Boeing’s Starliner Crewed Test Flight Delayed Again
The first crewed test flight of Boeing’s long-delayed Starliner spacecraft is not scheduled to launch on Saturday as planned, and it may be postponed further while engineers investigate a persistent helium leak from the capsule’s propulsion system.
Helium Leak Discovery
NASA declared that the Starliner test mission would be delayed once more. After learning of the little helium leak on the spacecraft’s service module, officials will deliberate longer over their options for how to carry out the mission. The space agency has not disclosed the choices available, but insiders have stated that they include operating the spacecraft “as is” with a full grasp of the leak and assurance that it won’t become more severe while in flight, to removing the capsule from its Atlas V rocket and taking it back to a hangar for repairs.
In theory, the first choice would allow for a launch attempt as early as next week. If the second option is chosen, the launch might not happen until at least late summer. NASA released a statement on Tuesday night stating, “The team has been in meetings for two consecutive days, assessing flight rationale, system performance, and redundancy.” “Work in these areas is still ongoing, and discussions are currently ongoing regarding the next potential launch opportunity. NASA will release further information as soon as our course is more apparent.”
History of Delays
For the Starliner program, delays are nothing new, but it’s unclear how this one will stack up against the spacecraft’s earlier mishaps. In 2019, Boeing was forced to conduct a second demonstration mission after an unpiloted test flight was cut short due to software issues. In 2021, Starliner was on the launch pad when pre-flight inspections discovered jammed valves in the propulsion system of the spaceship. In May 2022, Boeing successfully completed a round-trip flight with Starliner to the International Space Station. The crewed test flight of Starliner was postponed from last summer till this year due to concerns regarding the spacecraft’s flammable tape within the crew cabin and its parachutes.
After SpaceX launches its crew transportation service in 2020, Boeing hopes to be the second business contracted by NASA’s commercial crew program to launch astronauts to the space station. NASA intends to approve the Starliner spacecraft for six-month crew rotation flights to the space station starting next year, assuming a successful crewed test flight.
Ongoing Investigations
The helium leak was initially discovered by engineers during Starliner’s crewed test flight’s first launch attempt on May 6, but the mission was not aborted because of the small leak. Officials ultimately decided to scrap the launch attempt due to a different issue with a pressure regulating valve on the spacecraft’s United Launch Alliance (ULA) Atlas V rocket.
When authorities called an end to the May 6 countdown, NASA astronauts Butch Wilmore and Suni Williams were already securely fastened into their seats within the Starliner spacecraft on the launch pad at Cape Canaveral Space Force Station, Florida. Wilmore and Williams went back to their Houston residences to wait for the next chance to launch Starliner.
In time for a second launch attempt on May 17, ULA brought the Atlas V rocket back to its hangar, where technicians replaced the malfunctioning valve. Launch dates were rescheduled by NASA and Boeing to May 21 and May 25, respectively, as engineers evaluated the helium leak. While they wait for the next opportunity to launch, the Starliner spacecraft and Atlas V rocket are housed inside ULA’s Vertical Integration Facility.
Technical Details of the Helium Leak
The leak was identified by Boeing experts as coming from a flange on a single reaction control system thruster in one of the Starliner service module’s four doghouse-shaped propulsion pods. The Starliner service module has twenty-eight response control system thrusters, which are basically miniature rocket engines. These thrusters are used to steer the spacecraft in the right direction and make small course corrections while it is in orbit. Two sets of more potent engines are located in the service module to facilitate bigger orbital modifications and launch-abort maneuvers.
Helium is an inert gas that is used to pressurize the spacecraft’s propulsion system. Nitrogen tetroxide and hazardous hydrazine propellants are burned in the thrusters. Since helium is non-flammable, even a tiny leak is not likely to be a major safety issue on the ground. However, the system needs sufficient helium gas to force propellants from their internal storage tanks to Starliner’s thrusters.
Next Steps for Starliner
NASA claimed in a statement last week that the helium leak was “stable” and that, provided it didn’t get worse, there would be no risk to the Starliner mission. An Ars representative for Boeing denied to offer any information regarding the rate of helium leaks.
Should NASA and Boeing assuage their worries over the helium leak without necessitating extensive repairs, Starliner’s docking at the International Space Station may be possible through a portion of July. Wilmore and Williams will dock at the station, stay for at least eight days at the facility, and then undock to make their way to the Southwestern United States for an airbag-cushioned, parachute-assisted landing.
Future Launch Opportunities
There’s chaos in the timetable after July. August will see a full schedule of visiting crew and cargo vehicles visiting the space station, including the arrival of a new crew on a SpaceX Dragon and the departure of an outgoing crew on another Dragon. Before SpaceX’s upcoming cargo mission, which will take up the docking port Starliner must utilize, launches in late August or early September, there might be one more opportunity for Starliner to dock with the space station. In the fall, the docking port is available once more.
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