you can take a look at these two things: delta-v and Tsiolkovsky rocket equation

送交者: steven 于 2007-11-22, 01:34:03:

回答: 居然把你逼到去做功课了由 deadmeat 于 2007-11-21, 23:00:38:

You can find both of them on wiki. This two things tell us that how much weight needs to be throw out to change orbit, launching itself.