[extropy-chat] Space elevator numbers III

Fri Feb 16 12:13:40 UTC 2007

I believe that something is extremely flawed on this entire concept.
While I strongly agree that a space elevator could certainly be a benefit in a long run strategy for space missions, I also believe that our strategical approach to space development is wrong and that is the cause of all the major setbacks that we have since the Apollo days.
Our entire space strategy is based in sending,for now very limited payloads at unaffordable costs from the bottom of a deep gravity well, The earth, to other gravity wells, Moon or Mars .
The new Vision plans, Orion and Ares are nothing more than a revised Apollo and Saturn missions , fifty years later , putting aside all the experience and knowhow that the shuttle and ISS, despite their basically failure, has obtained.
Let's suppose that we are a Kardashev 3 society.
How would they approach the development of a new planetary system?
They would be coming with a "mother ship" with all their knowhow aand technology , they would utilize the most easily available materials for their requirements (comets and asteroids without costly gravity wells) and would deploy the required missions , first unmanned ,later , if possible, manned to the most interesting bodies.
We are not yet at Kardashev 1 level, we don't have a Mother ship and everything must come from the bottom of a deep gravity well:
So what it means all the above?
it means that we could develop the same capability , changing our startegy from the current earth-based  to a new space based approach.
That can be done in the following phases:
Phase 1-Rendez vous with a small ( 100 m ) water rich NEO asteroid
 mine it and utilize its minerals to manufacture , automatically, an exostructure of adequate size
once the exostructure is ready and propertly attached to the asteroid in such a way that a virtual line , connecting its ends, pass through the baricenter of the entire system, send a mission with two deflection nuclear electric engines and install them in the exostructure
Fire the engines and deflect the asteroid in an cyclical earth-Moon orbit.
Phase 2- build an embryonic mother ship
While close to earth , send manned missions and build a station utilizing the AstroHab system or similar utilizing mostly in-situ materials.
Once that is ready, only 3 missions will be needed for that task, we will have an affordable earthMoon trasnportation system
base all future Moon missions in such system  allowing manned Moon landings , contruction of a lunar base and developing a lunar technology.
About ten years could be necessary to build up the lunar infrstructure and , building a retriever exostructure, capture other Neos and put them in needed trajactories to build another permanent EarthMoon transportation system
Phase 3- Repeat the same procedure on the earth-Mars cycling trajectory, in the meantime adding and improving the NEO's station by building a bigger manned  settlement
Phase 4- Same for trans Mars missions with the due infarstructures and technology being developed in the NEO settlement.
It has been estimated that such system would jump start a space economy and develop the Moon and Mars at a 90% cost reduction compared to traditional earth based and centered approach, time needed will also be reduced by 70%.
The above concept, named Proyecto EVA (Eva being the first biblical "mother" ) is currently being conceptually designed in latin America and the first results and renderings will be available shortly
for papers to be delivered at main space conventions.

----- Messaggio originale -----
Da: David Masten <dmasten at piratelabs.org>
A: ExI chat list <extropy-chat at lists.extropy.org>
Inviato: Venerdì 16 febbraio 2007, 1:25:55
Oggetto: Re: [extropy-chat] Space elevator numbers III

On Thu, 2007-02-15 at 17:13 -0500, Keith Henson wrote:
> Yep.  Prices have to come down to cents per kg from thousands of dollars a 
> gram.  But nobody has yet given a serious look at the iron process, which 
> looks like (if it works) would cost a few cents per kg to make nanotubes.

How well does the iron process do in terms of flaws in the fiber? The
last presentation I saw on carbon nanotubes was that this was the crux
of the problem.

> This puppy is sized at 2000 tons per day capacity to GEO, with the ability 
> to double that in 100 days.  The Saturn 5 could put maybe 50 tons in 
> GEO?  You thinking about 40 of those a *day*? 

Sure, the only why not is $$. If the rocket industry can deliver
reusable once-around launch vehicles (like the USAF is asking for), you
are looking at 10 tons/vehicle per mission to LEO, mission duration plus
turnaround at 4 hours, so 6 per day (3 shifts). Allow a few vehicles out
at any time for maintenance, so say 40 launchers. Probably 120 LEO-GEO
tugs. I think that puts the whole operation on par with an airline.
Launchers and tugs have a cost to build in line with airliners. So, the
capitalization required is doable, now. That leaves us with a practical
technology problem, which I would submit is much easier than the
practical technology problem(s) of a tether.

>  This thing runs on electric 
> power in the high 90 percent efficient.  Is there any way for rockets to do 
> that?

I have always been under the impression that electric motors are much
less efficient than chemical motors. Am I not recalling correctly, or
are you talking about a different efficiency rating, or something else?

Dave

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