AKICIF: Simplified Hohmann Orbits

In message <7EUhDACSqBuIFw9O@xxxxxxxxxxxxxxxxx>, Marcus L. Rowland <forgottenfutures@xxxxxxxxxxxx> writes
Is there anywhere a "quick and dirty" calculator / spreadsheet / whatever that'll let you plug in any two planets of the solar system and a launch date and initial velocity and come up with the transit time for a Hohman orbit? Doesn't need to be incredibly accurate, approximately the right order of magnitude will suffice but it does need to be really easy to use - we're talking gamers here, not rocket scientists.

This is where I have to admit that I managed to miss a couple of lines on my first read-through of _The Red Peri_ which state that the ships use continuous acceleration:

"Bah! I told you why. Didn't I spend five hours figuring out the time it'd take to reach the nearest inhabited place? That's Titan near Saturn, just one billion -- one billion, I said -- miles from here. And at the speed we could make zigzagging, because we couldn't keep a constant acceleration, it would take us just exactly four years and three months. We've got food enough for three months, but what would we live on during the four years? Atomic energy?"

Which means that I can just use simple calculations based on acceleration and ignore orbital mechanics for game purposes.

Assuming that it'll take three months for the 1 billion mile trip under normal circumstances, that's about 0.01g cruising acceleration / deceleration, with much higher power used only during takeoff and landing. Plugging in a range of values gives 1 billion mile trip times of:

0.01g = 93.7 days
0.015g = 76.5
0.02g = 66.3
0.025g = 59.3
0.03g = 54.1

And Earth-Mars times at conjunction of:

0.01g = 20.2 days
0.015g = 16.5
0.02g = 14.3
0.025g = 12.8
0.03g = 11.7

I think I'm going to go with 0.01g for the earlier ships in e.g. _A Martian Odyssey_, 0.02g to 0.03g for later ships.

So no worries about Hohmann orbits, still the "why are they staging through Titan?" question for trips to Uranus and beyond, but maybe there's some sort of speed limit caused by meteors or the asteroid belt.

Many apologies for wasting everyone's time.
--
Marcus L. Rowland http://www.forgottenfutures.com/
http://www.forgottenfutures.org/
LJ:ffutures http://www.forgottenfutures.co.uk/
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