<i>> The first thing to consider is very simple ways to increase that payload. </i><br /><br />Actually, the question was what can be done with current state-of-the-art rockets. I'm all for Delta/EELV evolution but would like to keep this to that subject. Upper stage/payload changes, such as SEP or STR would be my #1 first upgrade, especially if it could incorporated as a tug/aerobrake stage for other cargo. <br /><br />From Boeing's web page, the Delta IV H as currently flown can put 17,600 TMI - roughly what your 1/5th rule indicates. That means a certain amount for aerobraking and other EDL hardware, but not necessarily half of the 9t TMI. If a 1-launch or 2-launch architecture (with mid-course rendezous) could put usable payload on the surface, it is a start. Past that, what would be the added in-situ resources to leverage? <br /><br />The idea is (roughly, if it works) a two-launch scenario where a 9t Mars Capsule is launched at the Mars window, followed by a high-IsP tug. The tug catches up with the capsule, docks and provides additional resources for crew, mainly power. At Mars insertion the tug aerobrakes to some Mars orbit and releases the capsule which descends to surface. Various aerobraking schemes (one-pass, direct entry, multipass, etc) are possible. The crew meets with an 6-8t ERV on the surface. <br /><br />Cargo missions could be a 9t capsule with limited cruise stage that does precision, hi-G entry, or could meet with tug. <br /><br />Taking Zubrin's greatest point (put something on Mars, fast) and what is actually available, what can we do today? If you had a GIANT roll of cash, where would you start knowing that you have access to Delta, Atlas, Ariane, SeaLaunch, Soyuz and Proton, later Falcon? This is about in-space systems more than the launch vehicle. <br /><br />Can a single 9t capsule support 2-4 people and land them safely? Does it need a tug? What about final landing? The next step is to surge-launch from several pads during the 26 month window - d <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>