Checking my work:::::

Have a 6000kg satellite, what does it weigh in Newtons and lbs on the ground? What will it weigh 400km above the earth?

I have this so far for the ground calculations: w=mg, 6000kg x 9.81 m/s^2 = 58860 N. For lbs, I took the 6000kg and multiplied by conversion of 2.20 and got weight on ground in lbs of 13200lbs.

Where I am stuck, is what will it weigh 400km above the earth? I'm not sure what I'm missing formula wise for this one...Please help, thank you!!