Mission Design - First Flight
Section 4.1.
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Lunar Lander Spacecraft - A Worked Example

Chemical rockets use up a majority of their mass getting to where they want to go. In this example, we start with a rocket delivered to low Earth orbit and fly it to the surface of the moon.
Start with the Rocket Equation:
delta_v = g * Isp * ln( Mo/Mf )
Mo/Mf = exp( delta_v/(g*Isp)
Mo = mass at the start of the burn
Mf = mass at the end of the burn
Fuel consumed = Mo - Mf
g = acceleration of gravity
(In whatever units you're using. I used 32.174 ft/sec^2 to go with delta_v in ft/sec.)

Isp = specific impulse of the rocket motor, in seconds
delta_v from LEO to lunar surface = 19,648 ft/sec
Isp = 350 sec (typical for hypergolic fuel)
Mo/Mf = 5.72
So, if your launcher can deliver 250,000 lbs to LEO, then you can land 250,000/572 = 43,670 lbs on the surface of the moon.

Mission Design - First Flight

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