Moon, Mars, or Asteroid? Which is the best goal?

[DarkenedOne]

We were talking about government operations here, the private sector can do what they please and I doubt they will be going to Mars before an international/government program does.

The Mars Base would do well to rely on ISRU, and in what way is agriculture a long way off? It can be done by the astronauts in a "Greenhouse" type dome with adequate soil and protection. The Mars atmosphere helps to block out all the harmful cosmic rays and solar radiation that you would otherwise receive on the moon. And as mentioned before, plants can not tolerate a 14 day period without light. And it takes a lot more power to grow them with electric light rather than using the sun.

A moon base will be able to generate some of its own resources, but it will require servicing from Earth as the ISS does. A mars base however can be fully self sufficient, and its a good thing because they are so far away. Mars is rich in the resources necessary for "normal" life.

If your purpose is just to build a government base for the sake of building one than I guess what your saying makes sense.

However I thought we were talking about comparing the moon and Mars for colonization. Colonization has always occurred privately by people looking for a better life. That being said the Moon will definitely be first because it is easier and cheaper to go to.

 

[HopDavid]

Hundreds of billions??? Have you even read about Mars Direct??? It can be accomplished with only $50 billion, a fraction of the Apollo program!

Before it was cancelled, Ares I was heading for 40 billion, never mind Ares V.

I regard Zubrin's projections as optimistic.

 

[HopDavid]

How astronauts could 'harvest' water on the moon
http://www.newscientist.com/article/dn17861-how-astronauts-could-harvest-water-on-the-moon.html
(Just pop it in the microwave method)

Possibly useful in the lower latitudes but unnecessary at the poles.

There are craters at the poles that evidently have sheets of relatively pure ice two meters thick.
http://www.nasa.gov/mission_pages/Mini- ... osits.html

 

[HopDavid]

The moon's biggest advantage is that it is closer, but if what you are looking for is resources then the moon is not necessarily the best place to go.

While Mars atmosphere makes it easier to send stuff to Mars, it makes export more difficult. And Mars' gravity well is much steeper than the moon's. It would take about 6 km/sec for a trans earth insertion from Mars. A Hohmann trip is 7 or 8 months.

In contrast the moon is only 2.5 km/sec from EML1 and 3.2 from LEO (using aerobraking) Trip time is in the order of days.

Exporting Mars propellent to earth's neighborhood isn't plausible, while exporting lunar propellent is.

Lunar supplied propellent depots at LEO and EML1 would make travel to Mars as well as asteroids much more plausible.

 

[Polishguy]

The moon's biggest advantage is that it is closer, but if what you are looking for is resources then the moon is not necessarily the best place to go.

While Mars atmosphere makes it easier to send stuff to Mars, it makes export more difficult. And Mars' gravity well is much steeper than the moon's. It would take about 6 km/sec for a trans earth insertion from Mars. A Hohmann trip is 7 or 8 months.

In contrast the moon is only 2.5 km/sec from EML1 and 3.2 from LEO (using aerobraking) Trip time is in the order of days.

Exporting Mars propellent to earth's neighborhood isn't plausible, while exporting lunar propellent is.

Lunar supplied propellent depots at LEO and EML1 would make travel to Mars as well as asteroids much more plausible.

Look, if you want to wait the 30-odd years it would take to get a functioning Lunar Mining Infrastructure and LEO propellant depots going, than by all means, go back to the Moon as your first goal. However, I would like to see a base on Mars constructed within the next 20 years. In the mean time, it is far easier to get to Mars with one or two Medium-Heavy Lift vehicles. If you design your equipment correctly, it can work on both Mars and the Moon, so if you have an active LEO production base (if we can launch the 120 tonne Space Shuttle 3 or 4 times a year, we can launch 3 or 4 heavy lift boosters of equal payload to LEO), you can land on each of those.

And I disagree that colonization has always been private. Sure, private enterprise takes over at some point, but it takes government funding to open the market first. Columbus was funded by the Spanish crown, and the Portuguese before him were funded by their King. After Columbus, private merchants and planters built colonies in Cuba. After that, the Governor of Cuba and the King of Spain funded an expedition to Mexico, which Hernan Cortes took over. After he proved that there was wealth to be found in the New World, lower-class people came in on their own money. But what incentive is there for private enterprise to attempt it at all without a government operation to find the wealth first? That's the point of going to Mars first. Send a government mission to test ways of sustaining an outpost on Mars and turning a profit (precious metals are more common on Mars than Luna, and they exist in more concentrated areas due to Mars's geological history). Then, when the methods have been proven, private enterprise will fill the new niche.

TBH, commercially, Mars and Luna make equally little sense as of now. While it is easier to take off from the Moon, it is more difficult to land useful payload on it to begin with (lack of atmosphere means you have to use fuel for the whole procedure). In addition, the Moon's previously noted volatile deficiencies and failure of agriculture mean that you need to import all your consumables except water and oxygen. Nitrogen, carbon and other nutrients must be brought from earth, whereas Mars already has them. The difficulty of launching off 1/3 G is compensated for by the fact that it's easier to support a crew on Mars.

If you really wanted to turn a profit, you'd skip 1/6 G entirely and go to the asteroids. However, it has been proven that Mars is in a far better position to supply asteroid mining. It is closer to the Main Belt, and you need less delta-v to get from Mars Orbit to the asteroids than from even the Moon to the asteroids. Mars can export food and volatiles needed to support the miners, while the miners can export their precious metals to earth, which exports finished goods to Mars and the asteroids. The Moon can fit into all of these by exporting Helium-3 and importing volatiles and food. But all of this requires that we set up shop at the place that has all the resources necessary to set up an outpost in the near-term: Mars.

 

[SpaceForAReason]

Except why would we bother with building in orbit when we can launch the whole mission on a pair of HLVs with surface rendezvous?

Because reuse of resources is cheaper than having to build them every single time. I don't buy a car every time I want to travel and I especially would not want to pay a huge delivery fee for each one.

And why have astronauts in orbit? All they'd do is soak up cosmic rays for two years and achieve nothing at all!

For Mars, Houston mission control is too far away for any practical intervention or control. Reaction time is at least 40 minutes to 3 hours. Having a command and control crew in Mars orbit and out of harms way would allow for proper handling of any emergencies and allows the possibilit of gathering and storing real-time mission information without the Mars/Earth time delay.

I mean, even if you were to leave infrastructure in orbit, why a station? Why not leave your landing vehicles in LEO and LMO unattended, the way we've been doing for 50 years?

Servicing a spacecraft is difficult enough without the proper resources. Having a fully supplied station (fuel, tools, parts, etc.) will help maintain a permanent fleet. The idea is to keep each mission launch as small and light-weight as possible. That is only possible if the infrastructure is already waiting for you and it can be reused and maintained.

Why bother with Transfer Vehicles that are fabricated in LEO? Why bother with a specialized Mars Ascent vehicle.

The machines that are the most effective are those that do one job, well. A transfer vehicle would need to be spacious and comfortable. The launch vehicles are necessarily small because of launch-time constraints. No such constraint exists between Earth and Mars so why not make the journey more pleasant?

And, I'm sorry to disappoint you, but when you're on the way to Mars, there's no rescue possible, even if you have that big useless space station!

Point taken. However, The most critical parts of the mission are the launch and departure and the arrival and landings. That is why there would be the stations at each end. If something goes wrong you may not be able to land on Mars and you will need a place that can give you more options.

 

[HopDavid]

In the mean time, it is far easier to get to Mars with one or two Medium-Heavy Lift vehicles.

Possibly a flags and footprints sortie mission, possibly two.

More than that, a pipe dream.

A tremendous waste of money.

If you design your equipment correctly, it can work on both Mars and the Moon, so if you have an active LEO production base (if we can launch the 120 tonne Space Shuttle 3 or 4 times a year, we can launch 3 or 4 heavy lift boosters of equal payload to LEO), you can land on each of those.

While Atlas Vs are sufficient for a lunar architecture, for Mars you need Ares Vs.

One is affordable, the other isn't.

That's the point of going to Mars first. Send a government mission to test ways of sustaining an outpost on Mars and turning a profit (precious metals are more common on Mars than Luna, and they exist in more concentrated areas due to Mars's geological history). Then, when the methods have been proven, private enterprise will fill the new niche.

Martian or asteroid gold, diamonds or platinum wouldn't be profitable, the cost of space transportation is too high. You could have an asteroid made of pure crack cocaine. Still wouldn't be profitable.

 

[Polishguy]

In the mean time, it is far easier to get to Mars with one or two Medium-Heavy Lift vehicles.

Possibly a flags and footprints sortie mission, possibly two.

More than that, a pipe dream.

A tremendous waste of money.

If you design your equipment correctly, it can work on both Mars and the Moon, so if you have an active LEO production base (if we can launch the 120 tonne Space Shuttle 3 or 4 times a year, we can launch 3 or 4 heavy lift boosters of equal payload to LEO), you can land on each of those.

While Atlas Vs are sufficient for a lunar architecture, for Mars you need Ares Vs.

One is affordable, the other isn't.

That's the point of going to Mars first. Send a government mission to test ways of sustaining an outpost on Mars and turning a profit (precious metals are more common on Mars than Luna, and they exist in more concentrated areas due to Mars's geological history). Then, when the methods have been proven, private enterprise will fill the new niche.

Martian or asteroid gold, diamonds or platinum wouldn't be profitable, the cost of space transportation is too high. You could have an asteroid made of pure crack cocaine. Still wouldn't be profitable.

If you don't want to expose your astronauts to many years of cosmic and solar radiation with a Venus flyby, they're going to have to be on Mars for about two years anyway. That's plenty of time to do science on the surface. And, as I said before, we have the budget to lauch one of these missions every two years, when the launch window opens.

And Atlas Vs are not sufficient for lunar architecture. They get what, 20-25 tonnes to LEO? That translates to 5 tonnes in Lunar Orbit, and 2.5 tonnes of usable payload on the surface. To get anything of meaning done there, you'd need to launch them about ten times per mission, increasing your chance of failure. And I'd like to see some reason as to why a 100tonne to LEO or greater vehicle is not affordable. We already fly one on a regular basis just to LEO (Shuttle weighs 120 tonnes and we've been launching it for 30 years).

And if Mars and the asteroids, with their comparatively forgiving delta-v budgets (9-10 km/s round trip to asteroid, 8.5 km/s round trip to Mars with aerobrake), then the Moon certainly isn't, with its high (12.8 km/s round trip) delta-v, and its very low-quality mining prospects. While it does have valuable materials, they are scattered mostly evenly throughout the regolith, not in small, easy-to-access concentrations as they are on Mars, or making up the entire rock as they would on an asteroid. Helium-3 is perhaps the only feasible export of the Moon, aside from science (geology and far-side astronomy). And its viability depends on two things. First, a viable He-3/deuterium fusion reactor has to be built. I'd give this 20 odd years. Next, methods of extracting it must be developed. This could be another ten years. Finally, it has to prove competetive with traditional deuterium-tritium designs. So, for 30 years, the Moon would not turn a profit. If you use lack of profit as a reason not to go, then we should just buzz around in LEO like flies around a carcass for another 30 years, as we have since Skylab.

 

[DarkenedOne]

Look, if you want to wait the 30-odd years it would take to get a functioning Lunar Mining Infrastructure and LEO propellant depots going, than by all means, go back to the Moon as your first goal. However, I would like to see a base on Mars constructed within the next 20 years. In the mean time, it is far easier to get to Mars with one or two Medium-Heavy Lift vehicles. If you design your equipment correctly, it can work on both Mars and the Moon, so if you have an active LEO production base (if we can launch the 120 tonne Space Shuttle 3 or 4 times a year, we can launch 3 or 4 heavy lift boosters of equal payload to LEO), you can land on each of those.

You know that is exactly the short term thinking the dominated Apollo. When the architecture for Apollo was hashed out many of the early space visionaries such as Von Braun called for a fuel depot architecture. The reason for this being that they knew that a fuel depot was flexible and lay the groundwork for a future Mars mission. Unfortunately NASA was not building a sustainable exploration program. Their only objective was to get to the moon as quickly as possible with no plans for exploration beyond that.

That is exactly what you seem to be advocating. Its a let just do it and get it over with approach rather than the lets lay the groundwork for humanities expansion into space approach. I support the latter, and in order to accomplish that we need to focus on the infrastructure and the technology in order to do so.

And I disagree that colonization has always been private. Sure, private enterprise takes over at some point, but it takes government funding to open the market first. Columbus was funded by the Spanish crown, and the Portuguese before him were funded by their King. After Columbus, private merchants and planters built colonies in Cuba. After that, the Governor of Cuba and the King of Spain funded an expedition to Mexico, which Hernan Cortes took over. After he proved that there was wealth to be found in the New World, lower-class people came in on their own money. But what incentive is there for private enterprise to attempt it at all without a government operation to find the wealth first? That's the point of going to Mars first. Send a government mission to test ways of sustaining an outpost on Mars and turning a profit (precious metals are more common on Mars than Luna, and they exist in more concentrated areas due to Mars's geological history). Then, when the methods have been proven, private enterprise will fill the new niche.

TBH, commercially, Mars and Luna make equally little sense as of now. While it is easier to take off from the Moon, it is more difficult to land useful payload on it to begin with (lack of atmosphere means you have to use fuel for the whole procedure). In addition, the Moon's previously noted volatile deficiencies and failure of agriculture mean that you need to import all your consumables except water and oxygen. Nitrogen, carbon and other nutrients must be brought from earth, whereas Mars already has them. The difficulty of launching off 1/3 G is compensated for by the fact that it's easier to support a crew on Mars.

If you really wanted to turn a profit, you'd skip 1/6 G entirely and go to the asteroids. However, it has been proven that Mars is in a far better position to supply asteroid mining. It is closer to the Main Belt, and you need less delta-v to get from Mars Orbit to the asteroids than from even the Moon to the asteroids. Mars can export food and volatiles needed to support the miners, while the miners can export their precious metals to earth, which exports finished goods to Mars and the asteroids. The Moon can fit into all of these by exporting Helium-3 and importing volatiles and food. But all of this requires that we set up shop at the place that has all the resources necessary to set up an outpost in the near-term: Mars.

Ultimately I think that we will expand out into space for the same reasons that the Europeans expanded into the Americas, and that is for the opportunity to expand both physically and economically. European rulers realized this thus invested in the initial stages of expansion as a means to increase both their power and their domain, and for the most part it worked. Well the same is going to be true in the coming century. At the same time people flocked to the new world in search of new land.

Today it is already painfully obvious that the constraints of our environment will slow down our growth both economically and in population. Thus we will have two choices. Expand into space or stay on Earth without growing physically or economically for ever and ever.

However in order to do so we must invest in both the infrastructure and the technology to do so. While NASA might be able to afford to send 3-4 astronauts at 10 billion dollars per person that is completely useless for any purpose beyond mere exploration. Even then it is not a good use of the exploration money either.

 

[HopDavid]

And Atlas Vs are not sufficient for lunar architecture.

False.

http://www.ulalaunch.com/site/docs/publ ... re2009.pdf

And if Mars and the asteroids, with their comparatively forgiving delta-v budgets (9-10 km/s round trip to asteroid, 8.5 km/s round trip to Mars with aerobrake), then the Moon certainly isn't, with its high (12.8 km/s round trip) delta-v, and its very low-quality mining prospects.

Your delta V is way off.

Here's a quick delta V map:

While it does have valuable materials, they are scattered mostly evenly throughout the regolith,

In the near term, the most valuable commodity will be propellent that's not at the bottom of a deep gravity well. The moon apparently has two meter thick sheets of relatively pure water ice at the north pole. It's 2.5 km/sec from EML1 and 3.2 km/sec from LEO (using aerobraking).

Propellent depots break up the delta V exponent in the rocket equation. Which enables single stage reusable vehicles rather than disposable mega rockets:

The disposable mega rocket architecture is the most cost effective architecture for flags and footprints sortie missions.

But if your goal is settlement of space, it is not a sustainable architecture.

 

[scottb50]

And Atlas Vs are not sufficient for lunar architecture.

False.

http://www.ulalaunch.com/site/docs/publ ... re2009.pdf

And if Mars and the asteroids, with their comparatively forgiving delta-v budgets (9-10 km/s round trip to asteroid, 8.5 km/s round trip to Mars with aerobrake), then the Moon certainly isn't, with its high (12.8 km/s round trip) delta-v, and its very low-quality mining prospects.

Your delta V is way off.

Here's a quick delta V map:

While it does have valuable materials, they are scattered mostly evenly throughout the regolith,

In the near term, the most valuable commodity will be propellent that's not at the bottom of a deep gravity well. The moon apparently has two meter thick sheets of relatively pure water ice at the north pole. It's 2.5 km/sec from EML1 and 3.2 km/sec from LEO (using aerobraking).

Propellent depots break up the delta V exponent in the rocket equation. Which enables single stage reusable vehicles rather than disposable mega rockets:

The disposable mega rocket architecture is the most cost effective architecture for flags and footprints sortie missions.

But if your goal is settlement of space, it is not a sustainable architecture.

The real problem is it takes nearly as much propellant to go to the moon as it takes to go to Mars, then, unless you had orbiting refueling you would need to get to the surface and back off.

At some point moon exports of water might be possible, but just about any rocket could put water into LEO a whole lot cheaper. Delta, Atlas, Falcon or any number of others could launch modules for assembly in LEO. Manned rating is possible with any of them. You could book a launch on any of them tomorrow, with enough money.

First group of Modules would form a Station, others would be attached temporarily as needed, or attached permanently as need to expand the facilities. Missions to other LEO locations, the moon, Mars, asteroids or whatever, would be assembled, and loaded in LEO. An identical facility in Mars orbit would accept transit to and from the surface. Mars landers would be refuel-able in orbit and at the surface.

Once the vehicle is assembled the passengers and cargo are sent up and it's off to Mars orbit.

Standard orbit Mr. Sulu.

 

[HopDavid]

The real problem is it takes nearly as much propellant to go to the moon as it takes to go to Mars, then, unless you had orbiting refueling you would need to get to the surface and back off.

Correct. Landing on the moon to go to Mars makes no sense.

However exporting lunar propellent to orbital depots makes sense.

At some point moon exports of water might be possible, but just about any rocket could put water into LEO a whole lot cheaper.

Delta V from moon to LEO is 3.2 km/sec. From earth's surface to LEO is about 9.5 km/sec.

One is doable with single stage reusable craft. The other isn't.

... with enough money.

With enough money, 1,000,000 disposable rocket ships are doable.

However "enough money" is roughly synonymous with "Harry Potter's Wand". It would take Harry Potter's Wand to make Constellation a viable architecture for settling space.

 

[DarkenedOne]

The real problem is it takes nearly as much propellant to go to the moon as it takes to go to Mars, then, unless you had orbiting refueling you would need to get to the surface and back off.

At some point moon exports of water might be possible, but just about any rocket could put water into LEO a whole lot cheaper. Delta, Atlas, Falcon or any number of others could launch modules for assembly in LEO. Manned rating is possible with any of them. You could book a launch on any of them tomorrow, with enough money.

First group of Modules would form a Station, others would be attached temporarily as needed, or attached permanently as need to expand the facilities. Missions to other LEO locations, the moon, Mars, asteroids or whatever, would be assembled, and loaded in LEO. An identical facility in Mars orbit would accept transit to and from the surface. Mars landers would be refuel-able in orbit and at the surface.

Once the vehicle is assembled the passengers and cargo are sent up and it's off to Mars orbit.

Standard orbit Mr. Sulu.

"The real problem is it takes nearly as much propellant to go to the moon as it takes to go to Mars, then, unless you had orbiting refueling you would need to get to the surface and back off."

That is only true for probes. Probes do not require extra resources as the length of travel increases, but humans do. A trip to the moon only takes 5 days. For such a short trip crewed vehicles can be pretty small. For such a short distance there is simply no need for exercise machines, advanced life support system, artificial, gravity, and etc. On top of that the amount of supplies needed is far less.

Of course a Mars mission would require much larger and more sophisticated spacecraft in order to support human life for such a long period of time.

 

[neutrino78x]

Why have propellant depots for lunar propellant when you could launch tanks of hydrogen from earth with a non-rocket launch method, such as maglev catapult or light gas gun? Such devices would be useful to fling fuel up to orbit, to link with a spacecraft you sent into orbit the same way, then the humans would go up in a man rated commercial rocket and dock with the spacecraft and fuel tank.

My point here is that you can accomplish the same goal without having to go to the Moon, in other words, I wouldn't put government personnel on the Moon just to generate fuel. An unmanned setup to generate fuel that is sent to LEO via mass driver wouldn't be bad idea, though, in my opinion.

--Brian

 

[scottb50]

My point here is that you can accomplish the same goal without having to go to the Moon, in other words, I wouldn't put government personnel on the Moon just to generate fuel. An unmanned setup to generate fuel that is sent to LEO via mass driver wouldn't be bad idea, though, in my opinion.

--Brian

One safe and store-able way to launch, store and transfer propellant is using water. Pretty much any launcher could be fitted with a tank and the tank could be mated to other tanks in LEO or directly attached to vehicles. This would mostly eliminate loses that large scale cryogenics would require.

Solar power would be used to breakdown water for boosting to Mars and propellant needed to brake into Mars orbit could be produced enroute reducing storage requirements. In addition the water could be used for electrical power generation, consumption and waste management. filtering and hydrolyzing would remove impurities and allow the same water to be used indefinitely.

As for using water from the moon I think it would be a definite possibility and agree the cost would probably be less after the equipment and facilities are considered. That it has to be in place to facilitate the first Mars missions is another thing. Basically it's a matter of creating the demand first, once Mars transit is established the same vehicles could be used for the moon as well as asteroids and issues of importing water can be addressed.

 

[HopDavid]

Why have propellant depots for lunar propellant when you could launch tanks of hydrogen from earth with a non-rocket launch method, such as maglev catapult or light gas gun?

Ummm.... Have you heard of the troposphere?

The abuse inflicted by the troposphere would be about a thousand times what the shuttle endures when re-entering the mesosphere.

Such launch schemes would work well on an airless world. The moon for example.

 

[rockett]

Why have propellant depots for lunar propellant when you could launch tanks of hydrogen from earth with a non-rocket launch method, such as maglev catapult or light gas gun?

Ummm.... Have you heard of the troposphere?

The abuse inflicted by the troposphere would be about a thousand times what the shuttle endures when re-entering the mesosphere.

Such launch schemes would work well on an airless world. The moon for example.

And to put it all together, why not launch chunks of lunar ice to earth orbit for processing with the rail gun?

 

[EarthlingX]

Here are some of the problems with the Moon mission which asteroid mission doesn't have :
1. Precision landing needed if you want to make a base.
2. Gravitational loss requires bigger engines to create enough thrust for launch and landing. Much smaller engines, like those used for RCS could be used for the asteroid mission, thus improving mass ratio. I also suspect that hydrazine, as an example, has much less of a problem with evaporation than hydrogen, which improves overall system Isp, among other.

There is a NASA mission for robotic Lunar landing, Project M, local thread : RoboNaut2: NASA+GM.

Perhaps capture some very small asteroid in Lunar orbit, and then go there ?

My preferred method for relocation :
SDC : Gravity-Powered Asteroid Tractor Proposed to Thwart Impact

Wiki : Gravity tractor

 

[rockett]

Here are some of the problems with the Moon mission which asteroid mission doesn't have :
1. Precision landing needed if you want to make a base.
2. Gravitational loss requires bigger engines to create enough thrust for launch and landing. Much smaller engines, like those used for RCS could be used for the asteroid mission, thus improving mass ratio. I also suspect that hydrazine, as an example, has much less of a problem with evaporation than hydrogen, which improves overall system Isp, among other.

There is a NASA mission for robotic Lunar landing, Project M, local thread : RoboNaut2: NASA+GM.

Perhaps capture some very small asteroid in Lunar orbit, and then go there ?

My preferred method for relocation :
SDC : Gravity-Powered Asteroid Tractor Proposed to Thwart Impact

Wiki : Gravity tractor

Couple of thoughts about the gravity tractor:
Expense vs return on investment. An effort like that would cost in the billions, maybe more. While the article suggests a 20 ton tractor, wouldn't a larger asteroid require still more mass? Wouldn't this approach require a great deal of fuel and months or years?
I simply can't see this approach being tried without the Earth being in danger. Congress seems to have a case of ADD, not being able to stay focused for very long.

•Often fails to give close attention to details or makes careless mistakes in schoolwork, work, or other activities
•Often has difficulty sustaining attention in tasks or play activities
•Often does not seem to listen when spoken to directly
•Often does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace (not due to oppositional behavior or failure to understand instructions)
•Often has difficulty organizing tasks and activities
•Often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort (such as schoolwork or homework)
•Often loses things necessary for tasks or activities (e.g., toys, school assignments, pencils, books, or tools)
•Is often easily distracted by extraneous stimuli
•Is often forgetful in daily activities
http://psychcentral.com/disorders/sx1.htm

:lol:

 

[rockett]

One safe and store-able way to launch, store and transfer propellant is using water. Pretty much any launcher could be fitted with a tank and the tank could be mated to other tanks in LEO or directly attached to vehicles. This would mostly eliminate loses that large scale cryogenics would require.

Solar power would be used to breakdown water for boosting to Mars and propellant needed to brake into Mars orbit could be produced enroute reducing storage requirements. In addition the water could be used for electrical power generation, consumption and waste management. filtering and hydrolyzing would remove impurities and allow the same water to be used indefinitely.

I like this idea, but for some unknown reason, most of the posters here won't consider it. Have no idea why, because it's a very elegant solution to the storage problem...

 

[scottb50]

I like this idea, but for some unknown reason, most of the posters here won't consider it. Have no idea why, because it's a very elegant solution to the storage problem...

Exactly my point. Ice exists on asteroids, Comets and the moon for millions of years. Containment could be as simple as a balloon. Also with people you need a lot of water anyway so why not get the most out of it?

Water is the primary asset we have in enough abundance to get to Space, pure and simple.

 

[bdewoody]

Until we can get living conditions comparable to living in a college dorm (i.e. a large structure with living accomodations featuring several different common areas, a connecting underground tunnel to the cafeteria and even connecting tunnels to some of the buildings that house lectures or even the gym), we shouldn't be setting our sights too far from LEO. Look how complicated the space station is to keep running, and it's not exactly luxurious. Get the resources to build things like this first, perhaps even by bringing an asteroid to a lagrange point and using it as a hull for the first "city" in space.

I like the moon. It's nice and close, yes, but the amount of energy that it takes to go to the surface and launch into orbit, while roughly 1/6 that of launching from the earth, is still prohibitively expensive considering the amount of launches necessary. An asteroid has negligible gravity, and as such is an economically desirable/feasible goal to begin with.

As for Mars...if we can't establish an outpost on our largest neighbour because it's too expensive, this should *not* be a goal for manned exploration in the near term. Once we have the technologies to get us on and off the moon, planning a Mars trip will involve 1-2 years, not the 20 years it would take for a highly dangerous trip with conventional technology. Work in logical steps, and we *will* get to Mars *much* faster than by making this enormous engineering challenge our first priority.

It is just because an asteroid has little or no gravitational influence that makes going to one impossible with current technology. For a manned space vehicle to get to a destination with acceptable quantities of fuel the destination needs to help by grabbing the vehicle to establish an orbit and then to land. This makes the moon the only logical choice for manned missions in the immediate future. Since we can't keep the ISS operating without constant resupply and repairs from the ground I don't give a Mars mission much of a chance of bringing them back alive.

 

[rockett]

It is just because an asteroid has little or no gravitational influence that makes going to one impossible with current technology. For a manned space vehicle to get to a destination with acceptable quantities of fuel the destination needs to help by grabbing the vehicle to establish an orbit and then to land. This makes the moon the only logical choice for manned missions in the immediate future. Since we can't keep the ISS operating without constant resupply and repairs from the ground I don't give a Mars mission much of a chance of bringing them back alive.

Agreed. We need to develop a space infrastructure to support ongoing exploration efforts. As for a lunar colony, it would make a great R&D location for building and testing long-term sustainable human habitation technology.
Mars at this stage of technical development would be "boots and flags", or possibly a fatal mistake if something like Apollo 13 happened. Same can be said for an asteroid mission. When we go BEO, we need to go to stay.

 

[rockett]

2. Gravitational loss requires bigger engines to create enough thrust for launch and landing. Much smaller engines, like those used for RCS could be used for the asteroid mission, thus improving mass ratio. I also suspect that hydrazine, as an example, has much less of a problem with evaporation than hydrogen, which improves overall system Isp, among other.

Why not...

In Robert A. Heinlein's classic novel The Moon Is a Harsh Mistress, rebelling Lunar colonists convert a kilometers-long mass driver system that delivers raw materials to Earth into a railgun that lobs metal-clad rocks, then commence an orbital bombardment.
One of the first depictions of a mass driver for space exploration was in the 1936 movie Things to Come.
http://en.wikipedia.org/wiki/List_of_electromagnetic_projectile_devices_in_fiction

A launcher like that could actually work on the moon unassisted, with no atmosphere.

 

[scottb50]

It is just because an asteroid has little or no gravitational influence that makes going to one impossible with current technology. For a manned space vehicle to get to a destination with acceptable quantities of fuel the destination needs to help by grabbing the vehicle to establish an orbit and then to land. This makes the moon the only logical choice for manned missions in the immediate future. Since we can't keep the ISS operating without constant resupply and repairs from the ground I don't give a Mars mission much of a chance of bringing them back alive.

It has been done a number of times, it's no big deal. Hover at a few feet, shoot a penetrating projectile and reel the vehicle down. The moon and Mars need landers based on the surface as well as in orbit. Built of structurally identical Modules, each self sufficient for months in a failure of adjacent Modules.