Ok, so I am tryting to calcualte the mass of an orbiting body.
I am using M = 4 * PI^2 * r^3 / ( G * T^2 )
Lets use the Earth as an example.
However I am not getting what Nasa has for answers of 5.9 E24 kg.
http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html
Using this...