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…
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”
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?
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
It’s pretty amazing how they figure all this stuff out. So the goal is to have ROSAT crash into a South American rain forest?
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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