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#540 by Chris Bergin on 24 Nov, 2011 18:10
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Meanwhile, in the real world
QuoteAccording to the source agency, there are two types of telemetry. "The first - the emergency telemetry, receive it in the worst case, if nothing else could not decipher. There is a complete telemetry received directly from the onboard control complex (SCU)," - said the source, noting that he is not yet known what type of telemetry was transcribed.
http://translate.googleusercontent.com/translate_c?hl=en&rurl=translate.google.com&sl=ru&tl=en&u=http://ria.ru/science/20111124/497098161.html&usg=ALkJrhj3_wXZcLf2P_BEP83xrOBof9oDQA
(Chris, that quote seems to be 'fair use', no copyright issues then?)
Correct sir
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#541 by Prober on 24 Nov, 2011 18:42
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If this is indeed orientation sensors ("stabilisers"?)(all of them?) at fault then how did it pass vibration tests? (assuming they were damaged during launch).
Too many questions.
Yes way, way too many questions and not enough "official" reports. I have major questions about this power supply issue. Were the solar panels really fully deployed? or in wait for higher orbit, and drop tanks commanded etc.?
How many AMPs does the fully deployed solar panels on FG generate?
If you look at the mission, how is the mission going to get enough energy to operate if the batteries can't hold a charge for 45 minutes.
questions, questions and more questions.
Edit: added ?'s -
#542 by Prober on 24 Nov, 2011 19:01
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The problems with putting the mission on a 2-year hiatus involve at least three potential problems: ..
The very remote upside would be that you could, in theory, mount a servicing/rescue mission.
It is a giant bomb, non starter for any manned servicing mission...
Besides the drop tank was not designed for an extended stay in LEO. It most likely does not have heaters to keep the props from freezing.
Maybe someone who knows can answer this?
If they get the power problem fixed......can FG be turned into the sun to warm up the drop tank enough to use the fuel?
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#543 by hop on 24 Nov, 2011 19:52
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Maybe someone who knows can answer this?
What "power problem" ? It's not certain there is one. The fact that the first signals were received in daylight passes is suggestive, but there are many other plausible scenarios.
If they get the power problem fixed......
edit:
Recent ESA posts suggests that only one of the LGAs is working, which would explains some failed passes http://www.esa.int/SPECIALS/Operations/SEM5AJZW5VG_0.html -
#544 by Skylab on 24 Nov, 2011 19:56
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Quote
The "Phobos-Grunt" refused stabilizing sensors in space - the source says. - Due to the failure of these sensors the satellite is not able to navigate by the stars, so that does not work propulsion.
http://translate.googleusercontent.com/translate_c?hl=en&rurl=translate.google.com&sl=ru&tl=en&u=http://www.lifenews.ru/news/75368&usg=ALkJrhjIY83Hi_Vn1N_2vspBNJXiWlCJ7Q
Yes, it's yet another unnamed source... Wish we'd see some official updates instead! -
#545 by alk3997 on 24 Nov, 2011 20:09
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The problems with putting the mission on a 2-year hiatus involve at least three potential problems: ..
The very remote upside would be that you could, in theory, mount a servicing/rescue mission.
It is a giant bomb, non starter for any manned servicing mission...
Besides the drop tank was not designed for an extended stay in LEO. It most likely does not have heaters to keep the props from freezing.
Maybe someone who knows can answer this?
If they get the power problem fixed......can FG be turned into the sun to warm up the drop tank enough to use the fuel?
Let's try this from the angle of a generic spacecraft rather than PG. If you are trying to warm frozen hydrazine, you have to remember that hydrazine is volatile by nature. If I remember right the Japanese Hayabusa lost its hydrazine when the tank froze and then thawed. This resulted in leaks developing and the hydrazine migrated out through leaks as the pressure rose.
So, that's the first problem.
Hydrazine is also corrosive and many Soviet/Russian spacecraft were designed to only be filled once. So, does corresive factor in here? Depends upon what you are planning to do.
There is also the effects of the frozen hydrazine on valves and sensors. If the valve that allows the hydrazine was damaged by the frozen state, how do you bypass that? Do the sensorsstill read properly after being frozen.
All of this comes down to a spacecraft not being used in the way it was designed. You would have to analyze the specifics (which we don't have) of the spacecraft to make a final determination of how it would respond.
Andy -
#546 by Svetoslav on 24 Nov, 2011 20:09
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http://ria.ru/science/20111125/497316493.html
Yet another failed attempt of ESA to contact the spacecraft -
#547 by Svetoslav on 24 Nov, 2011 20:21
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People on Novosti Kosmonavtiki forum say : Sun is not visible, so no signal...
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#548 by iamlucky13 on 24 Nov, 2011 20:21
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An English-language story about Rodionov's ravings is here:
Did US 'climate weapon' knock-out Russian probe?
http://rt.com/news/phobos-grunt-climate-weapon-129/
In particular don't miss the comments section.
If you yandex.ru the right terms you'll find
the story has gone viral in the Russian media, including in
official government newspapers [which didn't endorse it].
http://www.rg.ru/2011/11/24/kosmos-site-anons.html
Фобос-Грунт and Николай Родионов
Russia Today strikes again. It would be funny but for the fact that people will take it seriously.
The Sea Based X-Band missile defense radar is based in Alaska, and I presume is normally stationed somewhere out around the Aleutians.
Fobos-Grunt also operates on X-band. Although the US would have no reason to sabotage F-G, I suppose accidentally hitting its receivers with too much power is not inconceivable, although really it sounds like the general being quoted is speculating wildly. Someone should ask him if he thinks the US should launch a shuttle mission to rescue F-G in order to gauge his credibility.
X-band is roughly 1000 times the frequencies that HAARP broadcasts. The 10 octaves gap is a night and day difference. -
#549 by Sparky on 24 Nov, 2011 20:27
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Near as I can tell, the tank is on the opposite end of the stack as the pv panels. This might make keeping the fuel liquid and the craft powered at the same time a problem. Then again, the torus-snapped tank looks slightly wider than the rest of the vehicle, so it's possible that it part of it will be in sunlight at all times, and freezing might not happen at all.
Maybe someone who knows can answer this?
If they get the power problem fixed......can FG be turned into the sun to warm up the drop tank enough to use the fuel?
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#550 by hop on 24 Nov, 2011 20:32
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If I remember right the Japanese Hayabusa lost its hydrazine when the tank froze and then thawed. This resulted in leaks developing and the hydrazine migrated out through leaks as the pressure rose.
I think that was Nozomi, not Hayabusa.QuoteAll of this comes down to a spacecraft not being used in the way it was designed. You would have to analyze the specifics (which we don't have) of the spacecraft to make a final determination of how it would respond.
Agreed 100%. We don't really know the the characteristics of the spacecraft or it's current condition, so it's hard see much point in guessing. -
#551 by alk3997 on 24 Nov, 2011 21:56
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Turns out it was both Hayabusa and Nozomi. Hayabusa's hydrazine froze when the spacecraft sat on the asteroid for 1/2 an hour. From re-reading old articles, the hydrazine apparently leaked inside the spacecraft components rather than venting outside.
Thanks for catching the Nozomi reference.
Andy -
#552 by savuporo on 24 Nov, 2011 23:09
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Full diary of all contact attempts here:
http://www.zarya.info/Diaries/Misc/PhobosGrunt1.php#log
Also this :QuoteThe deputy head of the Phobos-Grunt project chief scientist, Alexander Zakharov of the Space Research Institute, said the telemetry would show whether the spacecraft could be "reanimated" and used in another research mission.
He said that if the spacecraft is fully operational, the best scientific mission for it would be to study a near-earth asteroid.
http://en.ria.ru/science/20111124/168984266.html -
#553 by ChileVerde on 24 Nov, 2011 23:25
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The Sea Based X-Band missile defense radar is based in Alaska, and I presume is normally stationed somewhere out around the Aleutians.
SBX is currently in port at Pearl Harbor, Hawaii, from which it's prohibited from using the X-band radar for safety reasons.
http://www.hawaiinewsnow.com/story/16105886/special-report-exclusive-tour-of-the-sbx-radar
As a totally off-topic footnote, SBX has visited the Aleutians for a couple of weeks twice since (I think) 2005 and has never put into its nominal homeport of Adak. -
#554 by iamlucky13 on 25 Nov, 2011 02:43
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SBX is currently in port at Pearl Harbor, Hawaii, from which it's prohibited from using the X-band radar for safety reasons.
http://www.hawaiinewsnow.com/story/16105886/special-report-exclusive-tour-of-the-sbx-radar
Interesting. It was here in Seattle for several months having some work done, and I just presumed when it left they were going to actually put it on station. I guess they're not done spending money on it yet. -
#555 by woods170 on 25 Nov, 2011 05:42
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Please people. Stay on topic before Chris intervenes.
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#556 by hop on 25 Nov, 2011 06:44
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According to Russian press reports (quoting ESAs Rene Pishel), today's attempts from Perth were unsuccessful: http://ria.ru/science/20111125/497498141.html
A couple of these passes were high elevation, daytime so they should have been favorable. -
#557 by Jorge on 25 Nov, 2011 07:53
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It is a giant bomb, non starter for any manned servicing mission...
You and others here, nobody said anything about manned.
Its entirely possible that someone could come up with a makeshift way of boosting or closing the required delta-v gap by a simple propulsion module launched on one of many russias cheap small launchers, assuming other longevity problems could be solved and the probe can at least regain attitude hold capability.
This is obviously all very hypothetical, which is why i said "very remote" from the outset, but i'm betting Roscosmos will be evaluating every single way of salvaging whats possible out of their investment. The reported mission cost is $170M, so no small change.
I'm betting that if/when Roscosmos evaluates rescue/servicing options, they will not find one that costs less than building and launching another Phobos-Grunt, and will therefore quite sensibly reject rescue/servicing. -
#558 by Sandro on 25 Nov, 2011 08:49
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Hi Everyone
I was a silent reader of this very interesting thread so far. Now I would like to ask a question to the one of you with more experience. I don't wanna speculate more about the future of the mission, but rather on the actual problem.
1)
From Novosti was speculated, that FG might think that it is currently on the way to Mars. Therefore an special emergency mode might be active, which turns off the transmitter every time when not enough energy is available. Unfortunately I don't have a reliable source for that, but did I get this point right?
2)
From Ted Molczan, an very experienced satellite observer was determined, that the orbit decrease of FG behaved different than it would be expected of a dead satellite:
http://www.satobs.org/seesat/Nov-2011/0257.html
This lead to the speculation, that FG was doing attitude control by itself, maybe to orient itself to the sun.
3)
Latest analysis from Ted show that this (speculative) attitude control might have stopped around November 21th 2011. From then on FG decays like expected of a dead (uncontrolled) satellite:
http://www.satobs.org/seesat/Nov-2011/0291.html
4)
When comparing the contact attempts with FG and the phases when it was in daylight, then it seems to become evident, that it is not always possible to establish a contact when FG is in sunlight:
http://www.zarya.info/Diaries/Misc/PhobosGrunt1.php#log
combined with the (sometimes unnamed sources) of positive or negative contacts.
==> So finally I could imagine, that FG is actually not (not anymore?) tracking the sun and therefore it's solar arrays are only by chance able to collect enough sunlight to leave the "emergency mode" and to switch on the transmitter..... Therefore each contact attempts would highly depend on the actual orientation of FG.
Since I'm not experienced at all, I would like to know from you what you think about this scenario? Do you think that is possible and if so, was there any similar case in the history with successful regain of the control?
Thanks in advance...
Cheers,
Sandro
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#559 by Michael J on 25 Nov, 2011 11:26
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Latest from Ria Novosti: http://translate.google.com/translate?hl=en&sl=ru&tl=en&u=http%3A%2F%2Fwww.ria.ru%2Fscience%2F20111125%2F497690314.html
Some of the telemetry decoded; telemetry came from main computer; not emergency telemetry; no further contact; another attempt when spacecraft passes over Baikonur.
