completed that work, and have determined that the spacecraft and launch vehicle are ready to take to the skies.

What is the timeline for coverage of the Boeing Starliner launch?

NASA’s coverage of the Boeing crew flight test will begin at 8:15 a.m. ET on Saturday, June 1. After a post-launch news conference later in the afternoon, coverage will begin again on Sunday, June 2, when the spacecraft docks with the International Space Station.

You can check out the full schedule here.