Tiangong-1 Re-entry

[GluttonyReaper]

http://www.popularmechanics.com/space/satellites/a22936/tiangong-falling-to-earth/

Not sure if this has been posted before, but apparently it's been suggested that China doesn't actually have full control of Tiangong-1. 

[Ultimate Steve]

I knew about it. Suggestion: send crew up to fix it and make an overly dramatic movie about it. Both China and SpaceX should have operational crew capsules by 2017 (SpaceX is a bit iffy, but if it is late 2017...).

[_Augustus_]

38 minutes ago, Ultimate Steve said:

I knew about it. Suggestion: send crew up to fix it and make an overly dramatic movie about it. Both China and SpaceX should have operational crew capsules by 2017 (SpaceX is a bit iffy, but if it is late 2017...).

Shenzhou is already operational.

[mrfox]

"It seems it may be much ado about nothing," said T.S. Kelso, a senior research astrodynamicist at the Center for Space Standards & Innovation (CSSI), a research arm of Analytical Graphics.

Kelso has plotted the altitude history of Tiangong-1 from just after its launch to more recent times. He told Space.com that the Chinese space lab's orbit was reboosted relatively recently, in mid-December 2015.

"That reboost put it higher than it had been anytime prior to that in its mission," Kelso said.

Kelso said he does not have "any direct way to measure" Tiangong-1's stability. "But we might expect to see the rate of decrease in altitude — the slope between reboosts— increase if it was tumbling, since the station would have higher drag," he added. "Instead, we see the slowest decrease in altitude in recent years — consistent with the lower drag at a higher altitude."

Kelso said his reading of the data suggests that Tiangong-1 is dormant but stable.

"So that might be why the Chinese aren't responding … they probably don't understand why they would need to," Kelso said. "I guess I would want to see some very specific data, notionally covering a period where Tiangong-1 was supposed to be stable, to show that it is now uncontrolled, before reading too much more into this."

Based on the latest tracking information, if there are no further reboosts of the Chinese craft, "we would expect to see Tiangong-1 re-enter just around the end of 2017," Kelso said.

If China does indeed have control over the space lab, why keep it in orbit rather than nudging it back to Earth immediately?

"The suggestion has been made," Dorman said, that "the reason China hasn't done a re-entry of Tiangong-1 is, the space station is low on fuel, and China is waiting on a natural decay to a much lower orbit before they can do a burn to bring the station down."

http://www.space.com/33140-china-tiangong-1-space-lab-falling-to-earth.html

 

 

[cubinator]

http://www.satflare.com/track.asp?q=37820#TOP

It seems Tiangong-1 has only about a month left in orbit. Here is a good website for tracking its status.

[YNM]

Maybe it's about time to make a new kiln off a rocket debris again.

[cubinator]

I saw Tiangong 1 fly overhead tonight, it was fairly bright and fast. I may not get a chance to see it again. 

[tater]

The forum seems to be working again. I should try and see a pass as well... I’m torn between wanting an ocean reentry, and seeing it, lol

[cubinator]

I totally want to see it go down. It's unlikely, of course, but in the last few days and hours I'll be keeping my eyes peeled every time it flies overhead.

[Nightside]

From ESA: http://blogs.esa.int/rocketscience/2018/01/12/tiangong-1-reentry-updates/

Where and when? I'm just north of 45 so I won't catch anything, but I could probably see a reentry at night.

This next chart is my favorite

 

Edited March 7, 2018 by Nightside

[PB666]

Hint: don't submit job application to chinese space agency.

[NSEP]

Something Flat Earthers will ignore.

I might have a look at it, but considering the FOV of my observatory (aka my bedroom) and my laziness the chance might be low.

[Vanamonde]

Overlapping threads have been merged. 

[michal.don]

On 21. 9. 2016 at 12:06 AM, Ultimate Steve said:

Suggestion: send crew up to fix it and make an overly dramatic movie about it. Both China and SpaceX should have operational crew capsules by 2017 (SpaceX is a bit iffy, but if it is late 2017...).

heh heh

[Ultimate Steve]

3 hours ago, michal.don said:

heh heh

If I could sum up spaceflight in one word - delays.

Still 5% expecting for China to pull off a mission to film it. They are planning to launch 40 times this year and they might have another Shenzhou lying around.

[tater]

 

[MaxwellsDemon]

:: squinting at map ::   Think I should start carrying an umbrella...    

[cubinator]

I'm gearing up right now to see it cross in front of the sun! I wonder how well I can see it in the <1 second window I have to get a good look.

 

Aaaaand nothing. Too small, I guess.

Edited March 16, 2018 by cubinator

[Zeiss Ikon]

17 hours ago, cubinator said:

I'm gearing up right now to see it cross in front of the sun! I wonder how well I can see it in the <1 second window I have to get a good look.

 

Aaaaand nothing. Too small, I guess.

Or it wasn't where you expected it to be.  With the station apparently tumbling (hence the large uncertainty in even date of reentry, never mind location), it could be tens of kilometers cross-range from the expected orbit at any given time.  It might also pass early (by several seconds to a couple minutes), since the orbit is decaying almost visibly, shortening the period.

Tiangong is smaller than ISS by a good margin, but larger than a Space Shuttle, and people have imaged Shuttles transiting the sun -- so I'm not sold on "too small" as the reason you didn't see it.

[cubinator]

20 minutes ago, Zeiss Ikon said:

Or it wasn't where you expected it to be.  With the station apparently tumbling (hence the large uncertainty in even date of reentry, never mind location), it could be tens of kilometers cross-range from the expected orbit at any given time.  It might also pass early (by several seconds to a couple minutes), since the orbit is decaying almost visibly, shortening the period.

Tiangong is smaller than ISS by a good margin, but larger than a Space Shuttle, and people have imaged Shuttles transiting the sun -- so I'm not sold on "too small" as the reason you didn't see it.

I've observed it passing overhead before, and Satflare was accurate within at least a few seconds. 

[tater]

 

[MaxwellsDemon]

Hm... on April Fool's Day?   

[Zeiss Ikon]

5 hours ago, cubinator said:

I've observed it passing overhead before, and Satflare was accurate within at least a few seconds. 

Was that before it started tumbling and decaying, though?

4 hours ago, MaxwellsDemon said:

Hm... on April Fool's Day?   

I'm pretty sure we won't hear the CNSA yelling "April Fool's!" right after thirty tonnes of space station crashes to Earth... 

[cubinator]

27 minutes ago, Zeiss Ikon said:

Was that before it started tumbling and decaying, though?

 

It was a couple weeks ago. It was stable in brightness and right where I expected it to be.

[Zeiss Ikon]

1 hour ago, cubinator said:

It was a couple weeks ago. It was stable in brightness and right where I expected it to be.

A five day tumble period (implied by the five day periodicity in a graph up the thread a bit) would look steady.  it was certainly already tumbling then; it's been out of control for a couple years.  Another factor that might have prevented you observing the solar transit is how old the predictions were that you were using.  With the station unstable in (presumably) both pitch and yaw, it may wander from predicted orbit fairly quickly; if your forecast was more than 24 hours old, the station might simply not have been where it was forecast to be.  A half degree (width of the solar disc) at a couple hundred kilometers is window only about 1700 m (just over a mile) wide.  At its last reported orbit height, with a more or less random two-axis tumble, a forecast 24 hours old might put the station outside that window, regardless of timing.