RC: Delta v isn't the issue (although it slants strongly towards NEOs & slightly towards the Moon - as always your friend conveniently fails to take into account the fact that we actually have to get back from Mars; which leaves the total delta v much higher for the Mars mission than anywhere else): the issues are time; mass; budget & public interest.

ME: I believe you are referring to my comments and I said "The numbers above also suggest that reaching NEO's is unlikely to be easier than reaching Mars. To say trips to the Moon or NEO's are easier requires calculating the total mission delta v including that needed for return and ignoring the possibility of insitu resource utilization. While NEO's and the Moon both have such possibilities, they will be far harder to implement than sucking in the Martian atmosphere followed by gas phase reaction"

It is misleading as I said to simply compare total delta v. It is about time; mass; budget & public interest, but Mars clearly wins the latter, is close on the middle two, and the importance of the first is drastically inflated by most Moon first people as noted below. You need to compare total mass and launcher requirements taking into account insitu resource utilization. Mars plans most certainly include getting home. What you appear to ignore is the drastic reduction in mass requirements using insitu resources allows. A Lunar or NEO mission does not have this as a near term option. It's about math not religion Robert. Zubrin, NASA, and Caltech have published Mars plans for comparison. Where's yours? I notice you provided absolutely no delta v data to back up your claim. Clearly a sign of sound reasoning and not simply parroting dogma.

RC: An NEO can be done in less than a year - some trajectories a >lot< less than a year; but easy ones can be done in 12 months - the Moon less than that;

ME: So you consider distance to be a primary concern for choosing targets? Frankly, I think that is a waste of money. The durability of systems can be tested on Earth or LEO to assure longer mission times are feasible. The oft mentioned rescue scenario is also pretty bogus. This is equivalent to wanting to drag race 2 miles from home instead of a few hours away so mom can take you to the hospital if you wreck. The danger is primarily in the racing not the distance from home. A 90 % immediate fatality rate in the case of an accident is not much mitigated by improving the odds on the remaining 10%. Airline and sub disasters happen too quick for rescue in most cases and space is more risky. Safety is primarily assured by system redundancy not distance from Earth. But I guess this is all just dogma not rational thought.

RC: but Mars takes 4 years & requires closed loop life support; probably artificial gravity;

ME: All false. Current plans call for a 2.5 to 3 year total mission including one year round trip. Lunar missions can of course be done much shorter. The thing is mission cost will be within a factor of two or three so your cost per hour of research will be orders of magnitude higher for a short lunar mission of weeks to months not to mention the value of the work done. What was the transit portion of your NEO mission? How much will it cost you per research hour and exactly what work do you consider of importance on such a mission?

Mars Direct does not require a closed loop system and I don't think the other plans do either. You can always avoid that requirement by setting aside more mass for supplies. It is absolutely false to claim this is an absolute requirement. I'd say the evidence is against the need for artificial gravity based on MIR experience, but the Mars Society is attempting to evaluate this. If a good exercise program can drastically reduce the effects of 0 g on many astronauts it is reasonable to assume the effects of Martian gravity should be minimal under a similar program.

RC: better solar - or nuclear - power generation;

ME: Based on what requirement?

RC: more demanding landing & reentry technology (an NEO mission doesn't require any specialised landing equipment at all, of course... you can just space walk to the surface from a low flying tranist craft) & larger boosters;

ME: Minimum booster requirements are determined by the delta v required to get there. Mars wins. You have shown nothing indicating otherwise. You are also making questionable claims without any detailed plan to back them up as far as total delta v goes. Your definition of more demanding technology is also questionable. Less delta v is required to land on Mars than the Moon or NEO's. I'm sure there other lenses through which to view it, but you have provided none.

RC: none of which have been built & few of which have any real commercial or scientific application beyond Mars

ME: This is BS. Closed loop recycling systems, big boosters, and better power generation would be of use on all space missions and artificial gravity would also benefit NEO missions. Technology to mitigate low g for use on Mars would certainly be of use on the Moon as well where it would certainly be in greater need.

RC: (conversely NEO missions can be flown fairly easily with existing technologies using simple LEO docking; Lunar missions require more specialised landing equipment & could use bigger boosters but don't actually need them).

ME: You are talking manned missions aren't you? Last I heard there are no longer any man rated boosters that can get out of LEO. So why aren't these missions on the planning docket? I think this claims is also BS, but will be glad to be proven wrong if you can provide a detailed plan.

Regards,
Mark