the short answer is yes.

and the long one is that countries like India with their space program ISRO have already used this method for their space ships to launch them further in space.

as we know ISRO functions on a fraction of budget compared to giants like NASA we have to find new and innovative ways to make our rockets cheaper.

when launching a spacecraft further in space one of the most laborious task is to design a powerful engine which can lift of heavy weights off the earths gravitational force, but this creates a paradox, if you build more powerful engine it gets heavier, so to lift this extra weight u need an even more powerful engine, but this new engine will be even heavier.

so in order to solve this problem ISRO used earths gravity to escape earth gravity, the encircled earth like a satellite and using a catapult like system they thrusted the space shuttle out of earths gravity and into the space to reach mars(the mangalyan)