spacecraft
pioneers 10 and 11 are not where they're supposed to be. or more precisely, they're exactly where they're supposed to be. they're just not where we think they're supposed to be. well, we kinda lost contact with them. so we really have no idea where they are now. exactly. but we have pretty good data on where they were. and they didn't go where we thought they should have gone. they slowed down a little faster than expected. maybe they were just homesick. and didn't want to leave home. ;-> okay. the most reasonable proposal is the heat from its power source was asymmetrically radiated away. which provided a very tiny force pointed mostly towards the sun. the pioneers are rotationally stabilized. that means their ass end is pointed directly at us and they're spinning around and around and around. so it doesn't really matter which direction the radiation asymmetry points. over one rotation it'll be averaged to point either directly towards or directly away from the sun. heh. hey! seems like we should take advantage of this effect to give our spacecraft a little extra push. instead of creating drag. heh. hrm. someone should patent this idea. oh yeah. i'm gonna be so rich.