Fobos-Grunt Troubleshooting Latest (Part 2)

#60 by Chris Bergin on 15 Nov, 2011 03:08
Welcome to the site's forum Simplex, but be careful with your direction as you're heading into conspiracy, which is a very dirty area around these parts.

Got to keep it at a decent level here.
#61 by Silmfeanor on 15 Nov, 2011 03:08
Quote from: simplex on 15 Nov, 2011 03:05
Honestly, I do not believe the story according to which they are not able to send any command to the spacecraft.
They say, or better suggest, that no uplink has been possible just to get rid of a lot of questions from journalists.
Such a big spacecraft has multiple communication systems, high gain and low gain omnidirectional antenna. Something is wrong with the spacecraft but they have some bidirectional communication.
The Mars rovers have at least three antenna, three communication systems, each and the rovers are much smaller.
This just makes no sense. What are your sources for this?
How does that even make sense?
#62 by simplex on 15 Nov, 2011 03:25
Just watch the spacecraft. Now it should look like this:
http://upload.wikimedia.org/wikipedia/commons/5/57/Cebit_2011-fobos-grunt_together_with_upper_stage.jpg
The lander, return module and Chinese satellite, each must have at least two communication systems, the main one and the backup. It is six in total! None of them is able to receive any data from earth?!!
#63 by hop on 15 Nov, 2011 03:29
Quote from: simplex on 15 Nov, 2011 03:25
It is six in total! None of them is able to receive any data from earth?!!
It doesn't matter how many antennas you have if the thing connected to them isn't talking.

The payloads weren't supposed to be activated until after the Earth departure, same for the HGA.

In reality, if they hear so much as a peep from it, I expect word will appear on the NK forum shortly thereafter.
#64 by Jim on 15 Nov, 2011 03:37
Quote from: simplex on 15 Nov, 2011 03:25
Just watch the spacecraft. Now it should look like this:
http://upload.wikimedia.org/wikipedia/commons/5/57/Cebit_2011-fobos-grunt_together_with_upper_stage.jpg
The lander, return module and Chinese satellite, each must have at least two communication systems, the main one and the backup. It is six in total! None of them is able to receive any data from earth?!!

The communication systems on the return module and Chinese satellite are useless since they are not connected to the upperstage.
#65 by Nickolai on 15 Nov, 2011 03:38
Quote from: simplex on 15 Nov, 2011 03:25
Just watch the spacecraft. Now it should look like this:
http://upload.wikimedia.org/wikipedia/commons/5/57/Cebit_2011-fobos-grunt_together_with_upper_stage.jpg
The lander, return module and Chinese satellite, each must have at least two communication systems, the main one and the backup. It is six in total! None of them is able to receive any data from earth?!!

They should each have at least 1 communications system that is capable of transmitting data. If you built your spacecraft perfectly, all you really need to do is transmit, since it should be able to take care of everything else on its own.

Of course, this is rocket science, and you pretty much never get anything completely right the first time (often not even the second time, or as is Russia's unfortunate case with Mars, 18th time...) so the lander and maybe the Chinese satellite will have receivers. The return capsule I believe only has transmitters for finding it upon return to Earth (unless it's capable of course corrections?).

However, this is not all interlinked. The Chinese satellite is a hitchhiker, and it was not planned to turned on until PG was outbound to Mars (and even then only in standyby mode). Even if it was on, I'm not sure how much it would be able to tell you and while my next thought is speculation, I'm sure many here would agree that the Chinese satellite is almost certainly not capable of controlling the Fregat-derived engine.

Likewise, it's unlikely the return capsule can control the engine either. It was also to be turned on in standby mode once the stack was on the Mars bound trajectory.

That leave the only comm system capable of transmit/receive on the lander. It has been suggested that the receiving antennas are blocked by the fuel tanks which were meant to be jettisoned after Trans Mars Injection (TMI). The programming of the craft has led it to shut off transmission for reasons not entirely known.

A lot of my information comes from these documents posted on the NK forum: http://www.novosti-kosmonavtiki.ru/phpBB2/viewtopic.php?t=12378

Also, I have trouble understanding your earlier statement about journalists. You think they would ask fewer questions if they are told comms are not working than if they are told comms are working? They're journalists, I'm sure they'll think of something to ask regardless of the situation.
#66 by simplex on 15 Nov, 2011 04:00
Quote from: ntrgc89 on 15 Nov, 2011 03:38
Also, I have trouble understanding your earlier statement about journalists. You think they would ask fewer questions if they are told comms are not working than if they are told comms are working?
Yes.

Do you remember this story:
"The MV Arctic Sea is a merchant vessel cargo ship, formerly of Malta that was reported as missing between late July and mid August 2009 en route from Finland to Algeria. On July 24, the Arctic Sea, manned by a Russian crew and carrying a cargo of what was declared to consist solely of timber ..."
http://en.wikipedia.org/wiki/MV_Arctic_Sea

The Russians maintained for weeks that the ship had disappeared and they had no communication with it just to finally acknowledge that they had been in touch with the crew all the time.
#67 by Jim on 15 Nov, 2011 04:07
Quote from: simplex on 15 Nov, 2011 04:00
Quote from: ntrgc89 on 15 Nov, 2011 03:38
Also, I have trouble understanding your earlier statement about journalists. You think they would ask fewer questions if they are told comms are not working than if they are told comms are working?
Yes.

Do you remember this story:
"The MV Arctic Sea is a merchant vessel cargo ship, formerly of Malta that was reported as missing between late July and mid August 2009 en route from Finland to Algeria. On July 24, the Arctic Sea, manned by a Russian crew and carrying a cargo of what was declared to consist solely of timber ..."
http://en.wikipedia.org/wiki/MV_Arctic_Sea

The Russians maintained for weeks that the ship had disappeared and they had no communication with it just to finally acknowledge that they had been in touch with the crew all the time.

This is not the same thing.
#68 by simplex on 15 Nov, 2011 04:15
Quote from: ntrgc89 on 15 Nov, 2011 03:38
They should each have at least 1 communications system that is capable of transmitting data. If you built your spacecraft perfectly, all you really need to do is transmit, since it should be able to take care of everything else on its own.
I am not aware of any previous Mars spaceship designed just to downlink, or at least to downlink for long intervals of time, without any possibility for the craft to receive commands.
#69 by just-nick on 15 Nov, 2011 04:29
Quote from: simplex on 15 Nov, 2011 04:15
Quote from: ntrgc89 on 15 Nov, 2011 03:38
They should each have at least 1 communications system that is capable of transmitting data. If you built your spacecraft perfectly, all you really need to do is transmit, since it should be able to take care of everything else on its own.
I am not aware of any previous Mars spaceship designed just to downlink, or at least to downlink for long intervals of time, without any possibility for the craft to receive commands.
I'm not sure it is accurate to say that PG was designed to not receive commands for a long interval of time.

It wasn't designed to receive commands, perhaps, for the initial period of parking orbit and TMI. But the fact that it isn't receiving commands now seems to be due to some combination of failures and unforseen circumstances.

Not receiving commands is hardly that unusual...at this point I think all US upper stages fly without ground command, and some of them execute quite extensive maneuvers autonomously. I tend to think of PG, at this point, as more like an upper stage/spacecraft composite that failed to execute a burn or to separate.
#70 by Prober on 15 Nov, 2011 04:37
Quote from: Eraser on 15 Nov, 2011 03:07
I now have very little confidence in any official statements, because the upcoming parliamentary elections. Phobos-Grunt simply can not be considered as lost before the election.

Interesting, when are the elections?

Many wonder why no information is forthcoming.

Yet if you watch yesterdays Soluz launch they showed the large Antenna complex. It was a very well done show of the launch.
#71 by simplex on 15 Nov, 2011 04:52
Hours after Phobos - Grunt became and earth satellite, the Russians said that maybe the craft had not found the right stars and in consequence it stopped taking any further decision, waiting for commands from the ground. They also said this scenario had been taken into account.

Now they say the spaceship is not designed to receive commands so close to the Earth surface. This contradicts their first statements.
#72 by Patchouli on 15 Nov, 2011 05:54
I hope they get this sorted out but it seems like the kind of failure that happens when you skimp on ground testing.
#73 by Eraser on 15 Nov, 2011 06:06
Quote from: Prober on 15 Nov, 2011 04:37
Interesting, when are the elections?
December 4.
#74 by Ben the Space Brit on 15 Nov, 2011 09:10
Quote from: simplex on 15 Nov, 2011 04:52
Hours after Phobos - Grunt became and earth satellite, the Russians said that maybe the craft had not found the right stars and in consequence it stopped taking any further decision, waiting for commands from the ground. They also said this scenario had been taken into account.

Now they say the spaceship is not designed to receive commands so close to the Earth surface. This contradicts their first statements.

The most likely explanation is a panicked Roskosmos PAO issuing a statement without bothering to talk to all those peasants in Engineering who actually knows what is the problem.

To me, the later the statement the more likely it is to be accurate. Earlier statements are likely to reflect preliminary findings or even the most popular theory held by the Brain Trust.
#75 by SiberianTiger on 15 Nov, 2011 10:12
Quote from: JimO on 14 Nov, 2011 20:06
FROM WHAT I'VE READ ABOUT NUREK-OKNO AND OTHERS, I AM NOT CONVINCED THEY EVEN HAVE THAT ANGULAR TRACKING RATE CAPABILITY. I HAVE NOT EVEN SEEN ANY VISUAL DAWN/DUSK OPPORTUNITIES LISTED FROM THE KNOWN SITES.

If I am allowed to add my two cents, it appears that Okno did have few possibilities to observe PhG after its launch. Maybe my approach is too simplistic for a real observation work, but given the current TLE...

Quote
Satellite passes / Orbitron 3.71 / www.stoff.pl

Location : Nurek - Okno (69.2250° E, 38.2750° N)
Time zone : UTC
Search period : 2011-11-08 10:21:34 - 7 days
2011-11-15 10:21:34
Conditions : Maximum sun elevation = -5 deg
Minimum sat elevation = 5 deg
Illumination required

Time Satellite Azm Elv Mag Range S.Azm S.Elv
--------------------------------------------------------------------------
2011-11-10 01:01:07 PHOBOS-GRUNT 318.5 18.4 ? 741 102.6 -11.5
2011-11-10 01:02:40 PHOBOS-GRUNT 37.7 64.1 ? 307 102.9 -11.2
2011-11-10 01:05:59 PHOBOS-GRUNT 123.2 5.0 ? 1479 103.3 -10.6

2011-11-11 01:01:26 PHOBOS-GRUNT 288.5 23.8 ? 615 102.9 -11.7
2011-11-11 01:02:36 PHOBOS-GRUNT 220.8 50.8 ? 351 103.1 -11.4
2011-11-11 01:05:51 PHOBOS-GRUNT 140.8 5.1 ? 1468 103.5 -10.8

2011-11-12 01:01:32 PHOBOS-GRUNT 249.5 20.1 ? 698 103.1 -11.8
2011-11-12 01:02:09 PHOBOS-GRUNT 224.6 22.4 ? 649 103.2 -11.7
2011-11-12 01:05:07 PHOBOS-GRUNT 159.9 5.0 ? 1461 103.6 -11.2

2011-11-13 01:01:24 PHOBOS-GRUNT 226.1 11.2 ? 1016 103.3 -12.0
2011-11-13 01:01:24 PHOBOS-GRUNT 226.1 11.2 ? 1016 103.3 -12.0
2011-11-13 01:03:38 PHOBOS-GRUNT 182.5 5.0 ? 1446 103.6 -11.6

Times are UTC.

The next period of dawn/dusk visibility shall begin no sooner that Nov. 19th.

It's too bad that Space Monitoring System of Russia never discloses their data to public, but it's probably not too bold to assume that their data is used by Roscosmos who are continuing their attempts to reestablish contact with the spacecraft knowing it's in a stable solar-facing attitude?
#76 by alk3997 on 15 Nov, 2011 13:51
Quote from: simplex on 15 Nov, 2011 04:52
Hours after Phobos - Grunt became and earth satellite, the Russians said that maybe the craft had not found the right stars and in consequence it stopped taking any further decision, waiting for commands from the ground. They also said this scenario had been taken into account.

Now they say the spaceship is not designed to receive commands so close to the Earth surface. This contradicts their first statements.

Let's go back to a standard satellite launch. Usually just before launch, the spacecraft goes to internal power (batteries) and then the satelitte becomes passive. Most transmit telemetry through the launcher but some do not. Depends mostly on the telemetry system of the launcher. But the bottom line is from a launcher standpoint, it's bad to have the satellite deploy appendages or output RF that could interfere with the launcher communications or do anything actively while being launched into space. The satellite is a passenger and the launcher has its own avionics systems.

Now once separated from the launcher's upper stage, a switch is thrown and the satellite starts chattering away. It knows it's on its own and can start transmitting.

In all cases, the available power for spacecraft activities is limited. There are still eclipse moments near Earth where the satellite goes into shadow. So, what devices get enabled and what stays off is a matter of how much power is available in worst case versus what benefit there is to turning on the devices.

So, that likely means that a passive Chinese satellite or lander would not be powered-up until check-out time on the way to Mars. I would be really surprised if the Chinese satellite or lander radio devices are on. So, strike those out of the available list.

The PG (or FG) integration with its upper stage seems strange to me. It is sometimes difficult to figure out who is supposed to control what. But in any event I would expect that the spacecraft would stay relatively quiet until the upper stage burn was completed so as not to disturb the burns. Unfortunately in this case, that means a very limited means for communicating with the spacecraft because the spacecraft is still waiting for the burns to occur.

Never chalk up a problem to malace that can be more easily explained by a not well-thoughtout design. Basically it seems likely that someone never thought of the consequences for the overall spacecraft if the first burn didn't occur.

Andy
#77 by Jim on 15 Nov, 2011 14:13
Quote from: alk3997 on 15 Nov, 2011 13:51

Let's go back to a standard satellite launch. Usually just before launch, the spacecraft goes to internal power (batteries) and then the satelitte becomes passive. Most transmit telemetry through the launcher but some do not.

Actually, the other way around, most don't transmit any telemetry during ascent
#78 by ChileVerde on 15 Nov, 2011 14:14
FWIW, I checked and the FGAN/TIRA imaging radar at Wachtberg, Germany is getting numerous good passes of Phobos-Grunt. They released some images of ROSAT recently, so perhaps we can hope for some of PG.
#79 by simplex on 15 Nov, 2011 14:37
The Russian Federal Space Agency has said 90% of Phobos Grunt is made of new and untested elements. The new instruments are being tested and will be tested during the flight.[41] According to lead scientist Alexander Zakharov, the entire spacecraft and most of the instruments are new, although they do draw on the heritance of the three successful Luna sample-return missions of the 1970s.[45] Zakharov has described the Phobos sample return project as "very difficult", possibly "the most difficult interplanetary one to date."[44]
http://en.wikipedia.org/wiki/Fobos-Grunt