I guess it it will be a while before we send a spaceship out to space at near the speed of light as in the original 1968 movie Planet of the Apes, as we gave up on sending men into orbit.
We got better investments for our $$$.
Afghanistan and Obamacare.
Yep, I say just go do it. Maybe offer a prize for the first manmade vehicle to exceed 1/10 the speed of light! If mass increases with velocity, then those propellants ejected will have more impulse as well, or so it seems to me.
It will happen—but it might take another 300 years.