Dear PF Forum, I have a question in mind. But I'm not sure if this belong to SR forum, cosmology or classical physics. So I post it here. And perhaps as some of you might have known before or thought it over. It's about kinetic energy. Supposed this... A rocket, with a rest mass 1 ton. And the rocket can somehow grab matter and anti matter in interstellar medium. I know that anti matter just can't scattered freely in interstellar medium, but let's just dispense with the technical difficulties. So in its journey the rocket always accelerates 1 g. And in doing so it has consumed, say..., 10 solar mass of matter and anti matter annihilation as its energy source. Now after some times its speed is 99.9999% the speed of light (or should I add more nines?) Then this 1 ton rocket hits a neutron star, say 1.5 solar mass. Can this neutron star become a black hole if it is hit by this rocket, considering this 1 ton rocket relativistic mass must be about, say 3 solar mass (or more/less?), after spending much of its energy in the form of momentum to eject its propelant? Thanks for any clarification.