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Jonathan McDowell'sTweet and Tweet say

Two objects cataloged from the CZ-5 launch: 180 x 67690 km x 19.4 deg, and 203 x 73395 km x 19.4 deg. One is the SJ-20 comms satellite and the other is the CZ-5 rocket's second stage.

and

The first stage (depending on how you count it.) The strapons and the fairing fall closer to China, and the core stage falls near Guam. The second stage reaches orbit.

Question: How close to Guam did China's recent Long March 5's first stage fall?

I suppose at least two if not three countries watched it by radar, but are these things every reported to the public anywhere? Or am I so used to watching first stages land on ships (or simulate landing on the water's surface, then fall over) that I'm projecting that thinking and they just fall "in the middle of nowhere" and nobody makes a note if it?

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    $\begingroup$ Interesting question! I presume this comes down to Jonathon McDowell: either he has a radar source or he has estimated it from his own hand-calc's/launch simulator. $\endgroup$ – Puffin Dec 29 '19 at 17:46
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    $\begingroup$ With some naive spherical cow assumptions, I believe the stage would not have impacted closer than about 180 miles north of Guam. I could show my work in an answer, but it won’t be an actual answer to what really occurred. $\endgroup$ – Russell Borogove Dec 29 '19 at 19:08
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    $\begingroup$ Coast Guard District 14 didn’t publish a NOTAM for the launch, so the planned flight path was outside the EECZ. I think that’s 200nm radius. $\endgroup$ – Bob Jacobsen Dec 30 '19 at 1:40
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    $\begingroup$ @RussellBorogove I'd be interested to see it; I think it would be in scope given that the question is based around someone's (Jonathon McDowell) assertion. $\endgroup$ – Puffin Dec 30 '19 at 16:23
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    $\begingroup$ @BobJacobsen That raises the question of whether China informs us of their flight path. $\endgroup$ – Russell Borogove Dec 30 '19 at 17:33
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@uhoh pointed to a tweet by LaunchStuff that shows images of what appear to be several Chinese notices to airmen (NOTAMs). (Weirdly, I can't find the originals of those; they don't seem to be in the international airman notification system, nor the corresponding system for notices to mariners) They show three danger areas, one of which is near Guam:

enter image description here Note Guam to the far right.

The nearest corner to Guam was about 150 (statute) miles from Guam: enter image description here

But it was a lot closer to Tinian and Saipan in the Northern Mariana Islands, which are definitely populated: 65 statute miles.

enter image description here

The two eastern areas are on either sides of populated islands in the north of the Philippines, and come even closer: (35 sm)

enter image description here

The Google map behind those images is available here. (does anybody know how to switch it to nautical miles or km?)

I've attached the image from the tweet below in case the original goes away. The data is:

18 45 17N 124 00 12E
19 12 09N 124 02 45E
19 19 02N 122 37 19E
18 52 09N 122 35 00E
18 45 17N 124 00 12E

19 07 11N 119 06 03E
19 34 07N 119 07 44E
19 37 26N 118 04 50E
19 10 29N 118 03 19E
19 07 11N 119 06 03E

14 25N 148 53E
15 18N 149 06E
15 47N 146 55E
14 54N 146 43E

enter image description here

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