Design
| Enviro |
Astro | Propulsion
| Power | Thermal
| Structures | AD&C
| CDHS |
Test
Chemical
reactions yield thermal energy
that nozzles convert to kinetic energy for thrust.
Chemical
Rockets
Liquid-chemical rockets
are either monopropellant or bipropellant. Monopropellant
Isp
ranges from 180-250 seconds;
bipropellant Isp ranges from 330-480 seconds.
Monopropellant
has a single propellant that
reacts with a catalyst to decompose and release
heat. They are unstable and difficult to handle.
Hydrazine is the most popular monopropellant but
is very toxic. These propulsion systems have relatively
simple designs compared to bipropellant systems.
Bipropellants
contain a fuel and an oxidizer, which react during
ignition to produce heat. For example, liquid hydrogen
is a fuel and liquid oxygen is an oxidizer. Both
are cryogenic and stored as supercooled liquids.
Bipropellant systems are more complex than monopropellant
systems, requiring two sets of tanks and associated
piping. Hypergolic bipropellants do not require
ignition.
Solid-chemical
rocket
motors contain a fuel and an oxidizer. An example
is Aluminum with an Ammonium perchlorate oxidizer.
Rocket motors are for a one-time use only. Once
the chemical reaction is started, it is difficult
to stop. Isp ranges from 300-540 seconds. Solid
rocket motors have few moving parts, relatively
simple mechanisms and logistically accommodating
propellants compared to liquid systems.
Hybrid
rockets contain a solid fuel and liquid oxidizer.
Oxidizer is introduced into the solid rocket motor
cavity for maximized combustion and heat. Isp ranges
from 330-440 seconds.
