M
MannyPim
Guest
The ISS's orbit decays slowly over time and it has to be periodically boosted to a higher orbit. <br /><br />Of course this discussion is purely theoretical. The ISS was not designed for anything beyond LEO and it will not work as cis-lunar transport.<br /><br />Still, something very large like the ISS or even bigger will one day be part of our cis-lunar transportation system. I actually like the Space Island Group's original concept of a rotating space hotel built by using spent shuttle external fuel tanks. <br />The rotation forces would create a 1/6G (Lunar) or 1/3G (Martian) gravity enviroment which would make daily activity much more convenient and familiar.<br /><br />You could then accelerate this large, rotating station into a a free return cis-lunar orbit which would swing back and forth between the Earth and the Moon ....<br /><br />One you established the free return orbit velocity, you would spend very little additional energy to trim your trajectory. <br /><br />Also, you could build as much heavy shielding as you wish on the crew and passanger compartments to keep radiation levels at about the same level as on Earth. <div class="Discussion_UserSignature"> <font size="2" color="#0000ff"><em>The only way to know what is possible is to attempt the impossible.</em></font> </div>