In this screen grab from a NASA livestream, the Boeing Starliner spacecraft can be seen pulling away from the International Space Station for its unmanned return to the surface of Earth on September 6, 2024.
| Photo Credit: AFP

After months of turmoil over its safety, Boeing’s new astronaut capsule departed the International Space Station on Friday (September 6, 2024) without its crew and headed back to Earth.

NASA’s two test pilots stayed behind at the space station — their home until next year — as the Starliner capsule undocked 260 miles (420 kilometres) over China, springs gently pushing it away from the orbiting laboratory. The return flight was expected to take six hours, with a nighttime touchdown in the New Mexico desert.

“She’s on her way home,” astronaut Suni Williams radioed after Starliner exited

Ms. Williams and Butch Wilmore should have flown Starliner back to Earth in June, a week after launching in it. But thruster failures and helium leaks marred their ride to the space station.

NASA ultimately decided it was too risky to return the duo on Starliner. So the fully automated capsule left with its empty seats and blue spacesuits along with some old station equipment. SpaceX will bring the duo back in late February, stretching their original eight-day mission to more than eight months.

Boeing’s first astronaut flight caps a journey filled with delays and setbacks. After the space shuttles retired more than a decade ago, NASA hired Boeing and SpaceX for orbital taxi service. Boeing ran into so many problems on its first test flight with no one aboard in 2019 that it had to repeat it. The 2022 do-over uncovered even more flaws and the repair bill topped $1 billion.

SpaceX’s crew ferry flight later this month will be its 10th for NASA since 2020. The Dragon capsule will launch on the half-year expedition with only two astronauts since two seats are reserved for Wilmore and Williams for the return leg.

As veteran astronauts and retired Navy captains, Mr. Wilmore and Ms. Williams anticipated hurdles on the test flight. They’ve kept busy in space, helping with repairs and experiments. The two are now full-time station crew members along with the seven others on board.

Even before the pair launched on June 5, Starliner’s propulsion system was leaking helium. The leak was small and thought to be isolated, but four more cropped up after liftoff. Then five thrusters failed. Although four of the thrusters were recovered, it gave NASA pause as to whether more malfunctions might hamper the capsule’s descent from orbit.

Boeing conducted numerous thruster tests in space and on the ground over the summer, and was convinced its spacecraft could safely bring Wilmore and Williams home. But NASA disagreed and opted for SpaceX.

A minute after separating from the space station, Starliner’s thrusters could be seen firing as the white, blue-trimmed capsule slowly backed away. NASA Mission Control called it a “perfect” departure.

Flight controllers planned more test firings of the capsule’s thrusters following undocking. Engineers suspect the more the thrusters are fired, the hotter they become, causing protective seals to swell and obstruct the flow of propellant. They won’t be able to examine any of the parts; the section holding the thrusters will be ditched just before reentry.

NASA’s commercial crew program manager Steve Stich said earlier this week that teams have been so focused on Starliner’s return that they’ve had no time to think about what’s next for Boeing. He said the space agency remains committed to having two competing U.S. companies transporting astronauts.

NASA’s Butch Wilmore and Sunita Williams will close the hatches between Starliner and the space station on Thursday (September 5, 2024). 
| Photo Credit: AP

Boeing will attempt to return its problem-plagued capsule from the International Space Station later this week — with empty seats.

The National Aeronautics and Space Administration (NASA) said on Wednesday (September 4, 2024) that everything is on track for the Starliner capsule to undock from the space station Friday evening. The fully automated capsule will aim for a touchdown in New Mexico’s White Sands Missile Range six hours later.

NASA’s two stuck astronauts who flew up on Starliner will remain behind at the orbiting lab. They will ride home with SpaceX in February, eight months after launching on what should have been a weeklong test flight. Thruster trouble and helium leaks kept delaying their return until NASA decided that it was too risky for them to accompany Starliner back as originally planned.

Also Read: Explained | What does spaceflight do to the human body?

“It’s been a journey to get here and we’re excited to have Starliner return,” said NASA’s commercial crew program manager Steve Stich.

NASA’s Butch Wilmore and Sunita Williams will close the hatches between Starliner and the space station on Thursday (September 5, 2024). They are now considered full-time station crew members along with the seven others on board, helping with experiments and maintenance and ramping up their exercise to keep their bones and muscles strong during their prolonged exposure to weightlessness.

To make room for them on SpaceX’s next taxi flight, the Dragon capsule will launch with two astronauts instead of the usual four. Two were cut late last week from the six-month expedition, which is due to blast off in late September. Boeing has to free up the parking place for SpaceX’s arrival.

Boeing encountered serious flaws with Starliner long before its June 5 liftoff on the long-delayed astronaut demo.

Starliner’s first test flight went so poorly in 2019 — the capsule never reached the space station because of software errors — that the mission was repeated three years later. More problems surfaced, resulting in even more delays and more than $1 billion in repairs.

Also Read: Explained | Significance of Boeing Starliner’s first crewed test flight on May 7,2024

The capsule had suffered multiple thruster failures and propulsion-system helium leaks by the time it pulled up at the space station after launch. Boeing conducted extensive thruster tests in space and on the ground and contended the capsule could safely bring the astronauts back. But NASA disagreed, setting the complex ride swap in motion.

Starliner will make a faster, simpler getaway than planned, using springs to push away from the space station and then short thruster firings to gradually increase the distance. The original plan called for an hour of dallying near the station, mostly for picture-taking; that was cut to 20 or so minutes to reduce the stress on the capsule’s thrusters and keep the station safe.

Additional test firings of Starliner’s 28 thrusters are planned before the all-important descent from orbit. Engineers want to learn as much as they can since the thrusters won’t return to Earth; the section containing them will be ditched before the capsule reenters.

The stuck astronauts — retired Navy captains — have lived on the space station before and settled in just fine, according to NASA officials. Even though their mission focus has changed, “they’re just as dedicated to the success of human spaceflight going forward,” flight director Anthony Vareha said.

The blue Boeing spacesuits will return with the capsule, along with some old station equipment.

NASA hired Boeing and SpaceX a decade ago to ferry its astronauts to and from the space station after its shuttles retired. SpaceX accomplished the feat in 2020 and has since launched nine crews for NASA and four for private customers.

In this photo provided by NASA, astronauts Butch Wilmore, left, and Suni Williams inspect safety hardware aboard the International Space Station on August 9, 2024.
| Photo Credit: AP

NASA decided on Saturday (August 24, 2024) it’s too risky to bring two astronauts back to Earth in Boeing’s troubled new capsule, and they’ll have to wait until next year for a ride home with SpaceX. What should have been a weeklong test flight for the pair will now last more than eight months.

The seasoned pilots have been stuck at the International Space Station since the beginning of June. A cascade of vexing thruster failures and helium leaks in the new capsule marred their trip to the space station, and they ended up in a holding pattern as engineers conducted tests and debated what to do about the trip back.

After almost three months, the decision finally came down from NASA’s highest ranks on Saturday (August 24, 2024). Butch Wilmore and Sunita Williams will come back in a SpaceX spacecraft in February. Their empty Starliner capsule will undock in early September and attempt to return on autopilot.

As Starliner’s test pilots, the pair should have overseen this critical last leg of the journey, with touchdown in the U.S. desert.

“A test flight by nature is neither safe nor routine,” said NASA Administration Bill Nelson. “And so the decision… is a commitment to safety.”

“This has not been an easy decision, but it is absolutely the right one,” added NASA Associate Administrator Jim Free.

It was a blow to Boeing, adding to the safety concerns plaguing the company on its airplane side. Boeing had counted on Starliner’s first crew trip to revive the troubled program after years of delays and ballooning costs. The company had insisted Starliner was safe based on all the recent thruster tests both in space and on the ground.

Boeing did not participate in Saturday’s news conference by NASA but released a statement: “Boeing continues to focus, first and foremost, on the safety of the crew and spacecraft. We are executing the mission as determined by NASA, and we are preparing the spacecraft for a safe and successful uncrewed return.”

Retired Navy captains with previous long-duration spaceflight experience, Wilmore, 61, and Williams, 58, anticipated surprises when they accepted the shakedown cruise of a new spacecraft, although not quite to this extent.

Before their June 5 launch from Cape Canaveral, Florida, they said their families bought into the uncertainty and stress of their professional careers decades ago. During their lone orbital news conference last month, they said they had trust in the thruster testing being conducted. They had no complaints, they added, and enjoyed pitching in with space station work.

Wilmore’s wife, Deanna, was equally stoic in an interview earlier this month with WVLT-TV in Knoxville, Tennessee, their home state. She was already bracing for a delay until next February: “You just sort of have to roll with it.”

There were few options.

The SpaceX capsule currently parked at the space station is reserved for the four residents who have been there since March. They will return in late September, their stay extended a month by the Starliner dilemma. NASA said it would be unsafe to squeeze two more into the capsule, except in an emergency.

The docked Russian Soyuz capsule is even tighter, capable of flying only three — two of them Russians wrapping up a yearlong stint.

So Wilmore and Williams will wait for SpaceX’s next taxi flight. It’s due to launch in late September with two astronauts instead of the usual four for a routine six-month stay. NASA yanked two to make room for Wilmore and Williams on the return flight in late February.

NASA said no serious consideration was given to asking SpaceX for a quick stand-alone rescue. Last year, the Russian Space Agency had to rush up a replacement Soyuz capsule for three men whose original craft was damaged by space junk. The switch pushed their mission beyond a year, a U.S. space endurance record still held by Frank Rubio.

Starliner’s woes began long before its latest flight.

Bad software fouled the first test flight without a crew in 2019, prompting a do-over in 2022. Then parachute and other issues cropped up, including a helium leak in the capsule’s propellant system that nixed a launch attempt in May. The leak eventually was deemed to be isolated and small enough to pose no concern. But more leaks sprouted following liftoff, and five thrusters also failed.

All but one of those small thrusters restarted in flight. But engineers remain perplexed as to why some thruster seals appear to swell, obstructing the propellant lines, then revert to their normal size.

These 28 thrusters are vital. Besides needed for space station rendezvous, they keep the capsule pointed in the right direction at flight’s end as bigger engines steer the craft out of orbit. Coming in crooked could result in catastrophe.

With the Columbia disaster still fresh in many minds — the shuttle broke apart during reentry in 2003, killing all seven aboard — NASA embraced open debate over Starliner’s return capability. Dissenting views were stifled during Columbia’s doomed flight, just as they were during Challenger’s in 1986.

Despite Saturday’s decision, NASA isn’t giving up on Boeing.

NASA went into its commercial crew program a decade ago wanting two competing U.S. companies ferrying astronauts in the post-shuttle era. Boeing won the bigger contract: more than $4 billion, compared with SpaceX’s $2.6 billion.

With station supply runs already under its belt, SpaceX aced its first of now nine astronaut flights in 2020, while Boeing got bogged down in design flaws that set the company back more than $1 billion. NASA officials still hold out hope that Starliner’s problems can be corrected in time for another crew flight in another year or so.

Washington:

Two NASA astronauts who flew to the International Space Station in June aboard Boeing’s faulty Starliner capsule will need to return to Earth on a SpaceX vehicle early next year, NASA said on Saturday, deeming issues with Starliner’s propulsion system too risky to carry its first crew home.

The agency’s decision, tapping Boeing’s top space rival to return the astronauts, is one of NASA’s most consequential in years. Boeing had hoped the test mission would redeem the Starliner program after years of development problems and over $1.6 billion in budget overruns since 2016.

Boeing is also struggling with quality issues on production of commercial planes, its most important products.

Veteran NASA astronauts Butch Wilmore and Sunita Williams, both former military test pilots, became the first crew to ride Starliner on June 5 when they were launched to the ISS for what was expected to be an eight-day test mission.

But Starliner’s propulsion system suffered a series of glitches beginning in the first 24 hours of its flight to the ISS, triggering months of cascading delays. Five of its 28 thrusters failed and it sprang several leaks of helium, which is used to pressurize the thrusters.

In a rare reshuffling of NASA’s astronaut operations, the two astronauts are now expected to return in February 2025 on a SpaceX Crew Dragon spacecraft due to launch next month as part of a routine astronaut rotation mission. Two of the Crew Dragon’s four astronaut seats will be kept empty for Wilmore and Williams. 

Starliner will undock from the ISS without a crew and attempt to return to Earth as it would have with astronauts aboard. 

Boeing struggled for years to develop Starliner, a gumdrop-shaped capsule designed to compete with Crew Dragon as a second U.S. option for sending astronaut crews to and from Earth’s orbit.

Starliner failed a 2019 test to launch to the ISS uncrewed, but mostly succeeded in a 2022 do-over attempt where it also encountered thruster problems. Its June mission with its first crew was required before NASA can certify the capsule for routine flights, but now Starliner’s crew certification path has been upended.

Since Starliner docked to the ISS in June, Boeing has scrambled to investigate what caused its thruster mishaps and helium leaks. The company arranged tests and simulations on Earth to gather data that it has used to try and convince NASA officials that Starliner is safe to fly the crew back home.

But results from that testing raised more difficult engineering questions and ultimately failed to quell NASA officials’ concerns about Starliner’s ability to make its crewed return trip – the most daunting and complex part of the test mission.

NASA’s decision, and Starliner’s now-uncertain path to certification, will add to the crises faced by new Boeing CEO Kelly Ortberg, who started this month with the goal to rebuild the planemaker’s reputation after a door panel dramatically blew off a 737 MAX passenger jet in midair in January.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

This undated handout picture from Nasa released on July 2, 2024 shows NASA’s Boeing Crew Flight Test astronauts (from top) Butch Wilmore and Sunita Williams inside the vestibule between the forward port on the International Space Station’s Harmony module and Boeing’s Starliner spacecraft.
| Photo Credit: AFP

NASA said on Wednesday (August 14, 2024) it’s still deciding whether to keep two astronauts at the International Space Station until early next year and send their troubled Boeing capsule back empty.

Rather than flying Boeing’s Starliner back to Earth, Butch Wilmore and Sunita Williams would catch a ride on SpaceX’s next flight. That option would keep them at the space station until next February.

Also read:Why NASA astronauts Butch Wilmore, Sunita Williams may be in space until 2025

The test pilots anticipated being away just a week or so when they rocketed away as Starliner’s first crew. But thruster failures and helium leaks marred the capsule’s trip to the space station, raising doubts about its ability to return safely and leaving the astronauts in limbo.

NASA officials said they’re analyzing more data before making a decision by end of next week or beginning of the next. These thrusters are crucial for holding the capsule in the right position when it comes time to descend from orbit.

“We’ve got time available before we bring Starliner home and we want to use that time wisely,” said Ken Bowersox, NASA’s space operations mission chief.

NASA’s safety chief Russ DeLoach added: “We don’t have enough insight and data to make some sort of simple, black-and-white calculation.”

DeLoach said the space agency wants to make room for all opinions unlike what happened on NASA’s two shuttle tragedies, Challenger and Columbia, when dissenting views were ignored.

“That may mean, at times, we don’t move very fast because we’re getting everything out, and I think you can kind of see that at play here,” he said.

Switching to SpaceX would require bumping two of the four astronauts assigned to the next ferry flight, currently targeted for late September. Wilmore and Williams would take the empty seats in SpaceX’s Dragon capsule once that half-year mission ends.

Another complication: The space station has just two parking places for U.S. capsules. Boeing’s capsule would have to depart ahead of the arrival of SpaceX’s Dragon in order to free up a spot.

Boeing maintains Starliner could still safely bring the astronauts home. The company earlier this month posted a list of testing done on thrusters in space and on the ground since liftoff.

NASA would like to keep SpaceX’s current crew up there until the replacements arrive, barring an emergency. Those four should have returned to Earth this month, but saw a seventh month added to their mission because of the uncertainty over Starliner, keeping them up there until the end of September. Most space station stays last six months, although some have gone a full year.

Wilmore and Williams are retired Navy captains who spent months aboard the space station years ago. They eased into space station work as soon as they arrived, helping with experiments and repairs.

“They will do what we ask them to do. That’s their job as astronauts,” said NASA chief astronaut Joe Acaba.

He added: “This mission is a test flight and as Butch and Suni expressed ahead of their launch, they knew this mission might not be perfect.”

Eager to have competing services and backup options, NASA hired SpaceX and Boeing to transport astronauts to and from the space station after the shuttles retired in 2011.

SpaceX’s first astronaut flight was in 2020. Boeing suffered so much trouble on its initial test flight without a crew in 2019 that a do-over was ordered. Then more problems cropped up, costing the company more than $1 billion to fix before finally flying astronauts.

Washington, United States:

NASA said on Wednesday that astronauts delivered to the International Space Station by Boeing’s Starliner could return on SpaceX’s Crew Dragon in February 2025 if Starliner is still deemed unsafe to return to Earth.

Starliner spacecraft launched in June carrying two astronauts to the ISS in a high-stakes test mission required before NASA can certify the spacecraft for routine astronaut flights.

But the mission, initially expected to last about eight days, has been drawn out far longer by an array of problems with the craft’s propulsion system that Boeing and NASA have been scrambling to fix.

Those problems have called into question Starliner’s ability to safely return to Earth its crew, veteran NASA astronauts Butch Wilmore and Suni Williams. NASA has been examining whether a Crew Dragon capsule will have to bring them home instead.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

Story so far: Veteran American astronauts Sunita Williams and Barry (Butch) Wilmore, are still docked with the International Space Station (ISS) since June 6 after facing delays, space debris threats, helium leaks and technical glitches on the Starliner spacecraft on which they travelled.

The U.S Space Agency — National Aeronautics and Space Administration (NASA) — held a ‘space-to-earth’ news conference with the two astronauts on July 10 to receive an update on their mission’s progress. Both astronauts said they ‘felt confident’ that they could return to Earth on Starliner itself.

Also read | How Boeing can bring NASA’s Sunita Williams, Barry Wilmore back to Earth

“I have a real good feeling in my heart that this spacecraft will bring us home, no problem,” said Ms. Williams, while Mr. Wilmore said, “That mantra you’ve heard, failure is not an option.” He added that both crew members were staying on the ISS to test the spacecraft

NASA along with the space capsule’s manufacturer Boeing is evaluating Starliner’s propulsion system and the five small helium leaks in the service module. The team is conducting ground tests on identical thrusters at New Mexico’s White Sands Missile Range while another investigation is underway at NASA’s Marshall Space Flight Center in Alabama to determine why the propulsion system’s seal failed, leading to helium leaks.

The continued delay in Ms. Williams and Mr. Wilmore’s safe return, which was initially scheduled to begin on June 18, has piqued concerns across the world, including India. Apart from Ms. Williams and Mr. Wilmore, NASA astronauts Michael Barratt, Matt Dominick, Tracy C. Dyson, Jeanette Epps and Russian Cosmonauts Nikolai Chub, Alexander Grebenkin, and Oleg Kononenko are aboard the ISS.

Here’s a look at the attempted launches, what went wrong, and current efforts for the crew’s safe return

Starliner’s attempted launches and success

Sunita Williams, 58, is the pilot of NASA’s Crew Flight Test mission aboard Boeing’s Starliner space capsule. The mission is a joint venture between NASA and American private space players to open up commercial travel to low-Earth orbits and the ISS to more people for scientific and commercial purposes.

United Launch Alliance, a joint venture by Boeing and Lockheed Martin manufactured the Atlas V rocket which transported the astronauts via Boeing’s space capsule Starliner to the ISS. With this, NASA will have a second space capsule option (apart from SpaceX’s Crew Dragon), which has a crew module which can house up to seven astronauts and a non-reusable service module which houses the equipment and systems (air, temperature controls, water supply etc) needed for a stay in space.

The first crewed test flight of Starliner with the above-mentioned astronauts was scheduled for May 6 for a week-long stay at the ISS. However, the flight was scrapped less than two hours before the launch after an issue was detected in an oxygen relief valve of the rocket’s second stage. All launch activities were suspended and the flight was postponed to May 17.

A helium leak was detected in a thruster in Starliner’s service module, further postponing the launch to June 1. On that day, the ground launch sequencer, the computer which launches the rocket, triggered an automatic hold stopping the countdown clock three minutes fifty seconds before the launch.

On June 5, Starliner was finally launched successfully from NASA’s Space Launch Complex-41 at Cape Canaveral Space Force Station in Florida and the two astronauts docked with the forward-facing port of the ISS. During their week long stay, the astronauts were tasked with verifying if Starliner was performing as intended by conducting tests on the various control systems and manoeuvring the thrusters. Prior to take-off, a small helium leak was noticed in the space capsule’s propulsion system but not deemed serious.

What went wrong?

En-route to the ISS, four more small helium leaks sprung up. Both NASA and Boeing officials reviewed flight data to find out the cause of the leaks. On June 6, NASA’s Commercial Crew Program manager Steve Stich admitted that similar thruster issues were revealed during the spacecraft’s uncrewed test flight in 2022, adding, “thought we had fixed that problem,” at a press conference.

The undocking and return journey of Starliner, which was scheduled for June 18, was postponed to June 22, then June 25 and later to July 2.

Mr. Stich opined that thruster issues may have been caused overheating when fuel was burned during the space capsule’s rendezvous with the ISS. According to CNN, the Starliner’s service module has 28 reaction control thrusters, of which five have failed during flight. Four were brought back online eventually.

The Starliner, which had its first uncrewed Orbital test flight in 2019, faced a software glitch, leaving the space capsule in the wrong orbit before it returned to ground without docking with the ISS. In 2022, the space capsule successfully conducted its first uncrewed test flight when it docked with the ISS and then undocked four days later to return to Earth. This flight too faced issues with the thrusters.

What is causing the delay?

Apart from technical issues, the crew also faced a debris collision threat on June 28. The US Space Command alerted the six astronauts onboard the ISS to execute ‘safe haven’ procedures i.e. crew members board the spacecraft they arrived in, in case an emergency departure is needed. This was necessitated after a defunct Russian satellite (RESURS-P1) broke into more than 100 pieces of debris in an orbit near the ISS. Ms. Williams and Mr. Wilmore were forced to board the Starliner to take shelter for an hour before they resumed their activities on the ISS.

On July 2, NASA said that the spacecraft was in good shape to remain docked to the ISS for over 45 days (its upper limit), giving the ground teams of NASA and Boeing time to conduct simulations and tests on the thrusters. Analysis is also underway to determine why several helium leaks have arisen in the capsule, said NASA. Currently, NASA has not set any end date to the mission, making the extension indefinite.

How will the crew return?

In the July 10 press conference, NASA has said, that if absolutely necessary, Starliner would be capable of returning to Earth – acting as an escape pod. Moreover, NASA also has the option of ferrying Mr. Wilmore and Ms. Williams to Earth aboard Crew Dragon. The SpaceX spaceship transported four astronauts to the ISS in March and is capable of fitting more people in case of an emergency. However, such an option has would be a last resort in case Starliner is deemed non-functional.

But NASA has reiterated its confidence in the Starliner to return the duo, dropping the option of using the Crew Dragon.

File picture of NASA astronauts Butch Wilmore and Sunita Williams at NASA’s Kennedy Space Center, ahead of Boeing’s Starliner-1 Crew Flight Test (CFT) mission
| Photo Credit: Reuters

Astronauts Sunita Williams and Butch Wilmore, who should have been back on Earth weeks ago said Wednesday that they’re confident that Boeing’s space capsule can return them safely, despite a string of vexing breakdowns.

NASA test pilots Wilmore and Indian-origin Williams launched aboard Boeing’s new Starliner capsule early last month, the first people to ride it.

Helium leaks and thruster failures almost derailed their arrival at the International Space Station, and has kept them there much longer than planned. Now the earliest they could return may be the end of July, officials said.

In their first news conference from orbit, the pair said they expect to return once thruster testing is complete here on Earth. They said they’re not complaining about getting extra time in orbit, and are enjoying helping the station crew. Both have previously spent stints at the orbiting lab, which is also home to seven others.

“I have a real good feeling in my heart that the spacecraft will bring us home, no problem,” Ms. Williams told reporters.

The test flight should have lasted eight days, ending on June 14.

NASA’s commercial crew program director Steve Stich said the earliest the Starliner astronauts might return is the end of July. The goal is to get them back before SpaceX delivers a fresh crew in mid-August, but that, too, could change, he noted.

This week, NASA and Boeing are trying to duplicate the Starliner’s thruster problems on a brand new unit at White Sands Missile Range in New Mexico, one of the prime landing sites in the US western desert. The trouble is in the propulsion system, used to maneuver the spacecraft.

Five thrusters failed as the capsule approached the space station on June 6, a day after liftoff. Four have since been reactivated. Wilmore said there should be enough working thrusters to get him and Williams out of orbit. There are also bigger engines that could fill in, if necessary.

“That mantra you’ve heard, failure is not an option, that’s why we are staying here now,” Mr. Wilmore said. “We trust that the tests that we’re doing are the ones we need to do to get the right answers, to give us the data that we need to come back.”

Boeing and NASA consider the ground tests essential to determine what might have gone wrong since that part of the capsule — the service module — is discarded before landing. The leaks also are located in this disposable section.

So far, testing has not replicated the hot temperatures reached during the flight, according to Mr. Stich. Managers want to make sure the suspect thrusters are not damaged, before bringing Starliner back. They were fired more frequently than anticipated early in the flight, and the extra demand on them may have caused them to fail, Mr. Stich noted.

At the same time, ground tests are being conducted to better understand the helium leaks, which could stem from bad seals. Officials have previously said there is ample helium left for the trip home.

Hurricane Beryl slowed some of the work. Johnson Space Centre in Houston, home to the control centres for both NASA and Boeing, was closed earlier this week to all but the most critical staff.

Boeing’s Mark Nappi stressed that in an emergency, Starliner and its crew could return right now. While the company does not believe the thrusters are damaged, “we want to fill in the blanks and run this test to assure ourselves of that.”

NASA ordered up the Starliner and SpaceX Dragon capsules a decade ago for astronaut flights to and from the space station, paying each company billions of dollars. SpaceX’s first taxi flight with astronauts was in 2020. Boeing’s first crew flight was repeatedly delayed because of software and other issues.

There have been no discussions with SpaceX about sending up a rescue capsule, Mr. Stich said.

Washington:

A pair of US astronauts stuck waiting to leave the International Space Station said Wednesday they were confident that the problem-plagued Boeing Starliner they rode up on would soon bring them home, even as significant uncertainties remain.

Butch Wilmore and Sunita Williams blasted off on June 5 aboard the brand new spaceship that NASA is hoping to certify to ferry crews to-and-from the orbital outpost.

They docked the following day for what was meant to be roughly a week-long stay, but their return was pushed back because of thruster malfunctions and helium leaks that came to light during the journey.

No date has been set for the return, but NASA officials said Wednesday they were eying “late July.”

Asked during a live press call from the station whether they still had faith in the Starliner team and the spaceship, mission commander Wilmore replied: “We’re absolutely confident.”

“I have a real good feeling in my heart that the spacecraft will bring us home, no problem,” added Sunita Williams.

She said they were continuing to enjoy their time aboard the ISS, performing tasks like changing out the pump on a machine that processes urine back into drinking water, and carrying out science experiments such as gene sequencing in the microgravity environment.

They have also tested Starliner as a “safe haven” vehicle in case of problems aboard the ISS and checked out how its life support performs when four people are inside.

Lingering uncertainty

Before Wilmore and Williams can come home, however, engineering teams need to run more simulations of similar thrusters and helium seals on the ground, to better understand the root causes of some of the technical issues Starliner experienced — and modify the way it will fly down, if necessary.

It was known there was one helium leak affecting the spaceship before the launch, but more leaks emerged during the flight. Helium, while non-combustible, provides pressure to the propulsion system.

What’s more, some of Starliner’s thrusters that provide fine maneuvering initially failed to kick in during its approach to the station, delaying docking.

Engineers are not sure why the craft’s computer “deselected” these thrusters, though they were able to restart all but one of them.

In a subsequent press call, Boeing executive Mark Nappi told reporters that the “working theory” for the thruster malfunction was overheating due to excessive firing.

Theories on the cause of the helium leaks ranged from debris entering the propulsion system to Boeing possibly installing seals that were undersized for the task.

NASA and Boeing insist Starliner could fly home in case of an emergency, particularly since the problems affected only certain thrusters that control orientation.

They have no concerns over any of the more powerful thrusters responsible for the “deorbit burn” that will bring the spaceship back.

But much remains unclear — including whether the orientation control thrusters that malfunctioned have become degraded, which would make it necessary to rely on other thrusters during descent, NASA official Steve Stich said.

He insisted that NASA wasn’t yet considering bringing Williams and Wilmore back on a SpaceX Crew Dragon, in what would amount to a major humiliation for the aerospace giant Boeing, whose reputation has taken a hit in recent years over the safety crisis affecting its commercial jets.

“The prime option today is to return Butch and Suni on Starliner,” said Stich, while conceding that a return flight on a SpaceX spaceship can’t be ruled out.

In 2014, both SpaceX and Boeing were awarded multibillion-dollar contracts by NASA to develop crewed spaceships after the retirement of the Space Shuttle program. SpaceX carried out a successful crewed test in 2020 and has flown dozens of people since.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)