One man one way suicide mission...

GCNRevenger · 2005-09-29 06:40:59

Whatever

You know, I think of him in the same group as srmeany or MartianRepublic... except that he hates America. Funny, being that he wants the CSA to cooperate with the country he equates to Soviet Russia.

clark · 2005-09-29 07:02:57

You see, that's the problem.

I hate Americans, but love America. Why make it so general, when you can make it so personal?

So, Mr. Suicide and squad, what the heck are you going to do on Mars, assumming that you make it?

You can recreate the martian environment in your backyard, build a greenhouse on it, and for all intents and purposes, it would be the same thing, for a fraction of the cost.

RobertDyck · 2005-09-29 14:19:10

So this is all about politics? I won't argue politics here, I'll respond (if I feel like it) in the politcs thread. But as for gouging the American tax payer, here's one statistic for you. Before the flight of Discovery the budget of NASA included costs for the Shuttle increased 50% for return-to-flight. For 2006 & 2007 costs should have gone back down, but the budget didn't go down, it stayed at the high rate. Now answer reasonably, why would the annual cost for Shuttle be maintained at the same cost as return-to-flight when that development was complete? After Discovery's flight it turns out there's still a foam problem, but that's not the point. Why would they budget on-going operational cost at the same level as return-to-flight before they discovered there's still a problem?

Josh Cryer · 2005-09-29 14:41:03

I just popped in to read responses here, I'm heading straight back out.

But heed this, guys. I'm going to delete any more off topic Robert/GCNR banter or other political banter without warning. Don't take it as an insult, I let you guys get away with a lot of crap here. But seriously, I don't want half this thread to be lame bickering between two posters. So if posts start disappearing you'll know why.

clark, as a short response, longer one to follow later, I think there would be a lot you could do. Nearby exploration is definitely possible, I honestly think just being able to observe a nice Martian sunset would be worth the whole trip, if even to die the next day. I don't know if we could plug a vehicle into this equation, but maybe you could. The whole suicide mission idea is still quite early in its development.

RobertDyck · 2005-09-29 15:03:16

Getting back to technical stuff, I'll let agriculture experts determine how big the greenhouse has to be. The film I recommended was PCTFE. I don't have results from Mullen burst test, but I do for FEP. Based on tensile strength, I calculated the bursting strength for 1 mil PCTFE as 19.4psi. One atmosphere is 14.69psi so that gives you a margin. Those who sell Tefzel for a greenhouse on Earth recommend 2 mil thickness for durability. Tensile strength of Tefzel is 6000psi, PCTFE is 5300psi, so I recommend 2 mil PCTFE as the minimum. Doubling thickness will double strength, so it gives PCTFE a bursting strength of 38.8psi. If you inflate the Mars greenhouse to 5psi then you have several times safety factor. Furthermore I recommend two layers with a gap between layers. If one film breaks the other will contain pressure. Make each layer 2 mil thick. The gap can be filled with argon because, as I said, argon conducts heat more slowly than air so it helps keep the greenhouse warm.

PCTFE has a mass of 54.1[tex:39c4a5d5da]g/m^2[/tex:39c4a5d5da] for 1 mil film. Double that for 2 mil film, double again for two layers. Then calculate greenhouse surface area including the area beneath the floor. To ensure a pressure seal, each layer will require film under the floor. Use hold-down straps to ensure it doesn't blow away in wind, and to squash it into an ellipse. Squashing will maximize floor space while maintaining reasonable head room. The inner film will require hold down straps as well to squash it; those straps will have to pass through the outer layer to tent pegs pounded in the ground. A greenhouse this big will require tent pegs as big as an event tent, that means something like a 1 metre long piece of re-bar. To ensure the pass-through doesn't create a leak, melt-seal a short piece of strap into the outer film with a ring on either side of the film. The roof strap for the inner film will hook onto that ring, and the hold-down to the tent peg will hook onto the outer ring. That's simpler than trying to melt-seal the strap part way along its length.

BWhite · 2005-09-29 15:53:24

The whole suicide mission idea is still quite early in its development.

No suicide necessary.

RobS pegged Proton at $100 million each. Some reports are for a much lower cost. One Proton could deliver a fairly large number of ration bars periodically.

Send Jesuits and the Catholics could have periodic 2nd collections at Mass to pay for the launches.

SpaceNut · 2005-09-29 19:36:31

Great response on the greenhouse RobertDyck. From a rough comparison of a simple roll of a Frost King 3.5 mil Plastic sheeting for winterizing the house, that I have just laying around waiting to reduce those drafty windows with. The typical roll is 10 ft by 25 ft and weighs about 4.18 lbs a roll. The estimated greenhouse weight would be around 50 to 60 lbs of cargo for your one way mission.

Josh Is there room for a stowaway...

SpaceNut · 2005-09-29 19:46:36

I have a question based on this info from another thread:

MirCorp was a company based in the US and western Europe to rent Mir and use it for profit. Although the core module was 14 years old, the other modules were 3 years old. Russia had already built the core module for Mir-2, a duplicate of the Mir core module but new, so MirCorp wanted to pay to fly it to Mir for replacement. Once the damaged module was replaced or scrapped, and the core module was replaced, the station would have been viable for another decade. That plan was in 2001 so Mir would have been viable until at least 2011.
Instead the Mir-2 core module was used for ISS. It's now called the Russian Service Module. I heard Russia has another one in a warehouse somewhere, but the one proposed for Mir is specifically the one current on ISS. I wonder if that discussion is one reason the Service Module wasn't launched in 1999.

If this unit was launch filled with lots of goodies for Josh's one way trip could it docked with a progress and a soyuz in orbit to make the trip have better odds of success.

RobertDyck · 2005-09-29 21:25:03

Actually, you have to be careful about service temperature. Mars gets very cold at night. The temperature recorded by Mars Pathfinder varied between -8°C at 2:30pm to -77°C at 5:30am. That was measured over 3 sols. Viking 2 recorded temperature for more than a Martian year, it recorded a low of -111°C. There aren't many plastics that can handle that. Saran is more impermeable to oxygen and nitrogen than PCTFE, but the sandwich wrap (Saran wrap) becomes brittle at -7°C and the professional version for underground pipes (Saran 540 or Saran 560) becomes brittle at -40°. Professional Saran can be used as cold as -50°C as long as you don't try to bend it, but an inflated greenhouse will have stress when cold. Nylon-6-6 is also slightly more impermeable to oxygen by it's service temperature only goes down to -60°C. Fluoropolymers can handle much deeper cold.
Teflon FEP: -240...+204°C
Tefzel: -185...+150°C
PCTFE: -240...+132°C
Gore-tex: -212...+260°C

Actually what I called Gore-tex is Gore Tenara architectural fabric, expanded PTFE. The chemical formula doesn't include chlorine (no 'C').

I had considered Tefzel until I found a vendor who said it can only handle -100°C. Viking data shows Mars gets colder than that. However it turns out the stuff from DuPont can handle deeper cold. The coldest spot on the southern pole gets to -140°C. But there's more to consider. Although Tefzel is relatively impermeable, PCTFE is so impermeable that air just doesn't go through. Furthermore, PCTFE is the second most transparent polymer known; only amorphous fluoropolymer is more transparent and it's highly permeable. You don't want a permeable film, air would go right through. PCTFE is also extremely UV resistant, primarily due to the fact it's also transparent to UV. UV just goes through it. As for water permeability, PCTFE is the most impermeable to water of any polymer of any kind period.

If you want the numbers or the light transmission spectrum they're on the local chapter web site here.

For chemical, temperature, and UV resistance I would make the hold-down strap out of Gore-tex.

SpaceNut also asked about using a Russian core module for this mission. RSC Energia's mission plan they pitched to the Russian government did use exactly that, but their vehicle was rather large. The problem is that vehicle is optimized for zero gravity, not landing on Mars. If you used it for transit and discarded it for the surface, then you have two habitats. That makes it larger, impractical if you have no intention of returning to Earth. Furthermore that equipment is sized for 3 astronauts, you would want to minimize each piece of equipment so you have room for as many different pieces of equipment as possible. Hmm, Russia's mission plan was for 6 cosmonauts, I guess the "interplanetary orbiter" would be bigger. Anyway, Josh's mission would require a custom hab if you want a single launch of LV Energia.

Rxke · 2005-09-30 07:26:57

I just popped in to read responses here, I'm heading straight back out.
But heed this, guys. I'm going to delete any more off topic Robert/GCNR banter or other political banter without warning. Don't take it as an insult, I let you guys get away with a lot of crap here. But seriously, I don't want half this thread to be lame bickering between two posters. So if posts start disappearing you'll know why.

Please do. This makes me sick.
Yet another enjoyable thread going down the drain, Aaargh!

Fuck that, it makes me mad. I'm fucking fucking fucking!!!! TIRED of this constant off-topic political wah-wah stuff.

Ye, and go ahead and clean up MY swearing. No offence taken.

SpaceNut · 2005-09-30 07:44:44

Was not actually meaning to have that product used on mars just trying to indicate how little weight it would cost the mission if it were sent.

As for the Mircorp concept sounds like it would lend itself to use for moon base use adaptation rather easily. Add a lunar lander and you are in business for moon base Russia.

Found the article that mentioned the MIRcorp interest:First Commercial Space Station Agreed to by MirCorp and Russians

Also posted an article that detailed the possible lunar mission in the klipper thread, which used the soyuz and a module to push it to the moon and back.

SpaceNut · 2005-09-30 08:48:06

Now for Josh's maybe not so mad idea but rather a possiblity as layed out by Russia granted it is a little dated but still valid espeacially in the light of our current decusions.

[url=http://www.msnbc.msn.com/id/4720408/]Russians talk of sending humans to Mars
Some say mission would cost $3.5 billion; others scoff[/url]

RobertDyck · 2005-09-30 09:32:17

I should add the temperature in LEO can vary from -120°C to +150°C. The high is slightly more than the service temperature of PCTFE. However the storage temperature of PCTFE goes up to +205°C. So just don't apply stress to it while in transit, leave it folded in its box or storage bag until on the surface of Mars.

The Moon's surface varies form +107°C in direct sunlight to -153°C in permanent shade at the poles. That means a greenhouse or pup tent made of PCTFE will work on the Moon as well. Again, just don't deploy until on the surface.

PCTFE will undergo pyrolysis at +400°C. That means the polymer breaks down. If heated long enough PCTFE will break right down to monomers, it will liquefy. If at or above +350°C while exposed to UV-B or UV-C it will undergo UV induced thermal depolymerization; again it would liquefy. So this stuff loves the cold but hates heat. However, temperature where it becomes UV sensitive is so high that you would have to be on fire. Water boils at +100°C in 1 atmosphere pressure so no human or plant cold survive temperature above that. Since it's service temperature can handle heat greater than the hottest on Mars or the Moon, and it's storage temperature is greater than LEO or interplanetary space, it's fine.

SpaceNut · 2005-09-30 10:27:31

So based on this info if one adds a solar blind above the greenhouse to filter some of the solar rays. We could place our greenhouse on the linar surface rather than beeing force to live and grow things totally below ground level in caves.

RobertDyck · 2005-09-30 11:56:11

The other thing to worry about on the Moon is radiation. Mars has an atmosphere. According to a report from the Marie instrument on Mars Odyssey, a lot of radiation is blocked. Look at page 20, the 3D graph that shows radiation in cell hits per year at different altitude. Heavy ion radiation is almost completely blocked; the scale is logarithmic so about 99% of heavy ion radion is shielded at 0km altitude. Shielding if medium ions is less effective, light ions even less, and proton radiation is practically unaffected. But heavy ions have the greatest energy so do the most damage, and shielding tends to break heavy ions into small pieces. That means you end up with more radiation particles than you started with. Thin shielding actually makes heavy ion radiation worse! That's nasty and insidious. But that is exactly what Mars atmosphere blocks. The best possible shielding for heavy ions is the atmosphere of Mars; just choose a base location below the datum.

Alpha radiation is so easy to block a single sheet of paper will do. You need light elements like carbon, nitrogen, oxygen, and hydrogen for shielding. Heavy elements will also tend to produce secondary radiation; you don't want that. That's why paper is so good for alpha. Plastic sheet is made from the same light elements so the plastic film of a greenhouse will stop it. The spectrally selective coating will block UV. You really only have to worry about proton. Gamma is blocked best by heavy elements, so sand bags are good to block it. Plants are also more resistant to radiation than humans. If they get a tumour the plant just drops off that leaf or twig. So on Mars we can use sand bags on the roof of the habitat, and don't need any shielding for the greenhouse.

In fact, if you look at the Marie report you'll see heavy ion radiation is actually less during solar maximum. That's because strong solar wind blows some cosmic radiation out of the solar system. Of course it increases proton radiation. But again, proton radiation can be blocked by sand bags.

The Moon is more difficult. You don't have an atmosphere so don't have any natural radiation shielding at all. You could use a PCTFE pup tent for extended missions from the base, but I'm not sure about the long term viability of a lunar greenhouse. Remember the sun is up constantly for 2 weeks, then night for 2 weeks. Plants don't like that. And if there's a solar flare or coronal mass ejection while the Moon is facing the sun, radiation would be enough to kill your crops. This isn't Mars, the Moon is a much more dangerous place.

I argue the safest place in our solar system is the surface of the Earth. The second safest place is the surface of Mars.

Yang Liwei Rocket · 2005-09-30 12:23:51

I think manned missons to Mars could be a great idea if done correctly

But I am totally against suck risky and potentially hazardous plans for Mars. NASA has been great in the past, and the United States has proven with Skylab, John Glenn flight, Apollo to the Moon, Shuttle repair and Apollo 13 that it is able to do some great work even when under extreme pressure.

If the United States were to suddenly have Americans go to Mars under such high-risk and unproven conditions, and see people fail it would be a disaster. If the USA sends people to the Red planet and they make an error and the people die, the fallout for NASA would be massive - worse than Challenger. It would set NASA and the United States back years, while NASA tried to get over this new obstacle and astonaut deaths - somebody else from ESA, China or Russia would soon have an opportunity to plant their flag on the red planet, this also would be the end of the United States as a superpower.

SpaceNut · 2005-09-30 18:54:29

If we are afraid to at least take some risk, we should then not be going into space at all.

Josh Cryer · 2005-09-30 20:35:21

Sorry for not responding in a couple of days.

BWhite, I could convert to Catholicism for the trip, definitely.

SpaceNut, actually, since it'd be a one way trip, if we used Energia I think that several people could go along quite nicely, it'd be cramped, but it could work. Are you up to sitting in very tight quarters for 8 months?

Robert, I have no doubts about PCTFE now. I agree with you that it seems to be the best form of plastic to use. I was thinking that the greenhouse itself could be composed of 'bubbles' of spherical PCTFE. Imagine the following 'O's are 'bubbles' of PCTFE.

OOOOOOO
OOOOOOO
OOOOOOO
OOOOOOO

Each bubble has a connection hole in it through which trays to grow the food would sit. These holes are essentially 1/4th the area of the sphere (so they're not perfect spheres).

What do you think of this? I think that the more surface area you have the better (your squishing idea), plus, since each bubble is essentially self-containable, if any holes occurred, you could just remove the bubble from the system, patching the bubble hole with a circular piece of plastic (and an extremely strong polymer, which is stronger than the plastic itself).

While googling I found this particular design: http://ag.arizona.edu/ceac/research/Sou … MarsGH.htm

I don't like it, because the airlock seems to be awfully weighty, but it's a thought, it throws some ideas up there.

Yang Liwei Rocket,

Well, this is a private venture, and it might not be this way where you come from, but here in America private venturists can do any crazy scheme they want. I can see you being against governments taking risks to getting into space, but I dunno why there would be a problem with private individuals like the guys on this forum (granted, we don't have the $500 mil/$1 billion to get there) taking risks to get into space.

If we failed, it would be seen as a courageous attempt, given how much money we'd be spending, given that it is for all intents going to end in our deaths anyway (it's a suicide mission!). That's really the point. So what, I think we should fail.

Getting back to the rocket we need. I'm still skeptical about Energia, however, Robert did say that they seem to be willing to restart parts of the program if someone made some orders. So who wants to start a space tourism company? That's where the money could come from. We'd need that big inflatable space hotel with gravity and everything, but that shouldn't be too hard to come by.

There are misgivings by people here about Russia, I don't see why, they had a really powerful space program for their time. Russians, in fact, have spent significantly more time in manned space than Americans ever thought about spending. Energia seems salvageable, certainly Proton can be used (especially if three to four shots were made). The question is whether or not Energia is salvageable for less than the cost of three to four Proton launches, because one launch can possibly send a human in very tight quarters as long as the chloroplast technology works. Lowering your metabolism and sleeping a lot would also lower your food consumption.

For the private industry, Russia is the way to go, they have the technology available, they just don't have the investor.

Anyone want to start that space hotel venture?

Rxke · 2005-10-01 01:03:53

Russia has one drawback: no launchbase near equator...
Of course, in the near future, there's french Guyana (ESA) or... they could launch from Cuba! (kidding, kidding!)

I do not think Energyia is salvable w/o major investments. But OTOH... it was a working heavy lifter, so re-building it would at least save you some cash from design etc...
OTOH, I'd bet they'd be more than willing to hire out their other infrastructure. Some time (years?) ago, there was this 'meet the press/investors' event where they showed the launchpad would be a good place to restart business, complete with nearby biiiig landingstrip etc... They had some scheme to restart it all, in private hands, IIRC...

RobertDyck · 2005-10-01 10:12:10

The Russian company KBKhA is willing to restore production of the RD-0120 engine at their cost if they get a solid order for new engines. However, RSC Energia wants the customer to pay for restoring their infrastructure. RSC Energia is the prime contractor for Launch Vehicle Energia. RSC stands for Rocket Space Corporation, in Russian that's RKK. So that means you can do it, but you would have to pay to fix building #112.

The Russian military maintained the Buran shuttle in launch ready status as a counter to the American shuttle. They were worried America would try to snatch one of satellites out of orbit, or something. Buran could launch on 3 days notice. The military maintained launch facilities, kept one Energia launch stack fully assembled on the transporter in the MIK, and parts for 2 more Energia launches. That would also explain why production equipment was mothballed rather than scrapped. As part of the break-up of the Soviet Union, the Buran and all its launch facilities were handed over to Kazakhstan on January 1, 2000. That's when degeneration really started. Many American's think Energia was scrapped in 1988, but news reports indicated Kazakhstan was thinking of restoring Buran to flight. After all, what's the point of taking ownership of they can't use it? The real end was the roof collapse of the MIK building in 2002.

That also means the 3 Energia LVs were reserved for the military until January 1, 2002, but were available for sale after that. The extra strap-on boosters were stripped of engines, but the set on the transporter weren't and each set was usable 10 times. According to Robert Zubrin in his book "The Case for Mars", the Mars Direct mission plan would require either 2 launches of Ares or 3 launches of Energia. That means an entire set of launch vehicles capable of a manned mission to Mars were in that building and available when the roof collapsed on them.

RobertDyck · 2005-10-01 10:21:27

The "squashing" idea wasn't mine, I got it from this painting from the Mars Society web site showing a Mars Direct landing. Painting by Robert Murray. Dr. Penelope Boston wrote a paper about that design at the time of "The Case for Mars" conferences, before the Mars Society was formed.

The airlock can be made of the same film. The door requires a firm frame that can form a solid pressure seal, but the majority of the surface of the door itself could be more of the same film. That means the frame of the door and the door jam must be solid. You might be able to make it from graphite/epoxy instead of metal if you design door cross braces to prevent twisting or bending. Keeping pressure down would help keep the door light. Again, Skylab and Apollo used 5.0psi with 60% oxygen / 40% nitrogen. That gives 3.0psi partial pressure oxygen, but I would reduce habitat oxygen further to 2.7psi.

Small amounts of nitrogen can be tolerated with zero pre-breathe time before decompressing. According to a paper from NASA's Advanced Life Support project, published in a web site of peer reviewed NASA papers, the ratio of partial pressure of nitrogen in cabin air to total pressure in the spacesuit is 1.2:1. That means if the suit has 3.0psi pure oxygen then the maximum partial pressure of nitrogen in cabin air is 3.0 * 1.2 = 3.6psi. If cabin air has 2.7psi partial pressure oxygen, and 3.6psi PP nitrogen, then the total will be 2.7 + 3.6 = 6.3psi. More nitrogen than that and rapid decompression would result in "the bends". But Skylab had lower total pressure than that, and lower cabin pressure means less decompression time.

Plant experiments by Guelph University in a hypobaric chamber showed lettuce can handle pressure as low as 10kPa (1.45psi) without slowing growth. The key is lots of water, lower pressure causes plants to transpire more water through their leaves. As long as the greenhouse is sealed that water will recycle back into the soil. Below 10kPa plants wilt. Actually they did an experiment where the reduced pressure to Mars ambient for 1 hour. Plants wilted extremely, but as soon as they restore pressure the plants perked back up. This shows plants can handle even lower pressure than humans. You might not want to grow wheat, that one requires as much partial pressure of oxygen as humans. But if the greenhouse is connected to the habitat, it will have that much oxygen so it's Ok.

Humans get dry lungs if pressure is too low. You can breathe 2.5psi pure oxygen if you undergo high altitude training, but lungs will dry out if it's prolonged. 3.0psi is safer for spacesuits. If the habitat uses the same 60/40 ratio as Skylab, but PP oxygen is reduced to 2.7psi then the result would be 1.8psi PP nitrogen for a total of 4.5psi total. I would recommend that.

RobertDyck · 2005-10-02 10:40:07

Josh, how would your bubbles work? If they're just sphere's with sections cut out where they join the will you have enough room to walk? How do you get to the plants. The reference you gave still uses a cylindrical greenhouse, but a lot of them connected off a central corridor. I think an ellipse (squashed cylinder) would give more growing area per surface area of film. As the painting showed, you can connect more ellipses together. Most importantly, the ellipse design uses a shaped section of plastic film for the end rather than a solid disk. A pressure tight solid bulkhead will be heavy.

As for door, I'm thinking of something like this. The picture is for a terrestrial greenhouse, not pressurized and with a frame, and the plastic is only PVC, but it shows a plastic film door with frame. We would need rounded corners on the door and a very stiff frame to ensure a good pressure seal between door and jam. I think using the same plastic for the door would reduce door mass. Of course you need 2 doors with a small chamber between to act as an airlock when going outside on Mars. Opening the door into the airlock or greenhouse, not out, would let pressure hold the door closed. When pressurized, the pressure itself would push the door against the jam and its neoprene seal. You also need a latching mechanism, but simply orienting the door correctly helps.

Josh Cryer · 2005-10-06 14:14:54

I was thinking of having the spheres half buried, but in retrospect that's just too complicated, and I hate complexity. I mean, in theory it's simple, lots of spheres interconnected, but installing them would be too much of a pain, and then, we're still looking at the bottom half of the surface area which would be lost to the ground (granted any sealed greenhouse is going to lose a lot of area to the ground, but I think that a large open squashed version would at least minimize that loss).

The flatened idea is a lot better. And there's nothing inherent in their design that precludes expandablity (expandablity is the main reason I wanted to go with spheres in the first place).

Will this low PSI cause any extended harm to people who are on Mars for a very long time? Skylab was a short experiment, we weren't there for decades, and I wonder what the effects might be. I mean, in the end I still think we should design for the highest PSI possible, and to be safe, keep it at lower a PSI, but I wonder what effect that lower PSI would have.

About Energia, I was thinking, wouldn't it be cheaper to simply, well, build your own Energia? Screw RSC Energia, buy some RD-0120 engines, get a contract opened up with them, and relocate to somewhere else on the equator. Surely the tens of millions to fix up building #122 could be better spent elsewhere? It seems like Shuttle tech (Energia/STS) is the only way we're going to reasonably get into space from a private point of view.

I noticed that the first stage of Energia is kerosene, can we change that to pure hydrogen/oxygen and what would that effect be?

RobertDyck · 2005-10-06 16:18:57

Ok, how about this. Use a tri-gas mix: oxygen/nitrogen/argon. Use the same nitrogen:argon ratio as Mars atmosphere. That let's you harvest diluent gas from Mars itself. I gave a paper how to do that at this year's Mars Society conference. Mars atmosphere consists of 95.32% carbon dioxide, 2.7% nitrogen, 1.6% argon, 0.13% oxygen, 0.07% carbon monoxide, 0.03% water, and trace amounts of noble gasses. If you remove carbon dioxide and carbon monoxide, the result is nitrogen and argon in a 2.7:1.6 ratio. If 3.6psi PP nitrogen then argon will be 3.6 / 2.7 * 1.6 = 2.133psi. So if the habitat has 2.7psi PP oxygen, 3.6psi PP nitrogen, and 2.133psi argon, the total is 8.433psi. That's the maximum habitat pressure for zero pre-breathe time if the suit uses 3.0psi pure oxygen.

This is the calculation I did for the Mars Homestead Project. Before I joined they started with the SWAG (Stupid Wild Ass Guess) of 0.6 atmospheres. After I did this calculation to get a precise number, they pointed out it's almost exactly what they guessed. Their 0.6 atmospheres calculates as 8.81757psi; 8.433psi is 0.5738 atmospheres. They're now planning to use 8.433psi habitat pressure.

With extremely low pressure you do have the human metabolic problem of lung tissue drying out. As I said, 3.0psi is the same partial pressure of oxygen as Earth at sea level. So astronauts can breathe pure oxygen at that pressure and not feel any difference. The Air Force found a strong, healthy fighter pilot who undergoes high altitude training can breathe 2.0psi PP indefinitely if the total pressure is 1/2 an atmosphere or more. Humans can't handle as low PP oxygen if the total pressure is lower. A strong healthy fighter pilot with acclimation (high altitude training) can withstand 2.5psi pure oxygen indefinitely, or even 2.0psi for up to 30 minutes before passing out. The 5.0psi that NASA used in Skylab is nothing, easy to live in. Reduction to 4.5psi is something I think wouldn't be a problem as long as you keep cabin humidity slightly elevated. Higher humidity will alleviate the drying of lung tissue.

However, if you want to raise the pressure, you can. Just use these guidelines: either 4.5psi, or 8.433psi, or somewhere between.

Mountain climbers will be familiar with pressure and oxygen. Base camp on Mount Everest, part way up the mountain, has a pressure of 2/3 atmospheres. Oxygen on Earth is 20.9% so that means 2.0psi PP oxygen. It takes a minimum of 6 weeks while exercising vigorously to acclimate to Base Camp, usually by carrying heavy backpacks filled with food up from the town. Exercising while breathing low oxygen will stimulate the body to grow more red blood cells, that's how the body acclimates and why it takes 6 weeks. The peak of Everest is 1/2 an atmosphere, or 1.5psi PP oxygen. You can't survive that indefinitely no matter how well prepared. Very strong and very well acclimated climbers can quickly climb to the top and rush back down to Base Camp before they pass out. Most climbers today bring bottled oxygen, but they still have to get down before their oxygen runs out. This demonstrates how well the human body can handle lower oxygen.

RobertDyck · 2005-10-06 17:02:44

The first stage or booster rockets of any launch vehicle are not so sensitive to specific impulse as upper stages. Most rockets use a cheap, low Isp first stage to control cost. Liquid hydrogen requires a very large fuel tank. That can negate the cost saving of a higher performance fuel. Saturn V used LOX/kerosene for its first stage. The Shuttle uses solid rocket boosters. Delta IV uses a LOX/LH2 core stage but uses small, non-segmented solid rocket boosters. The LOX/kerosene strap-on boosters of Energia are easier and cheaper to re-use than the SRBs of Shuttle. Furthermore, the RD-170 engines of those strap-on boosters are just about the highest specific impulse of any storable propellant rocket you'll find. The RD-180 engine used for the core module of Atlas V is half of an RD-170. That is, RD-170 is a 4 chamber engine while RD-180 is 2 chamber. The only improvement I can imaging for Energia is to replace the aluminum alloy with aluminum-lithium. That would make the core module lighter, but more expensive. For cost you may want to leave well enough alone.

The tanks of the core module of Energia were manufactured at the same factory that makes R-7 rockets. The oxygen and hydrogen tanks were transported separately on the back of an M4 aircraft. That aircraft is still around. You could transport the tanks to a different launch site. I imagine you could even use LC-39 at KSC if you built a custom MLP. What's cheaper? Building a new MLP and paying NASA to use KSC, or repairing building #112 at Baikonur?

A new launch facility at Kourou would require not only a vehicle assembly building, but a launch pad, transporter and erector. The proposal to build a Soyuz launch complex at Kourou has a price tag of $371 million; it hasn't been built due to lack of financing. Energia is bigger, would cost more.

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#26 2005-09-29 06:40:59

Re: One man one way suicide mission...

#27 2005-09-29 07:02:57

Re: One man one way suicide mission...

#28 2005-09-29 14:19:10

Re: One man one way suicide mission...

#29 2005-09-29 14:41:03

Re: One man one way suicide mission...

#30 2005-09-29 15:03:16

Re: One man one way suicide mission...

#31 2005-09-29 15:53:24

Re: One man one way suicide mission...

#32 2005-09-29 19:36:31

Re: One man one way suicide mission...

#33 2005-09-29 19:46:36

Re: One man one way suicide mission...

#34 2005-09-29 21:25:03

Re: One man one way suicide mission...

#35 2005-09-30 07:26:57

Re: One man one way suicide mission...

#36 2005-09-30 07:44:44

Re: One man one way suicide mission...

#37 2005-09-30 08:48:06

Re: One man one way suicide mission...

#38 2005-09-30 09:32:17

Re: One man one way suicide mission...

#39 2005-09-30 10:27:31

Re: One man one way suicide mission...

#40 2005-09-30 11:56:11

Re: One man one way suicide mission...

#41 2005-09-30 12:23:51

Re: One man one way suicide mission...

#42 2005-09-30 18:54:29

Re: One man one way suicide mission...

#43 2005-09-30 20:35:21

Re: One man one way suicide mission...

#44 2005-10-01 01:03:53

Re: One man one way suicide mission...

#45 2005-10-01 10:12:10

Re: One man one way suicide mission...

#46 2005-10-01 10:21:27

Re: One man one way suicide mission...

#47 2005-10-02 10:40:07

Re: One man one way suicide mission...

#48 2005-10-06 14:14:54

Re: One man one way suicide mission...

#49 2005-10-06 16:18:57

Re: One man one way suicide mission...

#50 2005-10-06 17:02:44

Re: One man one way suicide mission...

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