Mostly at the airport.
Are these concepts fundamentally different than a space elevator? If not, then of course the stress requirements on the tether would be lower, geostationary orbit would be closer to the surface*, so that’s less distance. But I’m sure you’d strill need several hundreds of kilometers of carbon nanofiber cable to set one up. A material we only have tiny samples of, and now I hear that one imperfection in its molecular structure can be catastrophic to its integrity. Plus the difficulty and cost of setting one up on another planet? May as well keep our eyes on Earth for such a structure.
*Or would it? Mars’s rotation is almost exactly Earths’s, despite its lower gravity.
You write as if astronauts will have all the water in the world to rinse and carry away perchlorates. In fact, the only liquid surface water that we know of (or at least, strongly hypothesize) on Mars are in recurring slope lineae (RSL), which are brines so saturated with percholorate salts that they prevent the water from vaporizing despite the almost vacuum conditions. There is no practical way of extracting water from these brines (more of a sludge, actually) other than using extremely high pressure and temperature to force the water out and then absorb it through some membrane to separate from the salts. This means that every drop of water (and every other resource that astronaut explorers will need to survive on Mars for almost a year and a half) will have to be brought with them.
Yes, if the logistics of moving mass from Earth’s surface to orbit were reduced to a trivial effort it would address many (but not all) of the logistical problems of a mission. But we’re really talking about a lot of mass; about a 10 m thick shell of water ice would be necessary to protect astronauts from the bulk of energetic cosmic rays and the daughter products produced by spallation. And landing large amounts of equipment and supplies on Mars in a controlled fashion is still a challenge insofar as Mars has just enough atmosphere to cause significant aeroheating during reentry but not enough to use parachutes or other normal aerodynamic deceleration systems for payloads much larger than 1 metric ton, hence why people who have studied Mars entry, descent, and landing (EDL) methods have the mantra that 'Mars is the most difficult solid body in the solar system to land on." An all-propulsive landing mode is plausible but requires substantial propellant-to-landed payload and of course the mass and complexity of a propulsion system for each.
The issue of thinking of a crewed Mars mission as just a somewhat longer Apollo mission is exactly on point. However, even if we just linearly scale the mission duration as a first pass cost estimate (against the Apollo program at $109B in 2010 dollars) we can see that the costs rise to beyond a 12 figure mark. And the Apollo missions were so comparatively “easy” that we were able to land in a vehicle so fragile that the skin was barely thicker than heavy foil, and we were able to recover a mission that lost its primary propulsion system (although Apoll 13 was fortunate to have failed where it did rather than later when it would have been unrecoverable).
Going to Mars isn’t just a twice as hard as going to the Moon, or 90 times as hard (the ratio of time to get to Mars versus the Moon) or even 350 times as hard (roughly the ratio of the difference traveled on a pseudo-Hohman trajectory to Mars versus that taken by the Apollo spacecraft to the Moon). It is many orders of magnitude more difficult. The duration and distance means that there is absolutely no possibility of rescue from Earth. Whereas the crew of the Apollo 13 mission could swing a pass around the Moon and make a free return trajectory to Earth, using the LEM engine for trajectory corrections, once a spacecraft bound for Mars leaves the Earth’s sphere of influence, it is gone for three years. Everything the crew may possibly need to survive for three years has to be carried on board, including air, water, and food. There is no stopping, returning, or getting any supplies or resources on the trip there or back. This argues for a fully redundant mission (e.g. two spacecraft, landers, full crew, et cetera), such that any catastrophic failure of a single ship is still recoverable as a mission and offers the potential to rescue the crew. Similarly, the duration the crew must survive on the Mars for over a year versus a few days on the Moon, and under a variety of environment conditions (such as dust storms and low solar incidence) which preclude solar power generation.
Sending people to explore Mars is not physically impossible, but it is well beyond the state of the art even if SpaceX or some other organization can get past the initial (and least difficult) hurdle of developing a propulsion system to send large payloads to Mars orbit.
I don’t know what the point of your stream-of-consciousness rants are but it is frustrating as fuck to see the easily-checked misapprehensions and factual errors in your post. For the record, the separation test occurred using the New Shepherd booster, which was developed and built by Blue Origin using their BE-3 engine. Please do the minimal amount of effort to check your claims before stating something that is blatantly factually incorrect.
No. Although the surface gravity is lower and aerostationary orbit is almost 1/3 the altitude as geostationary orbit above Earth, the strength requirements are still more than an order of magnitude beyond tensile capability of current materials, notwithstanding the logistical and engineering difficulty of actually building a structure from orbit to ground which is vastly beyond any construction experience or methodology. In any case, we would not build an orbital tether to support a single mission, or even multiple missions, and does not solve the essential problem of getting supplies and equipment to Mars orbit.
Stranger
I heard von Braun in am interview that he would want to send six ships to Mars.
Sure. But you’d only need tens of liters for a rinse, and I brought up water treatment methods to show that the water could be recycled without a lot of consumables. I really just wanted to point out that the modest toxicity of Martian soil isn’t a big hurdle.
While I, too, am confused by usedtobe’s antagonism towards BO, he’s right on this point. The solid rocket motor used in the capsule escape system was sourced from Aerojet Rocketdyne. But I have no idea why that’s relevant to… whatever usedtobe is going on about.
This raises the issue of whether the thus-far postulated Mars missions have included the development, manufacturing, and mass penalties of complete redundancy. Have they even reached the level of engineering detail to assess those? If not, what would the cost be to achieve that?
Most systems on Apollo were at least double-redundant within each spacecraft and the LM backup flight control system used a different type of computer from a different company using separately developed software to avoid the slightest chance of a common failure point.
If both flight control computers failed, the LM had a fully manual non-computerized mode with separate wiring and redundant RCS thruster solenoids for manual control. During training, the astronauts simulated lunar liftoff and orbital insertion using no computers at all, just a stopwatch and timed pitch changes to align window etchings with the lunar horizon. Astronaut Gene Cernan felt he could do that for real had it been necessary. I wonder if any planned Mars excursion vehicles have that level of fallback capability.
It’s points like this, and Stranger’s salient points on merely just attempting to scale up the Apollo missions and apply it to any proposed missions to Mars which makes me think the reality won’t have much resemblance to the Apollo missions at all.
Since a lot of the engineering and even human physiological/psychological hurdles are so fundamentally different than that which we used to land on the Moon, it makes me wonder when the actual time does come to send a human presence there*, I don’t think it will have all that many parallels to Apollo at all.
It’s my belief, in my lifetime, I’ll never witness a manned mission to Mars. I do believe the time will come, eventually, but when it does, it’ll be largely and fundamentally different than that which with what we applied to Apollo.
*I do believe it’s inevitable, but I’m 43. I think we’re at least 100 years away of a feasible/practical attempt of a human landing or occupation there.
If we were starting on Mars, it’d be easier to build our first space elevator than it is starting on Earth. But as it is, the easiest way to get a space elevator on Mars is probably to first build the Earth one and use it to launch the Mars one.
And as for water, I imagine that instead of bringing it with us from Earth, it’d be more economical to send an unmanned lander first to prepare for the humans, which takes its time using whatever energy-intensive process is necessary to distill local water (and also takes its time using energy-intensive processes to make the fuel for the return trip).
The best plan I’ve read about is to send ascent craft and supplies ahead of human landers. That was described in the novel, The Martian.
Aside from all the good points Stranger and others have made, the idea of having a self-sustaining colony on Mars in any reasonable timeframe is completely daft.
The difference between a constantly-supplied colony and a self-sustaining civilization is vast. Mars would retire a high-technology civilization before it could be self-sustaining. You can’t exactly live off the land in a tent. Estimates for how many people you would need to do that range into the millions. You need people to make the machines that make the machines that make the machines, ad infinitem. You not only need to find all the raw resources, you have to figure out how to mine them, then you have to build the machines required for mining them, and those in turn need thousands of small, machined parts. And so it goes.
And before you got to that point, you would need constant resupply from Earth. Can you imagine the immense cost of a logistical tail from Earth to Mars capable of sustaining, say, 100,000 people in a hostile environment?
As a comparison, McMurdo Station in Antarctica houses about 1,250 people - a very high estimate for how many people we could land on Mars in our lifetime, and not nearly enough to be even remotely self-sustaining. So how much material does McMurdo consume? 8 million US gallons of fuel per year, and about 5 million kg of food and supplies.
According to SpaceX, the new rocket system for the Mars missions can land 350 tons of material on Mars. Imagine having to send a fleet of 40-50 of those things every two years just to keep the people there alive.
Good point. They should try to make McMurdo self-sufficient first. If you can’t do that, Mars is impossible and a waste of resources trying…
Oh, and I’m not sure if Stranger or another poster has already mentioned this, but: One common rationale for establishing a Mars colony is as a hedge against global disaster, but that doesn’t really hold up. In the most likely global disaster scenarios, such as a large meteor impact, it would still be easier to survive in an equivalent base on Earth than on Mars, and that base would be much easier to construct. And any disaster scenario where an Earth base wouldn’t be sufficient, such as a nearby supernova, would also affect Mars just as bad. Interstellar colonies might provide a better hedge against some scenarios, and might (if we’re lucky) present more hospitable options, but those are so far away that a Mars colony isn’t any sort of meaningful stepping stone to it, and in any event before we can establish an interstellar colony, we’d need to be able to establish a deep-space colony (at least, absent FTL or some other equivalently indistinguishable-from-magic technology).
Well, I think a more likely scenario for humanity being wiped out would be something like a biological weapon.
But for Mars to be useful in regard, it has to have a self-sustaining high tech civilization. That’s something that would likely take a thousand years or more, assuming it could be done at all.
Overall Sam Stone’s post is on target about viable independent Mars colonies.
But we should remember that McMurdo is explicitly designed to *not *be self-sufficient. It’s cheaper to airlift that much fuel and other supplies in (and airlift the resulting waste out) than it is to design it as a logistics-lite or as a mostly self-sufficient colony. McMurdo *was *designed with the goal of waste sequestration instead of just throwing trash outdoors to let the wind carry it away. But it was not designed with the goal of minimizing how much it uses or how much waste that generates.
So the volume of McMurdo supplies does give us a useful pointer on how much total stuff we’d have to either supply from Earth, or obtain locally, or do without via the reduce, reuse, recycle paradigm. McMurdo says almost nothing about which of those routes is best used for what. Maximal use of the 3Rs at McMurdo might reduce that volume to 2% of what it presently is. Investing in a unattended nuke plant, RTGs, and/or some windmills might reduce the fossil fuel requirements to 10% of what they are now.
True self-sufficiency on Mars is beyond the pale as **Sam **says. But partial self-sufficiency is doable. e.g. Making replacement ICs locally is probably impractical on Mars. Making electricity locally certainly is. Everything else is somewhere in the middle.
Making McMurdo more fully 3R capable would certainly be an excellent testbed for tech useful for space exploration of any kind. But even with all that IMO a Mars colony is nothing but silly SF for the next many lifetimes.
For that matter, why don’t they grow greenhouse vegetables at McMurdo, unless the fuel to run grow lights would weigh more than just flying the vegetables in? Didn’t polar bases used to have nuclear power?
Well, the problem with McMurdo, and in general to the question “why don’t we colonize Antarctica first?” is because practically speaking, no one wants to and there are international treaties discouraging it. If a bunch of millionaires and billionaires want to colonize something, I’m sure they could do better than McMurdo.
Another example might be floating cities on the ocean. There are a few wealthy libertarians who would like to, but it’s hard and there’s just not quite enough interest and money.
There does seem to be a lot of interest in colonizing Mars though. I guess there is just something about it being another planet. Will there be enough interest and money for it? Beats me. Probably not anytime soon.