Power requirements

[ffutures]

I think someone told me that (ignoring travel times) it actually takes less energy to travel from Earth to Mars than between Jupiter's moons. Can anyone point me at a source for this? And for energy requirements for other interplanetary journeys? Preferably something that I can use without breaking copyright?

Comments

[nelc.livejournal.com]

Let's see if I can format this properly:






Diagonals are orbital velocities of the planets in km/s; other values are the deltaV's required to go from orbit to orbit. So Earth-to-Mars is 5.7 km/s, greater than any Jovian satellite transfer except Io-to-Ganymede and Io-to-Callisto. And as I said, relative sizes mean that surface-to-surface will add more to Earth-Mars requirements than any given pair of Gallilean satellites. (But it's late and I've forgotten how to work out exactly how much right now...)

[nelc.livejournal.com]

So, I guess if you define a fuel unit as 3 km/s, it takes roughly 1 fuel unit to from one moon to the next one, two units to move two orbits, and three to move three orbits in the Jovian system.

Meanwhile, Earth-to-Mars takes two units, Earth-to-Jupiter takes 6 units, and Mars-to-Jupiter takes 4 units.

(That's provided I haven't made a simple error somewhere... Where's that book, I swear it was right here just a couple of years ago....)

[ffutures.livejournal.com]

Thanks - I've got my own copy somewhere, so don't worry too much, it'll turn up.