Alternative fuel systems for aero-space

all the space vehicles today depend on combustion tech for launching
purposes . this technology which depends on an oxidiser and a fuel
gives just enough thrust to take a space vehicle from the earth surface
to the space against the gravity. now the speed and fuel capacityof
these vehicles will not be enough for long space missions ....so is
there a way by which we can use an alternate technology to launch space
vehicles without using combustion technology ...is there a way to over
come or anull the gravitational forces and make a body levitate ....?