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Going To Mars Via the Moon (mit.edu)
An anonymous reader writes: Getting anywhere in space is a difficult proposition — at least, if you want to get there in a timely manner. Rocket propulsion requires combustion mass. The more mass you take, the more you need. A team at MIT has found that establishing fuel-generating infrastructure on the Moon could reduce launch mass for missions to Mars by up to 68%. "They found the most mass-efficient path involves launching a crew from Earth with just enough fuel to get into orbit around the Earth. A fuel-producing plant on the surface of the moon would then launch tankers of fuel into space, where they would enter gravitational orbit. The tankers would eventually be picked up by the Mars-bound crew (PDF), which would then head to a nearby fueling station to gas up before ultimately heading to Mars." The technology to make this happen is not difficult to build; it just requires a lot of money. Once it's in place, it'll cut down on expensive launch costs. As the commercial space industry gets going and launches happen more often, such an investment starts to make more and more sense.
At some point in the past the Moon must have had lots of fuel. Oil most likely. Look at all the bomb craters on its surface visible even today. If didn't have oil why would have anyone bombed it? QED, the Moon had oil. It still might, but till unless we get the Moonstone XXL pipeline approved, it will remain unexploited.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
the rest is just commentary.
I would rather NASA goes somewhere, even the Moon, than plans to go somewhere even better, such as Mars, but never gets off the ground. The Mars discussions are like the Wright Brothers complaining it's not worth building the Wright Flyer until they solve how to cross the Atlantic, because who really wants to fly 259.7 meters on a sandy beach.
Just building a launchpad and fuel storage infrastructure on the moon does make more sense than blasting off from earth every time. The less gravity that the platform has, the more efficient it is to lift off from it.
I guess it might technically be cheaper to launch if you assemble ships using a space ladder and launch from that orbit... but it would likely be easier to make a moon base.
The question then becomes, how to make the fuel on the moon? They could send millions of tons of fuel up there waiting to be spent, but that would cost a huge amount of money anyway. So I'm not sure if there would actually be any savings overall.
It would be ideal to use the moon as a platform for all satellite launches, supposing we can find the raw materials there to make metals. There's enough water and oxygen for humans, and enough silicon to make photovoltaics. Electronics and rare or hard-to-purify materials could be imported from Earth. Fuel could be made using the PVs by reduction of water or other reactions. Once we have a good lunar base, putting satellites in orbit around the Earth or sending ships to Mars will be far more efficient and less polluting and wasteful. And we could use toxic or radioactive rockets that we can't launch from Earth, with fluorine as an oxidizer, or fission.
The problem with any space based mining/resources operation is that competition from just launching from Terra Firma doesn't go away. Let's say that SpaceX can get a fully reusable BFR flying regularly, putting 100 metric tons to leo on every launch at a vastly lower cost. Would it still worth the huge capital expenditure to develop space based resource mining/extraction to reduce the amount of mass that needs to go up form Earth? Maybe eventually -- the rocket equation is cruel, but we are no where near the limits of what we can do with technology on a $$$/kilo delivered to Mars.
...and IN SOVIET RUSSIA, beowulf clusters imagine 1, 2, 3 profit!!!! jokes made out of YOU!!!
I think the idea is to launch the fuel into orbit FROM the moon.
1.) Goto Moon
2.) Mine/Generate fuel
3.) Launch fuel into orbit - this step is key
4.) Launch smaller payload from Earth
5.) Payload meets fuel in orbit around the Moon
6.) Payload continues to Mars
If you only have to launch the payload with limited fuel, you don't need to use fuel to get other fuel into orbit. Also, the Moon has a much smaller gravity well and NO air resistance so launching anything into orbit around the moon is much more efficient than launching something into Earth orbit - this step 3 and I think where the 68% savings is supposed to come from. You only need rockets big enough to get a payload off the Earth and fuel into Lunar orbit - there is no need for the one big rocket launching everything at once.
If you want an "efficient" mars mission, the last thing you want is to send people. That sort of thinking is just stuck in the past, like old science fiction whose idea of an automated car was one driven by a robot. They are successfully reducing launch mass by using smaller robot probes. Miniaturisation is the key. Exploration and research is good, but does not need bodies in a can. If you want to establish a colony, do it somewhere far cheaper and more sensible, like the bottom of the Pacific.
There's always dull people on stories like these. You boring bastards are always there holding the doers back with your pathetic can't do attitude.
So Have these geniuses calculated exactly how much water is on the moon? And how do they know? Enough to fuel every lanuch to mars - plus the water needed by the operators?
What is the specific tonnage of water on the moon? Maybe that is important. Or maybe we can send water form earth there and still save money.
Every single MOON FIRST! scenario seems to need a "Here sumpin cool happens" placed right in the middle of the equation, and without it, the whole thing fails.
So instead of using present technology to develop and go to Mars, we're going to embark on a hundred year project to just get started.
Anyhow, it was quite cool reading the precise calculations based upon a wild-ass guess.
The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
Fuel is a small cost of a space launch. Only about $250,000 per low earth orbit launch is fuel. The big cost of space flight is the throw away rockets. Going to extreme measures to save fuel is not a wise use of resources. With the boost capability of the Falcon 9 it would take maybe 100 flights to carry the amount of fuel and resources needed for a flight to Mars and back. Assuming 100% reusability the cost to carry the fuel to orbit is only $25million. Developing and building a refueling station on the moon and manning it would probably cost many billions of dollars. Spending billions to save millions does not make much sense. The thing that will make space travel cost reasonable is getting to that 100% reusability and long operating life. A rocket with 120 flights to orbit would only have 40 hours of run time on it. Current Jet engines can run for thousands of hours between rebuilds. The Air frame can go much longer than that. Once we get rockets and engines with those same types of run times and perfect vertical return landings flying to space will not cost much more than the fuel and it is cheap.
An asteroid mining tug can bring back about 200 times it's starting mass over a reasonable operating life, making multiple trips. The right kind of asteroid is 20% carbon compounds and water, which can be reformed to hydrocarbons + oxygen, i.e. high thrust rocket fuel. So the fuel return ratio is 40:1. Extracting the carbon compounds and water requires an oven, which is pretty easy to do with sunlight and mirrors. You also need an electrolyzer, to split the water, refrigeration to liquefy the oxygen, and hydro-cracking unit to add the Hydrogen to the carbon compounds (they are typically polycyclic aromatics).
If you do the processing in high orbit near the Moon, like the L2 point, you can skip the launch step and just dock and tank up.
Most people also don't know you can "scoop mine" the Earth's upper atmosphere from orbit. Skimming air at 200 km altitude requires adding 7.5 km/s of velocity to bring it to orbit, but electric thrusters have exhaust velocity of ~30-50 km/s. Therefore a fraction of the air you scoop up can make up the drag you create. You need lots of solar arrays to power the thrusters, but they can power bringing multiple times their own mass in air to orbit. The part you keep can be used as additional propellant for other missions, or as air for breathing, or as 8/9ths of the mass of water (you still need to bring the Hydrogen somehow).
Self replicating, factory and habitat-building robots. The meat bags can show up once everything is ready for them.
You are starting to get the idea, but it's incomplete. Mine everywhere. Near-Earth asteroids, our upper atmosphere (scoop mining), the Moon, Phobos, Mars. Each place produces fuel and supplies to get to the next place. You develop mining and processing tech once in general, and use it everywhere. In reality, we already know a lot about mining and materials processing on Earth, that's where all our stuff comes from. What we need is to adapt what we know to the particular locations and what materials are found there.
Much of the progress of the human race has come from wide eyed dreamers. Bores like yourself have nothing to offer.
Please learn something about orbital mechanics. If you have enough fuel to reach the L2 point and "just dock" you have enough fuel to go anywhere in the solar system. It isn't like flying an airplane.
There is also fuel in the form of uranium and thorium.
Using solar power as you propose, spanning the moon with power lines so that there is always light shining on the panels, would be an exceedingly difficult and costly way to produce power. To get the oxygen and hydrogen from the lunar surface you'd already be digging up the rock and processing it. What do you do with all the stuff that isn't oxygen and hydrogen?
From that rock you are going to get a lot of iron, aluminum, silicon, magnesium and other elements useful for building material. There's also a lot of calcium, potassium, sodium, and other stuff useful for supporting life. After all of that is extracted you are going to have piles of uranium and thorium, while also useful as a building material it would be much more useful as a power source.
Building a power line that goes around the moon would be equivalent of building one across Russia. Granted it only has to go halfway around to work that just means going halfway across Russia, still a long way. All of that aluminum used to make that wire would be more useful in building other things, like tanks for the hydrogen and oxygen you'd be making from your nuclear powered fuel factory.
Unlike on Earth the disposal of any nuclear waste is not an issue. The entire surface of the moon is bombarded with radiation from space, no place is safe from radiation so anything additional from the reactors is trivial. After you've dug a hole to get your oxygen and hydrogen from the rocks then dump in your trash, including the radioactive stuff.
Actually there's probably a bunch of valuable stuff in the fission products, best not to throw that away.
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