assume if enough fuel is there is it possible to achieve near light speed? what are the factors preventing this? how we can link relativistic mass to the thrust of rocket at near light speed? assume mass of spacecraft is constant and enough fuel is there then can chemical rockets can reach near light speed? if not does relativistic mass has anything to do with this at higher speed does more energy is required to expel gases? if constant thrust is given is it possible to achieve near light speed? What is the relativistic version of thrust equation?