AE202
Problem Set 5:
DUE: 20 April 2011
Spring 2011
1.
Three astronauts are about to leave Mars, departing in their Martian lander vehicle.
a)
They need to leave the surface (v=0) for low Martian orbit, i.e. orbit at a constant altitude of
200km.
What velocity do they need to achieve to enter this orbit?
Mars mass = 0.1074 Earth mass, Martian equatorial radius = 3393km.
b)
Their spacecraft has an empty (unfueled) mass of 4000 kg. It contains 6500 kg of fuel. Each
astronaut has a mass of 80kg.
The specific impulse of the rocket motor is 408 s.
Ignoring gravity loss and atmospheric drag, can their spacecraft reach orbit?
c)
You should have found that the rocket’s performance is more than sufficient to reach orbit. So
the astronauts could bring some rock samples along as payload and still get to orbit. What is
the maximum mass (in kg) of samples they can bring and still reach this 200 km altitude orbit?
2.
We solved an example problem in class for the performance of a onestage rocket having a total
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 Spring '09
 Martin
 Spacecraft propulsion, Specific impulse, mass ratios

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