by For the past few weeks, NASA astronauts Butch Wilmore and Suni Williams have been stuck on the International Space Station (ISS) after the first crewed trip on the new Boeing Starliner spacecraft went down. Concerns raised by Boeing and NASA about thruster problems and some helium leaks (helium is used in the Starliner engine system) prevented the boat from making the return trip as scheduled. NASA has now said that the astronauts may have to wait until the next scheduled crew transfer in August – possibly to another ship.
Boeing and NASA are trying to put a positive spin on the extension by saying they are testing the systems needed for longer Starliner missions. But the project has already suffered some delays, after it first took off with a crew in 2017. This, along with the latest problems, raises questions about the entire Starliner program.
Starliner was noticed to have a small helium leak before it was even launched. Helium is an inert gas (like neon or xenon), which means it is very unreactive with other materials.
This makes it ideal when dealing with rocket fuel and high temperatures, although it is an expensive process to produce. It is pressurized and used to push fuel into the engines at the correct rate. A helium leak can mean that a thruster will not get enough fuel.
The leak seen while Starliner was on the launch pad was determined to be minor and the spacecraft was placed into orbit regardless. However, this led to a bigger problem when additional helium leaks were identified after launch, which meant that some of the spacecraft’s small maneuverable thrusters could not be used.
Four of the five thrusters have been repaired and Starliner is attached to the ISS, but other thrusters cut out during the trip back to Earth causing concern. When Starliner comes back, re-entry into Earth’s atmosphere requires a very specific “angle of attack” to ensure that the vessel’s heating is not caused by too much friction.
In the worst case, the inability to adjust the orientation of the craft or the orbital parameters for re-entry could lead to severe heat build-up and destruction of the spacecraft with two astronauts on board.
Additional thrusters and other so-called “redundancies” – back-up systems – are designed into the spacecraft, so this is a highly unlikely scenario. However, the helium leak was so. Although Boeing and NASA deemed it safe to return to Starliner, it’s amazing to imagine that the astronauts may have been horrified and worried – especially since these problems did not occur with the unmanned test flights.
The next particular problem is that Starliner returns and re-enters its service module when returning to the surface on land rather than at sea (as did the Russian Soyuz spacecraft and the SpaceX Dragon capsules ). This means that the part of the spacecraft that holds all the vital information will be burned, making it very difficult to determine what really happened.
Investigations in space
NASA is currently running ground tests and investigations are being carried out on the ISS to gather as much information as possible before the return.
The astronauts made it up to the ISS and are safe there. Although Starliner will likely return to Earth, if a major flaw is discovered and it is returned to the ISS, there are other return vehicles that can be used to bring the two crew members back home.
There is no doubt that astronaut safety will be paramount in the minds of both the agency and industry. But this is not the first problem with Starliner. The vehicle has been greatly delayed since its birth as part of the Commercial Crew Program in 2010.
The contract indicated that Starliner should be ready by 2017 with a two-year delay before the first successful unmanned launch in 2022 (there was a failed attempt in 2019). The launch of the main crew was then delayed by a month.
These delays indicate that Boeing is falling behind its main commercial competitor SpaceX, which won a contract at the same time as Boeing in 2010 to build vehicles that could carry a crew to the ISS. SpaceX successfully launched a crewed mission with the Dragon capsule in 2020. To demonstrate the success, Crew Dragon is currently completing its fifth manned mission to the ISS, and has also completed 30 cargo missions.
Boeing has played a major role in space missions with NASA for many years, and plays an important role in the space shuttle program, for example. This relationship continues the company’s role in the Space Launch System (SLS) rocket that will send astronauts on their way to the Moon.
The company is one of the largest and most respected contractors in the aerospace industry. However, the problems with the Starliner come soon after widely publicized incidents with Boeing aircraft, so the corporation could do without any additional problems with its crewed spacecraft to add to its woes.
This article from The Conversation is republished under a Creative Commons license. Read the original article.
Ian Whittaker does not work for, consult with, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
