So given that the hype thread should have hype rather than be dead (and filled with Team Jedi congratulating us and adding more pics than we have) I'll post what I've been working on:

So long story short, this is a different timeline than our own, where rather than going for Lunar Orbit Rendezvous or even Earth Orbit Rendezvous, the American moon landing was a direct ascent on a mammoth rocket design, essentially based on the [url="http://www.astronautix.com/lvs/saturnc8.htm"]Saturn C-8[/url] design study, but instead of an S-IVB for an upper stage it uses a stretched [url="http://www.astronautix.com/stages/slstageb.htm]SLS stage B[/url]; the original [url="http://www.astronautix.com/fam/sls.htm"]Space Launching System[/url] was a USAF project using high-thrust SRMs and a large LH2 + LOX core to put relatively large payloads into space.

Anyway, enough rambling, here's what we've got so far, and what we're going to have to uprate heavily to make it to Mars:

[spoiler="Saturn VIII Liftoff"][img]http://i.imgur.com/eejL10f.png[/img]

I guess it makes sense to call it the Saturn VIII, considering that it's based off of the C-8 design and has 8 F-1s on the 1st stage and 8 J-2s on the 2nd stage as opposed to 5 for the Saturn V.[/spoiler]

[spoiler="Why yes, that exhaust is underexpanded"][img]http://i.imgur.com/QrFhWvi.png[/img][/spoiler]

[spoiler="It ends up with quite a big flame"][img]http://i.imgur.com/eHhvEgr.png[/img]

If you can believe it, this is still too small compared to the real thing.[/spoiler]

[spoiler="In vacuum"][img]http://i.imgur.com/6sn8V7o.png[/img]

It kind of just expands too fast for a coherent flame to appear.  Also, note the lack of clouds to decrease loading times.[/spoiler]

[spoiler="1st stage separation"][img]http://i.imgur.com/lFmK9UN.png[/img][/spoiler]

[spoiler="2nd stage J-2s"][img]http://i.imgur.com/xQ7zTGO.png[/img]

Note that this is from a different launch.  Many test launches were made refining the design.  Also note clever use of procedural parts to put the tank on the bottom.[/spoiler]

[spoiler="2nd stage separation"][img]http://i.imgur.com/GhaCZuv.png[/img]

This leaves the SLS B stage to do the final push into orbit and make the TLI burn.  Note the roll markings painted on the stage for earlier in the ascent and the spherical tanks near the bottom of the stage for storing helium for pressurization.[/spoiler]

[spoiler="Detaching the spacecraft"][img]http://i.imgur.com/1bQcp85.png[/img]

It's much larger than our Apollo spacecraft; keep in mind that that's an Apollo CSM at the top.[/spoiler]

[spoiler="Lunar insertion and Crasher stage"][img]http://i.imgur.com/NR8agUP.png[/img]

This is an interesting design, using  a pair of LH2 + LOX -powered RL-10As for course corrections, LOI and for beginning the initial descent.  It's got much higher Isp than the engines that were used for this in our timeline (compare 444s to 311s), but there's boiloff that requires starting the landing soon after reaching the moon.  Basically, you start the descent with this stage, and then switch to...[/spoiler]

[spoiler="Terminal Landing Stage"][img]http://i.imgur.com/dCwm5jQ.png[/img]

...this guy, which has 4 Lunar Module Descent Engines (though they should probably be called something else in that timeline) for making the final descent and landing.  It's a much taller vehicle than the LEM was, so landing site choice is crucial.  When you're done, you ascend...[/spoiler]

[spoiler="Apollo CSM and Initial Ascent Motors"][img]http://i.imgur.com/0AxexIy.png[/img]

...using the Apollo SPS and a few small SRMs to get the CSM going.  The logic behind using the SRMs is to give an option for landing abort as well as ensuring that the SPS can be ignited away from the lower stage.  Dumping hot, high pressure exhaust onto tanks that may still have some hypergolic fuel in them might result in a descent stage tank rupturing and causing an explosion, so it's a (probably not completely necessary) safety precaution.  As it turns out, a nearly full CSM has enough dV to ascend from the moon and return to Earth.[/spoiler]

Now, you're probably wondering, why so much thought into the background and the design?  Well, fleshing that out helps us figure out exactly where to go in designing the Mars lander and the LVs to get them there.  It also provides us with a more-powerful-than-a-Saturn V rocket to begin the designing with, although (as you will likely see later) it has its own design issues.