GPE Required to Lift Object?

[highschoolphysics]

The question is: How much gravitational potential energy is required to lift a 9270 kg Progress spacecraft to the altitude of the International Space Station, 424 km above the surface of the Earth? I had used the equation Ugpe= - (GMm)/r and got an answer of -8.71*10^15 J and it said it was wrong. I have no clue where I went wrong or where I could go next.  

 

[Janus]

In the equation, r is measured from the center of the Earth. It seems that you just plugged 424 in for r.

The answer you got would have been the GPE for the spaceship if it were sitting on the surface of a world with the mass of the Earth, and just 424 m in radius.

For one, you have to convert km to meters, and for the other, you are looking for the difference in GPE between sitting at the surface of the Earth and being 424 km above it, not just the GPE for some point.