A friend of mine is doing a science-fiction project involving the dwarf planet Eris and wants to employ scientific accuracy. He would like to know, given the orbits, when approximately would be a good time to leave Earth to travel to Eris (using our best current space-travel technology), anytime within the next 1,000 years, and when the craft would arrive there. The craft would not be flying by but would be decelerating so as to orbit Eris -- which I imagine would necessitate coming to a nearly complete stop in Eris' rest frame. Not to be too demanding, but he'd also love to know how the leave-and-arrive dates would be different if the craft could go twice as fast as our current best technology allows. I realize these are difficult questions, but Physics Forums members have always been extremely helpful in the past, so I offered to post the problem here. Perhaps someone knows of a calculation applet or something. Thank for any help you can provide!