Helium and its use in rockets

Source: This post on Helium and its use in rockets has been created based on the article “What is helium and why is it used in rockets?”, published in Indian Express on 14^th Sep 2024.

Why in news?

The SpaceX Polaris Dawn Mission was recently delayed due to helium-related problems with ground equipment.

About Helium

1. Helium is an inert gas, meaning it does not react with other substances or combust. It has an atomic number of 2, making it the second lightest element after hydrogen.

3. Helium is represented by the symbol “He” and has an atomic number of 2. It is the second most abundant element in the universe, making up about 24% of its elemental mass.

3. Helium is a colorless, odorless, and tasteless gas under standard conditions.

4. It is used extensively in cryogenics, especially in cooling superconducting magnets, like those in MRI scanners. Helium is used in balloons and airships because it is lighter than air and non-flammable, unlike hydrogen.

5. Helium is produced in large quantities through nuclear fusion reactions in stars, including the Sun.

6. Helium is a non-renewable resource, and its depletion on Earth is a concern due to its wide range of applications.

Why is Helium Used in Rockets?

1. Low Weight: Due to its lightness, using helium helps reduce the weight of the rocket, which is crucial for achieving the necessary speed and altitude.

2. Energy Efficiency: A lighter rocket requires less energy to reach orbit, reducing fuel consumption and the need for more powerful, expensive engines.

3. Low Boiling Point: Helium’s boiling point is extremely low (–268.9°C), allowing it to remain in a gaseous state even in super-cold environments, where rocket fuels are often stored.

How is Helium Used in Spacecraft?

1. Pressurisation of Fuel Tanks: Helium pressurises fuel tanks, ensuring a steady flow of fuel to the rocket engines.

2. Cooling Systems: It is also used in the cooling systems of rockets and spacecraft.

3. Maintaining Pressure: As fuel is consumed, helium fills the empty space in the fuel tanks, maintaining pressure levels.

4. Non-Reactivity: Since helium is non-reactive, it can safely interact with the residual contents of the fuel tanks.

Is Helium Prone to Leaks?

Helium’s small atomic size and low molecular weight make it prone to escaping through tiny gaps or seals in fuel systems.

However, helium is rare in Earth’s atmosphere, leaks are easily detectable, making it useful for spotting faults in spacecraft or rocket fuel systems.

ISRO’s Chandrayaan 2, ESA’s Ariane 5 and NASA’s Starliner are few notable missions affected by helium Leaks.

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