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Heavier than What?
The answer, is that there are only two types of rockets which fuel modern spacecraft. they are solid fuel rockets, and liquid fuel rockets
The three kinds of rockets are solid fuel rockets, liquid fuel rockets, and ion powered rockets.
The two main types of rockets are, Solid Fuel and Liquid Fuel
There are two main types of rockets: liquid-fuel and solid-fuel. Liquid-fuel rockets consist of a fuel and oxygen (or other oxidizer) in liquid state. They are combined in a combustion chamber and ignited. The fuel flow to the engine can be controlled, the amount of thrust produced can be regulated and the engine can be turned off or on as needed. Solid-fuel rockets consist of a fuel and oxidizer that are pre-mixed in a solid form. Once the solid fuel is ignited, the resulting thrust cannot be regulated or turned off. This fuel system is simpler, safer, and cheaper-but less efficient-than that of a liquid-fuel rocket.
The earliest rockets--i.e., those built by the Chinese as early as the 14 century--used solid fuel.
Rockets typically use Liquid oxygen and liquid hydrogen for fuel. I suspect this is what you are asking. I know of no rocket that uses liquid nitrogen.
Liquid rockets can use a single liquid, two liquids or, rarely, three fuels (more correctly called propellants). The most common type uses two propellants, generally one liquid fuel and one oxidizer -- such as liquid hydrogen (fuel) and liquid oxygen (oxidizer).
A solid fuel rocket engine is just what it sounds like. The fuel inside the rocket is completely solid. In a liquid fuel rocket the fuel is a liquid. Bottle Rockets that you can buy in many stores are fueled with Solid Fuel. Most liquid fuel rockets contain 2 different types of fuel. Once that fuel is mixed and ignited you get your thrust.
Robert Goddard was the first to use liquid fuel in a rocket
unlike solid fuel, liquid fueled rockets are capable of being throttled, shut down, and restarted.
Liquid hydrogen IS used as a fuel. It's used in rockets - and some cars.