[extropy-chat] MARS: Because it is hard

[Dan Clemmensen]

Eugen Leitl wrote:

>On Wed, Apr 14, 2004 at 07:40:40PM -0400, Dan Clemmensen wrote:
>  
>
>>Thanks, Alan. OK, we'll make it 150 Km. in a vacuum and
>>ignoring the cost of land, the extra length is no big deal. We
>>    
>>
>
>How much is a km^2 of lunar surface worth now? Ignoring ineffectual treaties,
>and scamsters, effectively zero. One of the first worthwhile projects of the
>accelerator is to seed LLO with a cloud of active photovoltaics modules,
>capable of beaming microwave power in any direction, whether down to Luna (to
>power these linear motor launchers), to Earth, and into space (to propel
>probes).
>  
>
Sorry, I assumed everybody would get the joke. I was too subtle. Next time I
will add a smiley :-)

>  
>
>>can use the same linear induction technology for launch and
>>landing orbits and for local transportation.
>>    
>>
>
>Assuming, we want to transport stuff across lunar surface, maglev is one way
>to do it -- the lowest ELLO is Luna surface.
>
>  
>
Same problem:-) Yes, "ELLO"is surface-skimming, ignoring the odd mountain.
As I said, at these accelerations and distances, surface maglev and 
launch/land
systems are effectively identical. By adding minor inductive steering 
systems
at the fast end, you can safely hit any spot on a fairly wide belt from 
any other spot
in the belt. On the other hand, since each "station" is 150km long, we 
don't really
save much over a continuous track.

In another post you mentioned tall ramps for long launchers. I don't 
think this
is correct. The launcher simply follows the surface curvature of a 
sphere to put
a payload into ELLO. Of course. we want to pick a spot where that 
perfect theoretical
sphere terminates at the edge of a tall plateau overlooking a vast 
lowland to give the
payload a chance to raise its ELLO before it intersects the 
non-theoretical lunar
surface. and of course you would add a small vertical component near the 
end of the
launch.

Reminder: for any launch speed below lunar escape velocity, the payload 
must be accelerated
again after it leaves the surface. Otherwise, it will intersect the 
surface before it completes
one lunar orbit. I'm assuming an ion drive can provide sufficient 
acceleration. If not,we will
need to arrange for a space-based "catcher," or expend payload mass. 
(Yes ions are technically
mass, but you know what I mean.)