Watching Tiangong-1 Fall

And… It’s gone. Crashed into the Pacific Ocean, right here.

It’s coming down faster, every day. My estimate is that it will definitely not hit North America, at all, though. Also, I am predicting that it will not come down to Earth south of the equator.

Space.com article. | Space.com update at 10am EST on 3/31/18.

It will re-enter the atmosphere on a northeast trajectory, just north of the equator. Most of the ground footprint will be near the equator, and just to the north of it. Central America (including Costa Rica, Panama, Nicaragua, El Salvador, and Honduras), Ecuador, Columbia, Brazil, Nigeria, Central Africa, South Sudan, Ethiopia, Congo, Kenya, Singapore, Philippines, and Malaysia will be the most likely “targets”, if it hits land. However, there is a much higher chance that it will land in the water, from what I see.

An update (10:00am CST on 3/31/18): The most recent prediction of the timeline for re-entry (by the European Space Agency and Aerospace Corp.) has moved it back by one day. They now say that it will be falling back to Earth on April 2. My updated prediction (which I actually thought through, yesterday) has the re-entry happening on April 3rd or 4th.Still no “exact” time, of course, but the rate of descent, no matter what the upper level atmosphere is like, looks to my like it will still be later than their predictions.

Another update (9:44am CST on 4/1/18): Looks like I was off. The latest orbit lost more altitude than I expected. Seems like the gravitational effects (and other factors) are just pulling it in faster, now. Although my timing may be a little off, the location that I predicted remains the same.

I’ve been watching the orbit, here. (at about 13:00 local time on 3/31, they changed the live tracking. It’s now in a small javascript image on the right side of the page.) I don’t watch it all the time, and the ones that I’ve recorded have some gaps between them. There are two bounces in altitude on each orbit. This will explain some consecutive highs on the table. The biggest dip in the low altitude seems to always occur on the “upswing” from the southern hemisphere, just as it crosses the equator.

The estimated re-entry altitude is about 120 km.

Interestingly, there is an app on the Google Play Store called “Tiangong-1?”. I have not tried it, but one of the comments in the reviews is classic: