I think I've said this before (maybe that World Trade poster - forgive my memory) but I don't think stuff like this is really a big deal. It made alot of people sad when it happened, and that feeling lingers for alot longer for some people than others. That is not a good reason to not use an image.
This image is not unlike the Hindenburg crashing photo (iconized and over-used) or Titanic references or napalm Vietnam video clips or atomic bomb mushroom clouds over Japan. Those images clearly represent needless and tragic death (often on a much larger scale than a handful of astronauts), but nobody says "boo" about it because the events did not happen in their lifetimes.