Are there any disadvantages to using hydrogen as rocket fuel?

In one line

The rule

Hydrogen can be used as rocket fuel because it burns with oxygen to give a lot of energy, but it has several practical disadvantages.

Let's understand it simply

Imagine you want to carry water from the well to your house, but your bucket is full of holes. Even though the water is useful, it is hard to keep it from leaking out. Hydrogen is a bit like that. It gives rockets a big push (a lot of energy), but it is very hard to keep in one place. It is the smallest and lightest gas, so it slips through tiny gaps and needs special tanks. Also, it is very cold when stored as a liquid, so it can freeze things around it.

How it works

1. Hydrogen is stored as a liquid at very low temperatures (−253°C).
2. Tanks must be insulated (protected) to keep it cold, or it turns into gas and escapes.
3. Hydrogen molecules are tiny and can leak through small holes or even some metals.
4. It is highly flammable (catches fire easily), so any leak is dangerous.
5. Special pumps and pipes are needed to move liquid hydrogen safely.
6. Making and storing hydrogen uses a lot of energy and money.

The story behind it

Hydrogen has been used as rocket fuel since the 1960s. NASA first used it in the Saturn V rocket for the Apollo missions to the Moon. Scientists chose hydrogen because it gives the highest energy per kilogram when burned with oxygen. But they soon found it was tricky to handle. In 1986, the Challenger disaster partly involved leaking hydrogen, showing the risks. Today, space agencies still use hydrogen, but only for the biggest rockets, where its power is worth the trouble.

Where you see it in real life

• ISRO's GSLV Mk III rocket → uses hydrogen in its upper stage → needs special tanks and handling.
• NASA's Space Launch System → uses hydrogen for main engines → complex ground support needed.
• Cryogenic fuel trucks at rocket launch sites → carry liquid hydrogen → must be insulated and checked for leaks.
• Hydrogen-powered cars (rare in India) → need thick, strong tanks → show storage problems even on the ground.
• Balloons filled with hydrogen (not common now) → risk of fire → replaced by safer helium.
• Laboratories using hydrogen gas → strict safety rules → risk of explosion if leaked.

Why it matters

• Rocket engineers must design safe storage and delivery systems for hydrogen.
• Hydrogen's storage problems increase the cost of space missions.
• Handling hydrogen safely is a key skill for jobs in space science and chemical engineering.
• Questions on hydrogen fuel come in competitive exams like JEE, NEET, and ISRO recruitment.

Worked example

Let's compare hydrogen and kerosene as rocket fuels for storage:

Given: Hydrogen boils at −253°C, kerosene at 150–300°C
Step 1: Hydrogen must be kept very cold to stay liquid
Step 2: Kerosene can be stored at room temperature
Step 3: Hydrogen tanks need insulation, kerosene tanks do not
Step 4: Hydrogen leaks easily, kerosene does not
Step 5: Conclusion: Hydrogen is harder and costlier to store than kerosene

Common mistakes

• Thinking hydrogen is always the best fuel: It is only best for some rockets, not all.
• Forgetting about storage: Hydrogen's low temperature and leaks are big problems.
• Ignoring safety: Hydrogen fires are hard to see (almost invisible flame) and very dangerous.
• Believing hydrogen is cheap: Making, storing, and transporting it is expensive.

Remember it

Hydrogen gives rockets a big push, but is hard to keep, easy to leak, and dangerous if not handled right.