Washington, Dec 2 :At 13 billion miles from Earth, there’s no mechanic shop nearby to get a tune-up. But SA enginners have successfully fired up a set of “dormant” backup thrusters aboard the Voyager 1 spacecraft — the farthest and fastest spacecraft — after 37 years. The only human-made object in interstellar space — the environment between the stars — Voyager 1 has been flying for 40 years. It relies on small devices called thrusters to orient itself so it can communicate with Earth.