It's only fair that people wonder why it isn't doing that. The questions concerning its mass open an exciting door into lore. My personal theory is that the gravity is largely exerted on another dimension, funneling the light into the hands of our guardians. I also bet that the damage to the traveler is impact damage, caused by it turning off its antigravity and using itself to smash a fleet of some kind.

I'm just saying that questioning the physics of the traveller is probably one of the silliest things you could do if you have no problem accepting the rest of the game