- Joined
- Nov 2, 2014
- Messages
- 1,398
Yep...I often tell my colleagues what we really need to be working on is the “g” term in the rocket equation ... the gravitational constant.
Delta v = g * Isp * ln (Mass Ratio)
Delta v = 17,500 mph. To achieve orbit a rocket has to achieve 17,500 mph or ~Mach 22. (The SR-71 achieved Mach 3. The X-15 achieved Mach 6.)
Isp = specific impulse and is a measure of a rocket engine’s efficiency. We know how to achieve the best Isp using chemical or liquid propellants. Little improvement here.
The Mass Ratio is the wt of the rocket fully fueled divided by the wt at burn out. We have worked this to death. Minimal improvement is possible.
“g” is all we have left. We can measure gravity, we have equations for it, we can use it, we can demonstrate its existence. We do not fully understand it.
Delta v = g * Isp * ln (Mass Ratio)
Delta v = 17,500 mph. To achieve orbit a rocket has to achieve 17,500 mph or ~Mach 22. (The SR-71 achieved Mach 3. The X-15 achieved Mach 6.)
Isp = specific impulse and is a measure of a rocket engine’s efficiency. We know how to achieve the best Isp using chemical or liquid propellants. Little improvement here.
The Mass Ratio is the wt of the rocket fully fueled divided by the wt at burn out. We have worked this to death. Minimal improvement is possible.
“g” is all we have left. We can measure gravity, we have equations for it, we can use it, we can demonstrate its existence. We do not fully understand it.