What is the fastest speed we can travel in space?

[Tabaristiio]

Without taking into consideration any G forces or other phenomena's. So say we slowly and gradually speed up, eliminating any risks of G Force related issues. Fly in empty space without any obstacles in our way and will not be in our way in this scenario, and finally the spacecraft is perfectly engineered and cannot go faulty. Can we continue traveling faster provided we were below the speed of light? Or will we experience problems a long way before we reach anywhere near the speed of light? If so, at around what max speed could we safely travel and what would some of the safety risks be? Ship becoming unstable? Weight or energy increasing? Or could we theoretically travel safely at 99% of the speed of light? Please state what are some possible safety problems if there are any.

Thanks

 

[Brul]

In my opinion, keeping the acceleration going would be the most difficult problem of them all.

 

[cosmik debris]

Running into spurious matter might be a problem, even hitting hydrogen atoms at relativistic speeds will result in high radiation.

 

[Hatesmondays]

This is an extremely hypothetical situation; I think we would want to make mods for adjusting course and such.

 

[Khashishi]

We are basically limited by fuel. A big problem is that the more fuel you have, the more mass you have, and the more fuel it takes to move you. So, check out https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation

 

[phinds]

Totally ignoring the engineering / practical problems (fuel, mass, obstacles, etc) that make it completely impossible, there is nothing inherently stopping a spaceship from going at any arbitrary speed as long as the acceleration is low enough to keep it from suffering metal fatigue.

The point is, the ship doesn't CARE how fast it is going, only how much acceleration is being applied to it. A constant acceleration of 1G would likely in no way cause any mechanical problems with a ship and it would reach near light speed reasonably quickly. I've seen the calculations here on this forum and as I recall, .99c takes about a year of ship time at 1G.

As to what's practical, that's a whole other can of worms.