-
#100
by
Stan Black
on 18 Aug, 2011 17:08
-
-
#101
by
kevin-rf
on 18 Aug, 2011 17:33
-
-
#102
by
refsmmat
on 18 Aug, 2011 18:34
-
The pressure in the tanks may change over a long enough time. What is the effect of the fuel pressurizing system? Does it use helium? Comparing this to USA 193, that object was in a low orbit with time in shadow and its hydrazine tank may have frozen solid (one more tank that didn't have a fail-safe?) If Briz-M is in an elliptical orbit it will be in more sunlight, so reactants may vapourize. Batteries, coolant lines, other onboard tanks notwithstanding what the Hydrazine and N2O4 does.
That is why I said "may".
That is problem with storable propellants, how do you get them out of the tanks of a dead stage. In the prior case when you mentioned Centaur, due to the propellants, good or bad, something would have already happened. Now we wait for something to leak, corrode, or fatigue (from the thermal cycles) and hope nothing mixes.
The burst disks only work if the pressure is changing inside the tanks. With storable propellants, that should not be happening.
Don't forget that the satellite which by all accounts is still attached to the Briz-m, has consumables on board that can cause long term problems. It has not been, and it may not be possible at this point to safe. It has batteries that can potentially over charge and explode, it still has propellants on board, the system is still pressurized.
-
#103
by
Jim
on 18 Aug, 2011 18:40
-
That is certainly a poor system architecture, if the satellite cannot separate itself from a dead upper stage.
Heads will roll.
Could you please tell us how you would have designed the upper stage to avoid this problem?
Andy
A design that allows the payload to separate itself in the event of total system failure of the upper stage is not exactly rocket science.
It isn't SOP. The LV controls the interface. Also the interface has breakwires that prevents the spacecraft from doing anything while attached.
-
#104
by
Jim
on 18 Aug, 2011 18:41
-
You are suggesting that there are no launch systems that allow the satellite to initiate separation?
Most don't
-
#105
by
Jim
on 18 Aug, 2011 18:43
-
A simple relay to transfer the pyro circuits to Payload when the stage loses power would address most that. I'd guess an added on connector for the high current signals. Not as sexy as 3 million lines of code, but more the Russian way anyhow. It obviously wouldn't use the upper stage computer if the upper stage were dead. There's no problem with simple, last ditch efforts if you don't have anything to lose.
Not that simple. Two leads from two different sources to the pyros? Nope a relay isn't going to work.
-
#106
by
Nomadd
on 18 Aug, 2011 20:35
-
A simple relay to transfer the pyro circuits to Payload when the stage loses power would address most that. I'd guess an added on connector for the high current signals. Not as sexy as 3 million lines of code, but more the Russian way anyhow. It obviously wouldn't use the upper stage computer if the upper stage were dead. There's no problem with simple, last ditch efforts if you don't have anything to lose.
Not that simple. Two leads from two different sources to the pyros? Nope a relay isn't going to work.
The purpose of a relay is that there would never be two lines from two sources at once. Just one or the other.
-
#107
by
Danderman
on 18 Aug, 2011 23:16
-
Ironically, the Blok-DM, which was discarded for most Proton flights, does have a model in which all vehicle avionics are contained in the payload, not the upper stage.
-
#108
by
alk3997
on 18 Aug, 2011 23:43
-
Ironically, the Blok-DM, which was discarded for most Proton flights, does have a model in which all vehicle avionics are contained in the payload, not the upper stage.
Yes, you mean this reference from Energiya, "If the mass of spacecraft that can be delivered to orbit needs to be increased, the autonomous instrumentation bay, which houses the motion control system, can be removed from the upper stage, with control over the stage transferred to the spacecraft. "
Not sure if it is relevent since it's still an either-or situation. Either the autonomous instrument bay controls or the spacecraft controls. Not a situation where hand-off from one to the other could be accomplished.
-
#109
by
Nomadd
on 19 Aug, 2011 00:11
-
Might not have helped anyway. Aren't more non-separations from failed pyros or latches than failed commands?
-
#110
by
input~2
on 19 Aug, 2011 05:07
-
-
#111
by
Jim
on 19 Aug, 2011 08:29
-
Might not have helped anyway. Aren't more non-separations from failed pyros or latches than failed commands?
Not for US systems. Pryos work when fired.
-
#112
by
Nicolas PILLET
on 19 Aug, 2011 09:14
-
It seems that everybody missed this, but it was the 50th flight of the Briz-M upper stage !
-
#113
by
Olaf
on 19 Aug, 2011 09:58
-
-
#114
by
Skyrocket
on 19 Aug, 2011 10:05
-
This report http://de.rian.ru/space/20110819/260158907.html (in German) says, that they have located the position of Ekspress-AM4 detached with Briz-M.
And if the satellite is not demaged, it could be used as planned.
The report also says, that Ekspress-Am4 is still attached to Briz-M - and (regardless, if Ekspress is dmaged or not) precludes any usage.
There is only a chance, if the Briz can be commanded to seperate from the payload. And we do not have any info, that the Briz is responding.
-
#115
by
Nicolas PILLET
on 19 Aug, 2011 10:19
-
-
#116
by
Olaf
on 19 Aug, 2011 10:24
-
-
#117
by
Jim
on 19 Aug, 2011 11:12
-
There is only a chance, if the Briz can be commanded to seperate from the payload. And we do not have any info, that the Briz is responding.
And current US launchers do not have the ability to receive commands
-
#118
by
kevin-rf
on 19 Aug, 2011 12:28
-
There is only a chance, if the Briz can be commanded to seperate from the payload. And we do not have any info, that the Briz is responding.
And current US launchers do not have the ability to receive commands
Would the Briz-M it still be alive this many hours later?
-
#119
by
Galactic Penguin SST
on 19 Aug, 2011 13:02
-
Can any Russian member take a look at the discussion thread at the Novosti-Kosmonavtiki forum
here? The 50 page thread is full of technical jargon that the online translator can't understand. Can anybody confirm that no-one has seen the Breeze-M and the satellite for more than 24 hours, not even NORAD?