For here am I sitting in a tin can
Far above the world
Planet Earth is blue, and there’s nothing I can do

From Space Oddity by David Bowie

US astronauts Barry Wilmore (61) and Sunita Williams (58) are having a ‘Major Tom’ moment aboard the International Space Station (ISS). They arrived on June 6 for an 8-day mission but became stuck in space after their Boeing CST-100 Starliner spacecraft suffered a malfunction with its helium-powered thrusters.

Already stranded for two months, the astronauts may have to wait until February – another six months – for a ride home. Yesterday, NASA suggested it may turn to SpaceX for help. Elon Musk’s company has a mission planned later this month to deliver a new crew and fresh supplies to the space station. Instead of sending up four astronauts, SpaceX may leave two seats empty to bring back the astronauts. NASA has asked SpaceX to delay its next mission by a month so that the space agency may study the options.

NASA associate administrator Ken Bowersox emphasised that the agency has multiple options to bring the pair home and suggested using a replacement vehicle for the defective Starliner. Although their capsule has been attached to the ISS for over two months, Boeing engineers are still working to identify the source of the helium leaks which, in turn, causes 5 of the craft’s 28 manoeuvring thrusters to function erratically.

As its engineers struggle, Boeing denies that Mr Wilmore and Mrs Williams are stranded in space. The company said both astronauts can safely return back to earth ‘anytime’. Mr Bowersox, the NASA administrator, confirmed that Boeing had assured the agency that it was ‘very confident’ the capsule would function as expected.

Not Sure

However Steve Stich, manager for NASA’s Commercial Crew Program is not so sure and said he would like to “understand a little bit more of the root causes and the physics.” Mr Bowersox added that the agency is not wed to Starliner and may bring its crew back on ‘another vehicle’.

He also said that NASA is ‘getting more serious’ about evaluating other options. Industry watchers were surprised by the harsh words used by NASA officials which were interpreted as a clear sign that the agency’s patience with Boeing is waning. For weeks on end, NASA downplayed the Starliner’s problems.

The Boeing Starliner was supposed to offer some competition to SpaceX which can launch its Dragon 2 capsule atop a Facon 9 rocket for about $405 million versus $654 million for Boeing’s Starliner.

Even though Boeing received over $5 billion in taxpayer money to develop its spacecraft – $2 billion more than granted SpaceX – the company’s participation in the Commercial Crew Program has been plagued by technical setbacks, cost overruns, and long delays.

During a test in July 2018, leaks were found caused by faulty abort system valves. It took over a year to remedy the issue. The Starliner’s first uncrewed flight in December 2019 failed to reach the space station due to a misaligned internal clock and a critical software error.

It is estimated that Boeing’s foray into space has seen the already troubled company accumulate an extra $1.5 billion in losses.  

A second orbital test flight scheduled for August 2021 had to be scrubbed at the last minute due to, again, malfunctioning valves. The mission finally took off in May 2022 and successfully docked at the space station and returned safely to earth four days later. A first crewed flight test to the ISS, planned for May 2023, was delayed indefinitely when the craft’s parachute system and its associated wiring harness malfunctioned.

A Simple Fix

The error-prone craft was at long last successfully launched on June 5 of this year and delivered its two astronauts to the ISS but then promptly developed a series of malfunctions.

SpaceX also suffered a few setbacks but not nearly as many as Boeing. Already in May 2020, the company sent its capsule to the space station to deliver two astronauts and supplies. It has since tabulated over twenty return trips to the ISS. The SpaceX Falcon 9 rocket has been launched 370 times with only three mission failures to date.

However last June, the SpaceX rocket suffered a rare but catastrophic failure in its second stage, preventing the release of a batch of Starlink satellites. Afterwards, Mr Musk spoke of a ‘RUD’ – a rapid unscheduled disassembly.

Later, SpaceX released a statement saying that the rocket had survived and was able to offload its payload. It since transpired that the satellites were released in low orbit and are destined to eventually fall back down to earth for their ‘full demise’.

In a recent update, SpaceX revealed that the malfunction of its rocket had been caused by a leaky line used by an oxygen sensor. According to the company, the issues was fixed by removing both the sensor and the offending line.

NASA is hesitant to return Mr Wilmore and Mrs Williams to earth aboard the Starliner after extensive testing of thrusters similar to those that equip the Starliner’s capsule showed a significant degradation of the devices. Mr Stich said the test results ‘upped’ the level of discomfort at the agency.

Engineers Stumped

The tests carried out at the White Sands Test Facility in New Mexico, site of the world’s first nuclear explosion, showed a deformation of the thrusters’ teflon seals due to heat buildup, restricting the flow of propellant.

However, short test firings of the Starliner’s thrusters in orbit went smoothly even with the five units that earlier had functioned erratically. Engineers are unable to explain how the teflon seals reverted to their original shape and now suspect there may be additional issues causing the thrusters’ intermittent failure. Seals in the service module, a cylindrical unit sitting bellow the crew compartment, have buckled as well after exposure to the vapours of leaking propellant.

The Starliner is designed to spend a maximum of 45 days in orbit, attached to the space station. Boeing has stated that ‘at a push’ the timeframe may be extended to 72 days by using the capsule’s backup systems.

Whilst the two astronauts are stuck, they are not alone. In fact, the ISS is quite crowded. A Russian Soyuz spacecraft is expected to dock in September to take three visitors back down. However, before the two Americans can hitch a ride on a SpaceX craft, they must first don new space suits. The ones they came up with are incompatible with the Dragon Crew capsule. This sartorial issue may cause additional delays as the suits are individually fashioned to fit the intrepid space traveller.

Cover photo: Boeing’s CST-100 Starliner approaches the International Space Station on the company’s Orbital Flight Test-2 mission.

---

© 2022 Photo by NASA Johnson