Unrealized Reality (1) - S4-E11
Visible crew/equipment: When Crichton is about to take his last journey into the wormhole (in this episode at least) he pulls down the visor of his helmet. We can see four square and round white lights reflected that are not from the current scene.
Chosen answer: It's never explained. John mentions a theory that his less technologically developed craft simply interferes with the wormhole less than the "superior" Vipers, but they never make a concrete determination on that point. But we also have to take into account the fact that Moya traverses wormholes with no ill effect as well.
Garlonuss ★