HELIUM

Source: Hindu

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Context

• Two NASA astronauts aboard Boeing’s Starliner will stay on the International Space Station for months because of a faulty propulsion system whose problems included helium leaks.
• Back on Earth, SpaceX’s Polaris Dawn mission has been delayed because of helium issues on ground equipment.

Details

About Helium

Basic Facts

• Symbol: He
• Atomic Number: 2
• Atomic Mass: 4
• Group: 18 (Noble Gases)
• State at 20°C: Gas
• Density: 0.000164 g/cm³
• Boiling Point: 4.222 K
• Key Isotope: ⁴He

Discovery

• It was discovered in 1895 by Sir William Ramsay and independently by Per Teodor Cleve & Nils Abraham Langlet.
• The name is derived from the Greek word "Helios" meaning the Sun, since helium was first detected in the Sun's corona.

Physical Properties

• It is a colorless and odorless gas.
• Helium is inert and non-reactive, making it one of the most stable elements.

Uses of Helium

• Cooling Systems:
• Used in the Large Hadron Collider (LHC) and superconducting magnets of MRI scanners.
• Cools satellite instruments as well as liquid oxygen and hydrogen that power space vehicles, such as Apollo.
• Balloons and Airships:
• Used in filling decorative and weather balloons because of its low density.
• Much safer than hydrogen due to its very reactive nature.
• Protective Atmospheres: Inert atmospheres in the manufacture of fiber optics, semiconductors, and arc welding.
• Leak Detection: Targets leaks in systems such as car air-conditioning due to its ability to escape through small spaces.
• Deep-Sea Diving: A mixture of 80% helium and 20% oxygen is used by divers working under compressing conditions in their breathing apparatus.
• Helium-Neon Lasers: Applications include barcode scanning systems used in supermarket checkouts.
• Helium-Ion Microscopes: Provides higher image resolution compared to a traditional scanning electron microscope.

Biological Role

• Helium has no biological roleand is non-toxic.

Natural Abundance

• 2nd most abundant element in the universe, after hydrogen.
• Found in stars and produced through alpha-particle decay of radioactive elements on Earth.
• Earth's atmosphere contains about 5 parts per millionof helium, but it’s uneconomical to extract helium from the air. Natural gas is the primary source, with concentrations up to 7%.

Role played in rocket launches

• Pressurization of Fuel Tanks:
• Rockets burn fuel at high rates, and as the fuel depletes, the tanks empty, leading to pressure drops.
• Helium, being inert and non-reactive, is used to pressurize these tanks by filling the empty space, ensuring a steady fuel flow to the engines.
• Inert Nature:
• Helium makes it safe for pressurizing tanks filled with highly reactive rocket fuels like liquid oxygen or liquid hydrogen.
• It ensures the fuel remains uncontaminated while maintaining the necessary pressure levels.
• Low Boiling Point:
• Helium is ideal for use in cryogenic systems where rocket fuels are stored at low temperatures.
• Its ability to stay in gas form under such conditions ensures that it can function effectively as a pressurizing agent.
• Detection of Leaks:
• Helium's low atomic mass means it can easily escape through small gaps or imperfect seals.
• This characteristic helps engineers detect leaks in fuel tanks and valves quickly.
• Helium is also used in cooling various parts of the rocket, including sensitive electronics and propulsion systems, thanks to its thermal properties and inertness.

Sources:

IndianExpress