space travel again?

even in space a object has weight because it has mass. if you could create a sort of effect like antigravity, a way to make the space ship nearly weightless in space than would you solve the problem of inertia when speeding toward the speed of light? ps I know my spelling sucks get over it.

You are confusing weight and mass. In free fall, bodies are weightless - but they retain the same mass they always had.
Inertia, however, is an intrinsic property of mass - no one has any idea how to reduce the inertia of a given mass, or whether the question even makes sense.
But you're right that reducing the inertia of an object would solve a lot of space flight limits!
(Note that an 'inertia-less drive' is a common science fiction device). Maybe someday!

Weight is a direct measure of gravity on an object. If you have no gravity, you are weightless. Inertia is a function of mass, and it is a fundamental property. More mass = more inertia. So in space or on the surface of Mars, an object's inertia stays the same.

Astronauts in a space shuttle are floating around. That's weightless. We can't get any more weightless than that. Well ok, a little. But anti-gravity isn't going to mess with inertia.