So I finally got my first combat fleet in range of the *spoilers* that I'm trying to kick out of a system I want to colonize. Intelligence says the ships are capable of 10k km/s, and size (1000T) and engine signature (200) seem to confirm that, if I understand how that all works. My missiles go ~45k km/s, but for some reason, the "Missiles in Flight" tab shows range to target and time to target increasing.
Any ideas what's going wrong?