Mars Colony?

[Clonus]

Re: Mars Colony?

 

Same reason I would climb a mountain. Because I can, and it's there. Besides. Unless you're the lead dog, the view never changes.

 

~Rex

 

That's great if you can walk there. Not so great when it's a significant expense for even the biggest nation. (And truth is while people climb the tallest mountain peaks, they don't colonize them.)

[assault]

Re: Mars Colony?

 

I've always been impressed by how much Mars colony advocates try to justify their hobby horse in terms of (US) patriotism.

 

It shows they don't have any serious arguments.

 

Basically, it's a big waste of resources for no benefit that's obvious at this point in time.

 

Scientific research is something else - but that's very different from an adolescent/patriotic frontier fantasy.

[Gnaskar]

Re: Mars Colony?

 

We probably could go to Mars if we really wanted to, but why would we want to?

 

For the science. A crewed mission is the best way of finally figuring out if there's life there or not. As can be seen from one on sub-discussions in this very thread, there is much disagreement on that point. Finding life on another world in our solar system would imply that life is the rule, making the galaxy rich in life. It would revolutionize all fields of biology and, like it or not, bio-research is what will be feeding your children. Studying Mars up close would also revolutionize geology, but no one but geologists care (unless the result is finding resources on Earth we didn't know were there).

 

For the safety. We're a single planet civilization. That's a horribly vulnerable situation to be in. There is an asteroid with our name on it out there. It's only a matter of time before it finds us.

 

For the technology. Methane based engines and rockets are a new technology. Reliable unmanned nuclear reactors is a new technology. NERVA, if they ever actually launch one, is a new technology (and one of the few anti-asteroid tools we have). Necessity is the mother of invention, and frontiers cause necessities like nothing else.

 

For the challenge. It's there. We could get there. We haven't.

 

For the money. It's a bit of a stretch, but Mars was formed the same way Earth was, with ores and veins of valuable minerals covering it. Unlike Earth, however, it hasn't had us grabbing the easy to get stuff for the past 10,000 years. It's still behind a 4km/s gravity well, though. The asteroid belt isn't. But Mars has fuel and UV protected soil, and unlike Earth is only behind a 4km/s gravity well. Mars is a great resupply station for asteroid mining operations. In fact, it's easier to resupply a lunar colony from Mars than from Earth. So if mining the Moon for aluminium or He3 is your thing... (or mining Saturn for He3, for that matter). It's more a fact of a martian colony being able to make money, really.

 

For the history. Remember who said "We choose to go to the Moon this decade and do the other things, not because they are easy, but because they are hard"? Every one else does too. A politician or CEO wanting immortality need look no further. Heck, it's a decent premise to build an election campaign on, given that you'd get the entirety of Mars Society to back your campaign, as well as the Planetary Society and the National Space Society.

 

For the task. NASA has been "running on empty" since the end of Apollo, to the point were it's amazing they get some science done. The Shuttle project was devised to give NASA's rocket scientists something to do, and the ISS was devised to give the Shuttle something to do (rather than launching it from three Saturn V's, and crewing it from a Titan). And all of it designed to put as many jobs in as many states as they can, rather than to actually accomplish anything. Well, the Shuttle's dead and ISS has another 9 years to go (with a single Russian module left to launch). Curiosity is the last planed rover and its launching this year. Actually, see for yourselves: http://www.nasa.gov/missions/future/index.html 19 billion dollars a year, three future missions. All are nearing completion.

 

In short: It's about damn time.

 

Edit: I can't help but let another man conclude for me:

"Many years ago the great British explorer George Mallory, who was to die on Mount Everest, was asked why did he want to climb it. He said, "Because it is there."

Well, space is there, and we're going to climb it, and the moon and the planets are there, and new hopes for knowledge and peace are there. And, therefore, as we set sail we ask God's blessing on the most hazardous and dangerous and greatest adventure on which man has ever embarked."

[Lawnmower Boy]

Re: Mars Colony?

 

True, but sending supplies from Earth costs far more than making them onsite, and making them onsite has more long term advantages. Of course, if the refinery fails, you can always ship out supplies and have one of the engineers on the first crew mission figure out what went wrong.

 

 

 

On rats, nothing. It's been tried in an orbital spin grav satellite. On humans; well there's an obvious place we can check, assuming you can find four people willing to take the risk. Pro tip: you can.

 

 

 

No, they did it no Earth, which has far less of the operative ingredient; CO2. The CO2 soaker is a solid block of zeolite. The Martian night cools it down to a temperature where it absorbs CO2, the lid closes at dawn, and CO2 is released as the Martian day, and the exothermic reactions required, heat it up. No turbine means only a simple filter is needed. The required CO2 is gathered up in six days. Unless you landed it in a dust storm, the filters won't clog in that time. (see aerobraking later for why you don't have to land if there's a dust storm). The system has been built and tested in a pressure chamber designed to simulate Mars.

 

 

 

In total: 15% of the hydrogen brought along (even with up to 30% the return flight is possible; the rovers use the spare fuel). Oxygen loss from the air lock is countered by the next door oxygen factory. The crew launch with the hab, so no assembly or LEO waiting. Oxygen loss during flight (including poo venting): 160 kilo each way, so 320 kilo total (20% of the required air). Poop venting itself: 6 tons (that's worst case, with the crew having to stay 5 years on Mars). Unrecoverable water (including pee): 3.4 tons (again worst case). Anything I've missed?

 

 

 

The ISRU module has been built and tested already. 20 years ago. Landing it on an other planet will require some ruggedness testing, of course. But it should be possible. And the module they built out of spare parts weighs only half of the budgeted weight, so there's plenty of room for making it more rugged. Or bringing a spare.

 

The nuclear reactor, well, we'll need to develop them eventually, so why not use this project as our great chance? If we can't get a reactor working in time Radio Thermal Generators can provide a fifth of the power with the same weight. That slows the refining down significantly, but not fatally. (it's still done a year before the crew leaves; and the gathering of CO2 [which is sort of time critical due to dust] requires only the power to open and close a hatch).

 

 

 

All this would be true if the plan was to go strait from interplanetary travel to landing. The plan is to aerobrake into orbit and then land with the more traditional parachutes and rockets system. Which we've do with the Mars Reconnaissance Orbiter, the Mars Odyssey and even the Mars Global Surveyor (despite it being damaged during Earth take off). And none of these satellites even carried a shield; the used their solar panels to brake.

 

Landing on Mars (while under directions from Earth 40 minutes of communication lag away) has been consistently done with 50 kilometer accuracy or better (both the vikings did les than 30 km). The piloted hab only needs to land within 1000 kilometers of the return vehicle to be able to use it (the hab has a pressurized rover on board). Miss by more than that, and the back up return vehicle just needs to land within 1000 kilometers of the hab. It can be directed in real time from the hab.

 

Oh, and as for aerobrake into landing scheme, we did that with Pathfinder, Spirit, Opportunity, and Phoenix. We've done it a few times with unmanned probes.

 

 

 

The heavy booster is a Saturn V, or a shuttle derived equivalent. If we can't build a 60's booster any more, that's the first sign of technological decline I've seen, and the thought is frankly scary.

 

The interplanetary craft has 50m^2 of pressurized floor space per astronaut (with 2.5 m head room for some reason). That's about three times the area I live in as a student. It's probably a bit cramped for a 180 day trip without being able to leave, but it's plenty once you're on the surface. Actually, scratch that. The living space per person is equal to the ISS. Plenty of space. Mars Society has run isolated bases with less space to prove that it works without the crew killing each other, and ESA are running a simulated trip to mars as we speak, with six people locked in a box for 3 years.

 

Speaking of the ISS. 15 pressurized modules assembled in orbit. Granted, they had the shuttle, we don't any more. Mir assembled five modules without any crew, however. ISS has had on site refueling. We have the technology for orbital assembly.

 

But say the 25 ton hab (that's just the mars surface payload, by the way, the full interplanetary craft is 140 tons) is optimistic. A single 140 ton engine stage (Saturn V class launch required) could easily boost a 50 ton payload to Mars orbit. Said payload could land about 35 tons on the surface. So now you need to launch the crew in a Falcon Heavy and do a crewed orbital link up before departure. We've done that at least 28 times on ISS alone (I don't have the exact data, so that's just the number of crews that have docked). Need something even bigger? Using staging (a 40's technology) three heavy launches (2 engine sections, one payload) lands about 50 tons. That's still only two launches per year, methane can be stored indefinitely in space (with a tight launch schedule and hydrogen fuel you can land 60 tons). Even that requires just two link ups. Which we've done over fifty off already.

 

 

 

Yes and no. The Beagle (Dr. Zubrin's supposed name for the hab) has not been designed yet. The technology exists, it just needs to be put together and launched so we can actually get there. The "small stuff" remaining is engineering, not research; the building and testing of the actual stuff you need. And that's always going to have to be done; you can't skip it, can't wait to let it resolve itself. The reason it isn't on the agenda for the near future is that President Obama is leading a country with extreme dept, and any lofty sounding plan for Mars Now! is going to have pundits screaming for blood at an expense that is actually cheaper than the current NASA plans of building an orbital vehicle they can't launch.

 

EDIT: Wow. Two new post while I was typing. Mars Direct calls for 4 people, NASA's DRM calls for 6.

 

 

The cheapest we can do today is about 4000 USD per kilo for cargo. Into LEO. To get cargo to Mars takes about 5 kilo per kilo of cargo. To get it back again takes about the same. That's 25 kilo launched into orbit for each kilo you want to take back from Mars. The MArs Direct return vehicle weighs 10 tons when it enters Earth's atmosphere. Hence You'd need to launch 250 tons to get it back, compared to the 140 tons of the empty one and the refueling system. 440 million dollars saved.

 

 

 

A common rumor. NASA's policy is always to say "no comment" when asked and no papers have been published on the topic by NASA.

 

Other assorted arguments for Mars Direct:

Compatibility with other missions: A 25 ton pressure sealed hab with rocket landing technology can be used on the Moon as well. As can the pressurized closed cycle rover. A heavy booster can launch space stations extremely cheaply (compare a 420 ton space station put together in orbit from 20 ton pieces to a 420 ton station put together from three 140 ton pieces). A fuel production center on Mars can fuel asteroid belt missions (it's actually far cheaper to refuel there than go direct).

 

Leaves the hab, power plant, rovers and refinery behind: You want a permanent Mars colony? A twenty year Mars Direct program leaves you with quarters for over fifty people, plenty of EVA suits and infrastructure. Even better, a stripped down hab (no rovers, science lab, return supplies, etc) could serve as an 12 man transport. 24 men per launch if you allow for the use of a NERVA upper stage.

 

Alternative mission plans:

It might be prudent to talk about the different types of mission plans exist today (for reference purposes).

Mars Direct: As explained above. Uses local supplies and low tech solutions where ever possible. Also one of the cheapest.

Suicide Run: The best way to avoid the costs of returning to Earth is to not return to Earth. The Suicide Run mission plan involves a one way trip for everyone involved with the goal of establishing a colony from the very start.

Big dumb booster: Orion, Sea Dragon, it really doesn't matter. Overcomes the problem of supplies with pure brute force. By launching a bigger rocket.

The 90-day Plan: von Braun and NASA's plan, as cancelled by Bush Senior. Includes the need for an orbital assembly station, lunar mining operation and nuclear (NERVA) engine. And yet, for all that, they spend 30 days on the surface.

Design Reference Mission: NASA's current plan. Looks a lot like Mars Direct, but leaves a return vehicle in mars orbit, and only uses ISRU for launching into Mars orbit.

 

Personally I'm a fan of the Big dumb booster/suicide run combination. It gets us a colony, and does so fast, and it's one of the few missions where I have a chance of coming along. But Mars Direct has a greater chance of actually being used, and getting there is more important than getting a COLONY NOW!.

 

Oi. What we have here is a failure to communicate. I have my doubts about Mars Direct, which sounds like typical technological fantasy. Everything else, fine. I believe in ISRU, building a new generation of Saturn Vs, whatever.

 

But when I asked about lubrications and seals on the compressors of this self-contained chemical plant that's supposed to turn 8 tons of hydrogen into all of that fuel, what I got was another spiel about how elegant the proposed synthesis is.

 

I get it. It's cool. But will the plant work? I singled out lubrication and sealing as one of the more recondite problems that real world engineers face with projects like this. They're why it takes time to develop this kind of plant on Earth.

 

Time. We will go to Mars some day. In time. Because it will take time to develop this technology. Time. Time time time time time time time.

 

Just to repeat myself: it will take time. A generation. Or more.

[McCoy]

Re: Mars Colony?

 

For the science. A crewed mission is the best way of finally figuring out if there's life there or not. As can be seen from one on sub-discussions in this very thread, there is much disagreement on that point. Finding life on another world in our solar system would imply that life is the rule, making the galaxy rich in life. It would revolutionize all fields of biology and, like it or not, bio-research is what will be feeding your children.

Works for me. Mars is the next-to-least hostile location for life as we know it that we are aware of. We need to see if there is or isn't indigenous life, and that's going to require boots on the ground regolith for a number of years.

[McCoy]

Re: Mars Colony?

 

Oi. What we have here is a failure to communicate. I have my doubts about Mars Direct, which sounds like typical technological fantasy. Everything else, fine. I believe in ISRU, building a new generation of Saturn Vs, whatever.

 

But when I asked about lubrications and seals on the compressors of this self-contained chemical plant that's supposed to turn 8 tons of hydrogen into all of that fuel, what I got was another spiel about how elegant the proposed synthesis is.

Really? I thought the answer you got was that the prototype was built and tested under simulated Mars conditions decades ago.

 

No, they did it no Earth, which has far less of the operative ingredient; CO2. The CO2 soaker is a solid block of zeolite. The Martian night cools it down to a temperature where it absorbs CO2, the lid closes at dawn, and CO2 is released as the Martian day, and the exothermic reactions required, heat it up. No turbine means only a simple filter is needed. The required CO2 is gathered up in six days. Unless you landed it in a dust storm, the filters won't clog in that time. (see aerobraking later for why you don't have to land if there's a dust storm). The system has been built and tested in a pressure chamber designed to simulate Mars.

The ISRU module has been built and tested already. 20 years ago. Landing it on an other planet will require some ruggedness testing, of course. But it should be possible. And the module they built out of spare parts weighs only half of the budgeted weight, so there's plenty of room for making it more rugged. Or bringing a spare.

 

The nuclear reactor, well, we'll need to develop them eventually, so why not use this project as our great chance? If we can't get a reactor working in time Radio Thermal Generators can provide a fifth of the power with the same weight. That slows the refining down significantly, but not fatally. (it's still done a year before the crew leaves; and the gathering of CO2 [which is sort of time critical due to dust] requires only the power to open and close a hatch).

[Lawnmower Boy]

Re: Mars Colony?

 

Really? I thougt the answer you got was that the prototype was built and tested under simulaed Mars conditions drcades ago.

 

Really? I might have rushed through the alphabet-soup of nomenclature, assuming that the claims were being made for the interplanetary vehicle.

 

And I certainly do not believe that the ISRU module has been successfully prototyped. Nor, apparently, does NASA. They've got a Mars wind tunnel, though; excellent first step.

[Ranxerox]

Re: Mars Colony?

 

I've always been impressed by how much Mars colony advocates try to justify their hobby horse in terms of (US) patriotism.

 

It shows they don't have any serious arguments.

 

Basically, it's a big waste of resources for no benefit that's obvious at this point in time.

 

Scientific research is something else - but that's very different from an adolescent/patriotic frontier fantasy.

 

But there are reasons of patriotism and national identity to undertake this. It is important for people to have goals and it turns out that it is important for nations to have goals too. Without goals the tendency is is to spend too much time just watching TV or messing around on the internet and it is neither healthy or productive.

 

In recent years I have become convinced that one of America's biggest problems is that we as a nation lack purpose. Maybe I'm missing the forest for the trees, but I see a nation lost in celebrity gossip and reality TV shows. Our children need something to dream of besides landing a spot on Jersey Shore. Conquest of space is not the only possible goal for which the US could strive, but IMHO it is one of the better ones.

[Gnaskar]

Re: Mars Colony?

 

Really? I might have rushed through the alphabet-soup of nomenclature' date=' assuming that the claims were being made for the interplanetary vehicle. [/quote']

 

Yeah, sorry about that. I didn't mean to make the post that long, but more ideas kept popping into my head.

 

But when I asked about lubrications and seals on the compressors of this self-contained chemical plant that's supposed to turn 8 tons of hydrogen into all of that fuel' date=' what I got was another spiel about how elegant the proposed synthesis is. [/quote']

 

Yeah, sorry, my point disappeared in my own ramblings. You mentioned that sealing dust from the turbine and valve was going to be a problem; I pointed out that (a) there was no turbine, ( it would take only six days to get the CO2 from the air (which is an important point as this is the only time dust can clog the system; Mars has a very short time limit to wreck the system), and © we can choose when and where to land to avoid a coming dust storm.

 

b and c adds a lot to our system reliability.

 

And I certainly do not believe that the ISRU module has been successfully prototyped. Nor' date=' apparently, does NASA.[/url'] They've got a Mars wind tunnel, though; excellent first step.

 

Cool link. It doesn't actually say NASA hasn't done a prototype, though. In fact, they have, but I can't copy the link to it, because Chrome has some issues with PDFs. Instead just google "Report on the Construction and Operation of a Mars In-Situ Propellant Production Unit". It's the first one.

 

The article simply states that NASA is spending a lot of money on In-Situ capabilities. Including using local rocks to help rovers figure out where they are (in the Marscape Test Facility). They also have a wind tunnel that they can depressurize (which is, quite rightly, the first of it's kind). It is hardly the first pressure chamber that can simulate Martian atmosphere, however. The actual test was done even cheaper; they just sealed off the intake valve and inserted a cocktail of gasses at martian pressure.

 

The ISRU Report (my "link") does however state that they didn't build a liquidfier, a vital part of the final design. I didn't know NASA had continued this kind of research but (Quoting your link): "ARC developed a flight qualified pulse tube cryocooler in collaboration with DoD, and demonstrated a liquefier for ISRU."

 

That fixes the difficult part. The one last part they haven't built is the zeolite CO2 acquisition system (I admit I didn't know they hadn't, I was under the impression that they'd put Martian gasses in a pressure tank, and let it rip). So, yes, I concur, the intake valve needs to be tested. Preferably in the wind tunnel with martian like dust thrown into the equation. Repeatedly, too. And if it can't offer reliable refueling enough for a return trip, some form of backup must be examined.

 

But where I still disagree with you is in that we need time. Waiting does nothing. If an intake valve needs to be thoroughly tested before it can be used on Mars, then the only way of getting it tested is start a project aimed at going to Mars. You can't sit and wait for a mission specific technology to be developed. It won't be. It has no other use. So I say ten years. Ten years to build a prototype, run it through every possible test, build a rocket to launch it, and train a crew. If you can show me that the list of needed technologies means ten years isn't enough testing time, then it will take 15, even 20. The point is that nothing gets done until someone says let do it. Waiting a generation solves nothing.

 

We can't launch tomorrow. We can't even launch in the December launch window. Heck, I have some doubts that we could launch this decade. But we won't be able to launch next decade, either, unless we start doing the engineering.

 

So, in conclusion, unless you can point to some vital technological development that we (a) don't have yet, and ( couldn't develop within ten years if it were made a direct goal, or that the total technological development would be impossible with a 3 billion dollar budget over a eight year period (and yes, I'm man enough to request NASA's entire human space flight budget, and to hell with the ISS), then I'll continue to believe that we could launch the first manned flight to Mars in March 2019, and land on Mars by the end of the year, if the project was started up tomorrow (or in the 2012 budget).

 

PS: The Suicide Run apparently is called Mars to Stay in front of tax payers. I'd prefer calling a spade a spade, but hey, whatever gets the funds.

[RexMundi]

Re: Mars Colony?

 

Big Dumb Booster. Get's me away from all the "We can't Go it's to far it's to expensive there's no real reason to do it!" people that much faster.

 

~Rex......Mars or Bust.

[薔薇語]

Re: Mars Colony?

 

Wow. I can barely keep up with anything on this thread (me no good wit spacy stuffu)

 

But I do enjoy the reading and I've certainly learned quite a bit. All that is to say "keep it up!"

 

La Rose.

[McCoy]

Re: Mars Colony?

 

The interplanetary craft has 50m^2 of pressurized floor space per astronaut (with 2.5 m head room for some reason). That's about three times the area I live in as a student. It's probably a bit cramped for a 180 day trip without being able to leave' date=' but it's plenty once you're on the surface. Actually, scratch that. The living space per person is equal to the ISS. Plenty of space. Mars Society has run isolated bases with less space to prove that it works without the crew killing each other, and ESA are running a simulated trip to mars as we speak, with six people locked in a box for 3 years.[/quote']

Knew someone was working on this, glad to hear they are further along than I thought, and that I actually underestimated human beings (for once).

[Lawnmower Boy]

Re: Mars Colony?

 

Yeah, sorry about that. I didn't mean to make the post that long, but more ideas kept popping into my head.

 

 

 

Yeah, sorry, my point disappeared in my own ramblings. You mentioned that sealing dust from the turbine and valve was going to be a problem; I pointed out that (a) there was no turbine, ( it would take only six days to get the CO2 from the air (which is an important point as this is the only time dust can clog the system; Mars has a very short time limit to wreck the system), and © we can choose when and where to land to avoid a coming dust storm.

 

b and c adds a lot to our system reliability.

 

 

 

Cool link. It doesn't actually say NASA hasn't done a prototype, though. In fact, they have, but I can't copy the link to it, because Chrome has some issues with PDFs. Instead just google "Report on the Construction and Operation of a Mars In-Situ Propellant Production Unit". It's the first one.

 

The article simply states that NASA is spending a lot of money on In-Situ capabilities. Including using local rocks to help rovers figure out where they are (in the Marscape Test Facility). They also have a wind tunnel that they can depressurize (which is, quite rightly, the first of it's kind). It is hardly the first pressure chamber that can simulate Martian atmosphere, however. The actual test was done even cheaper; they just sealed off the intake valve and inserted a cocktail of gasses at martian pressure.

 

The ISRU Report (my "link") does however state that they didn't build a liquidfier, a vital part of the final design. I didn't know NASA had continued this kind of research but (Quoting your link): "ARC developed a flight qualified pulse tube cryocooler in collaboration with DoD, and demonstrated a liquefier for ISRU."

 

That fixes the difficult part. The one last part they haven't built is the zeolite CO2 acquisition system (I admit I didn't know they hadn't, I was under the impression that they'd put Martian gasses in a pressure tank, and let it rip). So, yes, I concur, the intake valve needs to be tested. Preferably in the wind tunnel with martian like dust thrown into the equation. Repeatedly, too. And if it can't offer reliable refueling enough for a return trip, some form of backup must be examined.

 

But where I still disagree with you is in that we need time. Waiting does nothing. If an intake valve needs to be thoroughly tested before it can be used on Mars, then the only way of getting it tested is start a project aimed at going to Mars. You can't sit and wait for a mission specific technology to be developed. It won't be. It has no other use. So I say ten years. Ten years to build a prototype, run it through every possible test, build a rocket to launch it, and train a crew. If you can show me that the list of needed technologies means ten years isn't enough testing time, then it will take 15, even 20. The point is that nothing gets done until someone says let do it. Waiting a generation solves nothing.

 

We can't launch tomorrow. We can't even launch in the December launch window. Heck, I have some doubts that we could launch this decade. But we won't be able to launch next decade, either, unless we start doing the engineering.

 

So, in conclusion, unless you can point to some vital technological development that we (a) don't have yet, and ( couldn't develop within ten years if it were made a direct goal, or that the total technological development would be impossible with a 3 billion dollar budget over a eight year period (and yes, I'm man enough to request NASA's entire human space flight budget, and to hell with the ISS), then I'll continue to believe that we could launch the first manned flight to Mars in March 2019, and land on Mars by the end of the year, if the project was started up tomorrow (or in the 2012 budget).

 

PS: The Suicide Run apparently is called Mars to Stay in front of tax payers. I'd prefer calling a spade a spade, but hey, whatever gets the funds.

 

Thanks for the pointer. For those who haven't read it, Zubrin and some colleagues received a small grant to build a Sabatier reactor at the Martin Marietta labs in late 1993. They assembled their testbed out of off-the-shelf components and did 12 runs in December and January 1993--4. They did not use "simulated Martian conditions."* They did not achieve anything like the volume of production needed. They did not purify the output, and waved in the direction of the technology needed to do it. Their longest production run was only 11 hours. They certainly did not achieve hands-off production run.

 

Anyone who thinks that this is what a prototyping run looks like can PM me for some awesome investment opportunities in 100mpg carburetors, hydrogen-powered cars, cold fusion reactors, gold plays, and the like.

 

But to come back to my original question, which was specifically about sealing off the compressor wheel, the first prong of the answer is that we're going to magically avoid dust storms. But dust storms aren't the only time that there are particulates in the air. The second prong is that you can hardly expect us to actually test this technology in Martian conditions without going to Mars first.

 

 

 

Well, yeah. So we're going to use this technology to go to Mars so that we can test it?

 

This is the point, in all visionary technological schemes, where advocates suddenly shift the ground and start talking about other proposals. And, indeed, we get exactly that move. Suddenly, we're talking about "the Suicide Run."

 

 

No. This is stupid. Do your homework. Then we can talk about Mars.

 

 

 

 

 

*What would that even entail? A massive low-temperature centrifuge in an even-more massive wind tunnel? Plus some trips to Mars to assess likely atmospheric particulate rates?

[McCoy]

Re: Mars Colony?

 

*What would that even entail? A massive low-temperature centrifuge in an even-more massive wind tunnel? Plus some trips to Mars to assess likely atmospheric particulate rates?

We know the composition of the Martian atmosphere well enough to identify meteorites as being of Martian origin by examining trapped gas bubbles. We've measured surface temperature, and the fact that we have successfully done aerobreaking there means we've got a pretty good idea of the density and therefore pressure. Those are the relevant factors for the methane generator.

 

What can be done to simulate Martian conditions in this case (what I thought had been done, and I now admit to failing to do due diligence), is

• Build the prototype
  
• Build an airtight box large enough to contain your prototype
  
• Put one inside the other and close the door
  
• Replace the air with a mixture of 95.3% CO2, 2.7% N2, and 1.6% Ar, with a trace amount of ozone and water vapor
  
• lower the temperature inside the box to about 220 degrees Kelvin
  
• Remove 99% of the gases inside the box to get the pressure down to 7 millibars (I believe this is the most challenging part, correct me if I'm wrong)
  
• Turn on your prototype

Again IIRC particulate density would be a function that would include gravity (known), air pressure (known), and wind speed (fairly accurate estimates if no direct measurement). Can cross check by how quickly particulates accumulated on solar panels of the probes on the surface (again, known). Without doing the math, feel safe estimating the density is going to be less than in an equal volume of Earth air. (And average particle size much smaller, which is a problem but not an insurmountable one.)

[Asperion]

Re: Mars Colony?

 

The last 50+ years that humans have been going into space have taught us alot about how to handle that environment - durability, maneuverability, design, and anyting else that is necessary. The Apollo program in the 1960's taught us so much that we puch on the shelf and are not using to the fullest of its ability. In addition, in 1991 the Biosphere 2 program gave us alot of information on environments that we could take with a crew into space on a long mission that will guarentee fresh air, water, and food for the entire mission if done correctly. That is both during travel and once we arrive on Mars.

[dmjalund]

Re: Mars Colony?

 

But there are reasons of patriotism and national identity to undertake this. It is important for people to have goals and it turns out that it is important for nations to have goals too. Without goals the tendency is is to spend too much time just watching TV or messing around on the internet and it is neither healthy or productive.

 

In recent years I have become convinced that one of America's biggest problems is that we as a nation lack purpose. Maybe I'm missing the forest for the trees, but I see a nation lost in celebrity gossip and reality TV shows. Our children need something to dream of besides landing a spot on Jersey Shore. Conquest of space is not the only possible goal for which the US could strive, but IMHO it is one of the better ones.

Yes, it's a matter of whether you'd rather see your child on a reality TV show, or on Mars

[Gnaskar]

Re: Mars Colony?

 

What can be done to simulate Martian conditions in this case (what I thought had been done, and I now admit to failing to do due diligence), is

• Build the prototype
  
• Build an airtight box large enough to contain your prototype
  
• Put one inside the other and close the door
  
• Replace the air with a mixture of 95.3% CO2, 2.7% N2, and 1.6% Ar, with a trace amount of ozone and water vapor
  
• lower the temperature inside the box to about 220 degrees Kelvin
  
• Remove 99% of the gases inside the box to get the pressure down to 7 millibars (I believe this is the most challenging part, correct me if I'm wrong)
  
• Turn on your prototype

Again IIRC particulate density would be a function that would include gravity (known), air pressure (known), and wind speed (fairly accurate estimates if no direct measurement). Can cross check by how quickly particulates accumulated on solar panels of the probes on the surface (again, known). Without doing the math, feel safe estimating the density is going to be less than in an equal volume of Earth air. (And average particle size much smaller, which is a problem but not an insurmountable one.)

 

All I can add to this is some high school level math. PV=nRT. The ideal gas law tells us that gravity simply isn't a factor in determining pressure. Hence, all we need to test this thing is a pressure tank and a strong fan. Like, say the Mars Surface Wind Tunnel Lawnmower Boy was so kind as to point our attention to. It can be tested on Earth. It can be tested with no expensive facility building cost.

 

 

Thanks for the pointer. For those who haven't read it' date=' Zubrin and some colleagues received a small grant to build a Sabatier reactor at the Martin Marietta labs in late 1993. They assembled their testbed out of off-the-shelf components and did 12 runs in December and January 1993--4. They did not use "simulated Martian conditions."* They did not achieve anything like the volume of production needed. They did not purify the output, and waved in the direction of the technology needed to do it. Their longest production run was only 11 hours. [/quote']

 

All technically true, and fair points. However, you failed to mention that "small grant" meant 47,000 dollars (which in a 50 billion dollar project is pretty damn tiny). That they managed to achieve a 94% percent pure output without any attempt to purify it. As they "waved in the direction of the technology needed to do it" they described five specific existing methods that they could easily have used, if they had had the budget for it.

 

They didn't produce anything near the 106 tons needed, but then their prototype weighed 20 kg, compared to the 500 kg device described in Mars Direct. They used 160 watt, compared to the 5000 watt a Mars Direct solar panel would produce (each module carries a literal ton of solar panels) or the 80 000 watt a nuclear reactor would provide (Even a Radio Thermal Generator Array produces 60 times the power used in the test).

 

They did not use "simulated Martian conditions"; that claim was simply me miss-reading "The Case For Mars". I read "can be fully tested in advance in Mars simulation chambers on Earth" as has been fully etc. My mistake.

 

They certainly did not achieve hands-off production run.

 

Meaning that they didn't produce enough fuel to lift a payload from Mars to Earth? Here's a fun fact for you: rocket fuel like methane, liquid hydrogen, CO2 and liquid oxygen (all in high purity form) generally costs about 50 cent per kilo. A Mars return trip calls for 106 000 kilo of fuel. The budget was 47 000 dollars. I'm sure you can do the math, but the conclusion is that they couldn't afford the gasses they'd need to do so much less the tank.

 

But then, they got more money. The improved version is described in this newspaper article or this paper (which sadly isn't available for free). They built the intake system and the storage system, got the whole thing down to 20 kilo, tested it with Martian Air at Martian Pressure, and ran it for ten days strait without interference (this last claim I have from "the Case for Mars", but I can't confirm it from the actual paper).

 

This particular system was designed for a Mars Sample Return Mission, involving bringing just 4 kilo of rock back from Mars, and not quite on the scale of our 500 kg refinery. On the other hand, the full sized refinery can expect improved efficiency as the control systems take up a far smaller percent of the payload.

 

But to come back to my original question' date=' which was specifically about sealing off the compressor wheel, the first prong of the answer is that we're going to magically avoid dust storms. But dust storms aren't the only time that there are particulates in the air. The second prong is that you can hardly expect us to actually test this technology in Martian conditions without going to Mars first.[/quote']

 

Another fun fact, Mars Global Surveyor ha found that most martian dust is magnetic, implying a possible further way of reducing the levels of dust hitting the intake valve. And again I point out that NASA built the Mars Surface Wind Tunnel specifically to test this kind of thing without going to Mars. It can, and must, be pretested.

 

But first, could you please explain what you find magical about leaving an unmanned vehicle in orbit until we can confirm that the landing site (or one of the backup landing sites) is not currently experiencing a dust storm? Or the magic involved in confirming that there is unlikely to be a dust storm there in the next six days (by for example landing outside the dust season)?

 

 

 

I'm scaling down my involvement in this thread on the grounds that it's caused me to spend far too many words defending a plan I only approve off because it's likely cheaper and more likely to be approved than the one I'd prefer. (which is to spend the two heavy launches per window launching six man habs without bothering to get them home; or ideally launch a Sea Dragon [a hundred fricking tons to Mars surface; 8 Sea Dragons equals one Orion] with a crew of 25 each window. I'll have to write up an outline for that one some time.).

[RexMundi]

Re: Mars Colony?

 

Don't scale down the involvement!! The Science, it is Awesome! Besides I want to see the Sea Dragon Outline. I skipped over those for my Hard Sci Fi game since most of the skimming I did on that all seemed to be LEO only stuff, so I went back to Mars Direct setup combined with some other things here and there....(Not to mention a sneaky set up involving a certain Project that looks like this):

 

 

 

~Rex

[Gnaskar]

Re: Mars Colony?

 

If you're going to go in an Orion, don't go in the battlecruiser variant. It's optimized to work as a LEO space station (or staying in Geosynchronous Orbit over Moscow*). You need the good old transport.

* Technically south of Moscow over the equator, but still within firing range.

[RexMundi]

Re: Mars Colony?

 

Oh I'm not going in the Battleship. That's just part of the Hard Sci Fi game I got rolling in the once a month phase. That particular party is in a tight spot right now and the POBB plays into something a bit down the road for them yet once they are out of their current "We're Doomed!" problem and playing around with all their Mars Direct stuff....

 

I just like that Model. So no scaling down the involvement we all thrive on the big words of Science!

 

~Rex

[Lawnmower Boy]

Re: Mars Colony?

 

All I can add to this is some high school level math. PV=nRT. The ideal gas law tells us that gravity simply isn't a factor in determining pressure. Hence, all we need to test this thing is a pressure tank and a strong fan. Like, say the Mars Surface Wind Tunnel Lawnmower Boy was so kind as to point our attention to. It can be tested on Earth. It can be tested with no expensive facility building cost.

 

 

 

 

All technically true, and fair points. However, you failed to mention that "small grant" meant 47,000 dollars (which in a 50 billion dollar project is pretty damn tiny). That they managed to achieve a 94% percent pure output without any attempt to purify it. As they "waved in the direction of the technology needed to do it" they described five specific existing methods that they could easily have used, if they had had the budget for it.

 

They didn't produce anything near the 106 tons needed, but then their prototype weighed 20 kg, compared to the 500 kg device described in Mars Direct. They used 160 watt, compared to the 5000 watt a Mars Direct solar panel would produce (each module carries a literal ton of solar panels) or the 80 000 watt a nuclear reactor would provide (Even a Radio Thermal Generator Array produces 60 times the power used in the test).

 

They did not use "simulated Martian conditions"; that claim was simply me miss-reading "The Case For Mars". I read "can be fully tested in advance in Mars simulation chambers on Earth" as has been fully etc. My mistake.

 

 

 

Meaning that they didn't produce enough fuel to lift a payload from Mars to Earth? Here's a fun fact for you: rocket fuel like methane, liquid hydrogen, CO2 and liquid oxygen (all in high purity form) generally costs about 50 cent per kilo. A Mars return trip calls for 106 000 kilo of fuel. The budget was 47 000 dollars. I'm sure you can do the math, but the conclusion is that they couldn't afford the gasses they'd need to do so much less the tank.

 

But then, they got more money. The improved version is described in this newspaper article or this paper (which sadly isn't available for free). They built the intake system and the storage system, got the whole thing down to 20 kilo, tested it with Martian Air at Martian Pressure, and ran it for ten days strait without interference (this last claim I have from "the Case for Mars", but I can't confirm it from the actual paper).

 

This particular system was designed for a Mars Sample Return Mission, involving bringing just 4 kilo of rock back from Mars, and not quite on the scale of our 500 kg refinery. On the other hand, the full sized refinery can expect improved efficiency as the control systems take up a far smaller percent of the payload.

 

 

 

Another fun fact, Mars Global Surveyor ha found that most martian dust is magnetic, implying a possible further way of reducing the levels of dust hitting the intake valve. And again I point out that NASA built the Mars Surface Wind Tunnel specifically to test this kind of thing without going to Mars. It can, and must, be pretested.

 

But first, could you please explain what you find magical about leaving an unmanned vehicle in orbit until we can confirm that the landing site (or one of the backup landing sites) is not currently experiencing a dust storm? Or the magic involved in confirming that there is unlikely to be a dust storm there in the next six days (by for example landing outside the dust season)?

 

 

 

I'm scaling down my involvement in this thread on the grounds that it's caused me to spend far too many words defending a plan I only approve off because it's likely cheaper and more likely to be approved than the one I'd prefer. (which is to spend the two heavy launches per window launching six man habs without bothering to get them home; or ideally launch a Sea Dragon [a hundred fricking tons to Mars surface; 8 Sea Dragons equals one Orion] with a crew of 25 each window. I'll have to write up an outline for that one some time.).

 

Look. I'm not arguing that the Sabatier process won't work. I'm arguing that it will take some time to build a Mars-ready prototype. It's the difference between claiming that the new automobile engine you've sketched on a napkin will work because, well, other automobile engines work, and actually prototyping it through a thousand hours test.

 

What's magical about planning to avoid dust storms? i) Deorbiting windows; ii) forecasting Mars weather. But that's beside the point. Your compressor is going to push 800 tons of Martian atmosphere through the system. (In six days??) There's your dust storm, right there.

 

But we have now all accepted that the ISRU will have to be prototyped before use, right? That's all I'm arguing. Well, I could argue that every other component in the mission has to be prototyped, too. But that should go without saying.

 

As I have said many times before, my only issue here is that we have to accept that all of this prototyping will take many years to do.

[McCoy]

Re: Mars Colony?

 

As I have said many times before' date=' my only issue here is that we have to accept that all of this prototyping will take many years to do.[/quote']

I don't believe you've said that before. I could be wrong.

 

Many years, more money than the current budget, and too late to start sooner. Let's see if we can get this thing prototyped and field test it on the sample return mission.

[Cancer]

Re: Mars Colony?

 

Aerobraking adds about six months to the mission duration for each planet rendezvous you're going to make, if you go that route, and if the aerobraking timeline is the same for a large manned craft as it is for a small unmanned one. I am far from convinced of that latter, as gas-drag forces generally don't scale linearly, and neither does mechanical strength for structures.

 

The shielding you want for the radiation environment in space is not the same as it is for near a reactor or a nuclear explosion. Neutrons are an issue for reacors and bombs; not so much in the space ambient environment. You can beat both by vast masses of high-Z stuff (Z here is atomic number, i.e., lead), but that's a lot of dead mass to schlep around. My understanding also for the Project Orion designs was that the shielding existed only between where the bombs go off and where the crew is, that is, on only one side of a six-sided house, if you see what I mean. While most of the radiation hazard in space comes from the solar wind, not all of it does, and in general the shielding needed for the solar particle flux has to be deployed in a different direction from the shileding from the drive explosions.

 

The last time I peeked at humans-to-Mars in any serious way, the hard unsolved problem is the environment, keeping people alive for the duration ... a couple years ... without resupply. Propulsion was never a serious issue, except that the mass, space (that is, volume of the spacecraft) and environmental requirements for humans make the payload larger by upwards of factors of thousands both in mass and in cubic yards.

[Gnaskar]

Re: Mars Colony?

 

Look. I'm not arguing that the Sabatier process won't work. I'm arguing that it will take some time to build a Mars-ready prototype. It's the difference between claiming that the new automobile engine you've sketched on a napkin will work because' date=' well, other automobile engines work, and actually prototyping it through a thousand hours test.[/quote']

 

One thousand hours of testing divided by 8 hour work days equals 125 days, which is far less than the six years of development before the first unit would have to be launched to get a man on Mars by the end of this decade. I'd suggest upping it to ten thousand hours of testing, actually, but that still gives 2 and half years to build it.

 

Looks to me like we have another failure to communicate. I'm saying we can and should start a Mars program ASAP, which would take some time to get ready to launch. Engineering takes time. Eighteen months in the computer world, 2 years in the automobile world, about 5 years in the rocket world. I'm not saying we can launch tomorrow. I'm saying we'll never launch unless we start engineering.

 

The last time I peeked at humans-to-Mars in any serious way' date=' the hard unsolved problem is the environment, keeping people alive for the duration ... a couple years ... without resupply. Propulsion was never a serious issue, except that the mass, space (that is, volume of the spacecraft) and environmental requirements for humans make the payload larger by upwards of factors of thousands both in mass and in cubic yards.[/quote']

 

The Space Shuttle had a payload of about 25 tons, and weighed about 109 tons (without payload). It was designed to keep 7 people alive in space for two weeks, and then land repeatedly; flying through a thick atmosphere at supersonic speeds.

 

A Mars Direct hab only has to maintain four people, and only has to land once through a trace atmosphere. Radiation shielding is on the order of the International Space Station's (shielding isn't that high of a priority; any one willing to spend three years 0.4 AU away from backup should be willing to risk increasing their chance to get cancer from 20% to 21%). Heat shielding is also minimal, as it can be made ablative (aka: it burn off on the way down, leaving the rest untouched).

 

Keeping people alive for two weeks (or the six months the ISS does) isn't any different from keeping them alive for 3 years; it just takes more supplies, and probably a couple of backup systems. Or better recycling systems. The most common estimate I've seen is that humans require 5 kilo of resources (air, water, food) a day if nothing is recycled. 5.5 tons per person for a 3 year mission (too much!).

 

If recycling is possible, that goes down fast (but you need a recycling plant). A plant that turns CO2 into O2 with 90% efficiency weighs about 20 kg, plus a number of 5 kilo carbon absorbing plates (they need to be replaced about every six months). Humans process about a kilo of oxygen per day, so installing such a plant reduces the amount of oxygen we need from 1.1 tons per person to 0.1 tons per person (upped to 0.2 to handle leaking). That also means lighter oxygen storage tanks, driving weight down further.

 

Water recycling is more complex, as it generally involves turning it to steam, moving it away from whatever gunk was in it, and cooling it down. It needs a bigger power plant, some strong pipes, and there's always so water left in the gunk when it's vented. Given 80% recycling (which is conservative, I've owned a more efficient one), the 3 kilo of water needed per day is cut down to 0.6 kilo per day, or 0.66 tons per person for the mission.

 

Mars Direct goes even further, drawing all needed oxygen and water needed while on the surface from the Martian air (saving us 600 days of supplies).

 

And that's it for environmental requirements and supplies, really. 7 tons of supplies (for a crew of four), 3 tons of life support, 1 ton of solar power (to run the life support) for a total life support requirement of less than 3 tons per person (additionally, the refinery for using martian air to resupply [with power, reaction mass, tankage , etc] weighs about the same, but it was launched on another rocket, and we don't leave until we know the supplies are waiting for us).

 

10 tons of life support, 20 tons of habitation space (equivalent to the planed hab modular of the ISS, which was supposed to house 6), and about 250 tons of propellant and engines. That's why propulsion is the problem. (The use of a refinery to make fuel on Mars cuts the propellant and engine wait from 550 to 250. That really helps).

 

Aerobraking adds about six months to the mission duration for each planet rendezvous you're going to make' date=' if you go that route, and if the aerobraking timeline is the same for a large manned craft as it is for a small unmanned one. I am far from convinced of that latter, as gas-drag forces generally don't scale linearly, and neither does mechanical strength for structures.[/quote']

 

This is all true, but. Actually using a shield to aerobrake cuts the slowing down period from months of careful nudging into a slightly declining orbit, dipping slightly into the upper atmosphere on each pass, shedding a few meters per second with each orbit to a single 0.5G deceleration (burning the shield in the progress). The Space Shuttle's nose is such a shield, as is the cone shape of the Apollo Command Module. (The space shuttle weighs trice what the Mars Direct hab does, and as you say mechanical strength and gas-drag forces don't scale linearly, making it far easier with this smaller module through a thinner atmosphere).

 

The typical Mars satellite and lander has to be as small as they can possibly be made because they have to be launched on boosters that can barely take 4 tons to Mars Transfer Orbit. The (Shuttle Derived) Ares or the Saturn V can take 46 tons into Mars Transfer orbit. With a 30 ton lander, that still leaves plenty of space for a heat shield for aerobraking and landing.

[Christopher]

Re: Mars Colony?

 

My understanding also for the Project Orion designs was that the shielding existed only between where the bombs go off and where the crew is' date=' that is, on only one side of a six-sided house, if you see what I mean. While most of the radiation hazard in space comes from the solar wind, not all of it does, and in general the shielding needed for the solar particle flux has to be deployed in a different direction from the shileding from the drive explosions.[/quote']

Okay, there is one flaw in your understanding of Projekt Orion you still got not away from:

A Orion Ship does not have to be light. The heavier you build it, the better gets the fuel efficiency. In fact manned Orion crafts have a minimum Weight of 880 tons for the Orbital test Vehicle.

The biggest design above is the "super" Orion design; at 8 million tonnes, it could easily be a city.[7] [...] This extreme design could be built with materials and techniques that could be obtained in 1958 or were anticipated to be available shortly after. The practical upper limit is likely to be higher with modern materials.

 

So when you ask a Orion designer "we need 100 tons for lead shielding" he says: "Sure, no problem. We just have to scale it up a little."