Rolf, thanks for the comment on 'planet04.gaz'. As you realized,
that line should have started with #, not ;. (Any line in a .gaz
file starting with # is ignored.) I've fixed
http://www.projectpluto.com/planet04.gaz
accordingly; anyone who downloaded the previous version ought to
either change that starting ; to a #, or just grab the above file
again and replace their existing copy.
Ray, you're right that you can't get data on the Earth through the
Horizons Web interface... matter of fact, there are all sorts of nifty
things that you can't get through the Web interface, such as orbital
elements and setting your viewpoint off the earth and so on. I did
get Horizons data for Earth with the sun as my "viewpoint" via the
e-mail interface (and I think I could have used the Telnet interface).
I've stuffed that data into the "notes" for Earth (and added in the
Hill sphere definition, too.)
BTW, nice link on the "astronaut orbiting the shuttle" question.
I wonder if the shuttle is actually a mere ten tons in mass, though...
seems kinda small. Perhaps the 104000 kg is a mass figure?
(This would only raise the Hill sphere by a bit more than two.
You'd still have to move the shuttle up somewhere between
geosynchronous and lunar distance before you could step out
and orbit it, with an orbital period on the order of hours to days.
Dunno how stable the orbit around so irregular an object would
be, either.)
-- Bill