"The Great Silence" -A Galaxy Classic

If we build a spacecraft that accelerates at the force of gravity (10 m.s-2) then we would reach near to the speed of light within about one year.

This would make it viable for earth-type people as the acceleration becomes a type of artifical gravity.

So why do the 'scientists' claim that only 10% of lightspeed is viable?

ok, possibly fuel.

But if we used an asteroid, with the entire body making up the fuel, then 99% of the asteroid-spacecraft is actually the fuel.

Then of course there is also the possibility of collecting hydrogen as we fly past it and ram it into the engine (once the asteroid is used up) using a scoop.

10 m.s-2 is not a great deal of acceleration, and I have not done all the calculations as regards the asteroid-fuel, but seeing as though energy is mass and vice versa, it seems viable on an intuitive level.

Anyone care to do the math?