I was flying a Manned Lunar Pass, and just after the Reentry step, the game crashed with this message:

raceintospace: /home/leon/raceintospace/src/game/intel.cpp:524: void MissionIntel(char, bool): Assertion `mis >= 0 && mis <= 56 + plr' failed.
Aborted (core dumped)

Edit: wait, I may have misremembered when it occurred. I just started the game again, loaded the save, and the mission succeeded. But then while showing my opponent's prestige first (a Mercury flyby), it crashed again with the same message.

But on my third try, it showed my opponent completing the Manned Lunar Pass just ahead of me, I flew mine, then it showed the computer's Mercury flyby prestige first with no trouble.

I have the save game if anyone wants to see it.