Platform Presentation For Space Elevator Conference


KHL 2011 August 7 version 0.6

John - sorry for the delay. The slides are finished (though I hope tweakable later) and uploaded to my account on the microsoft website. Here are the slides:


Note to John: I am using the parameters below. I have modified parameters on the slides in my open-office slide deck, but have not extracted the images and uploaded them yet. I had hoped to have all the slides finished by thursday AM UK time (ha!), but it was not to be.

I have a nice drawing of a laser, modeled on Jordin's images. I got a little carried away, thinking I could draw nice flexible pipes for fiber optics and cooling water, then I came to my senses - not necessary, move on to important stuff. I'm tired and my judgement is off.

Rather than 3 platforms with 2 lower ones for lasers, I will draw only one, and mention the possibility of moving them lower. The problem with lower platforms and a high center is the need for high tensile forces to keep the laser platforms from sliding down, and a long shallow angle above the laser platforms, increasing the horizontal extent.

It is easier if everything is up on top. The best way to arrange the platform is to put the lasers at the west end and the ribbon anchor on the east end, with the bulge of the curved platform in between. Coriolis acceleration will tend to pull the climber to the west. We can use a smaller laser, or "jumper cables", to power the climber into the laser working area.

I'm rooting for the jumper cables, as those would be safer than shining lasers around the climber assembly area.

Another alternative is a second platform for the lasers. Lots of possibilities here, but I don't think we need to elaborate the unicorn cage too much, just shake loose some thinking.

I spent an hour on a nice observation deck view, see below, a montage of a Dallas(?) observation platform and a cloud view from the shuttle. I still don't like the safety of a civilian observation platform, but I want to present your ideas in the best way, anyway. Somebody might have an idea about mitigating personal and legal risks.

Design parameters

Design Tensile Strength

1.04

MegaYuri

Platform Height

50.00

km

Surface angle

38.00

degrees

Track to Rotor ratio

1.542

Ground

All rotors, lineal dens.

1.50

kg/m

Rotor ground speed

3.500

km/s

Gnd horizontal velocity

2.76

km/s

Gnd vertical velocity

2.15

km/s

ground ramp depth

0.131

km

grav. and centrif. accel

9.764

m/s2

Incline

Incline horiz. distance

77.43

km

Incline vert. distance

50.00

km

Incline length

92.32

km

Incline time

26.95

sec

Incline total track mass

1101.54

tonnes

Incline total rotor mass

566.04

tonnes

Platform interface

track tension

2.85

MegaNewton

track lineal dens.

7.369

kg/m

rotor lineal dens.

3.127

kg/m

angle

26.65

degrees

rotor speed

3.358

km/s

rotor compression

1.0432

horizontal velocity

3.001

km/s

vertical velocity

1.506

km/s

grav. and centrif. accel

9.612

m/s2

end to end length

165.599

km

total rotor length

392.376

km

deployment stretch

1.180

Platform

platform length

7.626

km

platform center height

50.903

km

platform mass

3000

tonnes

Estimated costs, arbitrary units

cost of ground magnets

706

cost unit

cost of inclines

554

cost unit

cost of platform magnets

495

cost unit

cost total

1755

cost unit

computed with plat03.c


Power Budget



Other Notes

Keep in mind that the wiki saves past revisions, and I make nightly snapshot backups, so don't worry about messing anything up.

Cosmic Study: The part about 30MW lasers versus 50MW lasers is a bit confusing.

I suggest that we consider the platform as a narrow, long arc, perhaps with multiple elevators. That helps spread out the magnet loading. It also spreads out the radar systems and the lasers, which keeps lower climbers from occulting the upper ones.

See these pictures of clouds above the Galapagos, and Ascension Island. Clouds are light in our intended operating regions, but not especially rare. Frequently starting and stopping climbers because of lack of power can create nasty and hard-to-damp longitudinal vibrations in the SE cable.

Also, keep in mind that the Inter Tropical Convergence Zone (ITCZ) does not have cyclones, but it does have lots of thunderstorms with a lot of chaotic vertical air movement. The north-south position varies with time of year, but it is biased to the north in the Atlantic and eastern Pacific. The loops should be anchored well south of the southern extreme of the annual movement. I like 8° south latitude, which is well below convergence-related air upwellings, thunderstorms occur every few years, even there. Wherever there is equatorial heat, there will be moisture-laden upwelling air, and condensation as the rising air cools.


Process

I will assemble this in Openoffice.org, using slides each containing one big graphic (perhaps just text on a background). I will export to a PDF file, and what is hopefully PPT.

I do not have a recent powerpoint viewer (or a Windows machine to run it on) so I need to do this the safest way. Even different versions of PPT render text differently on different machines - the only repeatable format is prerendered text on a JPG or PNG image. That makes the presentation larger.

I will not be including animations, or using my preferred web-browser-based presentation tool. The Microsoft conference center has some expensive display tools, but they are very restricted and set up for powerpoint only. Two years ago, I had to bypass their computers entirely and connect my laptop, doing projector configuration for precious minutes. If it was any other venue, I would use my preferred tools, because I can do a much better job. Sigh.

Most new illustrations and text pages will be sketches using Openoffice.org. I will be using the POVRAY ray trace program to make some illustrations, using some launch loop slides as starting points. All drawings will be 1024x768

I try to do simple visual slides, few words. People listen to talk, see drawings, two channels. Generally, putting text on slides bolixes the listening channel (read Guy Kawasaki's "Art of the Start", other books on presentations).

I prefer using an rgb=<0.2,0.2,0.4> dark blue background for slide presentations, easy on the eyes. The synthesized slides can be quickly (though not automatically) redone with white background for your paper.

I can easily move the slides back and forth to my laptop, in a bunch. I can run a script on my server to make nightly zip files of all of the images so you can download them, if you think that will help.

I try to keep things as simple as possible, decide what I want the audience to walk away with, and leave out everything that doesn't help get them there.

Things I won't bring up

If questions are asked, I will answer them, but I don't need to talk about these things to tell the main story.


Slide List

(*) Marks slides complete


Section: Title/Intro


Title slide - illustration of SE platform with overlay text ( POVRAY, modified launchloop, see below)

Title.png


Challenges - Distant platform (sketch with highlights, )

[ATTACH]


Wind Pressure

WindP2.png

Lightning

I changed this to a different map from NASA. While the cylindrical projection map from John provides more detail in the infrequent strike areas, it does so with dark purple for one of the "infrequent strike" zones, does not label the scale, etc. The raw numbers are available, perhaps someday we should write a program to plot something more suited to our needs

Lightning.png


Cloud Cover

CloudCover.png


Rain

Rain.png


Air drag on climbers - Ben Shelef's picture *

BenClimber.png


High platform focus illustration (POVRAY,modified launchloop)

Platform.png


Section: Dynamic structures


Deflection of 1 kg stream at 1 meter per second *

Defl_1k_1m.png


Deflection of 1 kg stream at 2 meters per second *

Defl_1k_2m.png


Deflection of 1 kg stream at 100 meters per second *

Defl_1k_100m.png


Deflectinion of 1 kg stream with horseshoe magnet *

DeflHorseshoe.png


Deflection of continuous stream with distributed magnet *

DeflDistrib.png


Deflection of continuous stream, distributed magnet, distributed weight *

DeflDistrib2.png


Deflection of continuous stream in oval, with 180 turnarounds *

Oval.png


Angle deflection equation

Force01.png


Force02.png


Force03.png


Force04.png


Possible slide with


Simplified triangle structure, 180deg ambits, upward deflectors, top support deflector (POVRAY).

Simplified.png


Dynamic structure, curves. Don't bother with cable trusses or support cables. (POVRAY, modified launchloop)

Loop.png


Section: Platform Details


Platform specs (text)

[ATTACH]


Altitude, 50 km higher/lower (text)

[ATTACH]


Track with 3 tubes and rotors (there will be two, one supporting each side of the platform. 0.5 kg per rotor, with 3.0 kilograms (up and down paths) total providing platform lift. I can to back to the 6 rotor version if desired, but those will be pretty small rotors.

incline13.png


Arecibo pic (stock photo) *

Arecibo.png


Actuator base (POVRAY closeup)

[ATTACH]


Assembly bay (POVRAY closeup)

[ATTACH]


Radar/Lidar (POVRAY closeup)

[ATTACH]


Propulsion Lasers (POVRAY) This is only partial, a number of lasers will be shown attached to the platform in offset rows and columns. The "power trailers" will be below the lasers, with cooling water spraying down. Gravity and spray vector should send most of the water downwards, I just hope we don't create our own cloud that interferes with the lasers.

Laser.png


Cooling - water and spray (POVRAY)

Long pipes hanging down. Hopefully the weight of the vapor expanding will pull it downwards, and hopefully it will not ice up the insides of the pipes at night.

[ATTACH]


Elevator (POVRAY closeup), modified from launch loop Single cable loop.

[ATTACH]


Science: Telescopes (POVRAY plus stock photo)

[ATTACH]


Science: Observation deck (stock photo montage)

Observation.png


Conclusion: Advantages for Stage 1


Benefit List: Mesosphere science, Astronomy, Communications, Radar, Security (text on platform background}

[ATTACH]


John's notes:


Space Elevator Stage I


I have calculated a rotor speed of 3.5 km/sec at the surface with an inclination of 38 degrees to the horizontal. That only involves a 7% expansion at the top. Lower speeds are possible with a higher inclination and /or with a heavier rotor.

PlatformPresentation (last edited 2011-08-11 15:08:45 by KeithLofstrom)