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Lunar Tourism

Posted by: campbelp2002 - Fri Feb 11, 2005 9:36 pm
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Lunar Tourism 
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Post    Posted on: Wed Feb 16, 2005 8:48 pm
campbelp2002 wrote:
Marshall wrote:
maybe that Christo guy could put a bunch of flags or umbrellas up all over the place.

Now you’re talkin! This is exactly what we need. And these guys have the money too.


The moon is the perfect billboard....

campbelp2002 wrote:
Andy Hill wrote:
Nautilus Moon Cruiser

All we need to do is get to LEO. A suspect for double the price of LEO you could get an Apollo 8 type lunar orbit tour. For less you could get a free return trajectory swing once around the Moon trip. I definitely see that before the more expensive surface tours start.


Why not drop off a capsule while you swing around Farside? The cislunar transport itself doesn't have to land. That idea is the product of the same NASA take-everything-you-possibly-can-with-you mentality that got us stuck on this planet for thirty years in the first place!

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Post    Posted on: Wed Feb 16, 2005 10:27 pm
The idea is to have revenue generating flights to fund each step.
Suborbital thrill ride income funds orbital tourism development. This is the biggest step, I think.
Orbital tourism income funds development of a free return sightseeing swing by of the Moon. A rather small step I think, but a big revenue generator. This would be a big customer attracting trip for not much more cost than LEO.
Single swing by flight income funds development of insertion into lunar orbit trips, like Apollo 8, and finally surface excursions.
I am assuming a LM type vehicle for surface trips. Maybe an Armadillo vehicle fueled by propellant produced on the Moon.


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Post    Posted on: Wed Feb 16, 2005 10:52 pm
No, no: my point is that you don't have to place the cislunar transport vehicle into lunar orbit to land passengers and cargo on the moon!

Imagine this: a large cargo ship, with several individual capsules. Each capsule has an engine just powerful enough and fuel tanks just big enough to launch it off the Moon (maybe it doesn't even need those: Heinlein's idea of a EM Accelerator for the Moon is a pretty good one), and no more. The capsules aren't designed to get to or break out of Earth orbit. The cargo ship breaks from Earth orbit, heads out towards the Moon. It does not insert itself into Lunar orbit, but instead makes a single flyby, using the Moon's gravity as free fuel to accelerate itself back to Earth. At apolune, it releases the capsules containing the passengers and cargo, which proceed to enter lunar orbit and either dock with a station there or drop further to the lunar surface. The cargo ship heads back to Earth to pick up another shipment of capsules.

The cargo ship itself never enters Lunar orbit, and can't land on the Earth (no heat shielding). The capsules can't take off from or land on Earth (again, no heat shielding) nor do they have the required thrust to break from Earth orbit.

It's a minimalist approach, and should be far cheaper than the Apollo concept of taking the whole set of launch, Earth orbit, Lunar insertion, and re-entry vehicles along in one package.

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Post    Posted on: Thu Feb 17, 2005 4:22 am
I have a different idea.

Passengers for the Moon leave Earth in a vehicle capable of reentering Earth's atmosphere, but not carrying any lunar landing vehicles and having no lunar landing capability itself.

The Earth transport enters lunar orbit. It need not be a circular orbit. Lunar shuttles start fully fueled on the surface of the Moon, take off and rendezvous with the Earth transport. They dock, off load passengers returning to Earth, take on passengers for the Moon, and land back at the Lunar base where they are refueled with locally produced propellant. The Earth transport uses it's engine to leave lunar orbit and returns to Earth where it uses the atmosphere to slow down for landing. The very high cost of lifting fully fueled lunar landing vehicles from Earth is avoided. A reasonably low performance vehicle could be single stage to orbit on the Moon.

There could be LEO and LLO stations too, but I don't think that makes any difference in the propulsion requirements.


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Post    Posted on: Thu Feb 17, 2005 10:33 am
I think that trips around the moon sight seeing would be an excellent first step in getting back to lunar exploration. I hadn't even considered that Bigelow would do this, I thought that he would concentrate on his space station first but I suppose that theres not to much difference in basic design as you have to have some means of boosting the orbit of your station from time to time.

I think Bigelow might be designing in house propulsion modules for his inflatables as he is recruiting propulsion engineers on his site, wouldnt it be better to get someone else to do this? I would have thought he would not wish to get into designing rocket engines but perhaps he would use existing ones as a basis for a design?

I wonder if you could do the same thing with the ISS and move it into a lunar orbit instead of allowing it to fall back to earth eventually. That would make it useful as a lunar staging post for future exploration and give a quicker response time to react to problems on the surface. It also gets rid of the problem of trying to deorbit it back into the Earth's atmosphere where it is likely to break up.

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Post    Posted on: Thu Feb 17, 2005 10:43 am
Andy Hill wrote:
I wonder if you could do the same thing with the ISS and move it into a lunar orbit instead of allowing it to fall back to earth eventually. That would make it useful as a lunar staging post for future exploration and give a quicker response time to react to problems on the surface. It also gets rid of the problem of trying to deorbit it back into the Earth's atmosphere where it is likely to break up.


That would probably to expensive (like, not), they could have done that with MIR, just for testing purposes, instead of making a whole new design and building it again. It's almost like re-inventing the wheel all the time imo.


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Post    Posted on: Thu Feb 17, 2005 1:55 pm
It only takes a speed change of about 100 meters per second to deorbit an object in LEO. It takes a speed change of 3300 meters per second to escape from LEO and another 550 to decelerate into lunar orbit, a total of almost 40 times as much propulsion to go to lunar orbit as to reenter Earth's atmosphere.


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Post    Posted on: Thu Feb 17, 2005 9:56 pm
Space and Aircraft Industries will be First to Use Nanotubes
The market impetus behind such developments, then, is clear: the conventional space industry is anticipated as the first major customer, followed by aircraft manufacturers. However, as production costs drop (currently US$20–1200/g), nanotubes are expected to find widespread application in such large industries as automobiles and construction. In fact, it is possible to conceive of a market in any area of industry that will benefit from lighter and stronger materials

The Importance of Nanotubes
Nanotubes provide a good example of how basic R&D can take off into full-scale market application in one specific area. Described as ‘the most important material in nanotechnology today’, nanotubes are a new material with remarkable tensile strength. Indeed, taking current technical barriers into account, nanotube-based material is anticipated to become 50–100 times stronger than steel at one-sixth of the weight. This development would dwarf the improvements that carbon fibres brought to composites.

http://www.azonano.com/details.asp?Arti ... ies%20will

Spaceships, rockets etc.. will be MUCH lighter therefore costing less to get into orbit!


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Post    Posted on: Sat Feb 19, 2005 9:14 pm
Just found something about Nanotubes... In 2004 a few pounds of nanotubes a day could be made..

CNI plans to increase its manufacturing capacity to the point where the company can make 1,000 pounds of nanotubes a day by 2005

Could we see Nanotubes be used in Space vehicles before the end of the decade?

Is it not possible to use Nano materials in Space Ship 2 protect against heat for Safety ?

Look here too.

Mass Production of Carbon Nanotube Becomes Possible
http://times.hankooki.com/lpage/tech/20 ... 111810.htm


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Post    Posted on: Mon Feb 21, 2005 12:59 pm
This is all very interesting and exciting -- I've been a supporter of using nanostructures for a while now -- but, alas, it is also off-topic. Discussions of the uses of carbon nanotubes in space vehicle design belong more in the Technology forum than here.

Oh, and yeah: they make the vehicle lighter, stronger, and more heat resistant. A lot more expensive for the time being, but.... <points at sig>

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Post    Posted on: Mon Feb 21, 2005 1:22 pm
Instead of using an armadillo derived lunar ascent/descent vehicle why not use the X-33 as a starting point?

The craft had a total mass including fuel of 16,320kg and a core diameter of 3.05m so it should be able to be launched fully fueled on something like a Delta IV heavy into orbit where it would dock with a waiting commercial CEV.

The craft had a thrust of 26,800kgf from its 4 RL-10A-5 engines, this is not necessary for use on the moon so redesigning with only 1 engine would give a big weight saving that could be converted into extra cargo. Also for a purely lunar vehicle you would not need a heat shield saving further weight, although it might be better to retain this and use the X-33 to return from Earth obit on the return journey. If used as a Earth return vehicle the engine might have to be replaced with one giving slightly more thrust, as the 6,696kgf wont be enough given the craft's empty weight of 7,200kg (this is with 4 engines so the weight would be less if redesigned but the fuel would mean using a bigger engine).

As an example replacing the 4 RL-10A-5 engines with a single RL-10A-5KA would give a weight saving of 427kg. The engine has an Isp of 398, a thrust of 10,247kgf and is throttleable to 30%. What do you think, would this work?

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Post    Posted on: Mon Feb 21, 2005 4:08 pm
Well its not really that off topic since it will bring down cost of going to the moon if they were available in large amounts by then

So the weight of the craft could be reduced by a lot meaning it will bring down cost. refering to " how much will it cost " on first post.

but.. ok


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Post    Posted on: Mon Feb 21, 2005 4:44 pm
whoa182 wrote:
Well its not really that off topic since it will bring down cost of going to the moon if they were available in large amounts by then


I was really wondering how much already exists in the way of designs or ideas that could be adapted for use on lunar trips, particularly things that have progressed beyond the drawing board which have produced engineering data. The X-33 is a design that would require an awful lot of work and money to make it feasible on Earth but due to the lower gravity on the moon it would probably work there. The original X-33 would have needed to be scaled up considerably to work on Earth but its dimensions and weights look a fairly good match to what could be used on the moon.

With regard to cost, I'm sure a simplified version of the X-33 could be made a lot cheaper than NASA managed to do and if produced in reasonable numbers could be made cheaper still. Flight data exists for the original craft which could be used to develop the idea which would save time.

What else could be adapted in this way to support Lunar trips?

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Post    Posted on: Tue Feb 22, 2005 3:30 pm
The X-33 is designed to operate in the atmosphere. Use it to get to LEO, but not to go to the Moon. Once outside the atmosphere, wings and thermal protection are just useless weight.

By the way, have you seen this?
http://www.reactionengines.co.uk
I stumbled across it while reading about HOTOL.

Previously I proposed a lunar shuttle meeting an Earth shuttle in lunar orbit, but I have changed my mind about that.

LEO is about 8 km/s, but it takes a deltaV of about 9 or 10 km/s (including losses from gravity and atmospheric drag) to get to there from the ground.

It only takes a total deltaV of about 10 km/s to make a round trip to LEO starting from the surface of the Moon! So the half way point of a trip to the Moon, from a deltaV perspective, is LEO.

1.85 km/s Escape velocity from the Moon
3.22 km/s Decelerate into LEO
3.22 km/s Accelerate to Earth escape velocity from LEO.
1.85 km/s Decelerate and land on the Moon
Total 10.14 km/s

With existing engines, the mass ratio of a single stage vehicle that could do this would be about 10 to 1. A vehicle that never has to enter the atmosphere and only has to take off from the 1/6 G Moon could have a very light weight structure and comparatively small engine, so I think 10 to 1 is feasible.

Now, what propellant could be manufactured on the Moon? Theoretically, oxygen could be extracted from lunar rock, although no work has been done on actual hardware to do this yet. There is definitely hydrogen at the poles, but we don’t know yet what form it is in (possibly ice, possibly not) or how easily it could be extracted. Even if only oxygen were produced on the Moon, that accounts for most of the propellant weight for a LOX / LH2 engine.

So what is needed is a winged space plane that meets a lunar shuttle in LEO, as portrayed in the movie “2001, a space odyssey”. Now we just need affordable access to LEO to get started.

(EDIT) I just found that lunar escape velocity is 2.4 km/s, not 1.85. So the total deltaV becomes 11.24 which would require a mass ratio more like 12 to 1. More difficult, but maybe possible. For comparison, the S-IVB had a mass ratio of 11 to 1. However if the Earth shuttle could enter an elliptical orbit and meet the lunar shuttle there, the 3.22 to enter and leave LEO could be reduced. Also, use of aerobraking could reduce the cost to decelerate into Earth orbit. So with clever design of the overall transport system, a 10 to 1 mass ratio or even less may still be possible for the lunar shuttle.


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Post    Posted on: Wed Feb 23, 2005 1:26 pm
campbelp2002 wrote:
<snip>


I'm just curious, and I'm probably missing something: why LEO? Why not higher, to give the cislunar shuttle a little break? And you don't have to decelerate into any orbit: do the same thing that Apollo 8 and all the NASA vehicles have always done, and just sling yourself around the back side of the Earth without dropping into orbit. That way, you go even faster on the return trip.

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