A research satellite is falling back to Earth and is expected to land Friday or early Saturday morning, says NASA.

The exact location in which it will land is unknown at this point.

Debris from the satellite, made up of titanium, beryllium and stainless steel, will range from approximately 10 pounds to hundreds of pounds.

NASA said that it will be hours before it would be able to zero in on the time and place of entry.

"Part of the problem is, the spacecraft is tumbling in unpredictable ways, and it is very difficult to very precisely pinpoint where it's coming down even right before the re-entry."

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