Rocket Launch

Rocket Scientists Must Design Rocket Launch Systems that are Lighter Weight

Obesity was apparent from the get-go. NASA rocket launch systems are burdened by the incredible fuel weight they carry. Often the fuel comprises 90 percent of the vehicle’s total weight. Further, rocket fuel, normally hydrogen and oxygen, is by weight predominantly oxygen―with oxygen comprising 89 percent of the fuel weight. This is quite a waste since during the atmospheric portion of the orbital insertion flight (rocket launch); the spacecraft is within the atmosphere surrounded by plentiful oxygen. Our atmosphere is 20 percent oxygen and can provide 100 percent of the oxygen required for the booster phase of the rocket launch

If we switched to an air-breathing propulsion system, versus a traditional rocket launch, the need to carry oxygen fuel in the launch vehicle will be dramatically reduced.

The flight plan (envelope) would need to be modified so that the spacecraft stays within the upper atmosphere longer, until near orbital velocity is achieved. Atmospheric oxygen will support combustion as the spacecraft passes through the surrounding air. The goal would be to achieve near orbital velocities while still within the upper atmosphere, using air-breathing propulsion. A small traditional rocket engine would complete the final orbital insertion.

Since the bulk of the fuel is burned during the initial booster phase, while still within the atmosphere, dramatic oxygen fuel savings are possible. Since the weight of oxygen fuel can be dramatically reduced, a smaller amount of hydrogen fuel is required to propel the lighter vehicle. Switching to an air-breathing propulsion system dramatically changes the economics of orbital insertion and space travel—reducing weight and cost by 80 percent.

The goal should be to change the spacecraft and its flight envelope so that it uses the oxygen in the surrounding air for as long as possible and thus reduces the launch weight of the space craft by 80 percent. An air-breathing rocket launch system could place the same payload in orbit with a much lighter, smaller, and cheaper launch vehicle.

Would this require a huge leap in technology? The answer is absolutely not. A simple, old technology can achieve this goal when used in a new way. This technology was proven and tested by both the Americans and the Russians in the 1950s. Unfortunately this technology was abandoned due to Cold War political reasons and limited high-temperature tolerant materials availability in the 1950s. However, today’s technological advances justify re-examining this propulsion methodology.

An air-breathing rocket launch system can reduce the vehicle weight, size and cost by 80 percent. If we could also design the spacecraft to be reusable, the cost of space travel could be reduced by 95%.

 The book “What If We Made Space Travel Practical?” describes how today’s technology makes air-breathing propulsion at high-speeds and high-altitude practical and economical. Thus space launch economics would be vastly changed.

Rocket science is a risky business. Rocket scientists are most concern with safety when designing a new spacecraft or rocket launch systems. Continuing to choose the same design paths successfully used on previous spacecraft lowers the risk perception for the rocket designer. When rocket scientists consider radically different designs they are concerned about new risk that may arise from using new design methodologies. They are concerned about the dangers presented with what they call “the unknown unknowns”.

As a result, rocket scientists continue down the same familiar path to avoid a catastrophe that could occur if an untested design was chosen. We remain stuck with the same old incredibly expensive designs. The book “What If We Made Space Travel Practical?” describes how we can break this cycle of inefficient rocket launch designs.