Hohmann orbits, Launch windows, delta vees etc.

Recent conversations with Henry Spencer and James Nicoll have opened my
eyes to a pleasing fact:

It can cost much less delta vee to do a periapsis burn low in a gravity
well and capture a body to highly eccentric elliptical orbit. I had been
capturing bodies to circular parking orbits.

So I have made some changes to my Hohmann.xls spreadsheet. Instead of
entering altitude of circular parking orbit, the sheet now asks for
periapsis and apoapsis altitudes of the parking orbit.

If the user wishes, he (or she) can still get delta vee for capture to a
circular orbit: Just make the apo & periapsis the same altitude.

I've also added the planet's Sphere Of Influence. The apoapsis should
lie within the SOI for capture. The cell to the right of the apoapsis
gives the number it shouldn't exceed.

The spreadsheet has all the planets but Pluto. It gives synodic period,
Hohmann trip time, launch windows and some other stuff.

To download go to http://clowder.net/hop/railroad/sched.html
and a link for Hohmann.xls is just underneath a table near the top of
the page. Windows users can download with a right click, Mac users with
a sustained click.

I'm hoping some ssp readers find this useful for BOTECs. I also hope
some of the knowledgeable folks here will take a look & let me know if
there are errors in the spreadsheet.

--
Hop David
http://clowder.net/hop/index.html