(Undated) -- A massive chunk of Chinese space debris could crash land somewhere on Earth. China over the weekend launched a large rocket carrying a big piece of its new orbital Tiangong Space Station. The delivery was a success but astronomers say the launch left behind the rocket in a deteriorating orbit. The rocket weighs at least 23-tons and it's possible that not all of it will burn up on re-entry. Jonathan McDowell, an astronomer at the Center of Astrophysics, warns it could make an uncontrolled re-entry at an unpredictable location.