Oct 13 2008

The Aresian Well

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(The formatting below is a little off because it was mostly cut’n’paste from an HTML-ized version of an old Word doc. My apologies,and I’ll clean it up Real Soon Now.)



This paper discusses the exportation of Martian polar cap volatiles by means of a pipeline from the icecap to the equator, and thence up a “beanstalk” extending beyond Mars-synchronous orbit.


A convenient source of volatiles simple compounds of hydrogen, carbon, nitrogen and oxygen is highly desirable for the development of the inner Solar system. The Moon is relatively devoid of these, oxygen (in silicates) being the only common lunar volatile, although there may exist small quantaties of extra-lunar origin. Earth of course has these in abundance, but shipping these in any quantity up out of Earth’s large gravity well (the largest of any planet’s within the orbit of Jupiter) is prohibitive, even with greatly reduced launch costs. Mars appears to have significant quantities of these elements, and the delta-Vee requirements to ship them to, for example, cis-lunar space are relatively low, although transportation by rocket would still be costly.

A low operational-cost method of transporting material to orbit is the “beanstalk” or “space elevator”(3). Assume a satellite in a synchronous orbit, and now imagine a (massless) tether or cable lowered from it to the surface. This cable can then be used, elevator-like, to raise payloads from the surface to synchronous orbit. This concept has been independently invented several times (1,3). Taking it a step further, if the cable is extended upward beyond synchronous orbit, at some point the tether will be moving at a velocity exceeding escape velocity, and payloads released at that point can be flung to points elsewhere in the Solar system. Pearson (8,9) has described Earth-based systems of this sort.

Unfortunately, the Earth’s gravity and the altitude of geosynchronous orbit place high demands on the strength of materials for such a terrestrial space elevator. With very large (an impractical) taper factors, no known material can support a sufficient lenght of its own weight. However, due to Mars’ lesser gravity and lower synchronous orbit altitude, such a beanstalk is just feasible with known, existing materials.

Given such a Martian beanstalk, anchored at the equator, volatiles (or any other payload) could be lifted to Mars escape velocity with relatively modest amounts of electrical energy (that required simply to lift the payload). Most of the excess velocity comes as a momentum exchange, Mars losing a little angular momentum every time a payload is “launched”.

Most of the Martian volatiles appear to be concentrated as ices at the polar caps. Some means of transporting them from the cap(s) to the beanstalk base at the equator is needed. The Martian atmosphere being, alas, too thin for canals, a pipeline is suggested. From the edge of the polar cap to the equator, with some detours for local terrain, is about 3000 miles (4900km), comparable with many terrestrial pipeline projects.

Figure 1

Figure 1. Pipeline Elements

Martian volatiles vs. Lunar, LEO, etc.

Polar caps made up of CO2 ice in winter, H2O ice all year. Atmosphere composition, volume. Polar cap volume. Compare with Lunar availability, cost from Earth.

System Elements

The Beanstalk

The center of mass of the “beanstalk” must be at the altitude of a Mars-synchronous orbit, approximately 17,058 km above the Martian surface. The exact altitude will depend on the topography at the base of the beanstalk, and the actual center of mass may be at a slightly higher altitude that to maintain positive tension on the cables. The beanstalk itself extends beyond areosynchronous orbit, the upper section providing both counterweight and a means to reach Mars escape velocity.

The beanstalk must be capable of supporting its own weight, plus whatever loads are placed on it by the volatiles pipeline. No known material is suitable for this if the cable (or cables) is of uniform diameter, but there is no such requirement. With only modest taper factors, fT, (tapering the cable as it extends from the center of mass), either graphite fiber (fT @ 1.4:1) or Kevlar (fT ~ 9:1) fiber could be used.

It may be possible to produce graphite fiber on-site. Mars’ moons, Phobos and Deimos, resemble carbonaceous chondrites. If the carbon can be extracted in a form convertible to graphite fiber, this would provide a significant saving in the mass required to be sent to Mars for construction.

Anchor Location. The lower end of the space eleveator, Beanstalk Base, would be somewhere on the Martian equator. Fortuitously, there is a large volcano, Pavonis Mons, whose summit lies almost exactly on the equator, and gives a 21 km altitude advantage.

High end beyond areosynch for momentum boost.

The Phobos Problem. One major problem that any use of equatorial orbital towers on Mars is faced with is the moon Phobos. Its orbital altitude is significantly lower than areosynchronous (5990 km vs 17,058 km), and as such would eventually intersect the tether. There are several possible solutions, each with relative advantages and disadvantages:

  • Use up Phobos to construct tether.This would eliminate the problem, but Phobos masses about 107 times that needed for tether construction.
  • De-orbit PhobosAgain, this totally eliminates the problem, and Phobos is in any case expected to last only another 40 million years before its orbit decays totally. However, aside from the cataclysmic impact Mars, the propulsion requirements are enormous. This is also true of boosting Phobos to beyond areosynchronous orbit.
  • Wobble the TetherThis approach, suggested by Clarke (4), requires that the tether wobble or oscillate slightly, such that Phobos (whose orbital inclination is about 1°) always passes to one side or another of the beanstalk. The dynamics of this are interesting, and may require active monitoring for the life of the tether.
  • Anchor the tether at 5° off the equatorThis is feasible because of Phobos’ low orbital inclination. The tether would not be straight, but follow an inclined catenary. Phobos would always pass to one side of the tether. This complicates tether dynamics somewhat, and we lose the advantage of Pavonis Mons’ 21 km altitude.

The Pipeline

General description. Ideally the pipe would be constructed of locally (Mars) available materials, with relatively small investment in fabrication equipment. This could be steel or graphite or glass fiber, but is more likely to be some type of concrete. It is reasonable to expect a source of carbonate minerals suitable for binding the latter.

Use of concrete dictates a relatively low-pressure pipe, but still enough to maintain internal pressure above the vapor pressure of water at the ambient temperatures. (About 0.4 psi at 25°C). This points to the pipe being laid out more as a covered aquaduct than a pipeline, with minimal changes in elevation. In this case the pipe would be 1 to 2 meters in diameter, with the fluid level being 1/3 to 2/3 the diameter, and flow speeds low (0.3 m/sec). The pipe would have heaters at intervals to keep the water from freezing.

Figure 2

Figure 2. Pipe Detail

Upslope stretches would be designed to withstand the higher pressures necessary for uphill pumping, and here the pipeline material and diameter may differ. For example, 0.5 meter diameter with flow speed of 1.2 m/sec.

Ice Mining. The exact method of mining the ice will depend on the nature of the ice deposits at the edge of the polar cap. Large ice sheets could be “strip mined”, carving out large chunks and melting only enough to permit pumping the water as a water-ice slurry. On the other hand, if the ice deposits are highly admixed with layers of dust (as may indeed be the case) some kind of melting and separating process will be necessary. This could be combined with the mining by pumping steam or hot gas into drill holes and condensing the exhaust (similar to commercial sulfur mining techniques), or it could be done after the material is mined through strip mining techniques.

Any such mining operation will be energy intensive,. The most practical power source would be a nuclear reactor, providing both electrical power to drive machinery, and direct heat for melting the ice. Solar power is only 1/2 as strong at Mars as at Earth, and at the pole this is further reduced by angle of inclination, atmosphere effects, and so forth.

Pipeline route. The pipeline follows a route almost directly north-south route between the edge of the North Polar Cap and Pavonis Mons, along 115° W. The “wellhead” is at the edge of the cap, on a southerly lobe at approximately 115°W, 80°N. It proceeds almost directly south along 115°W, to and through the “dune sea” of Vastitas Borealis, to about 47°N where it encounters the rugged terrain near Alba Patera.

The route follows the terrain (a series of roughly north-south ridges and valleys deformed by the Tharsis bulge) around Alba Patera, e.g. along Alba Fossae, Rubicon Valles, and Alba Catena.

Once Alba Patera has been skirted, the pipeline proceeds south again along 115° W, crossing Olympica Fossae and avoiding Jovis Fossae, to the base of Pavonis Mons at 115°W 7°N. Assuming Beanstalk Base is at the summit (on the equator), it would then proceed up the slope in a south-southwest direction to the summit at 113°W 0°N.

The total length, Wellhead to Beanstalk Base, is approximately 4900 km.

Along the route, the pipeline could also serve outposts and colonies on Mars. One possible raison d’etre for such colonies is mining: hydrothermal activity is possible in areas on and around the Tharsis Bulge, and such activity may produce ores not created by purely tectonic forces. Uranium ore is one example, and non-terrestrial sources of uranium may be important as power sources for development of the solar system .

Piping up the beanstalk

Beanstalk base. Tether requirements, vertical pumping requirements. (or package as ice at base). Pipeline pressures, aux pumping stations. Momentum xfer.

Packaging and release. Trajectories at tether end. Launch windows and travel times.


Mass budgets. Improve mass budget with on site materials, NIMF vehicles, etc. Parameterized costs related to launch costs.

Construction cost of the pipeline and beanstalk depends on several factors: the amount of material producable locally vs needing transportation from Earth or the Moon, the cost of transportation from cis-Lunar space, and the degree of difficulty of construction. The surface pipeline is comparable in construction difficulty to the Alaska Pipeline, with Mars’s lower gravity and the low pressure pipe offsetting the added difficulty of working in pressure suits. We assume a per-km cost of about twice that of the Alaska Pipeline, about $18.5 million/km vs $8 million/km. This gives the cost of the surface pipeline as $90 billion.

The tether or orbital tower is perhaps simpler to construct, although longer. The tether, complete with necessary attachments, can in effect be “extruded” from a Mars-orbit fabrication facility. This facility would be something between the automatic “beam-builder” robots designed for solar powersat construction, and a terrestrial automated steel mill that takes ore in at one end and produces finished steel coil, wire, etc at the other. The cost of building and operating such a facility might also be about $90 billion, or about $3.5 million/km, possibly less.

Given this estimated total cost of $180 billion, how does this affect the price of the exported water, and how does that compare with launch costs from Earth? A business rule of thumb is that return on investment should be at least 5%. Five percent of $180 billion is $9 billion. From the pipe size and flow speeds, we have a flow rate of about 0.3 m3/sec (4750 gal/min) or 300 kg/sec.
At 31.5 million seconds per year, we would need to charge $9B/(300×31.5M) or about $0.95/kg (exclusive of operations cost) to make our 5% ROI. Charging an even $1/lbm ($2.20/kg) gives a $1.25 margin per kg, or $11.8 billion per year, to cover operating costs, additional ROI, or as a buffer against reduced demand.

How long will the polar ice last at this rate? Actually a rather long time. A single cubic km. of ice would last 100 years at this rate.

Further Research

Tether dynamics. Materials. Composition of Mars polar caps, moons. Pipeline etc. fabrication techniques, construction techniques. Propulsion (NIMF, etc).

Tether can work on Mars. Mars has volatiles. Pipeline can (someday) be built. It will be profitable (given inner solar system habitation, i.e. customers). But we need to do something about Phobos.


1. Artsutanov, Y.N., “V Kosmos na electrovoze”, Komsomolskaya Pravda, 31 July 1960.

2. Carr, M.H., The Surface of Mars, Yale University Press, 1981.

3. Clarke, A.C., “The Space Elevator: Though Experiment or Key to the Universe?”, Advances in Earth Oriented Applications of Space Technology, V1 N1, 1981, pp. 39-48. (Reprinted in Ascent to Orbit, John Wiley & Sons, 1984).

4. , The Fountains of Paradise, Harcourt Brace Jovanovich, 1979.

5. Hunt, G.E. “Some Aspects of Martian Dust Storms Observed During the Viking Mission”, in 1980 Yearbook of Astronomy, Sidgwick & Jackson Ltd, 1980.

6. Hunter, M., “The SSX A True Spaceship”, Journal of Practical Applications in Space, V1 N1, 1989, pp. 41-62.

7. Manly, P.L., “Near Earth Asteroid Densities and Their Detection Before Impact”, Journal of Practical Applications in Space, V2 N1, 1990, pp. 33-44.

8. Pearson, J., “The Orbital Tower; A Spacecraft Launcher Using the Earth’s Rotational Energy”, Acta Astronautica, V2, 1975, pp. 785-799.

9. , “Using the Orbital Tower to Launch Earth-escape Payloads Daily”, AIAA Paper 76-123, 27th IAF Congress, 1976.

10. Penzo, P.A., “Tethers for Mars Space Operations”, AAS Paper 84-174, Case for Mars II, 1984, pp. 445-465.

11. Tsiolkovski, K.E., Grezi o zemle i nebe, USSR Academy of Sciences edition, 1959, p. 35.

12. U.S. Geological Survey, Shaded Relief Maps of the Eastern, Western and Polar Regions of Mars, 1:15,000,000, Map I-1618, U.S. Geological Survey, 1985, sheets 1-2.

13. Vanderbilt, H., private communication, BIX mail, February, 1991.

14. Zubrin, R.M., “Indigenous Martian Propellant”, Aerospace America, August 1989, pp. 48-51.

Last modified 03-Jun-2002 — cleaned up stupid MS Word-generated HTML

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