Boeing Starliner launch: How to watch NASA-crewed mission lift off

The astronauts will test Starliner’s “safe haven” capability, designed to offer the space station crew a shelter if there is a problem on the space station, according to Steve Stich, manager of NASA’s Commercial Crew Program, who spoke during a Friday news conference.

When it’s time to head home, Williams and Wilmore will return using the same Starliner capsule and land at a site in the southwestern United States.

The earliest possible return for Williams and Wilmore is June 10, but there are other dates available in case of bad weather conditions, Stich said.

If the spacecraft does not lift off as planned Saturday, there are backup opportunities to launch on June 2, June 5 and June 6, according to NASA.

Years of development hang-ups, test flight problems and other costly setbacks have slowed Starliner’s path to the launchpad. Meanwhile, Boeing’s competitor under NASA’s commercial program — SpaceX — has become the go-to transportation provider for the space agency’s astronauts.

This mission could be the final major milestone before NASA deems Boeing’s Starliner spacecraft ready for routine operations to deliver astronauts and cargo to the space station.

“We look forward to flying this mission. This is a test flight; we know we’re going to learn things,” said Mark Nappi, vice president and program manager of the Commercial Crew Program at Boeing, in a statement. “We are going to improve, and that improvement starts with the Starliner-1 mission and it will be even better than the mission we’re about to fly.”

Starliner was only about two hours from its first crewed launch attempt on May 6 when engineers identified an issue with a valve on the second stage, or upper portion, of the Atlas V rocket. The entire stack, including the rocket and spacecraft, was rolled back from the launchpad for testing and repairs.

Then, mission teams reported a small helium leak within the spacecraft service module. The leak was traced to a part called a flange on a single reaction control system thruster, where helium is used to allow the thrusters to fire.

The space agency said the leak did not pose a threat to a mission.

“We looked really hard at what our options were with this particular flange,” he said. “A fuel line, an oxidizer line and a helium line all go into the flange, which makes it problematic to work on. It makes it almost unsafe to work on.”

Rather than making a replacement to fix the leak, the teams decided that the helium leak is small enough to be manageable, Stich said.

“When we looked at this problem, it didn’t come down to making trades,” Nappi said. “It came down to, ‘is it safe or not?’ And it is safe. And that’s why we determined that we could go fly with what we have.”

During the launch countdown, mission teams will monitor the leak to see whether it increases. The teams have spent the past two weeks assessing acceptable levels for the helium leak and troubleshooting, which have been laid out in the rulebook that engineers will use as they assess the leak Saturday morning, Nappi said.

While evaluating the helium issue, engineers also spotted a “design vulnerability” in the propulsion system — essentially identifying a remote scenario in which certain thrusters might fail as the vehicle leaves Earth’s orbit, without a backup method of getting home safely.

NASA and Boeing have since worked with the vendor of the thruster to come up with a backup plan to perform the deorbit burn, should that situation arise, Stich said in a May 24 news conference.

“We have restored that redundancy for the backup capability in a very remote set of failures for the direct burn,” Stich said.

After a flight readiness review meeting on May 29, leaders from NASA, Boeing and United Launch Alliance, which built the rocket, “verified launch readiness, including all systems, facilities, and teams supporting the test flight,” according to the space agency.

The mission teams also took a close look at Starliner’s parachutes after one parachute on Blue Origin’s recent suborbital crewed flight failed to fully inflate. Starliner uses components that are similar to that parachute system, Stich said.

Blue Origin shared flight data with Boeing and NASA, and after assessing Starliner’s parachutes, the team deemed them “good to fly.”

The space station experienced an anomaly on Wednesday that Starliner could help fix, said Dana Weigel, manager for NASA’s International Space Station Program.

A pump on the station’s urine processor assembly has failed.

“That urine processor takes all of the crew’s urine and processes in the first step of a water recovery system,” Weigel said. “It then sends it downstream to a water processor which turns it into drinking water. The station’s really designed to be a closed loop.”

The pump was expected to perform until the fall, and a replacement was set to fly aboard a cargo resupply mission slated for August. But the pump’s failure “put us in a position where we’d have to store an awful lot of urine,” Weigel said.

Now, the urine has to be stored on board in containers. To solve this issue, a replacement pump was quickly swapped into Starliner’s cargo. The pump weighs about 150 pounds, so the team removed two crew suitcases from Starliner carrying clothes and toiletries such as shampoo and soaps handpicked by Wilmore and Williams.

There is a contingency supply of generic clothes and toiletries on the space station that the astronaut duo will use instead for their short stay, Weigel said.

Wilmore and Williams have been in crew quarantine to protect their health prior to launch since the end of April, said NASA astronaut Mike Fincke, who is slated to serve as pilot for the upcoming Boeing Starliner-1 mission that would follow a successful test flight.

“Butch and Suni have every confidence in our rocket, our spacecraft and in our operations teams and leadership management teams, and they are definitely ready to go,” he said.

CNN’s Deblina Chakraborty contributed to this report.