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I did come up with a scheme to produce starch or sugar as a by-product of recycling oxygen. Electrolysis produces oxygen with hydrogen gas as its waste product, and carbon dioxide is simply dumped. That is the system currently on ISS, but it recycles only half the oxygen astronauts breathe. Water has to be shipped up to feed the electrolysis tank to produce enough oxygen. Adding a Sabatier reactor would convert the hydrogen and half the carbon dioxide into methane and water. That water would be enough to feed the electrolysis tank, so all oxygen breathed by astronauts would be recycled. The waste product of that system is methane and carbon dioxide gasses, both of which have to be dumped in space.
This alternative I am talking about is a biochemical device that may be described as biotech. It produces either sugar or starch instead of gasses. The starch could be fed to a fermentation tank where yeast would convert some into protein. Raw potatoes contain 78% water, 18% starch, 2.2% protein, 1% ash, and 0.1% fat. Yeast in starch can add protein to the same level as potatoes. The result would have the consistency of pudding and no taste at all. The Hawaiian food poi is made from Taro root. It has the same consistency and lack of flavour. You could consider this a synthetic form of poi.
The only caution is to select yeast that does not produce alcohol; most yeast does. The alcohol can easily be boiled off by cooking, but you have to be careful inside a sealed habitat. You don't want alcohol condensing inside electronics. The steam could be captured and temperature fractionated from water to ensure all water is recycled. Such a device is normally called a 'still, and alcohol produced from distilling fermented starchy food is normally called vodka. Somehow I don't see NASA planners accepting that. Yeast used for non-alcoholic beer should solve that problem.
As for growing hydroponics, there are several people conducting hydroponic experiments today. A couple are Mars Society members. Hydroponics do not rely on Mars soil, they use water and processed nutrients dissolved in that water. It does take some attention to maintain the nutrient balance, but it does work.
Processing Mars regolith into a fertile soil is possible. The problem right now is determining exactly what is there. Data from Mars right now is inconclusive. It appears there is some clay, and a great deal of feldspar. There is also a great deal of iron, but that may be tied up in minerals such as augite, chromite, bronzite, and olivine. There is almost no carbon or nitrogen in the soil, but nitrogen fixing plants can create nitrites and nitrates from nitrogen in the air. All plants fix carbon, they create organic matter from carbon dioxide, but higher plants requires some organic carbon compounds in the soil. This can be added with primitive plants. Pre-processing treatments can speed soil preparation; such as like soaking with water to neutralize super oxides, or bubbling carbon dioxide through the water to create carbonic acid to neutralize the alkali. It shouldn't take long to prepare fertile soil.
Greenhouse atmosphere can be created by pressurizing with Martian atmosphere, extracting carbon dioxide and pumping that out, and increasing oxygen content by capturing oxygen released by neutralizing super oxides. Depending on how much oxygen is released from the soil, and assuming 95% of the carbon dioxide and 80% of the carbon monoxide from Mars atmosphere is removed, the result should be about 45.3% nitrogen, 26.8% argon, 22.3% oxygen, 2.26% carbon dioxide, and 0.23% carbon monoxide. At only 5psi pressure that may not be enough for humans to breathe, but it should be suitable for plants.
I imagine veggie burgers will be a big deal on Mars. Animal feed will always mass more and provide more calories than the meat they provide. Until we can afford vast pressurized fields, we will have to make do with a vegetarian diet. Besides, Harvest Burgers taste quite good. Yves brand doesn't taste as good, but I kept a package label. Their burgers include soy protein product, wheat gluten, wheat protein product, canola oil, cane juice, carrageenan (from kelp), salt, malt extract (that's usually from barley), spices, yeast extract, vegetable gum, potato starch, konjac flour (makes you feel full), rice starch, beet root powder, vitamins, calcium pantothenate (preservative), reduced iron, and zinc oxide.
On Mars we could do without the low nutrition konjac flour that just absorbs water to expand and fill your stomach. We could do without the preservative as well; just mix a batch within a week before you cook it. We could easily grow soy, wheat, canola, sugar cane, kelp, barley, potatoes, rice, beets, and kelp. As I recall, Harvest burgers used brown rice liquor. Yves veggie ground round includes oat bran.
Of course, if you establish a tank to grow kelp, you can easily add fish. You would have to balance the ecosystem, but that sounds like farming.
I don't know about radiation, but interior walls don't have to be radiation shields. Interior partition walls could be similar to office cubicle partitions: fabric. You could make them lighter by using taught cables inside the wall for structure, Nomex wall surface, loose weave Kevlar or Spectra mesh inside the Nomex to distribute force to the cables, and drapeable aerogel interior for acoustic insulation. Nomex is the same material as the inner wall of TransHAB. The cables would require a rigid frame, but that would be just an outline of the wall. This would give a smooth, sheet plastic surface but very light-weight.
Actually, NASA came back with the 90-day report and a $450 billion price tag. Congress gagged at that. Robert Zubrin then came back with Mars Direct, and NASA budget guys estimate his plan with 7 manned missions to Mars would cost $20 billion. In the Case for Mars page 285, Robert Zubrin estimated that a private company could do a single manned mission to Mars for $3 billion in 1996. NASA budget for 2002 is $14.902 billion. Many Americans are expecting NASA to "go somewhere". With a reasonable mission plan, a manned mission to Mars could be NASA's next goal after the ISS without any increase in NASA's budget. That is, if Congress decided to actually do it.
I know, a mass of 3.2195 kg per square meter and 26.5% conversion rate may seem radical, but that is based on figures available now. The same manufacturer states the maximum conversion rate for those panels is 26.8%, but that is without anything using that power. They also make photovoltaic panels designed for use on Earth that have 30% conversion, but the ones for space have to be radiation resistant and designed for the light spectrum in space (more intense UV, etc). I even have a price quote for the space rated panels. The power figures I calculated are exact, but don't include the fact that the sun is only up half the time on Mars. Dividing by pi may be a good idea.
I can suggest how to make a bigger array. I notice you are following the design of Mars Pathfinder: opening petals covered by photovoltaic panels on the inside. However, satellites have used an accordion deployment mechanism for years. This permits stacked panels to become long wings. On Mars, to avoid the problem of the wing supporting its weight in gravity just "unroll" the wing onto the ground. Deployment could be by placing a floppy hose along the side of the panels, and inflating it. As the hose pressurizes it will become stiff and straight. This will push out the photovoltaic panels attached to it.
Here is another figure for you. SEO142 cable will remain flexible to -50?C and resists oil, acids, chemicals, solvents. It can carry 18 amps at 600 volts for 10.8kW along 2 conductor cable. It masses 224.7kg per km. Other gauges are available from 10 to 30 amp (6kW to 18kW), or 45 amp for 4 conductor cable (effectively 54kW). That last cable masses 977.7kg per km.
Hydrogen/oxygen generation this way is an interesting idea. In fact, the oxygen generating side has the same net effect as photosystem II from the light reaction of photosynthesis in plants.
Photosystem II uses 2 molecules of pheophytin to split water into oxygen, positive hydrogen ions, and electrons. Each pheophytin molecule splits one water molecule releasing one oxygen atom. The two oxygen atoms combine to form molecular oxygen (O2). Splitting two water molecules at a time so oxygen can directly recombine into O2 is more energy efficient than producing mono-atomic oxygen. Photosystem II has 50 molecules of chlorophyll "a" and a half dozen carotenoid molecules (such as beta-carotene), all of which act as antennas to convert light to electric charge. The carotenoids have a different absorption spectrum than chlorophyll, so that increases light collection efficiency. Electrons are then passed to the electron transport chain which uses a series of redox reactions.
In plants, all of this is embedded in a bilipid membrane. The Florida Solar Energy Center is attempting to this in a tank. An enzyme to do the same thing as photosystem II must hold itself together while floating free in water. In plants, the H+ ions are released on one side of the bilipid membrane, which forms a sealed bag. The first step of the electron transport chain pumps more H+ ions into the bag. Outflow of H+ ions drives production of ATP, the chemical "food" of cellular metabolism. These guys aren't producing a highly structured nano-machine; they are attempting to produce a simple pair of tanks. Producing oxygen in one tank and hydrogen in the other using two pairs of catalytic reactions sounds like an ingenious solution.
The only question now is how much water and enzymes this needs, and what is the total mass? Since this discussion is about rethinking Mars Direct, I assume you are proposing this as a replacement for the electrolysis tank for ISPP. If so, we have to compare its total mass against an electrolysis tank and the photovoltaic panels required to power it.
I checked photovoltaic panels. Space rated improved tripple junction photovoltaic panels from one supplier mass 2.06 kg/m^2 with 3 mil ceria doped coverslide. The coverslide is a thin glass coating. The ceria dopant will conduct static electricity away. The cell itself is 7.5 mil thick. This has a 26.5% conversion efficiency at load voltage, beginning-of-life, to produce 330W/m^2 for panels greater than 2.5m^2. That is in sunlight intensity at Earth orbit. Mars will have 43.075% the light intensity, so 142W/m^2 BOL. Radiation will degrade the panels. It has 22.3% at load voltage end-of-life. Designing for end-of-life, then 6kW on Mars would require 50.16m^2 area, and mass 103.3kg or 0.1033t. That mass doesn't include substrate: a backing on which to mount the cells. Light-weight aircraft wings are made from carbon fiber / epoxy composite. Two layers of 3K graphite fiber fabric mass 0.3865 kg/m^2. Add 50% mass for the epoxy and spars, so about 29kg for the support petals, or 132kg total mass. A "hollow wing" design support structure is overdesign for space, but provides additional structural support for atmospheric entry and landing.
That means 6kW solar panels only mass 0.132 tonne, not 1 tonne.
Pioneer Astronautics made a presentation about ISPP on August 28, 2002. They have come up with a MetaMars ractor that converts methane into benzene: 6 CH4 -> C6H6 + 9 H2. Together a Sabatier reactor, electrolysis, and MetaMars reactor convert 1 tonne of hydrogen into 45 tonnes of benzene / oxygen fuel. The presentation detailed several catalysts for the reaction, but didn't give total reactor mass or power requirement.
I just got spam from a company in China trying to sell fire proof ceiling tiles. I've never seen spam from China before. This makes me think that posting details like critical mass on a public form is a very bad idea. Numbers really do make the difference between an engine that works, and one that doesn't. However, numbers than could be applied to weapons should not be published here. I would like a paper study to see if this idea has merit, but could you contact me privately Preston? Thanks.
Hey, Preston. The 4,100 tonne spacecraft is probably the "Battlestar Galactica" design that came out of the 90-day report. They key points Mars Direct used to reduce mass were production of fuel on Mars for the return trip, and aerocapture. That is a hell of a lot less fuel you have to take with you. I believe "Battlestar Galactica" also included an onboard greenhouse to grow food. Mars Direct used a chemical-mechanical recycling system to recycle air and water, and brought packaged food.
Since you are studying nuclear engineering, could you tell us whether deuterium gas could be used as a moderator for a gas core nuclear reactor? After cooling the engine, liquid deuterium would be gas when injected into the combustion chamber. Fission combustion would require a reaction a lot faster than a reactor, combustion would require a reaction almost as fast as a bomb. What moderator is required to do this? What is the critical mass of uranium? Nerva used a radiation reflector to encase the reactor, that should permit lower critical mass. What material is available for a reflector, how effective is it, and what does that reduce critical mass to? What was used as a moderator for the gas-core nuclear reactor?
We could choke the exhaust to maintain critical mass in the combustion chamber. To ensure uranium doesn't exhaust before reaction, we could use the same vortex as the gas core nuclear thermal rocket. To use deuterium as a moderator, we would have to mix it with uranium gas rather than injecting it down the center. The keys to success are low uranium mass in the combustion chamber, and rapid reaction.
The 3 neutrons from cracking a uranium atom fly outward so fast that they cannot be absorbed by another uranium atom. Unless you slow the neutrons down, they will just bounce off. Light water reactors blend a moderator such as graphite with the fuel rods so it is all mixed together. Radiation does not have to travel far to be absorbed by the next uranium atom. Control in a light water reactor is with control rods that absorb radiation, controlling raction rate by reducing radiation density. This can "turn off" the reactor by reducing radiation density below the critical level. A heavy water reactor uses heavy water as the moderator instead of graphite (or some other material) blended with the uranium. Radiation has to pass through coolant water to be absorbed in the next fuel rod. However, that also means if a heavy water reactor has a coolant leak it doesn't melt down, it just stops.
The Americium-based engine does sound interesting. I would like to hear if anyone has done any work on it.
Actually, Space Shuttle was able to lift 27.85t to 204km orbit before the Challenger accident. Improved safety equipment reduced lift capacity to 24.4t to 204km orbit. In preparation for constructing ISS, the Space Shuttle was upgraded. This included replacing the aluminum alloy external tank with an aluminum-lithium alloy, replacing CRT's in the cockpit with LCD displays, replacing platinum based fuel cells with proton transport membrane fuel cells, etc. The result was increased lift to 27.5t to 204km orbit or 28.803t to 185km. To compare with Russian launch vehicles I calculated its lift to 200km.
Delta has several configurations. The largest one is Delta V with a 5 meter diameter fairing, 5 strap-on boosters, and 1 upper stage. The 3 digits following the model designate all this: 5 for fairing, 5 for boosters, 1 for upper stage, makes 551. There is a Delta V Large 552, but the second upper stage does not add lift capacity to LEO. It would be used to lift a smaller payload to a higher orbit.
Since you asked about Japanese and Chinese launch vehicles, I added the Japanese H-2 and Chinese Long March 2E and 2F. The Japanese booster is the most expensive. The Chinese are reportedly working on a new line of launch vehicles, the CZ-5. The CZ-5-5.0 would be similar to the Ariane 5 core, and could have 2 to 8 strap-on boosters. With all 8 boosters it is supposed to be able to lift 40t to 200km orbit, but it is still in development; scheduled for service 2008. The Japanese are also experimenting with a reusable launch vehicle based on the DC-X, and China is experimenting with an RLV based on Kistler's K-1. Both RLV's are a couple decades away from service.
I didn't include Angara for a few reasons. I thought we were restricting this to existing launch vehicles. Magnum will probably never be built, Energia requires a new manufacturing facility for its core module as well as either repairing the vehicle assembly building or constructing a new launch facility. Shuttle-C and Ares will definitely never be built. Long March CZ-5 is so far in the future it could be cancelled. Upgrades to Ariane 5 and production of Angara will probably be done, but aren't available yet. The configuration "Angara 5A" described in Astronautix does not match the configurations "Angara 5" and "Angara 5-UOHB" described by International Launch Services. It appears the UOHB upper stage will be larger than that described for "Angara 5A", but ILS does not give exact lift figures or prices.
I haven't included direct lift to geosynchronous transfer orbit because I thought we were designing for launch to LEO then spiral out using solar-electric propulsion.
For reentry capsule, I made a mistake. Based on the Soyuz descent module, capsule mass should be 1t for each astronaut. That would make a 6 crew capsule mass 6t, or a 4 crew capsule mass 4t.
I compiled a short list of launch vehicles available today. There are several smaller vehicles; I just included the big ones and vehicles that could carry a crew taxi. I left out the Angara and upgrades to Ariane 5 since they aren't available yet. Oribital inclination for LEO is only important to rendezvous payloads from different launches. If you want to assemble something in Earth orbit, the pieces must have the same inclination and altitude. I don't know how to format a table in a message here, so I created a web page here.
Orion is based on bombs. The international community will never allow nuclear bombs in space. Orion will never fly for that reason alone. Add to that the inherent inefficiency of Orion. If bomb designers were able to perfectly shape the bomb so the force was perfectly 1 dimensional, it would still require as much aft pressure as forward to push a shock wave toward the pusher plate. That means a perfect shape would have at most 50% efficiency. Such perfection is impossible. The pressure of the shock wave itself will cause expansion into the vacuum of space. Expect less than 1% efficiency. But that low efficiency can produce 2500 second Isp, then what would you get from completely containing the nuclear combustion?
Gas-core reactors are based on a nuclear reactor that uses a slow reaction to produces heat alone. That heat is used to boil liquid hydrogen into super heated gas. Liquid hydrogen is injected into the top center of the vortex, and hydrogen gas is expelled from the bottom center. Most of the uranium gas would be pushed away from the center of the vortex by hydrogen gas expansion. Since the exhaust aperture only permits central gas of the vortex to escape, the uranium is recirculated. The US military has been using uranium vortexes for years to separate isotopes for enrichment, so the physics of the vortex is well known.
Fission combustion would be different than a nuclear thermal rocket. It would use uranium as propellant rather than just an energy source. There are two ways to increase propulsive force of a rocket: increase exhaust velocity or increase exhaust mass. Increasing the mass means increasing propellant mass as well, so that tends not to translate into increased Isp. Nuclear combustion would produce a great deal of heat, as well as doubling the number of atoms by transmuting uranium into krypton and barium, and changing propellant phase from liquid to gas. All this translates to extreme combustion gas pressure, so extreme exhaust velocity. Hypersonic exhaust velocity can produce wear on engine parts, but these gasses have very high mass therefore relatively lower velocity for given force. Temperatures involved would be extremely high, but gas expansion reduces temperature. Heat has 4 modes: translational, rotational, vibrational, and electronic. After a nuclear reaction it may take time for the modes to even out. Only translational heat produces gas expansion, so the gas may continue to produce more translational heat as it expands. That heat will produce more expansion.
A nuclear combustion engine would have a radiation reflector instead of a pusher plate. The pusher plate and shock absorbers would be heavy. That means lower fixed mass. Both the Orion and a liquid fission rocket would have uranium fuel between the engine and living compartment of the spacecraft, so a great deal of mass to block radiation.
The by-products of uranium fission are not stable isotopes; they will continue to decay. They have a half-life, which means half of the material will decay in that time. Krypton Kr89 has a half-life of 3.15 minutes to become Rubidium Ru89. Ru89 half-life is 15.15 minutes to become Strontium Sr89. Sr89 half-life is 50.53 days to become yttrium Y89, which is stable. The other product of uranium fission was barium Ba144. Ba144 half-life is 11.5 seconds to become lanthanum La144. La144 half-life is 40.8 seconds to become cerium Ce144. Ce144 half-life is 284.893 days to become praseodymium Pr144. Pr144 half-life is 17.28 minutes to become neodymium Nd144. Nd144 half-life is 2.29 quadrillion years (10^15 years) to become cerium Ce140, which is stable. All of these decay steps emit a beta particle (electron), except the last one. Nd144 emits an alpha particle (helium nucleus) to become Ce140.
The initial by-products of uranium fission, however, have a half-life of 3.15 minutes or 11.5 seconds. Exhaust gas will be expelled in a fraction of a second, so there would be no significant decay while inside the engine.
The temperature of these reactions would still be very hot. That requires cryogenic propellant to cool the engine, such as liquid hydrogen. Heavy water reactors use heavy water as both the coolant and moderator. What makes heavy water heavy is that the hydrogen is an isotope called deuterium. Would liquid deuterium act as a moderator?
Actually when I asked how many launches we can reduce it to using existing launch vehicles, I was referring to Atlas V, Delta IV large, Ariane 5, Proton, Angara 5, Space Shuttle, and smaller launch vehicles. What would it take if Energia is not available?
We can minimize fuel to lift the spacecraft from LEO to staging orbit by using an elliptical orbit. The higher the apogee the less fuel required to escape Earth orbit. Raising the perigee is just a waste of fuel. Geosynchronous Transfer Orbit (GTO) has an apogee equal the altitude of Geosynchronous Earth Orbit (GEO). Staging orbit does require an apogee equal to GEO, but I would suggest that or higher to minimize fuel required for insertion into trans-Mars trajectory. The perigee could remain the same as LEO. Insertion into a Lagrange point requires circularization.
Is it possible to use principles of continuous combustion to create an efficient nuclear fission jet engine? The Orion was based on nuclear bombs exploded behind the spacecraft, with a heavy concussion plate to absorb the portion of the shockwave directed to the spacecraft, and shock absorbers to smooth the acceleration. Most of the force of explosion would be lost to space. That is highly inefficient; but it was still supposed have an Isp up to 2500 seconds. Internal combustion in car engines is a contained explosion that pushes a piston. Air breathing jet engines burn similar fuel but with continuous combustion. Could nuclear fission provide thrust on the scale of an atomic bomb but with continuous combustion, and be contained so all of the thrust is applied to the spacecraft?
Jet and rocket engines generate thrust by gas expansion. To ensure maximum expansion and low pressure propellant thanks, this is done through a phase change: solid or liquid to gas. Fission of U235 involves absorbing a moderated (slowed) neutron to become U236. That breaks down in a fraction of a second into Krypton Kr89, Barium Ba144, and 3 high-speed neutrons. Krypton is a gas above -153.35?C, and barium boils at +1640?C (+2984?F). The NERVA engine had an exhaust temperature of +5500?F. Uranium dissolves in hydrochloric and nitric acids, so it can be liquefied. Could that solvent, or a liquid uranium compound, be mixed with a liquid moderator in the combustion chamber? The moderator in a fission bomb permits a rapid reaction. Could a rapid, continuous reaction be sustained in a rocket engine? You wouldn't want the solvent itself to be the moderator; radiation from the engine could trigger the fuel tank to become a giant atomic bomb. Without anything to moderate the neutrons, uranium can't explode. A 2-part fuel is for safety. The nuclear thermal rocket was supposed to have a radiation reflector for the combustion chamber wall. That permits a nuclear reaction with sub-critical mass.
RobS, we obviously disagree on Energia. I'm sorry if my response sounds touchy, but I've encountered a number of people who want to belittle it, or before the accident tried to claim it was completely and irretrievably destroyed. However, since availability of it or any HLLV are highly suspect, would you be interested in working on a mission plan using existing launch vehicles? The mission plans we described on page 3 do sound similar.
I would like to propose several mission assumptions:
- 4 astronauts
- solar-electric propulsion
- expendable reentry capsule masses 4 tonnes
- use reentry capsule as crew taxi
- rendezvous in highly elliptical geosynchronous transfer orbit
How few launches can we reduce it to? How much existing equipment can we use to eliminate development cost?
Let us not fall into the trap of prejudice against Russia simply because they do something differently than America. Russia and Kazakhstan have a lot of unpopulated land. I'm sure arrangements have long since been made to ensure spent boosters do not fall on any urban areas. The Kazakhs are currently renting Baikonur to Russia, and that would have to include use of all land involved in operations. Personally I am aghast that building #112 would be so badly maintained that its roof collapsed. This destroyed infrastructure for a launch vehicle that was the only operational vehicle in its class, and the only space shuttle other than the American one. From a Mars perspective, that destroyed the only launch vehicle capable of sending a manned mission to Mars without extensive assembly in Earth orbit. It may have been the only launch vehicle with a cost per pound to orbit low enough to make a manned mission affordable. And if you are still worried about wildlife on the steppe getting crushed by a falling booster, realize Plesetsk is also land-locked. Both launch sites are too far north for economical launch of communication satellites, but that only affects orbital inclination. Centripetal force imparted by Earth's rotation is minor; the major propellant cost is inclination change necessary when your launch site is not beneath the desired orbit. A launch to Mars could depart from any inclination; that inclination is lost once you leave orbit. If an international mission to Mars is going to happen, we must respect all partners involved and make use of all assets they bring to the project. But all of this is moot if no one is willing to pay for repair of building #112, the vehicle assembly building.
You're probably right, NASA will want to launch from Kennedy. However, the US congress will never pay for development of Magnum or any other HLLV. The only reason they paid for development of Altas V and Delta IV Large was to compete against Ariene 5. They didn't like the fact that a non-American organization was taking the majority of the world's launch business and making a profit. Altas V and Delta IV Large were developed to make money and keep that money in America, period. Taxes on the launch industry will pay for government investment. As long as Magnum cannot pay for itself, it will never be built.
So that brings us back to LV Energia, the only launch vehicle that can get us to Mars cost effectively. I had been advocating use of existing equipment until the roof collapsed, but it's gone now. Building a launch facility in Kourou sounds like a good idea, and that lets the ESA into the picture. So how do we make it happen?
Oh, not to worry. There will be plenty to do on Mars. Astronauts will likely be science types, and that means study. They can get electronic books and PDF copies of technical journals radioed to them (modem). They can also send email requests for digital movies (MPEG), and a catalogue of the latest theatre releases. I'm sure studios would love to send a special MPEG release to Mars of a first-run movie as it's in the theatre. Imagine the publicity of saying an astronaut on Mars requested such-and-such movie. They could also have MPEG versions of the latest episode of their favourite TV shows. MPEG's could be stored on a habitat server rather than an individual workstation so every astronaut could watch at their leisure. There will be email discussions with scientists on Earth analyzing their results. Just because you're on Mars does not have to mean you're isolated. Then there is football in spacesuits, or soccer, or golf, etc. They could go mountain climbing, hiking, or driving. Imagine the ultimate off-road experience in a rover on Mars. You could even give them a small pressure tent the size of a small camping tent, an air mattress and space blanket. It could come with an extended duration life support system, using power from the unpressurized rover. If you set out in the pressurized rover you could just sleep in that like an RV.
Then there is work made fun: geology and search for signs of life. Experiments to use in-situ resources (stuff on Mars) to build stuff for the base. For example, can you make bricks from Mars soil? Can you build a habitat from those bricks that will hold pressure? There is gardening in the greenhouse, and converting Mars soil into fertile soil for the greenhouse. What interesting foods can you cook from food grown in the greenhouse? Can you find permafrost to supply enough water for the greenhouse or brick making?
Russia is planning to retire the Baikonur cosmodrome because it is in Kazakhstan. Soyuz and Angara will move to the Plesetsk cosmodrome. That facility is even farther north and was used for polar launches, but it's in Russia. They are talking about removing the disadvantage of orbital inclination change for communication satellites by looping them around the moon. Once Angara is operational they will retire Proton, primarilly because Proton is launched from Baikonur. Although RSC Energia wants to restore their big rocket, it may be difficult to convince the Russian government to invest in repairing the vehicle assembly building in Kazakhstan.
The only price estimate I have is from 1995, before the roof collapsed on the high bays of the vehicle assembly building. At that time the price quoted to NASA was between $60-100 million US dollars to restore infrastructure, and $120 million per launch. Since the vehicle assembly building is where launch vehicles were assembled, it would have to be repaired.
The per launch cost is particulary dramatic if you calculate it per pound to orbit. $120 million / 88,000kg = $1,363.6 per kg, or $3,006.3 per pound. The price to rent the entire cargo bay of Space Shuttle for a commercial launch was $142 million in 1992. NASA shuttle statistics state it can lift 28.803t to 185km orbit, and Astronautix states it can lift 27.5t to 204km orbit. Interpolating to 27.77t to 200km orbit (to compare apples-to-apples), that works out to $5,113 per kg, or $11,273 per pound.
NASA's mass estimates for a crew taxi are 11.34t for an X38 derived vehicle, 2.418t stage inert mass, 11.721t for stage propellant mass, for a total of 25.479t. A capsule is estimated at 6.5t plus 1.588t stage inert mass, and 6.89t propellant mass for a total of 14.979t. That is for a crew of 6. The Russian Soyuz-TM spacecraft carries 3 and masses 3.0t for the descent module (capsule), 2.95t for the service module, and 0.9t propellant. The descent module has life support for reentry, the orbital module has life support for an additional 2 weeks, not necessary for a crew taxi. The orbital module includes the docking collar and rendezvous antenna, but that's relatively low mass. The service module includes solar panels and maneuvering thrusters to perform the docking, and a total 390m/s delta v.
The launch vehicle Energia was built and launched. It carried the Buran space shuttle once, and the Polyus satellite once. With the Buran, it can carry 30 metric tonnes to 200km orbit. Alone, the Energia can lift 88 metric tonnes to a suborbital trajectory with 200km apogee. With the EUS Energia Upper Stage it can lift 88 metric tonnes into a 200km circularized orbit.
This is the reason I advocate the Energia. It was built, it launched twice, and it can be reactivated more cheaply than developing any new launch vehicle. With the EUS is can lift 88t to LEO, 22t to geosynchronous transfer orbit, or 29.3t directly into trans-Mars trajectory (C3=15). The Saturn V and Russian N1 are gone forever, while Shuttle-C and Magnum have never been built.
I hate to argue with C.COMMARMOND, but the 100 tonne to LEO figure for LV Energia is metric. It is simply the lift capability to a lower orbit. American launch vehicle manufacturers like to quote capacity to 185km, and they sometimes even quote the absolute minimum altitude for orbit: 100km.
Energia-M is a reduced size version of Energia. It had only 2 strap-on boosters instead of 4, and the core module was reduced from 7.8 metre diameter to 7.7 metre, and had 1 RD120 engine instead of 4. With no upper stage, this reduced lift capacity to 34 metric tonnes to 200km circularized orbit. A full size mockup of Energia-M was built, but engineering never proceeded beyond that. If you don't want to believe Astronautix.com you can read the letter from Aleksandr Derechin, Head of International Division, RSC Energia. His letter is available in English and the original Russian.
Thank you. I also remember watching the Apollo program live as it happened, from Apollo 1 through Apollo 17, Skylab, and Apollo-Soyuz. I wanted to be an aerospace engineer. I am now trying to start an aerospace engineering firm, and use that to enable Mars Society members to participate in projects like building a small probe to Mars. I also volunteered at the Mars Society steering committee meeting at the conference to be the Volunteer Coordinator. That means I match-up volunteers with projects for all members and all projects throughout the Mars Society internationally. Call me busy. But I do seriously want to become an aerospace engineer.
Not all discussion threads on this board will be applicable for all users. Different people have different interests and different aptitude. For example, I haven't been able to follow the civilization & culture discussions, and haven't looked for years. This thread was established to "fix the potholes in Zubrin's plan". That gets into the details of engineering and mission planning. This thread might not match your interest. Although I can read technical papers on Mars geology published in Science, and NASA engineering papers on ion engines, microwave regeneration of reusable CO2 sorbents, structural analysis of all-composite propellant tanks, etc; I couldn't write a poem or paint a picture to save my life. My artistic tallents are restructed to cut-and-paste. I don't have the patience to listen/read to long dissertations on civilization & culture. Different people have different tallents; we need to work together to ensure we can bring all skills necessary to the task of getting to Mars.
Enriched uranium has a higher proportion of U235 vs other isotopes. Natural uranium as it is dug out of the ground is 1% U235, about 99% U238, and a small proportion of other isotopes. Since only U235 is useful in a nuclear reactor, "enrichment" means to increase the proportion of that in fuel. Separating one isotope of an element from another is not easy, the only difference is weight and that difference is slight. Canadian reactors don't use enriched fuel for two reasons: enrichment is expensive, and if you don't have the ability to enrich uranium you can't make bombs. US reactors require 2% U235. Bombs use about 99% U235.
MIR must have had great CO2 scrubber systems, so the technology is there.
The Service Module of the ISS is an exact copy of the Core Module of Mir. It is just another unit of exactly the same model of module and manufactured at the same factory. The Russian engineer who designed it likes to refer to the ISS as Mir2. So yes, the technology is there.