Using Northern Polar Ice to Jump-Start Martian Interplanetary Economy
written by Remy Villeneuve on January 07, 2004 | contact me
number of views: 76729 | printable version (text) (PDF)
At the end of the 15th century, there was political, and economical, pressure for the Great European nations to explore the Western Atlantic, trying to find that elusive direct route to the Orient. It took a century before real efforts were made to establish colonies. Before that, it was merely flag and footprints, so to speak.
First it was gold, then furrs and rhum, which motivated the financing of those great endeavours. This might be oversimplified, but to do a correct analogy, we must place everything in the right context.
With Apollo and the Space Race, an offspring of the Cold War, we crossed the ocean and planted our flag. Some even dare say that we merely "marked our territory". But why would we go back to the moon? Or Mars? Why would we want to establish colonies in those harsh, unforgiving environments.?
Let's come back down to Earth for a moment and reflect on our history and accomplishments. We have scientific stations in Antarctica, the most unforgiving climate on the planet, yet, I have yet to see someone establishing himself there and raising kids. Why? The total dependence on imported goods for survival, and the high cost of transporting them. Yet, in other barren parts of the New World, some of the largest human cities have evolved.
Those places were often trading outposts, which grew over time, and expanded with both immigration and reproduction, or were key to the harvesting of natural resources. What natural resource does Mars have that would be cheaper to harvest there than anywhere else, and which would be helpful in sustaining other outposts? What could drive the human race to go to Mars, sooner than later, other than scientific curiosity?
Water. Billions of tons of water. And mapped out already. (See Also: Global Distribution of Water on Mars)
It is often said that we should first go to the Moon, and then go on to Mars, because the moon is closer. We can use the economic law of offer and demand to find what could be a motivation to go to Mars.
The moon doesn't have water, nor hydrogen for that mater. Sure, some studies have hinted that there might be traces of water in some craters on the moon, but the consensus at the moment is that it would be so painstakingly hard to exploit that you'd be better off importing the hydrogen all together.
However, hydrogen is hard to transport. It boils off and seeps out from it's tanks, requires energy to remain cryogenic, and must get quickly to it's destination. Sending hydrogen from the Earth to the Moon requires a lot of velocity to get it there too, which requires heavy and costly launch vehicles.
From the Earth surface, you need about 9500 m/s of delta-v to launch into LEO, including drag and gravity loses. Then, you need an additional 3900 m/s for a trans-lunar orbit followed by lunar orbit injection. And you're not on the Moon yet... Add another 2000 m/s for the descent and landing to the surface. Total is a delta-v of 15400 m/s From The Earth To The Moon.
Now, if you look at Mars, you start out with the same 9500 m/s to get to LEO, but then you add 5700 m/s to get to Mars orbit. As a bonus, you can use the Martian atmosphere to aerobrake... Total is 15200 m/s.
Since sending something to Mars and the Moon is similar, let's consider the Return on Investment. If you send hydrogen to the Moon, fine, but you won't be able to produce more hydrogen once it gets there. However, if you send a payload to Mars which could produce hydrogen and all you needed to provide was tankage, you could bring many more times the mass back to the Moon.
It might even be supposed that water containers would be built in-situ on Mars from iron, and water left to freeze solid inside (with appropriate relief to prevent tank bursts).
Why water? Well, remember, it's because of an handicap for long duration transport of hydrogen. It tends to manage to get into space slowly but surely.
Since we'd be using Mars-produced propellants (methane/oxygen and/or water steam nuclear rocket), we'd need about 8000 m/s to get off Mars and on a return trajectory to Earth. Once again, we use the atmosphere to be aerocaptured, and the trajectory is adjusted to get into lunar orbit with the least possible energy. It all has been more or less done before...
First step would be to land a probe at the North Pole, and determine water content in Martian polar ice. If it can be done remotely from an orbiting probe well that's ok, but before committing to the plan I have you'd need to be sure there was enough water ice on hand. I read that THEMIS data pointed in that direction, but better be certain before leaving the cradle.
Second step, which could be combined with the first one, would be to launch an automated CH4-H20-O2 factory. The robotic lander would be equipped to cut ice into blocks, and doing a spiral pattern from it's point of landing outward, then back to it's landing point carving 10-20 centimeters layers. Power would be provided by a small nuclear reactor, with capacity to be refueled (this is important for later steps).
The factory would take the dry/wet ice mix, and by warming, would cause the CO2 to sublimate. The water part would be kept liquid, filtered and electrolyzed to separate H2 and O2. A partial load of hydrogen would then be reacted with the C02 and produce CH4.
I won't elaborate much more since this is almost word-for-word what I heard about Zubrin's Case for Mars, but anyway, it's always good to restate the facts and objectives. Once the supply production is adequate, but not yet up to desirable levels, we launch the housing.
What I have in mind would be an inflatable habitat, which really would be 3 inflatable structures imbricked like Russian dolls. Landing would need to be relatively accurate to within a few hundred meters. This has been accomplished in the past with Surveyor on the moon.
A rover would then seek out the Power-Hydrogen-Oxygen-Methane Lander (PHOM). 3 lines would be rolled from the Habitat lander, one for each gaseous products, each The Outer structure would be inflated first by reacting methane and oxygen in a fuel cell, providing power for the instruments, as well as pure water vapor and CO2.
A second envelope, inside the first one, would then be inflated simultaneously with O2. A gap of about 30 centimeters would separate the two inflated envelopes. This gap, filled with water vapor, would slowly form an ice shell, like an igloo. Gas would be inserted by the center of the bags, the cold Martian air would cause condensation of the water vapor, which would drip to the external sides by gravity. Pressure would be monitored so that liquid water doesn't accumulate at the base of the dome, and fuel cell use would be adjusted accordingly. The ice shell protects the inhabitants from incoming radiation.
A tunnel would be pre-built into the bags for access to the innermost envelope from the outside, leaving an opening 2 meters wide on a side of the structure. The third envelope would only be used later...
Once the habitat would be set up, we would launch Human Payload #1, which would consist of 4 men. No women at this stage. You'll see why later... We'd need people with electrical, mechanical and material expertise, along with a medical and biology background. No need for "one of each", one expert per field would do at this stage. This launch would also include fish eggs, fertilized or not, and seeds
Transfer vehicle would have a sleeping compartment surrounded by a 30 centimeters wide water envelope at launch, and hydrogen/oxygen fuel cells would be used to ramp that up over time over the whole pressurized volume. The fuel cells would be used to supplement solar panels, since on board hydroponics (for CO2 and water recycling as well as -some- food) would require some serious power.
I won't speculate on an appropriate solar/fuel cell power output ratio, but failure of one should not mean doom-of-crew. This is precious cargo, and there's no way anyone would sign up for a 2/3 failure ratio toward Mars!
So our friends land near the polar complex. First duty, outfitting of the habitat. If, for whatever reasons, the gaseous lines could not be connected to the PHOM facility, human intervention would resolve whatever glitch occurred. Remember, we know before heading for Mars that essentials are being stocked so maybe terrain prevented the rover from plugging the hoses on it's own. It would be a minor set back.
A power line would be connected from the Habitat to the PHOM facility, enabling the pooling of electrical resources, and gaseous lines would be plugged between the Habitat and the Transfer Lander as well. Baseline consumption would be supported by the PHOM nuclear reactor, peak loads by the Habitat and Transfer Lander's fuel cells.
Depending on whether the solar panels were dumped before entry or folded back, they could either be used as a supplemental power source, or even removed and used to power land vehicles. Refueling of the Lander's methane-oxygen descent engine would begin, enabling return of the crew if a Bad Thing occurred.
After pooling of resources, the Habitat would be outfitted primarily as a biology/medical facility, with half of it's space fitted with sleeping accommodations for up to 8 adults. A common airlock, launched along with the Habitat, would be installed midway between the Lander and the Habitat, with ice-covered pressurized tunnels linking them. The gap between the 2nd and 3rd envelope would be filled with polyurethane foam brought for insulation. The emulsifying gas could be compressed CO2. The foam would act as an additional layer of protection against the cold and the radiations.
A concave cavity would be carved in the immediate area of the complex, to a depth of 4 meters at it's center, and a second Habitat-like envelope would be installed at it's center, inflated and ice-shelled. However, instead of oxygen, CO2 and water would be used for the innermost envelope, like the outer one. Being insulated by the foam layer, water would rise to the surface level.
The resulting basin would be used as a fish hatchery and hydroponics facility but the pure water would first be seeded with CO2 consuming algae. LEDs emitting light of the appropriate wavelengths would provide illumination. Radiation dosing would be performed to evaluate the living environment.
Until the environment is radiation-safe, comparable to flux encountered in high-altitude regions on Earth (about 5 km), non-reproducing teams would rotate every 2 years.
Once fish and plant production is up to sustainable levels for 12 adults, Human Heritage Expedition #1 would leave Earth, with 4 women and a very precious cargo of frozen human ovules and semen, from every race. Each woman would be of a different blood type, and the donor's blood type would also be recorded in the database.
The plan is to fertilize in-vitro, and check for DNA damage -before- implanting the embryo. I do not know if this is possible, but maybe cultivating a few stem cells while the embryo is in the first trimester, and then deciding if an interruption could be required. By bringing a diverse gene pool, it would be possible to avoid congeniality issues later, as well as provide additional shielding for the precious cargo en-route to Mars.
For obvious reasons, it would be preferable if the women crew were biologists, pediatricians, psychologists, or similar professions. Indeed, due to radiation exposure, it would be best for the pregnant women not to go outside, and access to certain areas could be restricted, depending on radiation measurements (i.e. The Transfer Landers).
There should be no real timeline for pregnancies. Pioneers are going to be so busy, let's not add problems by having a baby boom prematurely (no pun intended). But figuring 4 women having each 3 babies over a period of 6 years, every 2 years, the outpost would reach a population of 8 adults and 12 children by Year 6. On year 5, a third Transfer could be set up, this time bringing other living samples, whatever would be required.
For example, the biologists would study ways to use Martian soil to grow plants. Maybe after 5 years of research, they'd request for specific strands of bacteria to tinker with, or algae, moss, whatever.
First male crew rotation, exposed to more radiation than the women, would be after 4 years on the surface. Among equipment and supplies needed from Earth, those relating to quality of life would be the most needed. Electronics, Soap, etc.
Short term industry for such a colony might be the production of fuel for Earth-Mars-Earth round trips. Since Mars as a lower gravity, would it be cheaper to launch heavy loads of water from Mars toward the Moon, via a complex Earth aerobraking maneuver to put the cargo in Moon's orbit? This would be quite a feat, yet it's possible! Some rough calculations on my part gives me a total delta-v for a Martian Surface to an Earth fly-by of about 8 km/s. The same amount on Earth gets you up only to LEO.
There are lots of advantages, since Martian pressure is so low, you can use vacuum-optimized engines. Imports would be nuclear fuel rods, electronics, and other resources. Water would be "sold" to the Moon colonies, if they exist. I haven't calculated it yet, but I figure that 10 metric tons of water sent from Mars to a Lunar base could cost half the price of launching it from the Earth. Since the maximum mass for a Mars-bound payload is not that different than for a Lunar-bound one, I think it might be best to go back to the Moon, permanently, with this scheme.
This way, if dreams were to be made from the Moon, they would be fueled by Mars. Combining the relative abundance of water on Mars, it's low gravity, with the proximity of the Moon and it's ideal platform for heading out there...
So, here's my proposed timeline for Leaving the Cradle:
1) Complete remote-sensing of Mars at high-resolution to determine localizations of water concentrations and other useful resources;
2) Send an automated Polar Ice to Consumables factory;
3) Establish human presence at the Pole to evaluate the feasibility of self-sufficiency;
4) Equip the settlement to be self-sustaining for water and food requirements, Provide needed resources to set up accommodations;
5) Return water to Earth orbit with aerobraking on arrival(might be automated and done at step 2);
6) Use the returned water to help in establishing a human presence on the Moon;
7) Establish a space industry on the Moon, aimed at constructing structures, engines and other metal parts needed to assemble other EMEs (Earth-Mars-Earth) ferries. Such space transports would be modular, with a Habitat module, shielded from radiation by Martian water, a Power module (Solar, Nuclear, power source-of-the-day), and a Propulsion module, with a design such to accommodate relatively easy upgrades or maintenance.
8) Generate exchanges on the Moon-Earth-Mars triangle, with Earth providing living resources, human resources, and high-tech components, Mars fuel, and the Moon as a processing/transformation/assembly industry. Enable both Mars and the Moon to be as self-sufficient as possible in the fields of consumables.
The whole plan runs in the dozens-billion range, but at least it has the possibility of -some- Return on Investment, which 500-days to Mars plans and month-long stays on the Moon projects lack by themselves.
1) The Case for Mars - Robert Zubrin
2) European Colonization of the Americas, Wikipedia
3) Advanded Propulsion Concepts, Jet Propulsion Laboratory
4) Global Distribution of Water on Mars, Los Alamos National Laboratory
5) Mars Direct Home Page
6) Typical delta V value(s) for various space manoevres
7) Mars Odyssey Shows Intense, But Managable Radiation Risk for Astronauts, Robert Roy Britt
8) Space Life Sciences Reserach Highlights, part I, NASA
9) Space Life Sciences Reserach Highlights, part II, NASA
10) In-Vitro Fertilization, Georgia Reproductive Specialists
11) Required Elements for a Lunar Colony
12) Elements for a Sustainable Lunar Colony in the South Polar Region,
13) New Views on the Moon, PhysicsWeb
14) Space Transportation Facts & Figures