The ROSAT satellite (whose data I used in my thesis work) is due to come down this weekend. The link below shows the likely re-entry locations, but it’s very uncertain because 1) the uncontrolled re-entry is +/- 1 day and 2) the orbit is inclined so as the Earth rotates beneath it, the satellite’s shadow sweeps over very diverse areas.

Also interesting to see: there have been 28 satellite re-entries this year so far. It’s a much more common occurrence than I had realized.

The news is reporting a 1-in-2000 chance that some ROSAT debris will hit one of the 7 billion people on Earth. I’m curious how those calculations are made…

5 replies on “ROSAT”

  1. I think the odds were thought up by a reporter putting together a press release. I imagine it went something like this:

    Reporter 1: “Hey Ted! Can you think up a number for the odds of getting hit by this satellite that is small enough to scare people but still large enough to avoid lawsuits accusing us of trying to start a panic”

    Reporter 2: “1 in 2000”

  2. If it really in 1 in 2000 per satellite, that is better than 1 in 100 for 28 satellites, and I suspect the number of satellites will only be increasing.. Time to put on a crash helmet?

  3. Neil Brown: no, ROSAT (like UARS) is bigger than your average satellite and is making an uncontrolled re-entry. Most re-entering burn up before reaching the surface, so their odds of harm are much lower

  4. Keith Schulz – No, the satellite has been just drifting since 1999. It has no fuel or other means of control so it will come down where it comes down. The map I linked to shows a 12-hour orbital track. The best guess is +/- one day right now, so it could smack down anywhere on that track or even beyond. But most likely it will land in the Pacific.

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