I totally agree, Herb, and moreover, a manned space flight to Mars is premature.

It's a joy to read AJA and JB talk of the trip to Mars. I've been dreaming of such a thing since I first read SciFi before it was called Science Fiction when I was 11 or 12. I have no concerns that mankind is capable of such an undertaking and as time passes will be increasingly more capable. The problem, as I see it is cutting through the almost impenetrable web of politics that will engulf such an endeavor if backed by the state. Can private funding be raised for such a project? The costs will be immense and the returns will be much in the future.

A wheel based design for a space vessel sounds cool as hell. However it is fraught with physical complexity and unnecessary risks. We can achieve the effects of gravity with a tether & counterweight based system. With such a setup we require a slight fraction of the mass the linked design would require and without the need to figure out and master zero-g manufacturing and assembly and the support infrastructure needed to build it. A tether+counterweight system would be less than a quarter of your estimated trillion USD. This is because it is a relatively simple add-on to an existing design. You reinforce the habitat to be "suspended" where the tether attaches (not necessarily a single point, btw), keep your booster mass, and implement a simple reel system with thruster to provide control over the forces generated. Very little additional mass required and all of it can actually be tested and validated on terra firma.

Elon Musk is working on it.

Staging from LEO is a terrible idea. Any proposal built on it is one ignorant of the physics involved. Direct launch with TransLunar Injection to a direct Martian surface entry with aerobraking is the most efficient route, and something we have actual experience doing (We aerobrake to get back to earth, for example). It mat not sound as sexy or cool as building a battlestar in orbit and going from there, but it is incredibly efficient by comparison and reduces the cost from trillions to under 100B.

We've had the technology for a many decades now. It is proven and simple.

A quick summary:
Mars' atmosphere is heavily carbon dioxide (95%). We take Sabatier reactors with hydrogen as feedstock to run a basic exothermic chemical reaction process to produce methane (CO2 -> 4H2 -> (CH4 +H2O). This provides us with water and fuel. We then use electrolysis to produce oxygen and recapture some hydrogen from the water to cycle back into the system. We now have methane and oxygen. If we also combine this with the Reverse Water Gas Shift (RWGS) we have a single reactor capable of leveraging earth origined propellant mass of 18g propellant for every gram imported plus a high load of oxygen as well. If we consider the entirety of production from such a reactor we produce 34g of resources for every single gram we import. This system is entirely simple, predictable, one might even say boring, and automatable.

And we've already built those reactors proving the concept. They were/are simple, robust, and inexpensive. From here we can actually bootstrap the manufacture of plastics. Combine that with 3D printing and you've got some seriously useful, compact, and lightweight bootstrapping going on.

Getting back is so much easier than getting there. Anyone telling you it is the opposite is pushing an agenda or ignorant of basic physics. 90+% of the work done to get from a gravity well to anywhere in the solar system is done by getting out of the bottom of the well. With Martian gravity at less than half of Earth's, this is far, far easier. Indeed, this means we can send a shipment which has a return ship and this reactor system two years before sending humans. This would mean those going would know for certain before they even strapped into a rocket that they had a fully fueled base and return ship with more oxygen and water than they need already in place.

Ah, now we've hit one of my specialties: Mars. :)

FredTheViking, you have it completely backward. How do you establish an economy "in space"? You need something to produce, to sell, to exchange. To top that off you have to be able to do it at a price which is affordable by those who would be your market.

The moon does not provide this. Mars does.

Mars is actually the easier of the two. It takes more fuel to get to the surface of the moon than it does to get to the surface of Mars. Mars' atmosphere means less shielding is required to be shipped or used. Mars' atmosphere provides proven, simple, and reliable means for producing air, water, and fuel. Mars has mineral resources which are actually useful now as opposed to theoretical fusion fuel supply on the Moon.

The presence of Mars' gravity field means an easier adaptation - which is precisely what bone loss is.

Further, if you want to harvest asteroids from 'the belt', you'll need to do that from a Martian settlement/base, not from the Moon.

It isn't any "safer" to go to the moon than Mars in the event someone needs rescued. Indeed it is arguably the opposite. If you need to ship someone from Earth to Mars or the moon they will nearly always arrive just to collect the bodies and start over. Indeed, the resources and environment of Mars actually give an edge to survival efforts over Luna.

Going to Luna first is like going from New York to Colorado by way of Europe.

I've spent years studying and researching how to move us to a spacefaring race. Every alley and twist has lead me to discard my old beliefs in such things as "The Colony Ship" or the traditional NASA "Battlestar Galactica" model, and even space stations and moon bases as logical and practical first steps. They are not.

The facts of the matter are Mars is the least expensive and has the most to offer.

In order to support the notion we will also need to build a transportation infrastructure. As much as I love the idea of Cyclers (ships which non-stop cycle along a path and enable pick up and drop off - think of a mothership in sci-fi), I've come to conclude we could do it by building a tether system for slingshotting people and cargo around the solar system. In order to do this, however, we need mass - and a lot of it. This mass is best obtained from the asteroid belt - which means we are back to Mars. This system would be built from Mars to Earth, not the other way around.

If you analyze the history of mankind spreading across this planet you'll see parallels between what i am saying and how we've done it so far. The Moon is a traditional boondoggle in that it is currently and for the foreseeable future impossible for a moonbase to be self sustaining and not require vast infusions of resources from Earth. mars can start with a dozen people and take in more every couple of years. In many ways it is the ultimate expression, IMO, of many of the principles in the Gulch - though nobody will accidentally crash-land there. ;)

One final note for this post, regarding bone mass loss.

This is only a problem if you plan on returning to Earth in that condition. Those saying "well astronauts in space lose X% per month" are not looking at all the facts and data. Bone loss stops. Why? Because shedding the bone is a natural adaptation. "natural adaptation to space?!, you ask? Yes. You see, we are looking at it from the wrong angle. We are not in a steady state of bone mass. We are in a state of constantly building bone mass to cover bone loss. This building is in reaction to our physical environment's demands; not that dissimilar from muscle loss. Indeed we can replicate the bone and muscle reduction in studies where you are in a perpetual state of laying down. So you see, it isn't bone loss but a reduction in reactive bone production. Consider it in a similar manner as "centrifugal force" - we call it a force but it isn't one.

Thus, the apparent loss stops when the body and the environmental demands are balanced. Absent a gravity well this will be a comparatively low number. Mars has about two-thirds Earth's gravity so it is reasonable to expect our post-adaptation bone mass on Mars to be in that range. Yet this isn't a problem if we stay on Mars because we are adapted to it.

Conversely if we settled a planet with, for example, 1.2% Earth's gravity level we'd see in increase in bone density and muscle tissue (or more specifically, strength). And we would have the same issues a Mars adapted human would have in coming to Earth. We would be "weaker" and more vulnerable to falling damage but our bodies would adapt to the level of our environment.

This, too, is easily within our realm of existing technology to handle. A ship traveling to Mars or from Mars to Earth can have effective gravity. This is accomplished via a tether system to provide whatever level of gravity we want. This means going from Earth to Mars we can retain our Earthly level of physical adaptation and then adapt to the Martian level (approx. .38G). Or we can slowly reduce the level enroute. On the return leg we can do the inverse and slowly increase the level. By comparison the Moon has about 1/6th of a G, so any argument based on bone and muscle loss still favors Mars.


I've suspected for years now that the Gulch will be on Mars, and Earth will one day be saved by Martians. In my mind I've even named my initial slingshot route the John Galt Line. ;) If you want to know more about how and why Mars is the best first choice feel free to ask (we've hit my main passion) and I'll happily load you up on information. :D Just be prepared to potentially let go of your current beliefs about space travel and human settlement outside of Earth's gravity wells.

Some suggested resources:
The Case For Mars - Robert Zubrin
Failure is Not an Option - Gene Krantz (sp?)
Entering Space - Robert Zubrin

For now it has, but read my other answer to your post.

The key is very high frequency (100 Hz), very low strain (.00001) exercise. It is working on rats right now, but has not been tried yet on humans in space. It is being tried on humans at NASA. Think of a vibrating massage chair.

The chance to expand to space and live in liberty must be ultimately based on return on investment. First efforts should be self repairing, (and reproducing) mining robots, with scientific capabilities, controlled by humans on earth.
Robots are not nearly so "high maintenance" as humans: air, water, food, and waste processing are expensive to move out of a gravity well.
Ultimately robots can build the infrastructure for human colonies, after the costs of doing so have been reduced through improved production techniques. This could also include terraforming/farming efforts on Mars if practical.

Yes, lower gravity on Mars helps departure. Re the other point, unfortunately it does not work like that, unless you are stationary, as once on Mars they have the orbital velocity of Mars so requiring the same energy whether they want to depart inwards or outwards relative to the sun.

Besides which, didn't you know that the President re-tasked NASA to look into global climate change and Muslim reach-out efforts?

Look it up - it's absolutely true.

I don't think getting to Mars in the near future is a desirable goal. I think it is a waste of resources. No doubt there would be long-term benefits, but I think we should focus on what we are doing now. That is establishing a presences in Space. We need to build an economy there. We need a economic in Space before we spread out. Let's start by getting a moonbase. There is materials there that can havest there. If we can learn to sustain human life in space, then we can travel in space at a time when the economics make sense. We went to the moon too soon. We got there to look at it and left it with little show for it.

A trip to Mars will be a fool's errand. What would we do there, but to just check it out and leave. No, if we go, we go to establish something there. A way to survive when we get there. We do that only when we have establish our selves in space. That will take time and patience, but I think that is a better approach. For now, we can send out automonous robot to explore and gather data, which will be very helpful in the future when we are ready to go out and explore.

don't bet against the nasa budget increasing.

Astronauts lose 1.5% of bone mass each month in space. Exercise has been tried, unsuccessfully.

You would think that this would put an end to the discussion of travel to Mars.

I really love the idea. Such a trip would be one-way or be very expensive. Maybe the isolation and slow communication times would lead to it becoming Gulch of sorts.

It would have the intangible benefit of getting people excited about science.I would love to see a group of adventurers entrepreneurs set up some kind of zero-gee research facility on the moon.

All my life we've been 15-20 years away from a Mars mission.

Well, at least I'm glad to know you now, AJ. I'll be getting to your book as soon as I'm done with The Golden Pinnacle.

Fuel extraction is not something I have heard much about with regard to Mars, but the oxygen issue has been solved technically now.

Part of the key to dealing with the bone loss issue will be an invention by one of my fellow faculty members at Florida Tech. Larry Hench is the inventor of Bioglass, a ceramic that is pretty much at the only composition that is possible for bone to grow around an implant.

Wow! another comprehensive link from Wikipedia. Not the most rigorous scientific source, but interesting.

Sorry, forgot to include this link: http://www.universetoday.com/14859/gravi...

Martian gravity is only 38% that of earth's plus they would be falling towards the sun on the way back.

Note that the three scenarios posited all utilize staging from low gravity intermediates due to the strong gravity well that would have to otherwise have to be overcome in an earth-based launch. This would also enable a much larger craft to be constructed from components ferried up and integrated in and launched from a low gravity environment. As to skeletal degradation, a larger craft would enable mimicking gravity using centrifugal force while providing spin-stabilization.

OK, this is far-out, but considering the artificial knees and hips currently available, some form of cyborg technology might be developed to obviate bone density loss. The first Martians might be cyborgs!

Mars is obtainable now. My research for Shadows Live Under Seashells has shown me that its not only feasible but its probable. The setback would be the issue of literally brining everything one would need to survive for at least one year. When the planets are closest the trip would take 4 months. If timed properly the return trip could take an equal amount of time. The consideration, again, is supplying the pioneers with enough of everything to sustain them for a full rotation to realign the planets.

Jbrenner, I wish I knew you when I wrote Shadows Live Under Seashells. Talking to those folks would have saved me a lot of time and research.