Travel to the moon for $1.5 billion

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December 10th, 2012 at 9:27:37 PM permalink
Nareed
Member since: Oct 24, 2012
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Quote: Pacomartin
My whole point was that once space tourism reaches the orbital stage of the earth, I don't think it is a big technological hurdle to orbit the moon. With much better computers you can control that section of the voyage by using very little fuel.


That'a not how it works. Orbital mechanics is all about speeds relative to one or more objects. In order to reach the Moon, you ahve to match its speed relative to the Earth. The fuel needed to accelerate one ton of anything to that speed is dependent on the rocket engines and the craft's mass ratio, not on the computer.

For example, the Apollo craft burned two full stages and part of the third stage just to make it into low Earth orbit. Then they burned the rest of the third stage to get into a Lunar insertion orbit. If you'd had an orbiting station, you'd still need to accelerate the same payload (Apollo) to the same speed. And that would ahve taken the same fuel.

I wonder if a magnetic launch track could be built in low Earth orbit... Hmm.
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December 11th, 2012 at 3:41:35 PM permalink
Ayecarumba
Member since: Oct 24, 2012
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Quote: Nareed
If you'd had an orbiting station, you'd still need to accelerate the same payload (Apollo) to the same speed. And that would ahve taken the same fuel.

With a space station already in place, you wouldn't have to move the entire kit and kaboodle into orbit at one time. The total energy (fuel) expended might be the same (but probably more), but you don't have to carry all of it in one shot. Think two hops with a layover via a 737, instead of a single non-stop in a 747.
December 11th, 2012 at 9:01:01 PM permalink
Nareed
Member since: Oct 24, 2012
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Quote: Ayecarumba
With a space station already in place, you wouldn't have to move the entire kit and kaboodle into orbit at one time. The total energy (fuel) expended might be the same (but probably more), but you don't have to carry all of it in one shot. Think two hops with a layover via a 737, instead of a single non-stop in a 747.


It can get very complicated. Sure, if the Apollo CM didn't have to be launched each trip because you could reuse it, then it stands to reason you'd save on launch costs. but you still need to launch the astronauts, and the fuel for the Lunar trip, even if it's done in many small launches rather than one big one.

Them too the CM would need to expend fuel in order to lose velocity and get back into low Earth orbit. conceivably you could aerobrake with the Earth's atmosphere, but then you'd either need a new heat shield for each trip, or for every few trips (we assume it would wear off with time). And you still have to land the astronauts back on Earth....
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December 12th, 2012 at 5:09:54 AM permalink
DJTeddyBear
Member since: Oct 24, 2012
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Quote: Pacomartin
I can't believe that orbiting the moon (without a landing) . . .

Wait a sec.

"without a landing"?!?!?

Why bother? I mean, I can understand the desire to go to space. But if you're going to go to the moon, I think you'd also expect to do a moon walk (and I don't mean Michael Jackson style).
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December 12th, 2012 at 6:51:20 AM permalink
Nareed
Member since: Oct 24, 2012
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Quote: DJTeddyBear
"without a landing"?!?!?


It would be a lot cheaper. No need for a lander, no fuel for it, less fuel overall to get there.

Quote:
Why bother?


It does seem rather pointless. But going on an incremental approach, that is how things will likely play out.

BTW, by the time Apollo VIII orbited the Moon (no landing), all the full Apollo landing systems were already developed. They just hadn't been tested. Apollo IX tested the LEM in low Earth orbit, and Apollo X tested it in Lunar orbit.
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December 12th, 2012 at 8:35:12 AM permalink
DJTeddyBear
Member since: Oct 24, 2012
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Oh, I get the incremental thing.

It just seemed that doing that should be the company's responsibility, and that the end goal be a lunar landing.

Sure, you can sell seats on those test flights, but that should be a limited number of flights before the landings begin.
Ignorance is bliss and knowledge is power. But having only some facts can get you into trouble!
December 12th, 2012 at 10:14:57 AM permalink
Ayecarumba
Member since: Oct 24, 2012
Threads: 79
Posts: 1233
If three jillionaires split the cost, it's pretty reasonable. But oh what a probate mess they would leave behind if they got stuck up there.
December 12th, 2012 at 12:10:38 PM permalink
Pacomartin
Member since: Oct 24, 2012
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Quote: DJTeddyBear
Oh, I get the incremental thing.

It just seemed that doing that should be the company's responsibility, and that the end goal be a lunar landing.

Sure, you can sell seats on those test flights, but that should be a limited number of flights before the landings begin.


I believe that the $1.5 billion is only for an orbital flight of the moon. The complications of a lunar landing are high. Even though it is much easier than landing on earth, you have to bring everything you need with you. You also need multiple redundancy given the almost zero chance of a rescue mission.

For the space elevator concept, an elevator from the moon is exponentially easier than a space elevator to the earth. The moon can use Lagrangian points , which is orders of magnitude simpler than geostationary orbit. Because you may be talking about as little as 7 tons of material, you can probably build a lunar elevator with present day materials.
Lunar Space Elevator paper

The earth space elevator does require currently non-existent materials to handle the weight. A Japanese company has announced their intention to build one in less than 40 years. It will take 7 days for a one way trip.



If a lunar space elevator is built, there is also the possibility of taking a one man disposable vehicle down to the surface of the moon, and taking the elevator back up to catch a return flight.
December 12th, 2012 at 9:04:00 PM permalink
Nareed
Member since: Oct 24, 2012
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Quote: Pacomartin
For the space elevator concept, an elevator from the moon is exponentially easier than a space elevator to the earth. The moon can use Lagrangian points , which is orders of magnitude simpler than geostationary orbit. Because you may be talking about as little as 7 tons of material, you can probably build a lunar elevator with present day materials.


"Qua...?" Professor Hubert Farnsworth.

1) The stable Lagrange points where an object stays put are equidistant between the Earth and the Moon. in this case meaning around 300,000 (that's three hundred thousand) kilometers. by contrast Earth's Clarke Orbit is "only" about 36,000 kilometers.

2) Why build a space elevator on the Moon anyway? An electromagnetic launch track would be easier, cheaper, more versatile and a whole lot more convenient. Plus you could, in time, build as many as needed all over the Moon.

Quote:
The earth space elevator does require currently non-existent materials to handle the weight.


Not exactly. Carbon nanotubes do exist, but they have to be developed to the point that they can be used for constructio materials. And manufacturing techniques need to be developed as well.
If Trump where half as smart as he thinks he is, he'd be twice as smart as he really is.
December 13th, 2012 at 6:45:52 AM permalink
Nareed
Member since: Oct 24, 2012
Threads: 301
Posts: 10008
Quote: DJTeddyBear
Oh, I get the incremental thing.

It just seemed that doing that should be the company's responsibility, and that the end goal be a lunar landing.

Sure, you can sell seats on those test flights, but that should be a limited number of flights before the landings begin.


Think of it as a matter of cost. A landing requires a lander (duh, right? <w>). Now, you can go Apollo-style and use two ships, or you can have one ship that's lander, cruise and re-entry vehicle. And there are other possible combinations. But assuming launches from Earth, the lander adds a lot of mass, which means a more powerful rocket, which means more money.

And that's not yet considering transit time and alternative propulsion methods. I think fuel-wise you could save a lot of money if you were willing to take two weeks to reach the Moon (give or take). But who'd want to be cooped up in a small vehicle, breathing recycled air and drinking filtered "water" for that long? The good news is you could also save a ton of fuel, maybe, if you wanted to get there in a few hours (!)

Of course, the slow method involves an ion engine and solar pannels. The second, faster one, involves some uranium...

We'll see developments in this area soon, say within the next two to three decades. Why? Because many of the people runing the new private space launch companies are space travel enthusiasts. And the first step into colonizing Mars, and the Solar System, is to establish industries on the Moon.
If Trump where half as smart as he thinks he is, he'd be twice as smart as he really is.
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