Author Topic: FAILURE: Soyuz-2.1b/Fregat-M Meteor-M 2-1 et al. Vostochny - Nov 28, 2017  (Read 92901 times)

Offline russianhalo117

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They've launched Fregat from 63.34 E (Baikonur), 40.46 E (Plesetsk), and 52.8 W (Kourou), but never from 128.3 E.  Could there be a surprise due to the longitude, explaining the mention of Glonass in one theory?  I have to wonder if the real reason for the failure isn't as simple as we might currently believe.

 - Ed Kyle
yep this has been confirmed and narrowed down to the guidance computer commanding the upper stage to rotate 360 degrees resulting in complete gyro lock.

Offline CaptainScarlett

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Svobodny knows de trouble I seen.....

Offline Liss

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What's the difference between 372PH17 and other Soyuz-2.1B versions? Is it a special version for Vostochny?
Mainly new flight control computer system based on Malakhit-7 with changes to some other instruments.
This message reflects my personal opinion based on open sources of information.

Offline Alter Sachse

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https://www.roscosmos.ru/24410/

Google translation:
The calculations showed that the most probable place of the fall of the KGC is the northern part of the Atlantic Ocean, 42 'of northern latitude, 38' of western longitude with a spread along the fall path -120 +230 km, +-45 km perpendicular to the fall track.
« Last Edit: 12/01/2017 04:21 PM by Alter Sachse »

Offline Liss

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So the AIB cleared Soyuz-2 and confirmed the reentry point of the orbital block (КГЧ) = Fregat + payload.
This message reflects my personal opinion based on open sources of information.

Offline Ben the Space Brit

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I've got to say that it would have taken extraordinary evidence to point a finger at the Soyuz-2. From all accounts, the mission was running nominally right up to the point Fregat was in free flight and apparently had some kind of electronic nervous breakdown.
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Online deruch

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I've got to say that it would have taken extraordinary evidence to point a finger at the Soyuz-2. From all accounts, the mission was running nominally right up to the point Fregat was in free flight and apparently had some kind of electronic nervous breakdown.

Separation malfunction or some unexpected rotation rate prior to separation could certainly have been a contributing factor (I'm not suggesting this was the case).  There's no requirement that failures are single point.
« Last Edit: 12/01/2017 07:01 PM by deruch »
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Offline zubenelgenubi

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Assuming that the failure mode has been identified:

Is this a failure that could have been/should have been caught in pre-flight simulation?

Or the systems engineering?
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Offline russianhalo117

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What's the difference between 372PH17 and other Soyuz-2.1B versions? Is it a special version for Vostochny?
Mainly new flight control computer system based on Malakhit-7 with changes to some other instruments.
Fregat uses its own flight control computer whereas what you list only controls the basic Soyuz configuration.

Offline russianhalo117

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I've got to say that it would have taken extraordinary evidence to point a finger at the Soyuz-2. From all accounts, the mission was running nominally right up to the point Fregat was in free flight and apparently had some kind of electronic nervous breakdown.

Separation malfunction or some unexpected rotation rate prior to separation could certainly have been a contributing factor (I'm not suggesting this was the case).  There's no requirement that failures are single point.
that has pretty much been ruled out at this point. The data from Fregat-M on the flight clearly points to the inertial guidance system trying to align the upper stack to the correct orientation for the first burn but the flight computer overrode the IGS and sent additional commands to continue the rotation at which point the 2 sets of gyros experienced full gyro lock and an control was lost before the burn even started. That much is known at this point.

Offline Tomness

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So Soyuz did its job well and Fregat-M caused the failure or TBD?

Offline russianhalo117

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So Soyuz did its job well and Fregat-M caused the failure or TBD?
yes and kind of. Fregat-M issue is similar to an issue that occurred with Briz-M and even occurred with the Soyuz Launch escape system on its first launch attempt however are all azimuth based but were caused by different reasons.

The Fregat-M issue is both a design oversight and potential human error which is the part that the state commission is trying to answer at this point. Read the full article via the link below:

http://russianspaceweb.com/meteor-m2-1.html#1201
Quote
Roscosmos clears Soyuz-2 series, pinpoints Fregat crash site

On Dec. 1, 2017, the accident commission met to review causes of the November 28 Soyuz failure, Roskosmos State Corporation announced. According to Roskosmos, the latest calculations showed that the most likely crash site for the payload section is the Northern Atlantic at a point 42 degrees North latitude and 38 degrees West longitude, with a possible deviation of -120 or +230 kilometers along the ground track of the mission and 45 kilometers left and right from the ground track.

The accident commission decided to permit further launches of the Soyuz-2 rocket series according to the previously approved schedule, Roskosmos said. At the same time, the commission will continue work with the next meeting set on Dec. 12, 2017.
« Last Edit: 12/01/2017 08:35 PM by russianhalo117 »

Offline Liss

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The data from Fregat-M on the flight clearly points to the inertial guidance system trying to align the upper stack to the correct orientation for the first burn but the flight computer overrode the IGS and sent additional commands to continue the rotation at which point the 2 sets of gyros experienced full gyro lock and an control was lost before the burn even started.
Where did you get this strange idea of gyro lock experienced?
This message reflects my personal opinion based on open sources of information.

Offline Liss

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Fregat uses its own flight control computer whereas what you list only controls the basic Soyuz configuration.
Well, I was answering the ironical comment on Fregat being first time on Soyuz. My point is that Fregat indeed was for the first time on this particular version of Soyuz-2 launch vehicle with this control system. I do know there are two control systems there.
This message reflects my personal opinion based on open sources of information.

Offline russianhalo117

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The data from Fregat-M on the flight clearly points to the inertial guidance system trying to align the upper stack to the correct orientation for the first burn but the flight computer overrode the IGS and sent additional commands to continue the rotation at which point the 2 sets of gyros experienced full gyro lock and an control was lost before the burn even started.
Where did you get this strange idea of gyro lock experienced?

http://russianspaceweb.com/meteor-m2-1.html#1130
Quote
...
After a roughly 60-degree turn, the gyroscope system on the Fregat stalled, essentially leaving the vehicle without any ability to orient itself in space.

...

Offline Liss

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The data from Fregat-M on the flight clearly points to the inertial guidance system trying to align the upper stack to the correct orientation for the first burn but the flight computer overrode the IGS and sent additional commands to continue the rotation at which point the 2 sets of gyros experienced full gyro lock and an control was lost before the burn even started.
Where did you get this strange idea of gyro lock experienced?

http://russianspaceweb.com/meteor-m2-1.html#1130
Quote
...
After a roughly 60-degree turn, the gyroscope system on the Fregat stalled, essentially leaving the vehicle without any ability to orient itself in space.

...

Well, please explain me what is the referenced text about.

Quote
The geographical azimuth of previous Soyuz/Fregat launcher from Baikonur, Plesetsk and Kourou normally laid within a range from positive 140 to negative 140 degrees. To bring the gyroscopic guidance system into operational readiness, its main platform has to be rotated into a zero-degree position via a shortest possible route. The azimuth of the ill-fated Vostochny launch was 174 degrees, and with an additional 10 degrees for the Fregat's reference axis, it meant that its gyro platform had to turn 184 degrees in order to reach the required "zero" position.


Azimuth is, by definition, the angle between North (or South in some cases) and the direction. Which is the direction here with the azimuth of 174?

Below is the map of Soyuz pad at Vostochny for reference.
« Last Edit: 12/01/2017 10:06 PM by Liss »
This message reflects my personal opinion based on open sources of information.

Offline russianhalo117

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The data from Fregat-M on the flight clearly points to the inertial guidance system trying to align the upper stack to the correct orientation for the first burn but the flight computer overrode the IGS and sent additional commands to continue the rotation at which point the 2 sets of gyros experienced full gyro lock and an control was lost before the burn even started.
Where did you get this strange idea of gyro lock experienced?

http://russianspaceweb.com/meteor-m2-1.html#1130
Quote
...
After a roughly 60-degree turn, the gyroscope system on the Fregat stalled, essentially leaving the vehicle without any ability to orient itself in space.

...

Well, please explain me what is the referenced text about.

Quote
The geographical azimuth of previous Soyuz/Fregat launcher from Baikonur, Plesetsk and Kourou normally laid within a range from positive 140 to negative 140 degrees. To bring the gyroscopic guidance system into operational readiness, its main platform has to be rotated into a zero-degree position via a shortest possible route. The azimuth of the ill-fated Vostochny launch was 174 degrees, and with an additional 10 degrees for the Fregat's reference axis, it meant that its gyro platform had to turn 184 degrees in order to reach the required "zero" position.


Azimuth is, by definition, the angle between North (or South in some cases) and the direction. Which is the direction here with the azimuth of 174?

Below is the map of Soyuz pad at Vostochny for reference.

I don't know how to explain it very well but, as I understand it like Briz-M one ring of the Fregats Gyros cannot support the amount of rotation that occurred during the timeline to orient for the burn since the Azimuth that was programmed in to the IGS and main computer were read differently that resulted in a similar situation as below but under entirely different circumstances:

Reference: Ekspress-AM4
Someone on the NK forums saw the preliminary investigation report from ILS and reported the following findings:

Quote
Quote:
between the third and fourth main engine burns the "Briz-M" upper stage has lost inertial reference system.


Quote
Quote:
Telemetry from "Briz-M" upper stage was obtained after the 4th burn. Telemetry was unstable, the signal continued to decline up to the loss of telemetry in approximately 12 minutes after receiving it.


Quote
Quote:
It was concluded that the middle gimbal ring (Pitch ring), reached a hard stop. The remaining 2 rings - yaw and roll - have a degree of freedom of 360. At this point, inertial reference system was lost, and the error in the orientation of the pitch continued to accumulate over the length of flight.


Quote
Quote:
The entire flight program was studied. According to it, before maneuvering, guidance system of "Briz-M" upper stage performs a delta-turn of the second gimbal ring (pitch ring) in order to avoid the risk of locking the gyro. Analysis of the mission program revealed that the time allocated for the
delta-turn introduced into the program was incorrectly too little for preparing the maneuver before the third main engine burn.

http://russianspaceweb.com/meteor-m2-1.html#1130
Quote
In the Soyuz rocket, the gyro platform normally rotated from 174 degrees back to a zero position, providing the correct guidance. However on the Fregat, the shortest path for its platform to a zero-degree position was to increase its angle from 184 to 360 degrees. Essentially, the platform came to the same position, but this is not how the software in the main flight control computer on the Fregat interpreted the situation. Instead, the computer decided that the spacecraft had been 360 degrees off target and dutifully commanded its thrusters to fire to turn it around to the required zero-degree position. After a roughly 60-degree turn, the gyroscope system on the Fregat stalled, essentially leaving the vehicle without any ability to orient itself in space.

Offline Liss

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I don't know how to explain it very well but, as I understand it like Briz-M one ring of the Fregats Gyros cannot support the amount of rotation that occurred during the timeline to orient for the burn since the Azimuth that was programmed in to the IGS and main computer were read differently that resulted in a similar situation as below but under entirely different circumstances:
http://russianspaceweb.com/meteor-m2-1.html#1130
Quote
In the Soyuz rocket, the gyro platform normally rotated from 174 degrees back to a zero position, providing the correct guidance. However on the Fregat, the shortest path for its platform to a zero-degree position was to increase its angle from 184 to 360 degrees. Essentially, the platform came to the same position, but this is not how the software in the main flight control computer on the Fregat interpreted the situation. Instead, the computer decided that the spacecraft had been 360 degrees off target and dutifully commanded its thrusters to fire to turn it around to the required zero-degree position. After a roughly 60-degree turn, the gyroscope system on the Fregat stalled, essentially leaving the vehicle without any ability to orient itself in space.

I do not understand this at all.
Soyuz gyro platform normally rotated from 174 degrees back to a zero position -- when does it do this and for what purpose?
And what does the Fregat gyro platform do at the same time as the Soyuz gyro platform does this?
This message reflects my personal opinion based on open sources of information.

Offline russianhalo117

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I don't know how to explain it very well but, as I understand it like Briz-M one ring of the Fregats Gyros cannot support the amount of rotation that occurred during the timeline to orient for the burn since the Azimuth that was programmed in to the IGS and main computer were read differently that resulted in a similar situation as below but under entirely different circumstances:
http://russianspaceweb.com/meteor-m2-1.html#1130
Quote
In the Soyuz rocket, the gyro platform normally rotated from 174 degrees back to a zero position, providing the correct guidance. However on the Fregat, the shortest path for its platform to a zero-degree position was to increase its angle from 184 to 360 degrees. Essentially, the platform came to the same position, but this is not how the software in the main flight control computer on the Fregat interpreted the situation. Instead, the computer decided that the spacecraft had been 360 degrees off target and dutifully commanded its thrusters to fire to turn it around to the required zero-degree position. After a roughly 60-degree turn, the gyroscope system on the Fregat stalled, essentially leaving the vehicle without any ability to orient itself in space.

I do not understand this at all.
Soyuz gyro platform normally rotated from 174 degrees back to a zero position -- when does it do this and for what purpose?
And what does the Fregat gyro platform do at the same time as the Soyuz gyro platform does this?

The 2 Gyro platforms are aligned before liftoff just like an airplanes INU's . The 2 gyro platforms do not interact with each other upon liftoff until the Soyuz third stage triggers its shutdown and separation auto-command sequence and hands command and control over to Fregats Gyro Platform and Main computer.

Online deruch

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I've got to say that it would have taken extraordinary evidence to point a finger at the Soyuz-2. From all accounts, the mission was running nominally right up to the point Fregat was in free flight and apparently had some kind of electronic nervous breakdown.

Separation malfunction or some unexpected rotation rate prior to separation could certainly have been a contributing factor (I'm not suggesting this was the case).  There's no requirement that failures are single point.
that has pretty much been ruled out at this point. The data from Fregat-M on the flight clearly points to the inertial guidance system trying to align the upper stack to the correct orientation for the first burn but the flight computer overrode the IGS and sent additional commands to continue the rotation at which point the 2 sets of gyros experienced full gyro lock and an control was lost before the burn even started. That much is known at this point.

Ben, the guy I was replying to, was saying that it would have taken "extraordinary evidence" to implicate Soyuz, I was just pointing out that there were plenty of ways in which it was theoretically possible for Soyuz to have been involved in the failure.  I wasn't suggesting that any of them were true in this particular.  Based on released data and statements it seems that none of them apply, but I'm sure they were all investigated prior to "clearing" Soyuz.  Thanks for clarification anyways.
« Last Edit: 12/02/2017 01:19 AM by deruch »
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