The Hubble Space Telescope is not as big as the ISS. But Hubble is still one of the largest objects in orbit and a danger mostly for its collision potential. If Hubble were to strike another satellite or piece of debris, the amount of additional wreckage would significantly add to the space debris problem.
Initially, Hubble was launched aboard the Discovery space shuttle in 1990 after a multiyear delay following the destruction of Challenger. Currently, Hubble is not in a controlled orbit and is descending toward Earth.
As Hubble’s materials are so strong and dense, the space telescope is not likely to burn up in the Earth’s atmosphere during descent. After entry into the atmosphere, Hubble would then fall uncontrolled to the Earth’s surface. This is likely to occur sometime between now and 2040.