<p><em><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>The two month window only is for the least energy trip. You can launch any time if you do not limit to Hohmann orbits. Part of this proposal is that the intervening 2 years is spent getting things assembled so they are ready to go rapid fire when the proper alignment comes. <br /> Posted by ThereIWas</DIV></em></p><p>Exactly. Assuming the Delta IV-H as starter, this could be up to 16 flights in the window. Eight would fly from Vandenburg, eight from Cape Canaveral. At current estimated launch costs it would be roughly $4 Billion per two-year cycle to purchase Deltas, but this could see major price reductions with extended commmitment. The intervening 2 years is spent getting everything ready.</p><p>16 launches places 80t or more of useful payload on Mars, an extra 40-60t of carrier hardware and over a dozen cruise-stage/comsats in orbit. Not a bad start for a base-camp, esp. starting with advanced robotics. The goal would be to scale operational costs down enough to keep flying like that. The autonomous lander we specced out in this thread points toward a likely design. </p><p>A crew flight might consist of 4 rockets launching a capsule with 3 crew, a service module/node and 2 supply modules, all meeting up after TMI. A full host would consist of 4 crews outbound totalling 12 people. This sort of configuration, with several crew in light craft, may be more robust (due to cross-rescue) than a single larger ship. This configuration assumes ditching the capsule on Mars or a very tough reusable or using a separate lander-ascender.</p><p>I don't discount electric craft or starting in LEO/L1 for this, but the simplicity of Mars Lite makes so much sense. It plugs right into current hardware with no modification. We ran the numbers for staging in LEO somewhere in this thread, and even with ion thrust its' only about 50% more payload to Mars orbit with attendent development/deployment issues. With direct-throw via Delta everything through TMI is handled by the upper stage, the payload only needs to work cruise and EDL.</p><p><br />Things to remember about this include Delta IV-H nearly being able to put a SunDancer (~10t) on course for Mars. Same for a Dragon<br /> capsule, esp one with only 3 crew inside. For cargo an electric version of a light excavator or dozer can easily mass 5t or under. The two spacecraft mentioned are almost flying and a rocket to deliver them to Mars orbit is already flying. </p> <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>