From: Doug Jones (random@qnet.com)
Date: Tue Mar 07 2000 - 23:13:35 MST
Spike Jones wrote:
>
> Jeff Davis wrote:
>
> > So I puzzled over it for a week, and found no flaw in spike's reasoning,
> > or, to be more precise, no flaw in his conclusion. Quite elegant, actually.
> > ...
> > According to Kepler and Newton all planetary orbits are elliptical (a...
> > the earth at the other end is the perigee. Nifty.
>
> Jeffer, I must explain myself. I went down that exact line of reasoning
> when I first posted, then the flaw occurred to me while I was off calcing
> another nifty idea, so I created a diversion [which resulted in the
> thread with the unfortunate name english schminglish] to stall for time
> while I worked out my other idea, then returned to this. My other
> idea is working out really cool! But this one has languished, like my
> information game notion. {8-[
>
> The problem with the eliptical orbit notion, jumping off the tower
> at one earth diameter from the surface of the planet is that one's
> tangential velocity at three planet radii from the one focus is a
> function of the sidereal rotation rate of the planet. So I can
> immediately give you one case where the idea wont work: where
> the rotation rate of the planet is zero with respect to the stars.
> [Ignore for just a moment that no isosynchronous tower would
> be possible under those conditions.] With zero sidereal motion,
> one could be 3 radii out [or arbitrarily many radii out] leap off
> the tower and one would fall straight down, with unfortunate
> consequences.
>
> Another counterexample is if the sidereal rate is really fast, so
> that isosynchronous altitude is lower than a planet diameter
> from the surface. You step off of that and shhhhooooom!
> You might never be heard from again. {8-]
In my copious spare time (ugh) I'll slap together a simple excel
spreadsheet which calculates orbits for any drop altitude, then use the
solve function to find one with a perigee of 6571 km (200 km above
surface).
Right after I finish programming the PLC for our new engine controller,
set up a data acquision system, and calculate the orifices for a cooling
jacket's inlets, outlet, and mass flow control venturi. That's just
what I have to get done this week... one thing my job isn't is boring!
-- Doug Jones Rocket Plumber, XCOR Aerospace http://www.xcor-aerospace.com
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