Fobos-Grunt EOM Re-Entry Latest

[baldusi]

I've seen a NASA chart for UARS that shows individual debris piece impact
expected at ranges from 500 out to 1300 km downrange from entry point,

I've been told that is 'typical' for large satellites.

The landing capsule COULD be on dry land!!

The orbital path takes them through very sparsely populated areas. It went over Atacama Desert, the Bolivian altiplano and the deep Amazonas. It could very well have been seen by nobody, or at best a tribe on natives.

[JimO]

[JimO]

The orbital path takes them through very sparsely populated areas. It went over Atacama Desert, the Bolivian altiplano and the deep Amazonas.

Not on the maps I've seen -- can somebody blow up the 'last orbit' segment for closer study?

[jcm]

Heiner Klinkrad tells me:
 "The USSTRATCOM re-entry time refers to the pass of an altitude of ~80km, while
ESA's prediction refers to an altitude of ~10km. Travelling from 80km to 10km
during the re-entry takes about 7 minutes. If this is added to the median of
the USSTRATCOM epoch, then their 10km interface pass is at ~17:53 UTC, which
differs from our last prediction by +8 minutes. Our estimated "1-sigma"
uncertainty on the 10km epoch was +/-7.5 minutes (based on prediction
errors)"

So I can infer that the 1-sigma range is
                     80 km                   10 km
USSTRAT       1745-1747            1752-1754
ESA               1731-1746            1738-1753

Using the final TLE and ignoring uncertainties in orbit propagation and the effects
of drag in the atmosphere this corresponds to
positions of (note that these are my estimates, not those of the organizations quoted)
 
                      80 km                                          10 km
USSTRAT       96.4W 48.7S to  85.7W 45.5S   64.7W 33.6S to 59.3W 28.8S
ESA              172.9W 35.4S to 92.7W 47.8S   139.7W 49.6S to 61.4W 30.8S

Drag would presumably move these 10 km positions  uprange,  but taking them
at face value the USSTRAT range would then go from Cordoba, Argentina to close to the Paraguayan border. But this is probably too far downrange since the debris is
slowing a lot between 80 and 10 km, so using the Keplerian orbit speed to predict
their position is an overestimate.

If we instead use the UARS graph above as inspiration and extend the ground track by  800 - 1200 km for the heaviest debris relative to the 80 km interface point we get
                      80 km alt low plus 800 km range to
                         80 km alt mid + 1000 km range to  80 km alt high +1200 km range

USSTRAT     86.6W 45.8S to 79.7W 42.9S to 73.6W 39.6S
                   Pacific ocean to just off the Chile coast N of Valdivia

ESA             165.7W 40.1S to 124.3W 51.3S to 77.8W 42.0S
                  E of New Zealand to off the coast of Chile

So I conclude that the most probable debris area is still in the Pacific off the coast of Chile, but there's a very slight chance some heavy debris might have made it all the way to Chile or northern Argentina.

 - Jonathan McDowell

[baldusi]

Cordoba is the second most populated province in Argentina. And with very clear skies. It's also a tourist destination. And since we are in summer vacations, the province is packed. Trust me, that if it had fallen there, it would have been on the news, big time.
It's also where the communications and tracking station for Argentine satellites is. So they would have even had a tracking radar right there. It must have fallen much before that.

[jcm]

Cordoba is the second most populated province in Argentina. And with very clear skies. It's also a tourist destination. And since we are in summer vacations, the province is packed. Trust me, that if it had fallen there, it would have been on the news, big time.
It's also where the communications and tracking station for Argentine satellites is. So they would have even had a tracking radar right there. It must have fallen much before that.

Yes, well that's what I ended up concluding. Even the coast of Chile is a stretch;
SE Pacific is a good bet.

[kevin-rf]

Can I ask a dumb question, 10km equals about 32,000 feet. Would it really have been still trucking forward with significant speed at that low of an altitude?

[JimO]

Cordoba is the second most populated province in Argentina. And with very clear skies. It's also a tourist destination. And since we are in summer vacations, the province is packed. Trust me, that if it had fallen there, it would have been on the news, big time.
It's also where the communications and tracking station for Argentine satellites is. So they would have even had a tracking radar right there. It must have fallen much before that.

I think we need to question your assumptions.

First, terminal descent is past the fireball stage [even the shuttle entry fireball has died out by the time it passes over Louisiana, for example] so the absence of sightings is not definitive. How many meteors are seen in daylight versus darkness -- a factor of 10,000 less? The more likely manifestation would have been sonic booms, which would hardly attract attention compared to thunder.

Second, I doubt any space tracking site is running full-sky constantly, or could really detect the size of the objects we're talking about.

The Cordoba region has been haunted by Russian rockets for decades, as Molniya-orbit vehicles perform their standard post-insertion apogee kick and then safety fuel dump, creating -- when they occur soon after sunset -- a glowing cloud crossing the skies. These apparitions have sparked UFO panics across the entire region. Nobody in Argentina ever figured them out.

I agree with JCM we're talking about the far end of the debris path, but not unusually so.

[Chris Bergin]

More radar fun:

http://en.rian.ru/russia/20120126/170960852.html

[rdale]

Crackpot theories just can't seem to die quietly ever...

[wolfpack]

More radar fun:

http://en.rian.ru/russia/20120126/170960852.html

Call it "Radar Love".

[JimO]

More radar fun:

http://en.rian.ru/russia/20120126/170960852.html

They are now accepting comments. Let's see what discussion my comment sparks!!

[JimO]

My NASA HQ contacts have just gotten back to me to report that they spent half a day trying to track down any request from Roskosmos for cooperation in testing any theories about the probe's failure, and came up empty -- no mail, no email, no voicemail, no telephone calls -- NOTHING from anyone at Roskosmos to anyone at NASA requesting assistace. So the claimed 'refusal' was totally bogus.

[Chris Bergin]

Wow. This is a drama that keeps on giving!

[stockman]

good comments on the Russian web site as well Jim... maybe you should add the fact that no one at NASA knows anything about this mysterious request for cooperation...

[olasek]

Would it really have been still trucking forward with significant speed at that low of an altitude?

This is not a dumb question and I actually came across the answer fairly recently while doing my own simulation of debris caused during rocket launch failures (this relates to some air traffic control research we do here at NASA Ames). There can still be quite a bit of forward momentum, actually even with some moderate ballistic coefficients a piece of space debris can still be super-sonic in its horizontal velocity when it hits the ground.

[Space Pete]

This whole debacle has convinced me that we shouldn't trust US crew transportation to Russia. They should just stop all the smoke & mirrors and admit they failed, since the rumours are doing them more harm now than the truth would.

[Antares]

Apples and oranges.  The manufacturing standards are different, though CB's flight rationale seems to be almost entirely that there's a Russian sitting next to them onboard the Soyuz.

Politicians on both sides say weird things.  Leave it up to the engineers and engineering managers.  When THEY start disagreeing, yes, time to reconsider.

[olasek]

This http://www.novosti-kosmonavtiki.ru/content/news.shtml offers two theories on the failure of PG. The first one, there was some violent explosion on the Sun on Nov.4 and a piece of such ejected matter could have hit the spacecraft.

The other article is on the subject of electronics chips used in this spacecraft. The article raises possibility that some south-east Asian chip suppliers could have provided Roscosoms with substandard electronic parts. If my translation is not off the piece also seems to suggest the US controls the supply of truly space/military/radiation hardened electronics and Russians have no access to it.

[JimO]

The other article is on the subject of electronics chips used in this spacecraft.

Is it this article? -- an amazing story, highly recommended:

Mars didn't become 'Soviet' due to bad transistors, a scientist thinks

Марс не стал "советским" из-за плохих транзисторов, считает ученый
   http://www.spacephys.ru/en/node/1384   [published in February 2011]
   РИА Новости, Илья Ферапонтов //    from Лаборатория космических исследований
   Советский "штурм" Марса, предпринятый в 1960-х - начале 1970-х годов, провалился из-за технологического отставания СССР в сфере электроники, что не позволило создать достаточно надежные аппараты и привело к череде болезненных неудач, рассказал РИА Новости академик Михаил Маров, один из разработчиков советских марсианских и венерианских проектов.