-
#200
by
zaitcev
on 03 Sep, 2011 00:23
-
Ooooohhhhh, its made in the Ukraine. Look for some backwash from that.
The gyroscope flown was made by NII KP, an FGUP located in St. Petersbourg, as I and Anik mentioned. So, it is impossible to pin the failure on Ukrainians. I think Mr. Prober is trying to point out an alternative with a different technology base.
In any case, it is not established that frames have in fact folded and this is why the gyroscope exceeded the alotted time to orient. The State Commission apparently implied that giving it more time would let it orient itself, and thus the fault was with Mars Ltd. This is the official conclusion, as far as I know.
-
#201
by
Stan Black
on 03 Sep, 2011 05:57
-
Ooooohhhhh, its made in the Ukraine. Look for some backwash from that.
The gyroscope flown was made by NII KP, an FGUP located in St. Petersbourg, as I and Anik mentioned. So, it is impossible to pin the failure on Ukrainians. I think Mr. Prober is trying to point out an alternative with a different technology base.
In any case, it is not established that frames have in fact folded and this is why the gyroscope exceeded the alotted time to orient. The State Commission apparently implied that giving it more time would let it orient itself, and thus the fault was with Mars Ltd. This is the official conclusion, as far as I know.
Officially because of delays with payload, but Mr. Zak notes that the GEO-IK-2 failure could be a further reason.
GEO-IK-2 failure will not impact Proton Breeze M launches based upon the reported cause of the failure. The Breeze M uses a new control system and gyro that are different (hardware and vendor) than that used on Breeze KM.
So is there any differences in gyroscopes between Briz-KM, Briz-M 885-series and Briz-M 995-series?
-
#202
by
Danderman
on 03 Sep, 2011 14:03
-
So is there any differences in gyroscopes between Briz-KM, Briz-M 885-series and Briz-M 995-series?
Do any other upper stages share the same gyroscope with Briz?
-
#203
by
Galactic Penguin SST
on 09 Sep, 2011 18:09
-
Someone on the NK forums saw the preliminary investigation report from ILS and reported the following findings:
Quote:
between the third and fourth main engine burns the "Briz-M" upper stage has lost inertial reference system.
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:
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:
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.
-
#204
by
kevin-rf
on 09 Sep, 2011 18:29
-
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.
Do they reorient the stage or, just the ring?
-
#205
by
kevin-rf
on 09 Sep, 2011 18:43
-
Now this is interesting further on in the NK forums, legacy of it's ICBM heritage:
нее.. Это разные явления . Рамка на упор - это когда одна из рамок не может крутиться на 360. Скорее всего - тяжелое наследие военного дизайна. МБР летают по довольно плоским траекториям. (к тому же меньше чем на виток орбиты) Получается, что по 2-м осям из трех (по тангажу и вращению) можно сделать ход рамки 180 градусов - а то и поменьше.
А имея такие небольшие рабочие углы рамок можно сделать внутренний, а не внешний кардановый подвес - и сэкономить на размерах и массе. (и еще сэкономить на токосьемных кольцах - но кого в 21-первом это интересует)
А чтобы не было складывания рамок (на традиционных ГСП) - нужно либо подвеску делать в виде шара, плавающего в тяжелой жидкости (американцы - сначала на МХ ставили- затем на Минитмен3) - супер точная и супер дорогая штука.
Либо 4-ю рамку добавить. (лишняя масса -и сложность)
Google translated:
it .. This is a different phenomenon. Frame to stop - this is when one of the frames can not spin at 360. Most likely - a heavy legacy of military design. ICBM flying on a fairly flat trajectory. (Also less than a revolution orbit) It turns out that on the 2nd of three axes (pitch and rotation) can make a move frame 180 degrees - or even less.
And with such small working angles of the framework can be internal, and no external gimbals - and save on size and weight. (And save on tokosemnyh rings - but who in the first 21 interested in this)
And that was not folding frames (in the traditional GSP) - to make a pendant in the form of a ball floating in the heavy fluid (the Americans - first in the MX-set then on Minitmen3) - super accurate and super expensive stuff. Or the 4th frame to add. (Extra weight and complexity) Although AM4 out more
-
#206
by
sdsds
on 09 Sep, 2011 19:09
-
Trying to summarize this:
- The gyroscope design limits the motion of the pitch ring.
- Other gyroscope designs don't have this limit; this one does because its simpler to implement and was sufficient for (ICBM) heritage applications.
- There's a way to work around this limit, and Briz-M attempts to do that.
- On this mission the work-around was improperly implemented, thus exposing the underlying limitation of the gyroscope.
Correct thus far? Then more questions:
- Did the control logic for the stage fire the engine again even though the gyroscope data was detectably incorrect?
- Is the stage operation completely autonomous, or could it have gone into "safe" mode and awaited instructions from ground control?
-
#207
by
input~2
on 09 Sep, 2011 19:34
-
-
#208
by
input~2
on 10 Sep, 2011 05:27
-
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.
Do they reorient the stage or, just the ring?
AFAIU, it has to be the ring only, otherwise it wouldn't help.
-
#209
by
bolun
on 12 Sep, 2011 20:44
-
-
#210
by
zaitcev
on 13 Sep, 2011 17:45
-
-
#211
by
JimO
on 13 Sep, 2011 19:42
-
-
#212
by
zaitcev
on 13 Sep, 2011 20:09
-
No, Jim, it is not true. I've collected the list of Russian online sources. About half of them even refer SpaceNews by name. Others say "according to western MSM", which simply means the same SpaceNews article. ALL of them have the same made-up source. It's an astonishing lapse of basic journalism. Even Kommersant and Vedomosti fell for it.
Kosmicheskaya Svyaz' made it worse by posting a curiously worded release that is purported to deny all these reports, but it's formed in such a way that does NOT actually deny that the satellite is in a safe mode. That is because they simply do not know.
I am quite certain that the bird is dead based on the optical observations of the amateurs. After a few days in a stable orbit, its parameters changed. Since all normal drain tubes are terminated with a zero-moment T-ends, it means emergency, off-design outgassing. A safed satellite with working heaters would never do that.
-
#213
by
Sur2900
on 14 Sep, 2011 20:11
-
-
#214
by
rdale
on 14 Sep, 2011 20:16
-
zait - certainly not questioning your info, but even AV Week/AS Daily say it's alive.
"Evert Dudok, president of Astrium Satellites of Europe, says the Express-AM4 is now operating nominally, albeit in an orbit far from its intended dropoff point (Aerospace DAILY, Sept. 13)."
-
#215
by
agman25
on 14 Sep, 2011 20:25
-
Even if they managed to turn it on, will be satellite be of any use in it's existing orbit ?
-
#216
by
rdale
on 14 Sep, 2011 22:04
-
No - as indicated by the sentence right before...
"useless"
-
#217
by
JimO
on 15 Sep, 2011 04:14
-
So we still don't know if there is any live comm with it. Can any French colleagues contact Dudok directly, s'il vous plait?
-
#218
by
Nicolas PILLET
on 15 Sep, 2011 06:29
-
Mr. Dudok is from the Netherlands... :-)
-
#219
by
Stan Black
on 15 Sep, 2011 16:28
-
I guess they need to talk to Ekspress-AM4 to make sure it was not the cause of this accident.
