The Secrets of Rocket Design Revealed
I am going to share with you some of the little-known techniques and implications of rocket architectural design. Why big rockets sometimes do less. Why little rockets sometimes cost more. And why every rocket has its very own, perfect mission.
There is no single, best rocket. Different rockets do different things. As it turns out, the design of a rocket flows directly from the mission the rocket is intended to do, and there are many different missions. Any given rocket is optimal for a specific orbit and payload. Its efficiency falls off as we move away from that perfect case.
So, let’s start with understanding what the typical missions are that most space launch vehicles are designed to accomplish. This graph below captures the orbits that spacecraft are typically delivered to.
You will see right away that there are eight common orbits. These are from the rocket’s point of view, not the satellite’s. For example, the geosynchronous transfer orbit (GTO) is never the satellite’s final destination. Instead, this is the orbit the rocket delivers it to and considers its own job finished. In this case, the satellite will, after separation, and on its own, proceed to raise itself to its ultimate destination in geostationary orbit (GEO) over the span of weeks or months. Another crazy sounding example is the interplanetary mission. The spacecraft might be going to Mars, Jupiter, or even Pluto, but the rocket thinks of this as a “low earth orbit (LEO) mission” because that’s where its job is finished.
