# Homework Help: Mass in a satellite changes orbit

1. Sep 29, 2014

### Karol

1. The problem statement, all variables and given/known data
A i kg mass is in a satellite must move to a higher orbit. energy must be added.
Can this energy be added at one time, by shooting the mass?

2. Relevant equations
Potential energy: $E_p=\frac{GMm}{r}$
Gravitational force: $F=\frac{GMm}{r^2}$

3. The attempt at a solution
The velocity at the higher circular orbit is lower but the potential energy much higher so energy must be added. but if i shoot the mass it reaches the higher orbit with the correct, lower energy but the direction isn't correct, i must change the velocity direction to tangent to earth, right?

2. Sep 29, 2014

### Staff: Mentor

You are basically correct. A one time impulse will change the satellite's orbit into an ellipse that will continue to revisit the same height as the starting point. This doesn't really count as a "higher orbit".

You might find investigating Hohmann Transfer Orbits will give you insight into the problem and its solution.