The Schwarzschild radius (sometimes historically referred   
   to as the gravitational radius) is the radius of a sphere 
   such that, if all the mass of an object is compressed  
   within that sphere, the escape speed from the surface of    
   the sphere would equal the speed of light.
   --Wikipedia

Personally, I think your project getting so big that not even light can escape is a far better image (your project would literally be a black hole) than the on the article implies where you cannot get a rocket of the surface.