Heavy rain in the South. Chinese roulette.

[Homo Aeroportus]

Tiangong-1 is on final approach but nobody knows where or when it will "land".

ESA Spotted_in_space_highlight_std.jpg (9.5 KiB) Viewed 1672 times

Courtesy of ESA. See : http://blogs.esa.int/rocketscience/2018 ... y-updates/



The Chinese lost control of this satellite (actually a space station) for quite some time.
Re-entry will be somewhere between the latitudes of 43N and 43S due to the inclination of its orbit but it is impossible to determine where and when.

According to the latest projections this morning, see : http://www.aerospace.org/cords/reentry- ... 1-reentry/
Tiangong-1 should "land" in about 30 hours from now, i.e. tomorrow around 16:00 UTC.
The determining factor is the density of the thermosphere which slows down satellites and debris to a speed that makes the orbital flight unsustainable.
This is considered to be about 100km in the current conditions.
During the last orbits the satellite was at about 170km altitude.

TiangongStoryboard Alt Decay.png (39.88 KiB) Viewed 1672 times

Referring to "tomorrow" when the date is March 31st will make it difficult to have people taking this seriously but think twice before heading South if you don't have to.


H.A.

[Homo Aeroportus]

The Chinese realized they wouldn't be taken seriously by announcing the landing for April 1st, so we are now aiming at tomorrow instead.

ESA made a update early this morning :
With the latest available orbital data and space-weather forecasts, the reentry prediction window has stabilised and shrunk further to a time frame running from midnight 1 April to the early morning of 2 April (in UTC time).

This is also in line with the Aerospace Corp revision :
Tiangong-1 is currently predicted to re-enter the Earth’s atmosphere around April 2nd, 2018 02:00 UTC ± 7 hours.
This prediction was performed by The Aerospace Corporation on 2018 March 31.


The perigee is diminishing slower than earlier anticipated (and Aerospace Corp just "boosted" it up to 166km while it was 155 one hour ago ).

Even without considering this "boost", I wouldn't be surprised to see the re-entry happening later than 24 hours from now.

H.A.

[Homo Aeroportus]

One sure thing : it won't be hanging up there for ever.
But it seems totally impossible to predict with some degree of confidence when and where it will come back to Earth.

I figure that this is not simple ballistic as the mobile is swinging and dancing, constantly changing its aspect and hence the drag. Also when the solar panels will be torn off at one time, the drag will be reduced and consequently the loss of altitude will diminish at a lower rate.

Today at 1800UTC, the ESA provided their final estimate for re-entry forecasting a window of four hours centred around 02APR at 01:07 UTC.

On the other hand, the Aerospace Corporation has corrected their previous estimate of today to be now 02APR at 00:18 UTC with a tolerance of ...... +/- 2 hours

Anyhow, as ESA writes :
Each year, about 100 tonnes of defunct satellites, uncontrolled spacecraft, spent upper stages and discarded items like instrument covers are dragged down by Earth’s upper atmosphere, ending their lives in flaming arcs across the sky.


So fingers crossed that the Chinese 8-ton can behaves well !

H.A.

[jan_olieslagers]

It is a pity you are getting so little response on this. Be assured I follow with great interest! But I lack the inside knowledge to add any useful comment.

[sn26567]

It is a pity you are getting so little response on this.

Maybe little response, but certainly not a lack of interest with more than 300 views until now. I am also closely following the developments provided by H.A., without being able to add anything myself.

[Homo Aeroportus]

Thank you for these kind words but, if exchanging is always welcome, it is good to read that you found it interesting.

Just happened that my planets were in alignment today with a late minute cancellation family-wise combined with a on and off light work with a intermittent config of a new platform.

I admit that I'm in a passive attitude now as it is just impossible to determine anything accurate about Tiangong-1.
The future is not was it used to be.

According to AeroCorp the re-entry is still anticipated for 00:30 UTC, in 2 hours from now, yet with a tolerance of 1.7h.
The last orbits had a period of about 1h27 so go figure !
The altitude is now decaying faster though very unsteadily.

The beginning of the end could probably be in two orbits from the beginning of the rising node when the satellite will be running back up along the tip of south America.
If it clears Buenos Aires it will have about 20 minutes of Atlantic crossing before traversing Africa from Abidjan towards Cairo. Chances from someone to see the skies in fire then.
And if still alive and kicking, it could be a "return to sender"

Over and out.
Let's see tomorrow how things went.

H.A.

[luchtzak]

This is an interesting link: http://www.satview.org/?sat_id=37820U

[convair]

It is a pity you are getting so little response on this.

Maybe little response, but certainly not a lack of interest with more than 300 views until now. I am also closely following the developments provided by H.A., without being able to add anything myself.

Same with me, and I have my safety helmet on.

[luchtzak]

It is a pity you are getting so little response on this.

Maybe little response, but certainly not a lack of interest with more than 300 views until now. I am also closely following the developments provided by H.A., without being able to add anything myself.

And the article on the main page, with 460 views: https://www.aviation24.be/miscellaneous/ ... on-sunday/

[sn26567]

The eagle has landed, so to speak. In the South Pacific. At 02:16 CEST (00:16 GMT) according to the Americans. The Chinese pretend it was one minute earlier. But after two years of uncontrolled orbiting, who cares about one minute?