# Homework Help: Numerical on Hohmann tranfer

1. Apr 4, 2013

### godhilu

1. The problem statement, all variables and given/known data

Consider an initial circular low earth orbit act at a 300 km altitude, find the velocity change required to produce an elliptical orbit with a 300 km altitude at perigee and 3000 km altitude at apogee. Given gravitational parameter for earth μ=398600 kg3/s2, radius of earth R=6378 km.

3. The attempt at a solution

The perigee and apogee distance from center of earth is
rp= 6378+300=6678 km
ra= 6378+3000=9678 km

velocity in circular orbit =√(μ/rp)

angular momentum (H) of elliptical orbit is=√{(2μ*rp*ra/(ra+rp)}

velocity at perigee = H/rp

change in velocity (Δv)= [H/rp]- [√(μ/rp)]

2. Apr 5, 2013

### SteamKing

Staff Emeritus
And ... ?

3. Apr 5, 2013

### godhilu

I want to know the correct solution to the problem.

4. Apr 5, 2013

### SteamKing

Staff Emeritus
Well, you'll have to figure that out for yourself. As has been stated many times before, PF is not a homework service. If you provide an attempt at a solution, members will provide you with hints and feedback.

5. Apr 5, 2013

### godhilu

Oh sorry, may I know the relevant formulas used by me in the attempt are correct or not?? As I am not getting the correct ans by substituting values to those variables.