🚀 go-pugleaf

I *still* don't think we need an extra newsgroup for planets, and that
sci.astro works just fine.  Oh, what the heck.

In article <1992Oct1.015115.16293@aio.jsc.nasa.gov>, kjenks@gothamcity.jsc.nasa.gov writes:
> My ground-based lasers would get you a net thrust, albeit a small,
> inefficient one.  But we've got several centuries before we can 
> change the atmosphere, anyway.  Lasers are patient.  We can wait.

I've been waiting for somebody to point out (because I haven't
mustered the technical argruments) that Ken's proposal stinks because
the lasers are high-exhaust-velocity, low-thrust devices.  You have to
move a few trillion trillion kilograms, you're going to need *serious*
thrust.

If you are moving your planet with rocket engines, get some with
exhaust velocity just a little bigger than escape velocity (reason why
left as exercise for student) and with as much thrust as you can
afford.  

Where do you put them?  At the point on the surface where the planet's
orbit intersects it.  If it's a fixed installation, you fire a burst
once a day.  If the rocket engines are on wheels, not inconceivable on
Venus (Geoff Landis would love this), you track the sub-orbital point.

On Earth, you'd want to fire at sunset to make the orbit bigger, or
sunrise to make it smaller.  Interesting problem:  suppose the engine
is mounted on a barge in the Pacific.  Where do you move it to each
day to get optimal effect from your thrust?  Turns out to be an
inverted analemma... (proof also left as an exercise for the student).

On Venus... let's see, the rotation is retrograde, right?... does that
mean you'd fire at dawn to move outward?  Nope, I think you still want
to fire at sunset.  


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