Gnaskar

Re: Cybernetics and Bioengineering: what are YOUR limits?

What you describe isn't a destructive uploading' date=' from my POV. A destructive uploading would be one where your brain dies, and your existing consciousness with it. A "backup" copy of your brain/consciousness is then turned on, and this "new you" continues to live the life you once had. But "old you" doesn't know anything about it, because you're dead, period. [/quote']

 

Using different definitions of things; the number one way to argue past one another. Here are the terms as I use them.

 

Destructive Uploading: Originally a version that involved cutting a cryogenically frozen brain in to narrow slices to assist in the scanning process (as the idea of uploading is older than MRI and CAT scanners), the term has since been expanded to include any process that involves the biological brain being rendered useless (including non-destructive uploads on a dying body).

 

Non-destructive Uploading: A process that doesn't involve the host dying. IA any uploading that isn't destructive.

 

Memory Backup: The process you described. Having a backup "you" in storage, in case of the original dying [in such a way that a normal upload is no longer possible]. (The term here comes from Peter Hamilton's "Pandora's Star")

Re: Cybernetics and Bioengineering: what are YOUR limits?

Imagine the following scenario:

You're at the hospital, in the late stages of lethal effect X (Cancer, car accident, shooting, decease; pick your preference). At one point you black out to the dreaded sound of a flat lining heart monitor. When you next wake up you've been moved to a different room of the hospital. All your aches and pains are gone, vision is back and 20-20, and you think your hearing has improved. You are, however, paralyzed. A doctor is standing over you, checking something on a handheld device. "Good, you're awake. Don't worry, the paralysis will wear off shortly. *pause* I'm sorry, but we weren't able to save your body. Your new one is only temporary, and your insurance covers a custom fitted one, that will arrive sometime next week. In the mean time, you may find your limbs are not quite the length you are used to."

From a technical perspective, you just died. You were dead for maybe 3 minutes before the decision to move to more drastic measures than CPR was made. Your body is lying in the hospital morgue. But from your perspective, you blacked out and woke up again. Is this a copy, or is it "you" in any meta-physical sense? By what arguement can you say your soul didn't digitalize with the rest of your mind? Would it be any different if the body was biological (and your brainwaves and brain structure was "copied" on to a pile of stem cells inside the new body's skull)? Or if it was an actual brain transplant?

That was a so-called destructive uploading.

I assume here that it has become regular practice, but under that assumption I don't think my family and friends would have any more trouble adjusting to the new me than if I have been paralyzed or had a stroke. This might be a side effect of growing up in a rationalist family and hanging out with computer engineers, but it would probably become accepted by the general public fairly quickly as the number of uplifts increased (after all, they don't die, so their numbers accumulate quickly). The key factor is the lack of a grieving period. Your family aren't told that you're dead, they're told that extreme measures were taken to keep you from passing on. Grieving is replaced with adjustment, a far simpler process.

A whole other can of worms is the fanatics that claim that your soul passed on with your body, making you a defacto undead, or the ones that claim that by "cheating death" you are violating the agreements between humans and god, and thus must be killed to allow the rest of humanity access to the afterlife (which both have far more direct potential in a role-playing game than the philosophical questions behind them).

I'll leave arguing for non-destructive uploading to McCoy, as I still need to sort out my feelings on the matter.

Re: Cybernetics and Bioengineering: what are YOUR limits?

This is not a matter of believe. We can't be copy a file with 100% accuracy, 100% of the time. Maybe 99,999999999% of the times. A simple file transfer has in fact a dozen points where it could go wrong. Luckily there is a lot of redundancy and integrity check done, but no process in the IT can ever be flawless. The rules of entrophy and quantum physics do not allow it.

 

Also a digital file is digital by nature. The universe is not, it is a mass of analog signals (light, energy). The only thing with absolute precision is a analogous signal (you just need a conductor with physically impropable characteristics to transmit it without error).

Even if you manage to transmit the analogous singal without any error, every process to transform a analogous signal into a digital sequence is flawed by definition. Analog Signals can be sampeled (this is it what we do with color and sound). It can be very precisely sampeled. But it is still only a sample.

For telephones, music and image information the differences can be held in an margin "that the unaided brain cannot discern any difference". But you can never digitize a anlog signal and restore it 100% ever again.

On the other hand, there is actually far less errors in a file transfer (even one done thousands of times, like most P2P) than accumulates in the human brain over the course of a day. Between cosmic radiation, cells dieing, various infections, things being shaken around by moving, temperature change, etc. the brain is not the static system we'd like to believe. And the chemical markers used to store information in the brain are discrete, not analog. One could argue that the transfer signals are discrete too, as all energy levels are (it just takes so much computing power to be precise with it that for the moment it is considered impractical to model it that way).

Re: Cybernetics and Bioengineering: what are YOUR limits?

Think fast: You can have ONE superpower' date=' what do you want?[/quote']

 

Immortality was the first thing that came to mind (before all the stories that explain why that particular power sucks sink in). I just dislike death.

 

Any time I do answer that without thinking' date=' my answer is "duplication." If non-destructive uploading were possible, I would do it. Even though from the point of view of the carbon-based me we could not recombine. (I am assuming the silicon-based me would be able to integrate subsequent updates.) Maybe if there was a second me active in cyberspace, I could get things done.[/quote']

 

I like the idea of multiple me's working together in cyberspace, given the option of recombining afterwards. It’s permanently creating a “me” that renders my current being obsolete that scares me, especially as I tend to get on my nerves enough when there’s only one of me. I’d probably do it anyway, if non-destructive uploading was the first option that became available (and the doctors responsible have moral scruples about killing “me” before I wake up). Any shot at immortality will do.

 

So while I do see you point' date=' and respect your choice, it is not the choice I would make.[/quote']

I too see your point, and will have to consider me view point further (for example, if non-destructive uploading was possible, why not create an active digital copy now, and update him with my memories again later, and possibly even when I die, thus getting the best of both worlds?).

 

Congratulations. You may be the first person to change my mind through the internet.

Re: Cybernetics and Bioengineering: what are YOUR limits?

Thus' date=' we grow old, get sick and die. As long as we wish that didn't happen we suffer. When we accept the inevitability, we no longer suffer. [/quote']

 

Ironically, that fear of aging, decease and death is the driver behind nearly all research into cybernetics and bioengineering, and the last two pages are about a method to gain a measure of immortality through becoming software.

 

Getting back to the topic, the question of whether humans are software or hardware. As it happens, a computer scientist will tell you there is actually not much of a differance between the two. Software is an illusion invented to save programmers work. However, because software is an illusion in any case, one can use it to emulate perfectly any hardware less powerful than the one you are running it on. Meaning a human brain can be emulated on a sufficiently powerful computer; running a program identical to the brain it was copied from.

 

The disagreement, as far as I can see it, is on whether this computer brain IS the person it was copied from. To me the answer is simple: At the moment of transfer the two "selves" are identical. A second later they're not. This is why I'd only accept a "transfer" knowing the biological me would die (or lose his mind) shortly afterwards, or as a backup.

Re: Cybernetics and Bioengineering: what are YOUR limits?

Uploading is one of those things people can argue over until the cows come home (or until uploading becomes possible; which my AI professors seem to think is in the next few decades*). Personally I have no problem with destructive, last minute, or even post mortem uploading. While they create a "new" person on an engineering level, the end result is that there is only one me, and he is in the computer. It goes around the whole problem of identity by ignoring it, and the last two satisfy many moral arguments because the "original" was dieing or dead anyway.

As for the more the more typical uploading (creating a digital "copy" while the original still lives), it feels iffy to me. Unless it's as some kind of backup (I'd rather have a "younger" version of me wake up after I die than leave nothing of me alive), I have a bias against creating a clone. While I'm certain I'd be a cool bloke to hang around with, there would be some envy involved with knowing that I would grow old and die while "he" would live forever.

Hmm. There's a good plot for a game in that somewhere. Or a movie/book/videogame.

* For once, I personally am more pessimistic.

Re: Quote of the Week from my gaming group...

Crikey...sounds like Guildenstern's player's wife could be a member of the

Inquisition. Who else would make threats like that?

Orks, dark eldar, anything touched by chaos, Imperial Commissars, my mother, space marines, anything wielding a chainsword...

Re: Mars Colony?

Is "two launches per launch window" a defining characteristic of Mars Direct? If we launch three or even four rockets every time Mars is in the right position' date=' two or three uncrewed for each one with people, can we still call it Mars Direct? Seems like many of those objections can be overcome with additional launches. [/quote']

 

Depending on how stringently you want to follow it; yes, two launches is part of the requirements. For one thing, launch cost doesn’t scale linearly with rocket size (which is why Sea Dragons and Orions get proposed), so launching 3 rockets is generally more expensive than launching the same payload in two. For another, there’s a limited number of launch pads, and getting a heavy launch rocket in place, fueled up, and ready to go takes quite some time. Depending on the number of pads available (currently one for this scale launch), and the size of the ground crew, there’s only so many launches you can do before the window closes.

 

The fewer the pads you need to build, and the smaller the ground crew you have to hire, the cheaper the mission is. And the 50 billion budget is a defining characteristic.

 

OK, design the ERV for a crew of three, and have two of them on Mars and fueled up before we launch the crew of six.

 

That would certainly help, and, although no one ever likes to talk about it, would allow the mission to succeed even if one of the ERVs should blow up in transit or crash. Not putting all your eggs in one basket and all that.

 

Send the Rovers on ahead. In fact, design them so they can made operational, fueled, and driven by remote control in case the crew ends up more than a four hour walk from the ERV's.

 

The rovers weigh about 4 tons, so this could be launched by a Titan or a Delta if required. Which doesn’t take up valuable super-heavy launcher pad space, making it a viable option. On the other hand, it’s limited how much help adding 4 tons to the hab is going to be if 3.5 of that is required as supplies for the increased crew size.

 

I don't think it's that much of a political Issue. Not if you get the public behind you.

 

~Rex....says it worked for the other stuff....

 

Therein lays the problem. As of now, there really isn’t enough of a public interest in something like this. The days when Werner Von Braun could appear on national TV and inspire a generation are long gone. The Cold War is over (and has been my entire life span). There are very few things that could excite the public into supporting this kind of thing today.

Re: Cybernetics and Bioengineering: what are YOUR limits?

Possible meltdown/explosion aside' date=' what's wrong with Fusion power?[/quote']

 

Containment.

 

Fusion requires a near perfect magnetic confinement of high energy particles (really hot hydrogen gas) for long periods of time (500 seconds is the current goal). The only way we can do that kind of confinement is with super-conductors, which have to be kept at freezing temperatures. The result is some tricky engineering challenges.

 

Heating.

 

Getting the fuel pellets into plasma state requires a lot of heat delivered over a very small amount of time. The more energy you can give the particles at this point the more energy you can get out of them (the really high energy reactions only occur at really high temperatures) and the longer you can keep the plant running by just inserting more fuel. Lining up the 200+ lasers with nanometer precision isn't an easy job.

 

Current generation fusion reactors just barely brake even, using as much power as they produce before they have to shut down to prevent containment breach.

 

Luckly, all these challenges are computing issues at their heart (given a particularly broad definition of computing issues). Meaning that, with a few orders of magnitude more computing power (I love being able to say that and mean: within 10 years) we could have a computer solve them. That's the fact most people fail to grasp, by the way; the algorithms that can solve these kind of problems, which would have spent millennia trying to solve them when they were first designed now only take years, and will in ten years only take hours. And that's assuming quantum-computing doesn't pan out and make all classical algorithms obsolete.

Re: Cybernetics and Bioengineering: what are YOUR limits?

I wouldn't worry about it too much. Fusion power plants are 20 years away too.

To be fair, they're only about 10-15 years away from producing power from a fusion power plant. The first commercial power plant is planned to go online 2033. ITER, DEMO and PROTO are the power plants in question.

And 20 years for the hardware is pessimistic to the extreme. Assuming Moore's Law holds for another 2 years, well, see for yourselves:

[ATTACH=CONFIG]39698[/ATTACH]

Re: A thread for spaceship and starbase frameworks

I have a half finished system for my semi-hard-sci-fi setting here; though getting it to become self consistent is rapidly becoming a problem. I had to divide it into the parts of the design with stats based on how big they are compared to the rest of the ship (engines, armor and fuel tanks) and the parts that have stats based on how big they are in general (reactors, weapons, crew areas, sensors).

Re: Darkest Planet So Far.....???

Almost is relative. If they left 749 years ago (so we'd see them leave next year) at 95% of the speed of light, they're still 36 years away. And that's assuming they went straight for us, and not any closer stars. More likely, we'd notice them popping up on closer and closer stars at about 10 year intervals.

Of course, as difficult as this kind of spotting is, who's to say they haven't already spread far, far closer?

Re: Mars Colony?

A major part of it is Robert Zubrin himself. The cult leader metaphors flying around are entirely fair. "The Case for Mars" is occasionally painful to read, especially when he moves away from his area of expertise or launches off into inappropriate historical comparisons to the frontier life or the old sea trading routes. He's gotten better over the years, but his early stuff is the most famous (and he was louder back them).

Another problem is that 50,000,000,000 $ looks like a lot of money when you state it like that instead of as 15% of NASA's budget for the next 15 years. People don't like anything that looks like they have to pay more taxes. Everyone wants to explore the universe, no-one wants the bill. The end result is that NASA's budget is ten pages of relatively small budget projects that occasionally add up to something grand. The ISS budget is spread over eight or nine posts, which is part of why no-one knows the full cost of it.

Robotic missions are cheaper, and can do a lot of science when you can guess what experiments you'll want to do. There's also a push towards robotics from the military side of things. They're really fond of semi-autonomous units they don't have to send "deeply regrets to inform you" letters to the next of kin of.

It's an evil circle of no-one wants the bill because the public isn't interested enough, because there's no grand manned missions to draw their attention, because the grand missions are cancelled due to lack of funding.

A Sea Dragon isn't a grand engineering challenge, but it's still a (worst case) 20 year, 80 billion program. No one is willing to pay for that, because there is not enough stuff going into space to support it, because there is nothing that can launch big stuff into space, etc. That's the reason why the Romulus Project calls for their development and use, opening the way for the really cool stuff in space.

Re: Mars Colony?

The Ares V doesn't require the design of a new engine. The Sea Dragon requires two new engines. It's a simple matter of the Ares V being cheaper and faster to develop.

The Delta IV isn't crew rated while SpaceX has a capsule and a launcher. They're ready to go, and Boeing isn't. And there's the matter of a Delta IV launch costing about 50% more than a Falcon 9 (which, at 56 million, is a bargain).

Re: Mars Colony?

Let me just reaffirm the framework for this debate. The question is whether Mars Direct, as proposed by Robert Zubrin and David Baker and advocated by the Mars Society, is feasible using NASA’s human exploration budget with a human landing within, let’s say, 10-15 years. For the sake of argument we’re assuming that politics are not involved in the decision at any level, meaning no side project clambering for a share of the funding, no interference from the senate or the POTUS, no budget increase. 3.5 billion a year for the next 15 years is 52.5 billion, allowing 200 million a year for the next ten years to continue NASA’s involvement in ISS at a reduced rate.

With this in mind, I’m going to deliberately ignore that the current NASA director is good friends with the CEO of the private company designing the VASIMR, and consider the engine under its own merits. I’m going to keep in mind the lesions NASA has learned from ISS, and only point out in passing that the last module to be added to it, Nauka, is designed, built, tested, launched and attached by Roscosmos, and thus not much of an orbital assembly test bed for NASA (just to not be called on ignoring that argument). I will also note the VASIMR is, objectively, a fantastic station keeping device, capable of boosting the station up several hundred meters a month on virtually no propellant, or ramping up the mass flow and doing a short, 3 week, boost of almost a kilometer.

So, let us address NASA’s concerns about Mars Direct as described in Portree, 91ff:

1: ERV is too small to transport a crew of 4, let alone 6, back from Mars.

2: A crew of four is too small.

3: A Mars orbit rendezvous is risky for a human crew.

4: Zubrin’s weight estimate for the hab is optimistic.

5: The Ares booster described by Zubrin is too small to handle the above concerns.

I’m not adding the ISRU to the list of concerns, because every NASA plan since then has called for it. The Design Reference Mission (both scrubbed and not) and the Solar Electric Transfer Vehicle called for it. NASA has set up a facility to test ISRU, implying that they expect to use it at some point. So while I agree that the compressor is a weak point, it is not in and of itself a show stopper. If we want, we can organize a robotic Mars Sample Return Mission based on it (this would fit under the robotic exploration budget, which is due for a new mission anyway) before sending the first ERV. The cross feeding of these two missions adds a tiny but exploitable leniency in the budget for ISRU development.

Now then. To work.

Let’s start by noting that concern 1, 4, and 5, and indirectly 3, can be solved with the same solution. They all point towards either a bigger booster or orbital assembly. We don’t really have a choice here, as it would no longer be Zubrin’s Mars Direct with orbital assembly. So to start with we have to look at the Ares Booster.

Now, the Ares Booster is not the brainchild of Robert Zubrin. It was designed David Baker and Sid Early of Martin Mariette in the early nineties. It was designed around the following concept: place four Space Shuttle Main Engines (SSMEs) under a modified Space Shuttle External Tank, add two Space Shuttle Solid Rocket Boosters (SRBs), and put a standard H2/LOX upper stage on top of it. The idea was that since all components already existed, the Ares would be cheap to design.

What immediately strikes me as wrong with the Ares design is the SSMEs. The Space Shuttle’s engines were designed to be reusable, driving up their cost and complexity, while decreasing the efficiency. I would have used some older, cheaper engine, like the RL10 (Saturn V’s second stage engine, still used today in Delta IV rockets) or the RS-68 (another Delta IV rocket). As it turned out, NASA agrees with me. Meet the Ares V. The Heavy Launch Booster of the Constellation program replaced Baker’s 4 Space Shuttle Main Engines with 6 cheaper RS-68s, increasing capacity significantly (by 34%, in fact, for 188 tons to LEO).

Constellation was, of course, cancelled a year ago, and it was noted that the Ares V would only be ready sometime in the mid to late 2020s under Constellation and the Constellation project would cost 100 billion by then. This has to be addressed before I claim the possibility of using the Ares for a 2020 manned mission.

So here is where Constellation went wrong. The Constellation program was designed around the following parameters: First design a crew launch vehicle with a 25 ton payload, the Ares I, to allow continued ISS operations after caning the Shuttle. Then develop a spacecraft akin to the Apollo spacecraft (the combination service module and command module), known as Orion or the Multi-Purpose Crew Vehicle, first as an ISS life boat and later as a transport for Moon/Mars missions. Then develop the Ares V along with an Earth Departure Stage and a Moon/Mars Hab (Altair).

My proposed alternative is as follows: Ares I’s tasks can be done by a Falcon 9 (expected to be crew rated by 2015) with a Dragon capsule. At 56 million per launch, SpaceX’s Falcon is cheaper than the Ares I’s construction cost alone. Orion is useless of this kind of mission, especially if we want to rule out orbital rendezvous (concern 3). Altair is designed for Moon operation, and thus is mostly fuel (as the moon has very limited ISRU capability). Cut all of those from the budget and development plan.

Shutting down Orion gives us another billion a year, but using them would be going away from our framework (total cost of up to 50 billion), so that money goes to ISS.

So, under this new framework, an accelerated design process for the Ares V combined with an increased budget for it can allow us to get it ready within the 8 years before we first need it. One can also argue that we could share the design costs of this particular vehicle with other projects given the obvious usefulness of a heavy booster. The Lunar Quest Program, New Frontiers, Space Technology, and Space Launch Systems programs, for example.

So, with a 188 ton booster in hand, let’s see what we can do to deal with our concerns.

Concern 2: Crew Size.

The only concern that is independent of booster sized, so it has to be addressed first. NASA generally wants a 6 man crew for its Mars missions. NASA generally also wants one of those crew members to stay in orbit over the planet to keep an eye on the orbiting return vehicle Mars Direct rules out. So, given no orbiter, we could do a five man crew.

The one thing Mars Society is doing to promote its plans is leaving a crew of four in the middle of nowhere to look at how that works out in practice. The answer is that it works out quite well. To be fair, I’ll look at the feasibility of the mission with both a 4 and a five man crew.

Concern 1: ERV is too small.

The ERV cabin weighs 11.5 tons. With the increased load of the Ares V, that can be increased 34%, to 15.4 tons. Can this be shown to be a significant improvement in cabin size?

The cabin mass is broken down thusly:

• Structure, furniture, shielding, control systems and spare parts: 5.7 tons
  
• Life support, power and consumables (scales with number of crew): 5.8 tons
  

So, if we keep the four man crew the increase in size for the cabin is from 5.7 tons to 9.6 tons. That’s a 68% increase in size. If I had to estimate its size based on ISS modules of a similar weight I’d say it was around 75m^3-100m^3 in pressurized volume. Enough to give each crew member a private 10m^3 room and still have a spacious common area. Note that the ERV would be a micro gee environment, meaning cubic meters are more descriptive of size than square meters.

But what about a 5 man crew? Increasing the consumables by 25% gives us 7.2 tons of non-structure, and 8.2 tons of structure. A 43% increase in size, or a 15% increase in size per crew member. Note that it’s just 1.4 tons smaller than the four man version, so still has somewhere between 50m^3-75m^3 of interior space. That still allows a 6m^3 private room for each of the crew.

In conclusion: The Ares V allows the use of an expanded ERV capable of handling a crew of four in conditions equivalent to current standards, or a crew of five in conditions that aren’t too rough. The analysis is extremely sensitive to the weight of the life support systems, a field that has seen advances since the proposal of Mars Direct (for example, we’re carrying 500 kg of washing water per person on this trip, which could be halved with a 5% improvement of the recycling, giving us a ton of more space).

Concern 3: Mars orbit rendezvous is risky.

We don’t need orbital rendezvous around Mars. We do do one in Earth orbit, as the Ares V isn’t crew rated, so we need a Falcon 9 to load the crew onboard.

Concern 4: Zubrin’s weight estimate for the hab is optimistic.

The Ares V gives us a capacity of 33.9 tons for the hab, compared to Zubrin’s 25.2 tons; an increase of 8.7 tons.

The Hab’s landing mass, by the original plan, is as follows:

• Structure, furniture, shielding, control systems, science kit and spare parts: 11.2 tons
  
• Life support, power and consumables (scales with number of crew): 11.8 tons
  
• Rovers brought along: 2.2 tons.
  

This allows us to increase structure by 8.7 tons (with a four man crew), or 5.8 tons (with a five man crew). At worst, that’s a 50% increase. Assuming Zubrin wasn’t off by more than that, we’d still have 200m^2 to divide amongst a crew of 5, and ESA studies seem to show that 200m^2 is good enough for a crew of six for this kind of mission. We can also further increase the ratio by going with the NASA standards for rations, for 2 tons less food brought along, but better rations give us a happier crew so that’s a worst case option.

Concern 5: The Ares booster is too small.

We’ve upgraded to the Ares V, making use of the research that has already been done on it, and reducing development time by cutting the crew capable requirement.

Can we do it for 50 billion?

That is the million dollar question. It also requires a financial background to determine with any certainty, so unless there is someone with that background and access to a budget breakdown of the Constellation program on these forums we could argue ‘til the cows come home. With typical NASA launch costs for the Ares V we lose 10 billion for the heavy six launches required and 0.2 billion for the Falcon 9 launches. If the Ares V launch costs were at market standard instead, launch costs would only be 3 billion total (keep in mind that bigger boosters tend to be cheaper per kilo than smaller ones).

Is waiting for the VASIMR to be capable of Crewed Mars Missions a viable option?

The VASIMR engine is a) far more expensive than a chemical rocket, about ten times the weight of a chemical rocket for the same weight class craft, c) requires a heavy power plant. Given a potential near future power density of 2kg/Watt, a VASIMR capable of transporting a mission of this type (50 tons to Mars orbit) in less than 180 days would have a payload fraction around 3%.

The result is a requirement of a 1600 ton monstrosity the size of four International Space Stations to move the payload to Mars. This battleship is reusable, but this really doesn’t help it’s case much. A smaller SETV type craft could be used (it would spend a year bringing the payload into Earth escape velocity before the crew dock from a smaller chemical rocket), but these can only be used twice and require four launches to put together (plus one per payload).

When Charles Bolden talks of a manned 39 day flight to Mars, he’s assuming a power density of 0.5kg/Watt. That would be optimistic if he was talking about an unshielded nuclear reactor with no cooling system. But he’s talking about solar panels, which currently do about 20kg/watt. That kind of improvement is nanotech age stuff that we might find sometime next century, not the stuff of near future Mars missions.

Re: Mars Colony?

I just don't believe that you're Smarter Than All NASA. NASA concluded that a direct-to-Mars project was impractical (short of nuclear-thermal rockets).

The assumption here is that NASA decides what to do with it's budget. Except Nixon was the one to shut down Apollo and started the Shuttle Program, Bush senior killed the 90-day plan but started the ISS, Bush junior started Constellations, which was then canceled by Obama (who's also shutting down the other two). And the senate is keeping Orion (the Multi-Purpose Crew Vehicle, not the Pulsed Plasma Propulsion variant) alive, despite NASA's desires.

With Apollo or the 90-day plan we'd have a man on Mars already, with a total price for the project equivalent to the ISS (and the Shuttle for the Apollo). With Constellations we'd have had a heavy booster (190 ton class) and a crew launcher (25 ton class, Shuttle Derived) by the time the Shuttle went offline, allowing it to be cheaply replaced by a more traditional launch architecture. We'd also have a Moon Return Mission by 2020. They were too expensive for the presidents' PR advisers, so were cancelled. But, except for Nixon all of these guys increased NASA's budget. With or without Mars Direct, NASA isn't the problem. NASA loved Constellations, but it was cancelled for being "lacking in innovation" and "over budget". Lacking in innovation was the whole point. It's what one would call incremental development.

That's how we got to the current schedule:

 

i) Space station (learn how to build stuff in space);

ii) To the asteroids, with ion drives;

iii) Make fuel in space (with lunar ice or asteroidal ice or some other brain storm; but make fuel in space);

iv) On to Mars by, say, 2035, although that date seems to be slipping back.

And Ion Drives will not be used for anything but light satellites for a long time. No one seriously suggesting using them for crewed flight. The Solar-Electric Transfer Vehicle mentioned in the 50 years of planning document is spending months in the Van Allen belt (which is like being in a constant solar flare). Obama's "flexible path to Mars" basically means spend money randomly (design a 21 ton crew vehicle, discontinue your only crew rated launch vehicle with a capacity over 20 tons, continue the ISS zero gee health studies and micro gravity production studies, but stop all orbital assembly and refueling studies. Vaguely point at the asteroid belts [but no money toward a space-rated EVA suit that allow any flexibility, no system to leave the Orion space for EVAs, and no actual way to do anything but an asteroid flyby]).

So, yes, the current plan vaguely pointed at an asteroid. Not in the belt, though, but a Near Earth Asteroid. There is no plan of mining them, either, and the crew vehicle runs on a propane chemical rocket. The original plan was for a methane rocket, but it was changed at the last minute. No plan has called for making fuel in space (here defined as in vacuum) since O'Neill’s Island Three plan.

If you’re going to use NASA’s current plan as an argument, look at it first. The Space Station is finished; scheduled to crash in 2020. No new NASA modules will be added, so no more building in space. Current Schedule is thus:

i) Deorbit Space Station, after spending another 100 million or so getting our last crews up on Russian rockets. Research human research, space medicine, life sciences, physical sciences, astronomy and meteorology in the last few years of the program.

ii) Decide in 2015 what to do about the lack of crew rated boosters and heavy lift vehicles. Cancel all half finished projects relevant to this.

iii) Do an asteroid flyby sometime in the next decade. Maybe. If a booster is made.

iv) Make light Ion Satellites with RTG power for exploring the outer solar system.

None of this is relevant to the question of how to send a crew to Mars.

Re: Mars Colony?

What I meant was that while we can go to Mars' date=' given time and effort, the precise details of Mars Direct (that is, a 50 billion dollar project doable with current technology) make it an impossibility. [/quote']

 

I respect that that's your educated opinion as technology historian (hope I got that right). Mine, as an engineer (soon to be, anyway; I finish my first master in about 18 months), is contrary (but see my discussions of the word “technology” later).

 

See Portree' date=' 91ff.[/url'] The ERV was judged too small, a docking manoeuvre in Mars orbit was rejected as too dangerous, and the weight estimate for the Mars landing vehicle was raised by 50%.

 

The weight estimate was increased 50%, and number of crew was raised 50%. There's a bit of a correlation there. The ERV was definitely too small for the increased crew. (He notes that the Mars Direct ERV was too small for 4 "in the options of many", then sources an unpublished section of a report published two years before Mars Direct was proposed. An report infamous for proclaiming the need for giant ships to house a crew of four for a 30 day stay on Mars. Including the construction of "Space Station Freedom" as a construction site for it's assembly.*)

 

6 ESA and Roscosmos astronauts are currently spending their second year in a 200m^2 facility designed to simulate a Martian mission. The Mars Direct ERV is about 80-100m^2 (depending on how much of the rations have been eaten), and is in use for 6 months. The Mars Direct Hab is 200m^2, like the dummy one, but has only four crew.

 

And, though I scarce need repeat it at this point, and Lawnmower Boy only referred to it as NASA’s alternative to expanding the ERV, Mars Direct calls for no docking maneuvers or orbital construction. Hence the name.

 

*Space Station Freedom eventually became the ISS. The original budget estimate for it closely matches the ISS's cost, despite the ISS being a quarter of the size.

 

As usual' date=' that has led to calls to use the more realistic VASIMR and solar-electric drives instead. At which point we're back to relying on orbital infrastructure and working on the International Space Station. And, so, welcome to 2011.[/quote']

 

I'm sorry? MORE REALISTIC? The best Ion Drives in existence require 25kW per Newton. VASIMR (the flagship of the Ion Drive Advocates can manage a whopping 5 newtons. If you feed it 200,000We).

 

By comparison, a metric ton of solar power panels gives off 5,000We. So a solar powered VASIMR ship is 40 tons of panels, half a ton of engine, 100 tons of payload (going by the Design Reference Mission requirements), and 20 tons argon and tankage.

 

A day worth of acceleration provides this ship with 0.27m/s. It needs 3,386m/s to escape Earth gravity from low earth orbit. So, in 34 years or so it will be good to go. (Yes, you can cheat, using tricks to get this down to about 5 years). VASIMR is brilliant when your payload's weight is around a ton or so, and can really benefit from the power available when the engines turn off.

 

The Solar-Electric Transfer Vehicle calls for ultra-thin, self erecting, radiation hardened solar panels 200 meters across. At that point, using the panels as a solar sail would actually increase thrust noticeably. Now who's asking for magi-tech?

 

Nuclear Electric Ion Engines will be the cargo transport of the twenty second century, largely because they can travel between Mars and Earth at any time, rather than waiting for launch windows. They may be able to carry a 50 ton payload to Mars in about a year (with a mega watt VASIMR and reactor). But that would require a vacuum rated nuclear power plant, and those are taboo.

 

And' date=' Chris: minimum nuclear bursting charge [i']still [/i]does not mean minimum radiation. Here. Knock yourself out.

Project Orion still doesn't use off the shelf nukes, Here, see the other side of the story.

 

I've been very polite about Zubrin's Mars Direct proposal' date=' the one that you seem determined to push. [/quote']

 

As I’ve tried to make clear from the start, I only support Mars Direct because it’s cheap enough that you can pitch them to politicians without them running for the hills (50 billion over 15 years sounds a lot better than 150 billion over ten). I’m a Mars to Stay advocate at heart. In fact, my alternative to Mars Direct is published in this very topic (and I’d love to have you take a look at it and point out any weak points. I only sat down to think about a few days ago, there’s bound to be some bugs that should be ironed out before I start seriously spreading it around.)

 

I even conceded that it might be possible with technology that hasn't been fully developed yet.

 

And that is, indeed, if you're out for blood, a contradiction.

 

If that is a contradiction then we are using different definitions of either technology or develop. I’m not thinking the kind of development you’d need to get a fusion drive here, we’re talking the challenges involved in making a filter that can let 200 tons of Martian air pass without clogging. I’m thinking technology ala making a duel core computer instead of a single core, not building the world’s first computer.

 

You are not making it easy to stay polite here.

 

At the time I started writing my last post, you had just written a blanket denial ignoring the last four pages of debate. You had also used the word “impossible” which has always been a bit of a berserk button when the claim in question doesn’t violate known physics (calling an engineering challenge impossible to an engineer is a good way of making him build it just to prove you wrong). By the time I had posted, you had clarified your view point, making the second half of my post obsolete and inappropriate.

 

I considered removing it, but by the time I had clicked edit you had made your newest post, and it would have been bad form to edit the post. I apologize if this caused you offence. I’ve already apologized for the post itself within the actual post.

 

On the other hand, if I misunderstood you here, and it’s my pigheaded insistence that Mars Direct is possible that’s making it hard to remain civil, then I suggest we agree to disagree. Neither one of us is likely to budge at this point, anyway, and we’ve provided enough of a background to let the others decide on their own opinions on the matter.

 

This seems easy enough to resolve. Each of you put up $25 Billion and we'll see who's right.

If I had 25 billion I’d start the program myself and hope NASA or private investors would provide the other half. As stage one is developing a 140 ton LEO booster, I could fall back to making money on commercial space flight until I had the rest.

Re: Mars Colony?

but I need 50 billion to do Mars Direct

No. You. Don't.

 

Mars Direct is impossible. We've been through this. Pick at a "detail," and the whole thing falls apart. I think it's pretty clear that this is a fantasy number. A little more respect for your erstwhile interlocutors, please.

I'm sorry. I should have said: "The Johnson Space Center Costing Group (Aka NASA) estimated a cost of 55 billion 1993 dollars for 3 six man Mars-Semi Direct missions (a variant that includes a Mars Orbiter for more space on the return trip) landing a decade later, including 'the development of all required technology'*, which I think I could get down to 50 billion by going with a 4 man crew and dropping the orbiter (thus saving myself six 140 ton launches with a crew rated transport, or an estimated 4.2 billion in launch costs alone)."

*Source is The Case For Mars; take that as you will.

We did not agree that Mars Direct is impossible. That was not the conclusion.

But I am not saying "nay." I'm saying that a realistic timetable is quite long. That's it. It's all I'm saying. The endless prolongation of this thread by people unwilling to take my fairly well-informed objections on board thus seem to me to justify a measure of repetition.

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.

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.

There seems to be a failure of communication here. I'm not arguing that the ISRU is impractical. I'm arguing that the Mars Direct developmental timeline is unrealistic. I personally don't think that even 10 years would be enough time for such an ambitious developmental programme; but a century seems far too long.

 

To summarise, and perhaps I should have put this more clearly at an earlier point in the discussion, it will take a good length of time for us to develop the technology required for Mars Direct or various related projects.

 

That is, it will take time.

Again. Nothing about a Mars trip is implausible. We just don't know how to do it yet. Mostly because we haven't worked out the concrete details of tedious sweat-the-small-stuff. That's why it isn't on the agenda for the near future.

Sorry. Quoting someone contradicting themselves is a low blow as debates go, but come on, nothing is truly impossible.

Edit: Cross posting. Always a drag.

Re: Mars Colony?

Sea Dragon looks like a Lot of Gusto' date=' just think of the Marketing Revenue if you Paint a Sea Dragon like a Can of *Insert Beer of Choice*.....[/quote']

 

Or have the big car producers scrambling to give you money so the rovers on the Mars Colony can have their logo on front.

Or having the fast food chains fight over what wrapping to have around the first meal eaten on another planet.

Or TV rights for the big-brother 24 hour cameras in the hab.

Or a seat on the aircraft carrier for the launch (camera crews extra, of course).

Or the first video game played, the first book read, first movie seen, first roleplaying system used, which TV channel is beamed to the crew.

Or the logos on the EVA suits, brand of clothing worn under, type of boot used, shipyard that built the launcher, country who's citizen was first out the airlock.

Or whether the computers used are Macs or Windows based, Dell, HP, Amilo, etc.

Or auctioning out the first words spoken on Mars.

 

I don't like this kind of marketing, but I need 50 billion to do Mars Direct, or 150 billion to do Romulus. If I can't get that from NASA...

 

Hm, looking at all the options, I'm temped to start up an indiegogo.com account and see if the money actually is there.

Re: Mars Colony?

Seriously' date=' are we just STUPID when it comes to our Space Program? How Hard is it to look at some paper and go, "Gee Whiz, if we use the Shuttle to do this it's gonna cost a lot by golly, Why not build a Sea Dragon and just do it in one shot?"[/quote']

 

The dream behind the Shuttle was that it could be launched once a month for virtually nothing, do maintenance, experiments and construction in space, and come back two weeks later. Once it was pointed out that they didn't actually have anything planned that would demand sending up 300 tons a year, let alone the 6,000 provided by the whole fleet, they came up with the idea to make the ISS.

 

Then the shuttle dream died, and it turned out that it could only launch once every six months, it cost more than planned and the first stage wasn't reusable. The fleet was down sized, and the ISS, originally a five year experience become a 30 year marathon and the single most expensive thing ever built. Someone should probably have pulled the plug back then, but the shuttle created jobs in just about every state (part of why it cost so much in the first place) so was the Senate's darling.

Re: Mars Colony?

Table of Contents:

• The Romulus Project
  
• The Sea Dragon
  
• Landing Habitats
  
• Mission Summary
  
• Phase one: Finding a site for the base.
  
• Phase two: Human verification.
  
• Phase three: Colonization.
  
• Phase four: Profit?
  
• A Quick Guide to Payload, or How to Make Your Own Mission (This part applies to all non-Orion Mars Missions)
  

The Romulus Project

Well, I had to name my plan something. Romulus, the legendary founder of Rome (which, as we all know, wasn’t built in a day), claimed by some to be the son of Mars, makes an obvious name for a Mars colonization project. And let’s be clear, the goal of a mission to Mars is to colonize it. No “flags and footprints”, no “been there, done that”, not even a 600 day mission but a permanent research base on another planet.

The idea of The Romulus Project is based on some lessons learned from Mars Direct, the Space Shuttle Program and the International Space Station. And the main lesson learned is this: Orbital Assembly is expensive and complex, well beyond the costs of building a bigger rocket. Or as a more general rule: Don’t muck about.

The Sea Dragon

Made mostly from 8mm steel plating in a submarine construction facility, but featuring the single largest rocket engine ever built, the Sea Dragon is an awesome sight. Its 150 meters long, 23 meters in diameter, and towed out to its ocean launch site by an aircraft carrier (which also carries the payload, refueling system and mission command out). A launching Sea Dragon moves with a force of 360 Mega Newtons, 45 times more than the current record holding rocket engine, the Soviet RD-171, and 11 times the biggest rocket ever launched (The Soviet Energia, which used four RD-171’s for its first stage).

The two stage Sea Dragon could lift a completed International Space Station into orbit with a single launch. Put a third stage on top instead and it can take 180 tons into a low energy (250 day) Mars Transfer Orbit or 160 tons into a higher energy (180 day) Mars Transfer Orbit. You could go even faster, but payload fraction drops off rapidly and aerobraking gets more difficult the faster you’re going.

With current technology going from Low Mars Orbit to the surface requires about 38% of the ship’s mass for braking systems and landing rockets. That leaves us with 110 tons landed from a low energy (cargo) transfer and 100 tons landed from a high energy (crewed) transfer. This can be improved slightly with careful optimization of the stages, but makes a decent base line assumption for a rocket designed to be cheap rather than efficient.

The Sea Dragon is an expensive launch (a rough estimate would be a billion dollars initially, brought down to about half that within 20 years), but with a capacity three times anything else on the planet, it’s still cheaper per kilo of payload than any alternative. It’s also going to be expensive to design (to the point where it may be worthwhile to team up with SpaceX or some other agent with experience with multiengine launches (in the age the spawned the Sea Dragon getting multiple engines to work safely together was considered an enormously complex computing challenge; today my calculator could probably do it and building a bigger engine is considered a complex challenge).

Landing Habitats

There are some pretty definitive limits to how much you can safely land in one piece on a planet. Especially if that something has crew inside. As these limits are completely unknown at the moment, I choose to go with 50 tons; Well, technically 80 tons, 50 of which is useful payload. If that offends your sensibilities feel free to assume I mean two 25 ton habitats whenever I talk about a 50 ton one.

The standard way of landing something like this is having it ride in on a shield, looking vaguely like a mushroom falling upside down. The shield is discarded a few kilometers from the surface, and the lander starts burning retros. In less pop-sci-fi vernacular, we use rockets to brake. Smaller (up to about 20 tons) payloads can also use parachutes to help slow down. Assuming everything works correctly, the payload lands gently, hitting the ground at about 0.5m/s. Even so, most mission plans call for the crew to be suited up in these kinds of operations. It doesn’t take a very hard landing to split parts of the hull.

While we’re on the subject there are a few traits of all Martian habs, and for that matter rovers, that bares mentioning. First of all, Mars is cold. And not just Norway cold. The Martian equator is about as warm as northern Norway, and it gets colder the further you get from it. At the poles CO2 is frozen most of the year. As such, pressurized areas on Mars have a large number of small Radioisotope Thermoelectric Generators (RTG) imbedded in the hull, that heat the interior and provides something for the air to leach from without harming the crew.

What they’ll do with the Extra Vehicle Activity (EVA) suits I don’t know, though current ideas involve a backpack mounted RTG and a network of heat conductive wire. I’m not sure how I’d feel about being heated by a nuclear backpack, even knowing that Plutonium 238 is only dangerous to me if I eat it (or touch it; it’s warm, that’s why it’s there in the first place), but at least it works.

Mission Summary

Phase one: Finding a site for the base. A satellite network and twenty rovers are boosted into Mars orbit with the goal of finding viable colony sites. The rovers offer detailed evaluations of up to twenty potential areas.

Phase two: Human verification. Depending on the exact technologies available either 3 crews of 3 or 5 crews of 2 are launched to examine the top potential sites. The crews are equipped with a rocket capable of sending them to the selected site upon the completion of the study.

Phase three: Colonization. Human colonization begins at a rate of 56 per launch window (about 26 per year). A large and semi self sufficient base is built, with on site production of more and more vital resources established. Wide spread planetary research commences.

Phase four: Profit? Reusable commercial transportation to Mars established, with maintenance costs inflicted on “native” Martians rather than Terran investors or emigrants. Prospects of mining on Mars examined, as well as Mars based asteroid belt exploitation. The operation will never be profitable to the initial investors, but profit motives may at some point begin to drive the effort to colonize Mars.

Phase one: Finding a site for the base.

In this phase a 100 ton satellite network, powered by Radioisotope Thermoelectric Generators (RTGs) is put in orbit around Mars, along with 20 2.5 ton rovers and their landing gear. Over the course of 2 years this network will map the planet and it’s weather patterns, search for locations with accessible water, as well as exploitable local resources. The network consists of 30 light (1-2 ton) satellites for Low Mars Orbit examinations, 9 dedicated short range communication satellites providing GPS signals and planetary communications for later phases, 3 high powered long range communications satellites for rapid Earth-Mars communication, and 30 disposable light (up to half a ton) probes.

The top twenty sites get a visit from a rover, each of which is equipped with a ten meter drilling rig for deep sample retrieval, a deep ground penetrating radar, and a small science lab geared toward soil analysis. With access to a small machine shop, all of this equipment can be removed, turning the scientific rover into an automated transport truck. The rovers are also powered by RTGs (the same model as the satellites, in fact, for economy of scale purposes).

Phase two: Human verification.

In the second launch window a pair of Sea Dragons are launched. One with three hab modules (each weighing 30 tons) and 5 spare communication satellites, and one with three 40 ton, fully fueled Mars Ascent Vehicles (MAV). The hab modules are each met by a crew of three in orbit. The MAVs will stay in Mars orbit until a site has been determined, when one will land at each failed site, with the last acting as a spare.

Should in-situ propellant development (ISPD) be available, five 20 ton habs and 8 unfueled MAVs (each weighing 10 tons, but with a 5 ton refinery system for each included) with be sent instead, and the crew for each hab reduced to two. These will land at the top three (five) colony sites along with a MAV. One MAV lands at each site, and we have three spare should something go wrong with the propellant production.

Note that while the MAV launch seems to violate our landing capacity by being 120 tons of payload to the Martian surface, the extra 10 tons are in the form of rocket engines that are both used for a soft landing and the later launch. They would normally be counted amongst the 38% payload wasted for landing on Mars, but count as payload in this instance.

Phase three: Colonization.

A pair of Sea Dragons leave Earth in the third launch window, each carrying two 50 ton habitats and a crew of 28 (14 per hab). Each hab is a 3 story structure with each story slightly smaller than the one beneath (diameters ranging from 11 to 13 meters). The top floor is a storage/research center (storage in flight, research center on arrival). The central floor consists of a ring of 14 6m^2 bed rooms, with bathrooms in the central area. The first floor has the communal parts of the structure, including kitchen, living room, gym and several offices. The central part of this floor, the mess hall, is protected against solar flares, and works as a storm cellar against solar activity.

The habs additionally have a number of rovers, construction tools and power sources with them (making up about 10 tons worth per hab). Note that these first habs don’t leave with a full crew (each hab launches two or three short), leaving space for the crew that left two years ago.

The first crew of 56 Martians have the following priorities for their first (Martian 668 day) year: Become self sufficient with regards to food production (including paving the way for a later transport to bring chickens, salmon and goats), obtain a steady supply of water, construct large scale underground habitat (capable of supporting 500 people), and create a materials industry capable of supporting the population with bulk materials (steel, aluminum, bricks, concrete, rebar, glass, wires, fuel, air, water) leaving only highly technical equipment to be imported.

The next several launch windows feature three launches. Two with more habitats and one pure cargo launch. As the underground habitat on Mars is finished, the sent habs will start featuring bunk beds for the crew, doubling their capacity for crew (at the expense of bringing less equipment). The first cargo hauler will carry up a nuclear reactor, giving the crew the energy they need for any early challenge.

Phase four: Profit?

In addition to survival, planetary research and expansion of reach for such research (by setting up remote refueling stations around the base camp, or even a small satellite community near some interesting feature [with its own food production, allowing expeditions to resupply there]) joint Martian/Terran efforts will go towards developing a reusable methane Single Stage To Orbit (SSTO) craft for Martian operations. When such a vehicle exists transport to Mars becomes much cheaper. A methane powered rocket launchable with a Sea Dragon can take about 120 tons to Mars Orbit. If it could be refueled there, it could be returned to Earth for another trip. This still requires about one Sea Dragon launch per two trips to bring up the fuel needed, but with more people sent per trip and fewer launches per trip, it’s clear how this becomes cheaper.

Even if orbital refueling is not available a Martian SSTO still makes the mission more efficient, as each Sea Dragon launch can put 160 to 180 tons in Mars Orbit, where the SSTOs can retrieve them (increasing payload capacity by 38%; or effectively more as the payload no longer needs to be sturdy enough to land on its own). A Martian SSTO is also an invaluable tool for long distance travel on Mars; allowing research posts to be set up anywhere on the planet.

A late stage Earth launch might consist of a 50 ton transport designed to make a number of trips between Earth and Mars. It would be fully refueled and possibly even resupplied in Mars orbit (meaning no further heavy launches for Earth), putting much of the cost of colonization to Mars instead. This could eventually allow private citizens the chance to buy a one way trip to Mars for about a million dollars (assuming the most efficient launch cost of today becomes the normal launch costs of the future). Each such transport can take one group of 30 colonists each four years (every second launch window), so only eight would be required to maintain the 112 per launch window travel rate of the early transports. Assuming the transport is rated for about twenty trips they’d be ten times as price efficient as the early transports.

If water is found to be plentiful on Mars, as is consistent with current understanding, another potential advancement for a transmartian transport would be the Nuclear Thermal Rocket (several prototypes of these were built in the 60’s; google NERVA if you want the retro-tech variant). An NTR driven transport could make the trip with about 100 tons, or do a one way delivery with about 275 tons. (Yes, a 1975 Mars Mission in an alternative universe could have landed 170 tons on Mars in a single launch.)

Mars is ideally suited to launch expeditions into the asteroid belt or into the outer solar system, making it a valuable outpost for later exploration and resource utilization. Armed with cheap access to orbit, plenty of farmable land, significant supplies of metallic materials, and (potentially) cheap geothermal energy supply, Mars has the potential to become an economic powerhouse within the solar system.

A Quick Guide to Payload, or How to Make Your Own Mission

First of all, a lot of these calculations are based on work by Robert Zubrin, and are estimates only. This is simply a collection of short hands used to avoid having to do detailed examinations of all designs.

All of these percentages are Payload fractions, that is "how much of the vehicle is not engines, fuel, tankage, etc, but actually the stuff I want with me." When combining them simply multiply. A 3% launch followed by a 33% trip to Mars Orbit is an even 1%.

A hydrogen-fueled rocket on the launch pad, ready to launch its payload into Low Earth Orbit (LEO) is about 1-5% payload, with 3% being a typical number. Bigger rockets have smaller percentages. Putting stuff in LEO costs typically 10,000 dollars per kilo for NASA in 2015. For the private sector, the cheapest you can get is about 2,500$ for cargo or 5,000$ for crew rated transport. With near future technologies this can drop to the 1,500$ range, but much cheaper than that isn’t expected.

Payload fractions going from LEO to Low Mars Orbit varies extremely based on the rocket used, whether aerobraking is involved, when you leave and how fast you want to get there. A standard hydrogen rocket can do 33% in a slow (250 day) run or 29% on a fast (180 day) run. Methane rockets (who can store their fuel for years, unlike hydrogen) does from 20%-25% percent (they remain untested, so these specs are based on estimates). Nuclear Thermal Rockets running on hydrogen 53% in a slow run or 50% in a fast run. If you run it on CO2 instead, allowing it to refuel for free on Mars, it’s roughly equivalent to a standard hydrogen rocket. You can do up to 80% with Nuclear Electric or Nuclear Ion, but those take over a year to get there and cost to hell and back.

Modern Mars Landing systems make up about 38% of the weight, for a payload fraction of 62%. A SSTO system in place on Mars would make that 100%, but requires some heavy infrastructure on Mars.

Launching from mars with local produced (or long term storable) methane gives a payload fraction or 10-12% to Mars orbit. A reusable SSTO does maybe 5-10%.

Getting from Mars back to Earth orbit is about the same as getting them there in the first place.

PS: I had a three page essay based on Lawmower Boy's last post, but I'll leave it with only this:

I anticipate the further objection that all of this development can so be done overnight.

I'll reiterate my fundamental argument: We have all the technology needed for a Mars Direct style program. This does not mean it should be put together and sent without being tested. It does not mean there aren't significant engineering challenges left. My point is that these engineering challenges can't be solved without actually setting the goal. A Mars rated compressor is never going to be developed except as a part of mission to Mars that needs one. Waiting solves nothing.

Looks to me like we have another failure to communicate. I'm saying we can and should start a Mars program ASAP' date=' which would take some time to get ready to launch. Engineering takes time.[...'] I'm not saying we can launch tomorrow. I'm saying we'll never launch unless we start engineering.

It can' date=' and must, be pretested.[/quote']

We can't launch tomorrow. We can't even launch in the December launch window. Heck' date=' 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. [/quote']

Two people shouting past each other in cyberspace isn’t a very fruitful debate, hence my leaving it.

 

PSS: I miss Nyrath. I'd have loved to hear his view on Mars Direct and the Romulus Project.

Re: Star Hero 6th Edition: my first take

No High Frontier? How will you ever be able to handle low tech strategic maneuvering about the solar system without it?

Re: Mars Colony?

Chris' date=' I never called you a utopian promoter, although Gnaskar's been listening to them too much. You're young. You're unrealistic. You've been taken. I don't wish wisdom on you, because it will come with age and aches and pains and regrets. Save those for later.[/quote']

 

And that's the last word in our Mars Direct debate. Between Ad Hominem, Argument From Age, Statement Of Conversion, Argument Ad Nauseam, Argument From Personal Astonishment and whatever fallacy it is to claim your opponent has been conned (probably Ad Hominem against Zubrin) this debate stopped proving useful information pages ago.*

 

*This last paragraph itself is an Ad Hominem attack, so should not be considered a part of my argument, merely an explanation for why I stopped.

 

However, I'm working on writing up the Sea Dragon based Project Romulus plan for colonization of Mars, and will of course provide that for use in the original topic.

Re: Mars Colony?

Gnaskar' date=' you must be aware of how different the incremental development of a new Mars lander is from a compressor designed to work in an unfamiliar environment, automatically, for however long it is intended to work [/quote']

 

And yet you compared it to the incremental development of a jet engine? At least the rover (any moving platform is going to be more complex than a lander; our last Moon lander was developed in to years) was designed to work, automatically, for 680 days in the same unfamiliar environment.

 

I'll reiterate my fundamental argument: We have all the technology needed for a Mars Direct style program. This does not mean it should be put together and sent without being tested. It does not mean there aren't significant engineering challenges left. My point is that these engineering challenges can't be solved without actually setting the goal. A Mars rated compressor is never going to be developed except as a part of mission to Mars that needs one. Waiting solves nothing.

 

 

I understand that I'm making the world seem like a boring and tedious place to you. I'm sorry. If I'd thought my role as killjoy through before responding to this thread' date=' I would probably have stayed out of it. There's probably some second order political damage done by Mars Direct advocates, but it's as nothing compared with the first order political damage done by more directly engaged idealists who post here, and whom I usually let slide.[/quote']

 

Political Damage caused by Mars Direct advocates? They're not asking for more money for NASA, so the worst case scenario is NASA missuses it's budget for a while. A bit like SEI, Constellation, the Orion crew capsule (the senate's insisting they develop a crew capsule; mostly so people will associate Orion with something else. There is no mission that calls for it, and no booster that can launch it), the Space Shuttle (Arguably. The ISS could have been launched by a single Sea Dragon).

Re: Mars Colony?

That's just nuts. Here's a paper laying out the expected design history of a modern high performance jet engine' date=' a not inappropriate parallel. As you can see, the interval between submission of a complete design and approval for production converges on 51 months. I would expect ISRU development to take rather longer, given that the developmental infrastructure hasn't even been built yet.[/quote']

 

Developmental Infrastructure? Like, say, a wind tunnel that simulates Martian conditions? Like the Mars Surface Wind Tunnel at Ames Research Center?

 

A not inappropriate parallel? You're comparing a jet engine to a chemical refining plant. If we'd been talking about a rocket, that might have been an appropriate parallel. Here's a better parallel for you: The Mars Science Laboratory launches in about 100 days. The initial mission concept was approved at the end of 2004. Seven years from start to launch. And that includes developing an entirely new landing system, a entirely new power system (first RTG on the Martian surface), engine system, AI system, and 80 kg of scientific payload. 6 years for something with a conventional landing system, no AI, no frail science experiments, and no required mobility is perfectly reasonable, especially with ten to twenty times the budget NASA gave this "flagship" project. (IMHO it's not a "flagship" project if it only gets 2% of your budget).

 

Speaking of the Mars Rovers; something has always bothered me about NASA's rover design. They've sent three rovers on relatively similar missions over relatively similar terrain. And yet they've designed each one from scratch. Say they instead sent Curiosity up (in 106 days). By the mid part of it's mission (two years from now) it becomes clear that it's missing a number of vital instruments to determine if there is life on Mars. Instead of spending 7 years designing a new rover to carry those instruments, why not just take a Curiosity-class rover and replace the scientific payload? The second mission can then be done far faster and cheaper, and the third one even more so. By the fourth there is probably some new tech available to make use of (computers come to mind), but it must be cheaper to upgrade those parts of the design rather than starting with a blank page every damn time.