Hybrid Rockets: All You Need to Know

Vishal Kaushik

Blogger, Web Designer and Content Writer

Hybrid rockets are taking off (quite literally)! But beyond all the buzzwords and hype, what are hybrid rockets, exactly? What differentiates them from existing launch technologies, and why should you be interested in them?

In this article, we’ll take a brief look at the concept and technologies behind hybrid rockets, and we’ll also look at how they compare to other types of rocket engines (solid fuel, liquid fuel, solid-liquid hybrid).

By the end of the article, you’ll know everything you need to know about hybrid rockets!

What are hybrid rockets?

Hybrid rockets are a type of rocket that uses a solid fuel and a liquid oxidizer. The solid fuel is usually a rubber or plastic compound, and the liquid oxidizer is usually nitrous oxide.

Hybrid rockets offer a number of advantages over traditional rockets, including increased safety, lower cost, and greater flexibility. In particular, they have been used in air-launched ballistic missiles like Trident II, which was launched from nuclear submarines.

They are also very common in research experiments because they can be used to test a wide variety of materials at once without needing any modifications to the combustion chamber. This is a critical factor that reduces costs and mission risks, which is of great value to Space Agencies and private Space companies.

However, hybrid rockets still suffer from several disadvantages relative to other types of engines. One disadvantage is that the fuel doesn't ignite as easily when it's under pressure (in fact, this may be the reason why so many people think hybrids don't work).

Another disadvantage is that they use more oxidizer than other engines. There are also some limitations on what kind of engine design can work with hybrid rockets, though it's hard to say exactly what those limitations are because there aren't many hybrid engines being built today. Though this is the beauty of the engineering prowess and creativity shown by men & women in the Indian & international Space sector: never saying ‘no’ to possible technological improvements and advancements – if something is not working quite right, they experiment and iterate endlessly till it does.

What makes hybrid rocket technology unique?

Hybrid rocket technology is unique because it uses a solid fuel and a liquid oxidizer, which allows for more control over the combustion process. Additionally, hybrid rockets can be throttled and restarted, which is not possible with traditional solid rocket motors.

Hybrid rockets are also safer than their solid rocket counterparts because the fuel is not as volatile. If there is an issue with one of the engines, the other engine continues to power through safely.

Lastly, hybrids have higher thrust-to-weight ratios which means they’re lighter in weight but still pack a punch when it comes to acceleration.

Advantages of hybrid rocket propulsion:

  • Hybrid rocket motors offer a number of advantages over solid rocket motors and liquid rocket motors.
  • They are safer than solid rocket motors because the fuel and oxidizer are not mixed until just before combustion.
  • They can be shut down and restarted as needed, which gives them greater flexibility than solid rocket motors.
  • Hybrid rocket motors can be throttled, or their thrust can be varied, which is not possible with solid rocket motors.
  • They have higher specific impulse than liquid rocket motors, making them more efficient for long-distance missions such as reaching Earth orbit from the ground.
  • They also have relatively short lead times in comparison to other propulsion systems, requiring months instead of years for development and testing.

The disadvantages of hybrid rocket propulsion include a low mass fraction (which means that the engine must burn its fuel quickly) and difficulty controlling the direction of thrust, meaning that steering requires multiple small engines rather than one large one.

How they work in comparison with other fuel sources?

Hybrid rockets offer a number of advantages over traditional solid and liquid-fueled rockets. For one, they can be shut down and restarted multiple times, which is ideal for applications like space tourism where a rocket may need to make multiple short trips. It is also highly advantageous in situations where an entire mission’s progress doesn’t have to be aborted (which leads to massive losses of resources and thousands of man hours of effort) and can be resumed from a certain stage of progress after corrections.

Hybrid rockets also tend to be safer and more reliable than their solid or liquid-fueled counterparts. And because they use a combination of fuel sources, they can offer the best of both worlds in terms of performance.

In addition, hybrid fuels are less toxic than solids or liquids making them safer for people and easier to transport. This is a major factor in favor of this technology as the whole world is increasingly focused on sustainability as an equally important part of Space exploration.

Finally, many hybrid fuels have higher energy densities compared with other propellants; this means that it takes less material to produce a given amount of thrust.

Two main types of hybrid engines:

There are two main types of hybrid engines: solid and liquid. Solid hybrid engines use a solid fuel, such as rubber or plastic, that is mixed with a liquid oxidizer.

Liquid hybrid engines use a liquid fuel, such as kerosene or alcohol, that is mixed with a solid oxidizer. The ignition system can be either an electric spark plug or a pyrotechnic charge.

Liquid hybrids have more thrust than solids but less endurance due to their higher fuel consumption rate. Solid hybrids have lower thrust than liquids but better endurance because they don't lose much energy as heat.

Both types of engine systems offer advantages in different areas for specific applications which make them both very useful when developing new rocket designs for space flight, research projects, and recreational purposes.

Some real life applications:

Hybrid rockets are a type of rocket that uses both solid and liquid propellants. They offer several advantages over traditional rockets, including safety, cost, and simplicity.

Hybrid rockets have been used in a variety of applications, including spaceflight, model rocketry, and amateur rocketry. A hybrid rocket is an engine or motor that uses two types of propellant, a solid fuel and a liquid oxidizer.

The first use of hybrid rockets was in the 1930s for research purposes. The U.S Air Force has also researched the technology for use on missiles but found them impractical due to their high complexity compared with other propulsion systems such as turbojets or ramjets which were easier to mass produce.

Research continues today, although so far it has only been successful for low-powered engines. One example is a hybrid rocket called BEAR (Ballistic Ejection Array Rocket) that's used by NASA to explore Mars' atmosphere.


A hybrid rocket is a type of rocket that uses two or more propellants. Typically, one of these is a solid fuel and the other is a liquid oxidizer. This combination can provide some advantages over traditional rockets, which use either all solid or all liquid propellants.

Hybrid rockets tend to be safer than their all-solid or all-liquid counterparts, and they can also be more efficient.

Originally published July 27, 2022