Not sure what you mean. Gravity does not "build up" in the space shuttle.
Gravity is an effect of every object with mass in the Universe. For the shuttle, the primary source of gravity affecting it is the earth, since it is the closest large mass. It also feels gravity from the moon, the sun, Jupiter, the Andromeda galaxy, the astronauts in the shuttle, the ISS, and any object within about 13 billion light years of us, but all of those are much smaller than that from the earth. In fact, if the earth's gravity wasn't there, the shuttle would fly off into space, rather than orbit the planet.