There’s a cool story on Slashdot about the continued slight deceleration of Voyager 10 and 11 due to some as-yet-unexplained force that seems to be dragging the probes every so slightly toward the Sun. Wild theories floated thus far include electromagnetic effects, the Oort cloud or dust in that region of space, and, of course, the old standby: dark matter.
Every so often I feel a pang of regret that a mission like Genesis goes awry, and then I remember that we have these probes out there that were expected to be useless 15 years ago, but are still returning useful data. It makes the loss a little more bearable.