You're in a DGIV with low fuel and oxygen running on battery power. Try to get back to earth without the crew dying. If you want this to be realistic don't mess with the generators.
I am not responsible for any damage to files or computer his comes with no warranty.
I've made an update for this scenario. You can find it here:
http://www.orbithangar.com/searchid.php?ID=3454
This version is not required to run the newer one.