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Subject: 
Re: We're here to go
Newsgroups: 
lugnet.off-topic.geek
Date: 
Thu, 22 Jan 2004 19:33:00 GMT
Viewed: 
503 times
  
In lugnet.off-topic.geek, Dave Schuler wrote:
Here's my quandary:  Don't we still need to transport the fuel from Earth to
the Moon, and doesn't it take fuel to get there?  If so, is this really more
efficient?  If so, it is sufficiently more efficient to justify a multi-
billion dollar construction project on the Moon?

Dollar cost of the total amount of fuel aside, it is more efficient.  When you
launch a rocket into space, it has to carry itself, its payload, its crew, and
its fuel.  Making a rocket that can manage that from an Earth-based launch site
would be astronomically difficult.  Making a rocket that can manage that from a
Moon-based launch site would be a lot easier because you don't need nearly as
much total fuel capacity for a Moon-Mars-Moon run.  Yes, you'd have to transport
everything to the Moon, and yes, that would include launching "fuel-trucks" of
some sort, but the rocket technology required to pull it off is a lot simpler
than that required to do an Earth-Mars-Earth run.  A permanent moon-colony, on
the other hand, does kinda up the stakes a bit, since the Apollo missions, which
used the most powerful spacecraft ever created, couldn't carry enough excess
fuel payload to make a Mars flight feasible within our lifetimes.  The space
shuttles could ferry large payloads to an orbital platform, but then you have
other problems to worry about.  The ISS is in a decaying orbit, so it needs a
constant supply of fuel just to stay out of the atmosphere.  The only two ways
to make a permanently stable orbit for a space-borne launch platform would be to
put it in geosynchronous orbit (_much_ farther than the moon, and with a serious
lack of large masses to use for major navigational adjustments.) or to park it
halfway between Earth and the Moon (which still has the problem of not being
able to use fuel-efficient gravitational navigation methods).  I don't know what
the space-plane is theoretically capable of doing, but a Lunar colony sounds
like something that could require the equivalent of plunking a space shuttle on
top of a Titan IV rocket.

What it all boils down to, though, is that you'd need to be able to safely land
a craft with enough fuel to break Mars orbit and return to Earth.  This makes
Lunar missions look like a walk to the mailbox.



Message has 1 Reply:
  Re: We're here to go
 
(...) Um, no, you wouldn't. Not necessarily, anyway. (...) Again, no, it wouldn't. Not necessarily, anyway. Read the rest of the thread before you start in on responding to the first post in it, that's often a good approach in my view. Especially (...) (21 years ago, 23-Jan-04, to lugnet.off-topic.geek)

Message is in Reply To:
  We're here to go
 
By now, everyone knows about Dubya's Brave New Vision of America's future in space, specifically regarding the Moon and Mars. One of Dubya's selling points for a permanent Moon base (perhaps modular, in 48x48 squares) is that it will make it easier (...) (21 years ago, 16-Jan-04, to lugnet.off-topic.geek)

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