Two NASA astronauts will remain on the International Space Station for months due to a faulty propulsion system on Boeing’s Starliner, which experienced helium leaks.
SpaceX’s Polaris Dawn mission has been delayed due to helium issues with ground equipment.
Boeing’s Starliner spacecraft landed uncrewed in a New Mexico desert late on Friday.
Helium leaks have previously impacted ISRO’s Chandrayaan 2 and ESA’s Ariane 5 missions.
Properties of Helium:
Helium is inert, non-reactive, and the second lightest element after hydrogen.
It has a very low boiling point (-268.9 °C), which allows it to remain a gas in super-cold environments.
Helium is non-toxic but can displace oxygen if breathed in large quantities.
Uses in Rockets:
Helium pressurizes fuel tanks to ensure uninterrupted fuel flow to rocket engines.
It also helps in cooling systems and fills empty spaces in tanks as fuel is used.
Its non-reactive nature allows it to safely mix with residual tank contents.
Challenges with Helium:
Helium’s low density means it can escape through small gaps or seals in tanks and fuel systems.
The scarcity of helium in the Earth's atmosphere makes leaks easy to detect.
Starliner Issues:
A small helium leak was detected before Boeing’s Starliner initial crewed launch attempt in May, deemed low-risk by NASA.
Additional leaks detected in space led to the decision to return Starliner to Earth uncrewed.
The frequency of helium leaks highlights a need for improved valve design and fitting in the industry.
Some rockets have experimented with argon and nitrogen as alternatives to helium.
Ariane 6 Innovation:
Europe’s Ariane 6 rocket used a new pressurization system that converts a portion of its liquid oxygen and hydrogen propellants to gas.
This system failed in space during the final phase of the rocket’s debut launch in July, despite the rocket’s overall success.
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