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Forget Mars. Should We Go To The Moon?
me98411 writes "We have discussed earlier about the President's Commission on Moon, Mars and Beyond and about how a direct trip to Mars is the way to go (or way not to). In a BBC article, the division in the astronomers and space geeks community about the use of the Moon as a base to develop ways to travel to Mars is highlighted. Now, Nature is asking: Should we go back to the moon? Is a manned mission to the moon even necessary?"
Yes, going to the moon would be nice and if we mine it for hydrogen-3 it will also be profitable.
I belive that resupplying a Moon base would be as expensive as resupplying a Mars base and could even be more. The main cost is boosting mass out of Earth's gravity well which you have to do in both cases. To land something on the moon you also have to carry propellant to decelerate to rest on the surface. Landing something on Mars you at least have the option of aerobraking, reducing the amount of mass that needs to be sent. For supplies, cost would have little to do with flight times.
It's a lot more expensive to go to the moon. The net energy to go to the moon is only a teensy bit less than it takes to get to Mars, and the moon doesn't have the variety of chemical compounds (or a 24 hour day) like Mars does. It's actually cheaper to set up a Mars colony because they can do things like grow their own food and make their own air and water, provided there's a small nuclear reactor to provide power.
Also, the moon is thought to only have water in very small quantities in remote craters on the north and south poles, whereas Mars, according to recent reports, is covered with mud, from which water can be extracted easily.
A lot of people think that because the moon is closer, it's somehow a better place to go. However, in the terms that matter (the energy it takes to get there), the Moon is about the same distance, and doesn't offer resources. I see moon as a space port, easily reached by the population from earth (cause people are really the only things worth shipping there), as well as easily reachable from the solar system, and with low launch costs. Fuel and food shipped in from Mars, materials shipped in from the asteroid belt, and people passing through on their way elsewhere. Oh, and a massive scientific base on the far side, for observatories.
I'm in the hole of the broadband donut.
You seem to be under the impression that the moon's spin is locked relative to the sun so that the sun never rises or sets. That's not true. The moon is locked relative to its orbit around the Earth. The moon's "day" is approximately one month long: two weeks of sunlight followed by two weeks of darkness.
This would cause big logistical problems and huge temperature swings for a moon base.
> strand a group of humans 2 years away from earth.
...right up until they ran out of food, air, water, or any of the other supplies that you sent them. At least on Mars you can make your own supplies from Hydrogen feedstock.
I'd like you to examine the Mars Direct concept. "Two years away" is irrelevant. Would you rather be locked in a grocery store in the Sahara, or stranded on a life raft with no food or water, two miles off the coast of Boston? At least on Mars you can continue to make you own water and air. By sending Earth Return Vehicles ahead of time, stocked with extra supplies, the chances of anyone getting "stranded" are remote, and the consequences aren't very dire.
The moon's low gravity also makes it easier to access. Less fuel is needed to land, and take off.
As has been pointed out in other threads here, the delta-V to get from LEO to the Moon is 6 km/s, whereas the delta-V to get from LEO to Mars is 4.5 km/s. The moon is only "closer" when you speak about distance; from an energy perspective, it's farther away than Mars, and always will be.
>If for some reason something went horribly wrong, there would at least be a chance to rectify it, or help. A moon base would be a stones throw away, and with the proper planning the crew of that base could be very safe.
>From a scientific perspective examining the individuals that do staff the base will provide vital information about what living in the solar environment is like and how if affects the body.
However, while Mars' atmosphere protects Martian explorers from solar flares, there is no such guarantee on the Moon. A solar flare that occurred in August, 1972 would have killed any astronauts on the moon; nobody on earth (except the astronomers!) even noticed it. Mars explorers would be safe from solar radiation; moon explorers would be risking death (and guaranteeing a higher occurrence of cancer) every day they spent out-of-doors on the moon.
>Make no mistake - the moon must be the beginning
If the moon is the beginning, you've already made your mistake. I just hope I'm not the astronaut who has to die to prove you wrong.
Compare sending a robotic probe to the bottom of the Marianas trench vs. a Manned one (the latter we haven't been able to do yet).
Uh, Jacques Piccard might disagree with you there.
The only reason we have the rights we have is that people just like us died to gain those rights. -- Cheerio Boy
And don't forget the 2-week day/night cycle that makes growing plants on the moon impractical.
Good grief. You talk like we're going to plant crops on the lunar surface. They're called greenhouses, and you close the blinds every twelve hours. At night, you flip on the growlights. Sheesh.
You can tell a great deal about the character of a man by observing those who hate him.
The Mars Society is testing out mission concepts by mucking around in deserts, in Nevada and up above the Arctic circle. Going to the moon would not help. While it might be worthwhile in its own right, it is not a stepping stone and should not be represented as such.
Scientists restrict study to entire physical universe; creationist
True, but misleading. The trip is about 9 months longer; and getting back again takes a much bigger delta-v from Mars than the Moon- in fact the round trip to Mars is a rather higher delta-v than the round trip to the Moon.
So if you are sending people, it's longer, further and more dangerous mission (solar flares and equipment reliability are issues).
And then when you get to Mars, you either turn around and come back within a few days, or you're stuck there for 18 months due to orbital dynamics (Mars has to be opposite the Earth from the Sub for the return trip and this happens every 18 months.) You can stay on the moon for as long or short as you want.
Sure, the Moon isn't as exciting, but nevertherless, it's much easier. And if the water is there in mineable quantities, the Moon is immediately useful- for, for example, enabling passage to Mars.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"Actually, Zubrin has you covered there, too. I probably won't do his plan justice with my summary (after all, he wrote a whole book on it), but off the top of my head, here are several safety factors he described.
First of all, his plan involves sending as much as possible ahead of the manned mission. Beyond the obvious launch of critical supplies, he describes a very cheap system for generating huge amounts of fuel using the Martian atmosphere. On top of that, we'd send the RETURN vehicle to the surface ahead of a manned mission.
That means you know in advance that you have a return vehicle and fuel already waiting for you -- before you even leave.
Second, the most optimal trajectory for a Mars mission automatically results in a "free return trajectory" -- which means if something goes wrong, the ship will automatically slingshot around Mars and return to Earth, without any fuel usage or other manuvering input from the crew whatsoever.
That means the main risks are surviving space itself (radiation, lack of gravity, isolation psychology), landing (this will remain high risk for a long time to come), and living in the relatively harsh Mars environment until the return launch window opens. (I no longer remember the numbers, but that isn't a terribly long wait.) Of those risks, only the last one requires much from a technological development perspective, and we can learn a lot from a very relevant example of survival under similarly extreme conditions: long term nuclear submarine missions.
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