At an annual conference regarding just this material I believe last year, 2 of the top researchers on this question were asked what problems they might encounter if they finally are able to propel something other than a proton and an electron (because of the gamma principle) at the speed of light or close to it.
The answer? Dust.
At that speed, there is no material, no steel strong enough that would stop little microscopic specs of dust from piercing the hull of a ship.
Long story short, you would be impaled by microscopic pieces of dust that would fly right through you, piercing every square inch of you body, all of your organs, veins and arteries almost instantaneously, and you’d essentially disintegrate.
Sweet
“At that speed, there is no material, no steel strong enough that would stop little microscopic specs of dust from piercing the hull of a ship.”
Shields up Mr. Zulu.
I have read a potential solution to that. She ship creates its own dust projected ahead of it, to obliterate the dust that is in the path of the ship. A sort of Dust shield.