Talk:Space elevator/Archive 2

message: My yesterday's change to the economics section has been reverted by Rei.  Please explain why or I will revert back ....  Refrain from ad hominem attack, please.  Paul Beardsell 17:18, 5 May 2004 (UTC)
thread_title:  plea for politeness 

message: */Archive 1 - Prior to May 8 2004
Okay, I trimmed it down to only 62 k. I don't think I cut any live discussions, but you can check the page history, and copy & paste it back if necessary.
--wwoods 08:00, 8 May 2004 (UTC)
replies: text: The elevator doesn't really go to LEO -- it goes to GEO, and beyond. --wwoods 00:24, 12 May 2004 (UTC)
replies: text: Regeneration is hampered by transmission losses.  Elsewhere these are said to be very high.  If the 0.5% efficiency figure is used again then it is almost not worth bothering.  Or is there another flaw in my thinking?  Paul Beardsell 14:43, 6 May 2004 (UTC)

text: Will we build the advanced version after we have built the basic version?  To solve other problems we have people suggesting here we detach the cars at the top to send them back.  Is that a feature of the the basic version?  And the energy you have to recover is not only the up/down potential energy but the sideways kinetic energy.  Any plan for that?  Paul Beardsell 06:23, 2 May 2004 (UTC)

text: OK, I've reworded the section. I believe it now incorporates both views without making a stronger case for either. Comments are welcome. Fredrik 16:19, 1 May 2004 (UTC)
thread_title:  discussion trimming 

message: ::Regeneration is hampered by transmission losses.  Elsewhere these are said to be very high.  If the 0.5% efficiency figure is used again then it is almost not worth bothering.  Or is there another flaw in my thinking?  Paul Beardsell 14:43, 6 May 2004 (UTC)
replies: text: Will we build the advanced version after we have built the basic version?  To solve other problems we have people suggesting here we detach the cars at the top to send them back.  Is that a feature of the the basic version?  And the energy you have to recover is not only the up/down potential energy but the sideways kinetic energy.  Any plan for that?  Paul Beardsell 06:23, 2 May 2004 (UTC)

text: OK, I've reworded the section. I believe it now incorporates both views without making a stronger case for either. Comments are welcome. Fredrik 16:19, 1 May 2004 (UTC)
thread_title:  advanced versions 

message: "vertical and tangential energy"
I put some numeric calculations dealing with
* up/down potential energy
* sideways kinetic energy.
at
http://c2.com/cgi/wiki?SpaceElevator
.
Want me to move them here to wikipedia ?
-- DavidCary
: First off, people need to stop trying to distinguish between vertical and tangential energy.
Why ? -- DavidCary 17:23, 11 May 2004 (UTC)
thread_title:  vertical potential energy and sideways kinetic energy 

message: : By the way: there ARE cheaper ways to get things to space than standard chemical rockets being worked on.
: Excellent. Do any wikipedia pages exist for these other ways ?
Yes:
* the  HARP project, which uses ballistically launched sabot-fired projectiles to get a chemical rocket into the upper atmosphere; it was cheap per launch, the development costs were proportionally tiny, and they were almost to orbit (they had reached the altitude, and had demonstrated that a rocket can survive the launch and fire at altitude; they just needed to apply the proper thrust to make it orbit).
* Other methods are things like the high powered coil guns, railguns, and ram accelerators (also with a second-stage rocket); as well as combining any of these methods and/or conventional ballistics with a scramjet engine (and second stage rocket).
However, the space elevator is the "maximum cost efficiency per launch" method physically possible - and it *is* feasable if materials tech advances.  Rei 17:40, 5 May 2004 (UTC)
thread_title:  alternative ways to space 

message: Do you think that the sway will only be 200m?  I just guessed a figure.  But if the cable is 2m or 20m wide this is a tiny proportion of the length.  The cable needs to be light and tension will have to be limited to limit the necessary strngth of the cable.  How stiff will the cable be?  If the sway is 2km and we want a 1km safety margin either side then it is a 4km swathe being cut through the sky.  Space traffic control is going to be very difficult!  And the sway could be 20km or more!  A 22km swathe would surely be impossible to manage.  Every low earth satellite would have to have its orbit adjusted every several hundred revolutions.  Every second week!
:I answered this one already, but it looks like my answer's been deleted without the question also being removed. Paul's way overblowing the scale of the sway and the magnitude of the space traffic control problem the elevator would present. Next time someone archives this page, please be more careful about how you cut things; this whole talk page has become a colossal mess. Bryan 04:27, 12 May 2004 (UTC)
thread_title:  sway 

message: ::I agree with your comment about ion drives.  The biggest problem with that, furthermore, is the sheer cost of getting them to LEO to begin with, due to the inherent inefficiencies in chemical rocket propulsion. Rei 16:15, 5 May 2004 (UTC)
thread_title:  above the weather 

message: ::Ok, again, I'll ask you not to intersperse comments.  It makes it hard to follow.  
:::I would rather intersperse my comments.  I find it easier to follow.  And it avoids the illusion you create of answering my points by quoting selectively from my post.  Which needlessly increases the length of the post and makes it hard to follow.
::::I would rather intersperse my comments.  Well, it's your choice if you want to be a pain to the person you're debating with.
This is something that applies to every talk page, not just the space elevator talk page. Could we take this to
* http://CommunityWiki/TurnBasedVsInterruptedThreadMode
* http://en.wikipedia.org/wiki/Wikipedia:Tutorial_(Talk_pages)
? -- DavidCary 17:23, 11 May 2004 (UTC)
thread_title:  meta wikipedia: intersperse vs. quote 

message: As I suspected (and as you all knew) it seems that the economic justification of the space elevator depends on lifting a whole lot more stuff into orbit than we currently do.  If all we want to do is to have GPS (and the new Euro equivalent) and telecoms and weather forecasting and infra red astronomy and the occasional probe to the rings of Saturn then the financial justification of the elevator is difficult.  
So, what is the elevator for?
Can we not remind ourselves that the solar system has no other planet which is habitable on economic grounds.  That no nearby star has a habitable planet.  That we could do a lot with US$40bn other than build an elevator.
Paul Beardsell 23:55, 7 May 2004 (UTC)
replies: text: Holy potatoes, I spend a day away from Wikipedia and this talk: page doubles in size to 100 kilobytes. Sorry I left you to do all the heavy lifting, Rei. Anyway, Paul, the purpose of a space elevator would be to lift a whole lot more stuff into orbit than we currently do. Do you think the only things that can be done in space are the things that we've already been doing for the past few decades, launching handfuls of small robotic satellites and probes? There's tons of other stuff that could be done - colonization of the Moon, Mars, and other bodies (just because you can't walk around in shirt sleeves doesn't mean they aren't habitable, it simply requires more work to live there), the construction of solar power satellites, etc. If all you want to do is what we're already doing then of course a space elevator would be pointless; the whole point of having a space elevator (or other cheap "mass transit" system for getting stuff to and from orbit) is to expand the scope of the things that people can do there. Bryan 00:13, 8 May 2004 (UTC)
replies: text:  How much mass *did* we lift into orbit last year ? -- DavidCary 17:23, 11 May 2004 (UTC)

text: You want a justification for cheaper access to space?  Here's one: Gold, silver, platinum, rhenium, and other rare metals.  There are several hundred near earth metallic asteroids with an average 1.4 *trillion* dollars worth of rare metals in a form far purer than is typically ever found on earth (due to the way that they're formed).  Even better, asteroids are often relatively poorly held together, and if they have any significant rotational momentum, mini-elevators (made out of materials as mundane as steel, and only a few miles long) can toss the mined material back to earth with no energy required, and power can be generated by tossing junk out into space.   Even with conventional lift costs, this is being seriously considered.  With low lift costs, it would be a *huge* industry. Rei 00:35, 8 May 2004 (UTC)
thread_title: Justification of the Space Elevator