For my NewMars forum correspondents: I need help. Somehow, I cannot find the forums page to sign on ("page not available" and "error 404"). Did someone block me somehow? If so, by mistake, I hope?
The access issue has been resolved. I don't know what happened there, but I was not the only one who saw the error messages.
NewMars forums guys who spot this message might want to peruse two articles just below. The one dated 8-23-12 is the design rough-out for a manned chemically-powered lander for Mars, plus an unmanned cargo-only variant of the same vehicle. This is a rough-out to the level of mass statement and volume reconciliation. It's a useful startpoint for a real design process, and it is "in the ballpark" as regards performance. These designs move between low Mars orbit and the surface.
The article dated 9-3-12 defines the configuration changes and estimates the performance of that same basic lander used instead at Mercury. One can delete the heavy heatshield, and most of the aeroshell, but one must still add extra propellant for the airless descent. Mercury is somewhat similar to Mars in size and gravity, but utterly airless. No entry deceleration there.
However, the final answer is that both the manned and unmanned cargo landers designed for Mars could actually be used successfully at Mercury. This is MMH-NTO storable propellant stuff, and these are one-shot throwaway vehicles, same idea that we used decades ago on the moon.
More of this is in the works. Our moon, the big moons of Jupiter and Saturn, the largest 4 asteroids. I just have to find the time to get it done. But, I expect the one basic design, reconfigured for each site, could be used quite successfully.
Eventually, I want to run a similar design family based on nuclear thermal rocketry, that is fully re-usable. Over the long haul, that would be the better deal from a bang-for-the-buck standpoint.