Moon base for Mars Landing?

On Mon, 20 Jul 2009 21:22:09 -0400, Van Chocstraw wrote:

Marvin the Martian wrote:

So, no, the moon isn't hidden beneath comet dust. We know from
Clementine, the Apollo missions, and other lunar surveys that the moon
doesn't have carbon. Since the moon is dead, and has little water and
no volcanic activity, there never were ore deposits formed.

Ore would have come from the earth when it was struck by a sister planet
and spewed up large amounts of surface matter. Remember, we mine all our
minerals from the top layer of the crust.

Even if the "struck by a sister planet" theory is correct, and making the
assumption that ore had already formed on Earth 1, it would have heated
up the ejected materials to where the ore and other rock until it once
again would have been dispersed.

Which is why there were no discovered ore deposits on the moon.

Len Lekx wrote:
Except for buying the engine for it, they probably didn't spend all that
much money on it at all; just a lot of man-hours making all the parts
for it, as other than the engine it was pretty much hand fabricated and
built out of readily available materials;


Thanks for the correction, Pat... :-) although I rather assumed
that the amount of time they spent on it should be taken into account
as well.

They were doing it on their own time - but how much would it have
cost, if someone else had paid them to do all that work?


It's awfully hard to figure out the man-hours put into it, as they had
built a lot of kites and gliders before they got around to building the
Flyer itself that were done specifically as steps toward building the
powered aircraft.
According to Wikipedia, the Flyer cost under $1,000 to build:
http://en.wikipedia.org/wiki/Wright_brothers
The engine was built by their shop mechanic, and I don't know how he was
reimbursed for building it.
When they did get around to selling one to the Army, they got $30,000
dollars for it, $5,000 of which was a bonus for it being faster than the
specification demanded.

Pat

On Thu, 23 Jul 2009 17:21:50 -0500, Pat Flannery
wrote:

It's awfully hard to figure out the man-hours put into it, as they had
built a lot of kites and gliders before they got around to building the
Flyer itself that were done specifically as steps toward building the
powered aircraft.

That's just it - they put a LOT of work into what we would call
Research and Development... and I feel that ought to be included in
the equation.

When I build my own rockets, the cost of the materials isn't
anywhere NEAR the cost in labour - if I were being billed for my time
and effort. :-)

"Len Lekx" wrote in message
...
On Mon, 13 Jul 2009 19:35:17 -0400, "Greg D. Moore \(Strider\)"
wrote:

that would be allowed to fly. The cost of the airfame is hugely
dependent
on the propulsion technology.

Cite for that? How does the cost change if you go with LOX-RP1 vs say
LOX-H2?

Actually, I did a back-of-the-envelope calculation for that not
long ago. I compared the masses, volumes, and costs for two vehicles
- one using RP-1 and LOX, the other H2 and LOX.

I used three basic assumptions - a 10,000 kilogram dry mass, 5000
m/s Delta-V, and engines optimized for sea-level air pressure.

The RP-1/LOX version required 39695 kilograms of propellant - 10321
kg of RP-1 and 29374 kg of LOX.

The H2/O2 version required 25216 kg of propellant - 3782 kg of
hydrogen and 21433 kg of oxygen.

Doing a Google search on fuel costs per kilo (which may or may not
be current... if someone would be good enough to check my
figures...?), I found that RP-1 costs 20 cents per kilo, oxygen 10
cents, and hydrogen three dollars.

From those, I determined the fuel costs for each...


H2/O2 - Hydrogen $11350, Oxygen $2144, total $13494
RP/O2 - RP-1 $ 2100, Oxygen $2938, total $5038

So - by my admittedly clumsy calculations, the fuel cost for
vehicles of equal capability is cut by over 50% through using kerosene
over hydrogen. Add in the savings from smaller tanks, smaller feed
lines, lower insulation requirements, etc., it would seem that the
cost consideration would favour the LOX/RP1 vehicle...

Been meaning to reply for awhile. Again, as always, a great, informative
post.

I will go back to my original point though that despite all that, fuel costs
really have very little effect on launch prices in the current environment.

I'd love to get to the point where fuel costs dominate the price equation.

For comparison, just picked the Atlass II, with a dry mass about 20x of your
proposed rocket. Doing a first order estimate of multiplying fuel/lox by
20x gets a fuel/lox cost of about $100K. or .1 million.

http://www.astronautix.com/articles/costhing.htm gives a launch price of 116
million.

So fuel is about 1% of the total launch costs. Even if fuel were free, none
of us would be buying a launch anytime soon.

Others, feel free to correct my assumptions and math.

Thanks.

--
Greg Moore
Ask me about lily, an RPI based CMC.

On Jul 17, 1:33*pm, Marvin the Martian wrote:
On Thu, 16 Jul 2009 04:29:22 -0500, Pat Flannery wrote:
wrote:
:

Ever hear the phrase 'flyback booster'? *Ever hear the phrase "Single
Stage To Orbit"?

Yep, and the whole thing lands in one piece, ready to be refueled and
relaunched, doesn't it?

Easy to hear of... a lot more tough to build.

Pat

The best known fuel and oxidizer, liquid hydrogen and liquid oxygen,
indicate that single stage to orbit is bad engineering. One simply must
consider some part of the structure to be expendable; the economics works
out that way.

The idea of a SSTO is that the craft would be an air breather or a
nuclear rocket. Nuclear rockets would work but are banned, and the
technology for a mach 20 air breather simply doesn't exist yet. If it
did, it probably wouldn't compete with staged rockets.

h2o2+synfuel is still a far better SSTO, w/reusable booster option.

~ BG

On Jul 17, 5:57*am, "Greg D. Moore \(Strider\)"
wrote:
wrote in message

...



The requirements to fuel an airplane are to attach the grounding line and
put out your cigarette.

That may be the requirements, but that's far from the maintenance required
to fly an airliner.

And of course you continue to ignore the fact that maintenance requirements
for airliners and their jet engines have gone DOWN over time due to better
design and a larger database of knowledge to work from.

But you continue to take a fairly limited set of data and draw a very large
conclusion based on that.

I'll give you a hint, there's a lot more effort in the current generation of
boosters to try to make them as simple as "put it on the pad and hook up the
fuel lines and fuel it".



How do you not drop chunks of your airframe into the ocean using
chemical rockets for power?

You continue to build and refine more craft until you have a design that
works. *Atlas nearly demonstrated SSTO 50 years ago.



How do you keep the airframe from having to withstand temperatures in
excess of 1000 deg C on reentry with chemical rockets?

I'm going to pretend you're not as stupid as that question makes you sound.



It is kind of hard not to burn the crap out of something when the reentry
temperature in areas exceeds 1200 degrees C.

Right, which is why no object has ever re-entered from space successfully..

Oh wait, it happens all the time and engineers have solutions and each
generation has built upon the previous generation of knowledge to make the
current design even better. *Hell, even the amount of "touch" required for
the shuttle tiles has gone down over the years as we've gained more
knowledge about how to better bond them, repair.

But you continue to take a very limited data set and project from there. *Is
what you say true TODAY in 2009, yes. *Certainly, *no one is arguing in
their right mind. *To argue that things 50, 100, 150 years from now will not
change is ludicrous.



--
Jim Pennino

Remove .spam.sux to reply.

--
Greg Moore
Ask me about lily, an RPI based CMC.

Change in a given devout mindset comes from the deaths of one stubborn
generation being replaced by the new and improved (less dumbfounded)
generation.

Max Planck once said: "A new scientific truth does not triumph
by convincing its opponents and making them see the light, but
rather because its opponents eventually die, and a new generation
grows up that is familiar with it."

~ BG