21 votes
Accepted

Is there real footage of Tiangong 1 reentry?

As of this point we do not have actual footage of the reentry. It occurred somewhere over the Pacific Ocean, there is very little to no population there. Almost no planes were at the reentry point. ...
Hans's user avatar
  • 3,566
16 votes
Accepted

Detailed radar imaging of Tiangong-1; how do they do that?

It was done with one single dish, ...in Ku-band (16.7 GHz) and ... currently equipped with a high target resolution. The Fraunhofer Institute for High Frequency Physics and Radar Techniques (FHR)'s ...
GNiklasch's user avatar
  • 1,430
15 votes

Do we have any idea when Tiangong-1 will deorbit?

This issue was discussed recently in SpaceDaily where it explains why this is a known unknown: Right now, it's impossible to make an educated guess on even a rough "window" for Tiangong's return. ...
Brian Tompsett - 汤莱恩's user avatar
11 votes
Accepted

Why are Tiangong-1's Apogee and Perigee Graphs Wobbly?

Is it because the Earth is not exactly a sphere and also due to uneven mass distribution? Yes! Is it an atmospheric effect? No. Earth's large J2 or oblateness term is always trying to perturb ...
uhoh's user avatar
  • 149k
6 votes

Why are Tiangong-1's Apogee and Perigee Graphs Wobbly?

After the uhoh's excellent answer, there’s no need for another answer, but with a simulation we can see the effect of the Earth's oblateness and of the atmosphere. The simulation includes the ...
Cristiano's user avatar
  • 1,760
5 votes

Do we have any idea when Tiangong-1 will deorbit?

Tiangong-1 will deorbit sometime in late 2017 As recently reported in Popular Mechanics The China National Space Agency recently announced that Tiangong-1 will deorbit sometime late in 2017, although ...
Lumberjack's user avatar
4 votes

Did Tiangong-1 turn the engines on?

(Posting as an answer so I can insert images) Lending credence to the idea that this is "sensitive response to measurement noise", consider these two plots from SatFlare.com (arrows added). They show ...
Bob Jacobsen's user avatar
  • 12.6k
3 votes
Accepted

Where on Earth can one view the entry of tiangong-1?

No-one knows for sure where it will come down: there are still wide margins on the estimates. But it's not looking likely to be the US. You can see a graphic of one estimate here (click for the latest ...
Peter Taylor's user avatar
3 votes
Accepted

What is used to monitor objects burning up in the atmosphere on descent?

There's a "Global Infrasound Network" that monitors for nuclear explosions. If a reentry is big enough, I expect they'll "hear" it. It might have to be pretty big, perhaps larger ...
Bob Jacobsen's user avatar
  • 12.6k
3 votes
Accepted

Why does N2YO list Tiangong 1 as an ISS satellite? Is it just a mistake? yes/no?

Seems to be a mistake based on both common sense and backup from @OrganicMarble's comment above - not to imply that the later is not also a subset of the former :) Apparently, not everything on the ...
uhoh's user avatar
  • 149k
3 votes

Did Tiangong-1 turn the engines on?

Edit: The question has been updated and the plot showing a "blip" in inclination which has the same shape as the "blib" in eccentricity. I've incorporated my comments here: The only phenomenon I'm ...
uhoh's user avatar
  • 149k
2 votes
Accepted

PSLV-C39/IRNSS-1H TLE accuracy

I'll elaborate on @pericynthion's answer a bit, with regard to what the "noise" may be, and speculate on the cause. Despite the visual appearance in the question, a plot of apogee is not any smoother ...
uhoh's user avatar
  • 149k
2 votes

PSLV-C39/IRNSS-1H TLE accuracy

The perigee altitude for PSLV-C39/IRNSS-1H is very low (< 200 km) in the timespan you selected. This makes it much more sensitive to atmospheric drag than an object at higher altitude. Atmospheric ...
pericynthion's user avatar
  • 10.1k
2 votes

Is there real footage of Tiangong 1 reentry?

The Fraunhofer Institute for High Frequency Physics and Radar Techniques near Bonn, Germany released a picture from a distance of 270 kms. There is some interesting information about how they tracked ...
James Poulose's user avatar
1 vote
Accepted

Why Celestrak has Archived TLEs for most space stations from Russia and the US, but not Tiangong-1, Tiangong-2 or Skylab?

@RussellBorogove's comment is fairly conclusive. ...I note that Celestrak was established in 1985, at which point Salyut 7 was up, but Skylab was not. The Archived TLE data page says 1980-2004, but ...
uhoh's user avatar
  • 149k
1 vote

What is used to monitor objects burning up in the atmosphere on descent?

Several satellite radar tracking stations are being used to track the doomed station. This .png is updated every few minutes by The Aerospace Corporation. In the lower left a list of tracking radars ...
Organic Marble's user avatar

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