Your argument against Mars is fundamentally flawed in that it is not necessarily much more expensive to get to Mars. Review the concept of delta v. Your argumernt also ignores the relative value of targets based on the potential expense of staying there. It is also typical of what I am condeming by refering to someone else's opinion as some form of religion rather than rational thought. We would all be better off sticking to technical details rather than assigning motives and states of mind except when discussing the relavent politics. With regard to politics, 40 years of stagnation suggests that the Moon is not crying out to the general public or politicians. On the other hand it is obvious that many do not realize Mars is about as easy to reach as the Moon in terms of expense and energy and that is a major barrier to going there. That is something we can all help remedy. Here is a copy of something I wrote for someone else recently in answer to supposedly cheaper options:

Hi Will,

I can't answer authoritatively, but I can provide some background and tough questions for your opponent. My responses are based on reading "The Case For Mars", trying to stay current on space news, and the basic technical background of a chemical engineer. Comments below.

----- Original Message -----
From: Will Cooper
To: Mars Chicago
Sent: Wednesday, February 06, 2002 7:24 PM
Subject: [mars-chicago] Comments please

Hi, everybody. I'm involved in a conversation on a space forum with a person critical of Mars Direct. I've quoted the exchange below, and I'd like to hear your responses to what he says before I make my reply. This forum (on the NYT site) is read by quite a few people, so I'd like to make sure I have my facts straight before posting. Thanks!

--Will Cooper

My comments to the poster are in the blockquote at the beginning. The rest of the message are the poster's words.

What is the source of your information leading you to condemn Mars Direct (Zubrin's mission plan) as based on incorrect assumptions or wrong data.

"There's no single volume that you can Tolkein"

??? So what's Tolkein got to do with Zubrin?

"around like Zubrin's Case for Mars; but his orbital trajectory claims that Mars is easier to reach in delta v terms "

It's not Zubrin's work. This is well known data that Zubrin quotes or has duplicated. Similar delta v's were quoted in my 1988 book "Race To Mars" by two non-engineers based on their interviews with Soviet and American space scientists working on potential missions to Mars. The values given in it were:

3.2 km/s LEO to Moon + 2.7 km/s to land = 5.9 km/s total (notice almost half is to land). Zubrin's number = 6 km/s

3.6 km/s LEO to Mars + 1.0 km/s to land with aero breaking = 4.6 km/s total (notice huge advantage of aerobreaking). Zubrin's number = 4.5 km/s

3.6 km/s LEO to Phobos or Deimos + 1.9 km/s to land = 5.5 km/s total.

I'd expect the landing delta v for a NEO to be similar to Phobos or Deimos and the orbital match to be as high as for the Moon or greater giving NEO values of >= 5.1 in most cases. I'm guessing the few exceptions are those rare NEO's which pass between the Moon and Earth. If I'm correct, simple convenience is a poor way to choose a target. Even then I don't believe the delta v is a lot lower. Just reaching GSO requires a substantial portion of the energy to reach the Moon. That is why the Hughes satellite maneuver discussed below was possible. It was just a little shy of the energy it needed for GSO and carefull timing using its orbital maintenance thrusters and the gravity of the Moon sent it to the Moon and back. The cost was a loss of much of its fuel for controlling its orbit. It was no free lunch, just a bargain one.

"... is discredited by a massive body of work done on weak stability boundary transfer orbits to the Moon & by the work of Ostro & others on low delta v returns missions to near Earth asteroids."

I doubt the "weak stability boundary transfer orbits" result in any massive savings in delta v. Ask your antagonist what the delta v reduction is. I doubt he really knows. I think he is referring to the type of transfer used on the crippled Hughes satellite. That transfer required months if I remember correctly and undercuts one of the Moon supporters chief arguments of faster transfer times. These orbits would require cutting the transfer energy by almost half to bring the delta v low enough to match that for reaching Mars.

I think the asteroid comments are misleading for several reasons. Zubrin did not claim asteroids were harder to reach than Mars, he didn't even address them in "The Case For Mars". Any reasonable person should be able to see that any single asteroid is of much more limited value than a whole planet and I doubt Zubrin even considered this an issue. He certainly did not give asteroids siren status as he did the Moon.

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.

Asteroids are a key resource for developing space, but their role will most likely be in a supportive rather than primary until space technology advances greatly. 100 % efficient closed loop life support systems and advanced medical technology to deal with many space hazards are much more important on asteroids than Mars or even the Moon which both offer more protection and resources to compensate for recycle inefficiencies. A caveat is that many asteroids will be richer in life support materials than either the Mars or Moon, and others will be richer in structural materials. The advantage is in not needing a rocket to reach what is missing. I'm betting asteroids/comets will be our stepping stones to an interstellar civilization, but Mars is the prerequisite stepping stone to an interplanetary civilization.

"His work on the magsail is superceded by new work on physical (ie, solar - various source; including the Planetary Society's Cosmos 1 test) & virtual sails such as the M2P2 (minimagnetospheric plasma propulsion) of Dr Robert Wing Lee;"

That tells you right there the guy is BSing because Mars Direct doesn't use magsails. He is most likely quoting information from others which he understands only partially at best. I'd bet money he doesn't understand the details of Mars direct and that you could demonstrate that fairly easily with some pointed questions. While "The Case for Mars" does mention mag sails it is simply as one potential future propulsion method of possible use for colonization but not likely to be of use for the initial missions for which Mars Direct was designed. It is hardly a method Zubrin has placed at any critical cornerstone in Martian exploration/colonization. Talk about a strawman argument!

"while his budgetary estimates have been badly discredited even by sympathetic studies such as Caltech Mars plan (which costs the proposal at between 7 & 4 times Zubrin's vague US$10-20b guesstimate)... "

The Caltech mission is not a repricing of Mars Direct. It is a different mission plan designed to increase safety Margins. Zubrin was clear that he designed a mission with a higher level of risk than NASA's previous plans. The Caltech plan back tracked from that. A major factor was increasing the crew size which obviously increases the mission mass requirements and hence cost. Another was a larger return vehicle. Both of these changes were also included in NASA's semi-direct plan. It is obvious that your average person would feel cramped if not claustrophobic in Zubrin's return vehicle. Zubrin's point, which seems to me to have been ignored by both Caltech and NASA, is that you don't need to design the mission around average humans. Explorers of new lands have seldom been average individuals. A low cost mission is going to be one that is human doable not human comfortable. The risk levels of earlier missions of exploration were much higher than Zubrin's ranging from 10's of percent to near certain death. It is obvious from current human endeavors that there are many people willing to risk a few percent risk of death for thrills alone let alone actions of significant value. NASA's low risk tolerance is not a requirement for sending human's to Mars, it is NASA's requirement and the Caltech team or their advisors.

"the biggest chunk of problem with his cost estimates is that they are to a line woefully optimistic in guessing how much it will take to development mission critical technology such as large orbit-orbit transfer vehicles (which even in the Mars Direct trajectory is required for the return flight) & advanced life support technology."

I'm pretty certain this guy has never designed a launch vehicle. I suggest you ask him how many he has designed and what his basis for that claim was.

"Many of his claims about the Moon are factually wrong, of course: for eg, the 14 day/night cycle doesn't exist at the Lunar poles (the primary target for most manned Lunar missions),"

I'd say it was pretty obvious Zubrin was comparing the majority of the Moon to the majority of Mars. The main falsehood here is this guy trying to portray Zubrin as making a dishonest comparison. Zubrin did not claim the poles had 14 day/night cycle.

Besides, who says the poles are the primary target for most manned Lunar missions? There has never been a manned mission to the poles. Future missions may go there for water and sunlight, but it depends on what the mission is for. If this guy is willing to limit human colonization of the Moon to the poles, it is obvious that a world without such limitations has superior developmental potential.

"so purely solar powered Lunar missions - even Lunar agriculture - are perfectly feasible. He ignores the scientific potential of the Moon as an observatory site (despite the mythology, even optical telescopes ca be used full time on the lunar farside if baffled properly);"

Actually Zubrin pointed out the Moon would be a good place for at least radio telescopes and other forms of research. The issue is which is the best suited for human civilization as a whole. It is also certain that even as a science base, Mars wins hands down in terms of astrobiology, and probably in terms of comparative planetology as well. I do think plants could grow well in continuous sunlight based on the experience of Antarctic researchers provided other nutritional requirements could be met on the carbon/nitrogen poor Moon.

"& massively over cooks the level of public interest in Mars. "

Reference the recent Planetary Society poll. Mars clearly wins over the Moon among those interested in space. Is the public as a whole interested? I think news coverage the public is at least mildly interested in Mars compared to other news. Stories that aren't likely to sell papers and magazines get left out. I think Zubrin over estimates the depth of support myself though. The key point for space fans though is pushing a program most likely to have the backing of the general public.

"None of this aggressive spin doctoring would be so much of a problem if his followers didn't sweat on his every overstated word, of course."

The spin doctor here is obvious. A bait and switcher for sure. I don't sweat disagreements with Zubrin. Many in the MS have them. I do however, get irritated with space boosters who paint misleading pictures and then claim Zubrin does intentionally. I hold different opinions on many things from Zubrin, but think he is sincere in his beliefs. Bob is certainly not noted for subtle powers of persuasion. He frequently says what he believes without apparent concern for potential negative interpretations.

Hope that helps, perhaps some of the real rocket jocks on the msalabama list from Huntsville can elaborate on or correct my estimates.

Regards,

Mark Eby

Will's original message to clarify any confusion over response and initial comments.

Hi, everybody. I'm involved in a conversation on a space forum with a person critical of Mars Direct. I've quoted the exchange below, and I'd like to hear your responses to what he says before I make my reply. This forum (on the NYT site) is read by quite a few people, so I'd like to make sure I have my facts straight before posting. Thanks!

--Will Cooper

My comments to the poster are in the blockquote at the beginning. The rest of the message are the poster's words.

What is the source of your information leading you to condemn Mars Direct (Zubrin's mission plan) as based on incorrect assumptions or wrong data.

There's no single volume that you can Tolkein around like Zubrin's Case for Mars; but his orbital trajectory claims that Mars is easier to reach in delta v terms is discredited by a massive body of work done on weak stability boundary transfer orbits to the Moon & by the work of Ostro & others on low delta v returns missions to near Earth asteroids. His work on the magsail is superceded by new work on physical (ie, solar - various source; including the Planetary Society's Cosmos 1 test) & virtual sails such as the M2P2 (minimagnetospheric plasma propulsion) of Dr Robert Wing Lee; while his budgetary estimates have been badly discredited even by sympathetic studies such as Caltech Mars plan (which costs the proposal at between 7 & 4 times Zubrin's vague US$10-20b guesstimate)... the biggest chunk of problem with his cost estimates is that they are to a line woefully optimistic in guessing how much it will take to development mission critical technology such as large orbit-orbit transfer vehicles (which even in the Mars Direct trajectory is required for the return flight) & advanced life support technology.

Many of his claims about the Moon are factually wrong, of course: for eg, the 14 day/night cycle doesn't exist at the Lunar poles (the primary target for most manned Lunar missions), so purely solar powered Lunar missions - even Lunar agriculture - are perfectly feasible. He ignores the scientific potential of the Moon as an observatory site (despite the mythology, even optical telescopes ca be used full time on the lunar farside if baffled properly); & massively over cooks the level of public interest in Mars. None of this aggressive spin doctoring would be so much of a problem if his followers didn't sweat on his every overstated word, of course.