Air - Breathing Launch Systems
One of the main reasons for rocket inefficiency is the fact that, unlike jet planes, they carry their own oxidizer. Thus, a jet is much more efficient than a regular launch because they rely on the air and atmosphere to act as their oxidizer. An oxidizer makes up 75% of the total propellant weight and could therefore drastically increase the potential of a rocket if they used the same operating ideas as the jet.
Unfortunately, lack of will and funding have impeded the development of such hypersonic air – breathing propulsion. Ramjet engines are now able to achieve mach 5.5, but over that speed the air cannot be effectively slowed to sub – sonic speeds without creating too much heat. Therefore, the combustion in the engine must take place in a supersonic flow. An engine possible of such a feat is a scramjet. The NASP, canceled in 1993, conducted advanced computations and testing that proved that scramjets would work. An alternative technology, not as high level and hard to develop, is the air – augmented rocket. This rocket is designed to obtain some of its oxidizing agent from the atmosphere. In fact, these engines were tested at the Marquardt Company in 1966. However, a change in the government caused the canceling of that program and never allowed the engines to reach the flight testing stage.
The use of one of these engines on a single stage rocket would greatly increase the ability to carry a larger payload of cargo and would decrease the price of transport of cargo to be sent to a newly developing civilization on Mars.