It's actually harder than it intuitively seems. Because of the high velocities involved, changing from say 0deg to 90 deg inclination would require a delta-V of about 1.4 times the actual orbital speed. Think of it another way. Changing from equatorial orbit to polar would require probably more fuel than the initial launch (I could be wrong here). I think it's more efficient actually to raise apoapsis, do the inclination change further out, and then lower apoapsis again. It's relatively easy to raise the high point, and the gain in height lowers the velocity change required to change inclination. Much easier to explain in pictures. :) If I'm incorrect about (or omitting) anything, someone please put me in line. But I think that's the gist of it. It may be possible to exploit some perturbation effect in Earth orbit, but that would take much time. Too much for shuttle, which simply didn't have the fuel, no matter how you slice it. For an ion engine, it would be possible to significantly change inclination. Depends on how much fuel, and how fast you can spit it out the back. Regards, -- JCA Skywise wrote: > I have what seems a simple question that I know is going to have > a not so simple answer, but... > > Just how difficult is it to change the inclination of an orbit? > > I'm thinking on the order of 25 or more degrees. It doesn't have to > be "overnight" but could take a period of time, perhaps up to a > year. > > I know a lot of people asked why Columbia couldn't have rendezvoused > with the ISS if they knew they were in trouble and the obvious answer > was they were in the wrong orbit without enough fuel to change it. > > But, I'm thinking of unmanned craft with little or no time > constraints. > > Could it be done with an ion engine? > > Brian > > ------------------------------------------------------------------------- > Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L > archive: http://www.satobs.org/seesat/seesatindex.html > > ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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