The German Aerospace Center says it expects one of its satellites to re-enter Earth's atmosphere in the coming days, but is unsure where the fragments will land.

The German scientists said Thursday the satellite, named ROSAT, is the size of a large car. It should should partially burn up as it re-enters the atmosphere at a speed of 28,000 kilometers per hour, but some chunks are expected to reach the ground either Saturday or Sunday. Latest estimates say 30 fragments weighing a total of 1.7 tonnes could hit the Earth's surface.

The Aerospace Center says it can no longer communicate with the satellite, which was launched in 1990 as an x-ray observatory. Scientists believe they will be able to narrow the timeframe for the satellite's arrival as it gets closer to the earth.

According to the scientists, the largest fragment to hit the ground will be the satellite's telescope mirror, which is described as “heat resistant.”