Artist's impression of the ROSAT satellite in space.
Credit: German Aerospace Center
The defunct 2.7-ton German ROSAT satellite is slated to make a fiery, uncontrolled re-entry to our atmosphere sometime Saturday or Sunday (Oct. 22 or 23). Experts say the broken-up bits of ROSAT have a roughly 1-in-2,000 chance of hitting someone somewhere on Earth, though they won't know where until a few hours before it enters the atmosphere.
Let us be clear: There's an extremely remote chance that ROSAT will fall on you. But, for good measure, if ROSAT, or some other spacecraft, did fall on your property, could you keep it? And, if the bus-size satellite flattened your house, who would be on the hook for the repair bill?
ROSAT is an X-ray space observatory that launched in 1990 and was shut down in February 1999 after a star tracker failed. The spacecraft weighs about 5,348 pounds (2,426 kilograms).
First off, ROSAT was a joint venture between Germany, the United Kingdom and the United States, and remains the property of those countries even after it comes back to Earth. To keep a piece, or to try to sell it, would be illegal — unless the angencies relinquish ownership of the debris.
There isn't a ton of precedent here, but when people tried to sell pieces of the Space Shuttle Columbia, for example, the government shut them down, pulled their auctions from eBay and reclaimed the debris. But that was a special case because the Columbia accident was under investigation at the time. When parts of the space station Skylab landed in Australia in 1979, NASA did not reclaim them. In the present case, the trio of countries may or may not ask for ROSAT debris back. [Photos: Germany's ROSAT Satellite Falling to Earth]
The good news is that if the satellite, or even just sizable chunks of it, did in fact slam into your house, you wouldn't need to sell your new space souvenir to pay for repairs. By international law, the three countries would have to foot the bill.
Liability for damage caused by objects falling from space is regulated by the 1972 Convention on International Liability for Damage Caused by Space Objects. All three countries involved with ROSAT have signed the pact, and in doing so agreed to be "absolutely liable to pay compensation for damage caused by its space object on the surface of the Earth or to aircraft in flight." That goes if ROSAT crashes down in Kansas, France or Zimbabwe.
The terms cover just about everything. In this case, "damage" is defined as loss of life, personal injury or other impairment of health; or loss of or damage to property of states or of persons, natural or juridical, or property of international intergovernmental organizations.
And the payout is fairly good. Again, quoting the treaty: "The compensation which the launching State shall be liable to pay for damage under this Convention shall be determined in accordance with international law and the principles of justice and equity, in order to provide such reparation in respect of the damage as will restore the person, natural or juridical, State or international organization on whose behalf the claim is presented to the condition which would have existed if the damage had not occurred."
One slight hitch in the treaty is that you have to present your claim no later than one year following the incident (or discovery of the damage). If you've got a truck-size satellite sitting in your living room, however, we suspect that satisfying this condition would not be an issue.
This story was provided by Life's Little Mysteries, a sister site to SPACE.com. Follow Bjorn Carey on Twitter @thebjorncarey. Follow Life's Little Mysteries on Twitter @llmysteries, then join us on Facebook.