Total Members Voted: 34
Voting closed: 12/14/2012 04:35 pm
a) rework the avionics so that in the event that a main engine failure is detected, rather than immediate separation of the satellite, the entire unit should go into safe mode.b) institute an uplink command channel so that the stage could be commanded from the ground.
Quote from: Danderman on 12/10/2012 04:35 pma) rework the avionics so that in the event that a main engine failure is detected, rather than immediate separation of the satellite, the entire unit should go into safe mode.b) institute an uplink command channel so that the stage could be commanded from the ground.As you point out in 'b', 'a' requires uplink and assumes the "problem" can be fixed by simple uplink before the Briz's batteries die. This assumes the Briz is shutting down for silly reasons and not an unsafe state that could lead to a very rapidly evolving and exciting situation. I do not believe that is the case. In the sense of the paying customer, salvaging the payload through immediate separation and getting it the heck away from the stage is the safest option in an off nominal situation. What they need is a fool proof way to safe the stage in the event of these situations. A RUD some months later is not a good way to safe the stage.
I would imagine that an abort system could differentiate between a true emergency, where the spacecraft should be separated immediately, and a condition where the engine is shutting down in a relatively safe manner. And, yes, the a+b+c I listed above are not separate options, but instead an integrate approach to the problem.
Btw a list of Briz failures over the last few years:14 March 2008 - Ruptured plumbing, you can not continue to use the system after that. 6 August 2012 - FOD, clogged line. Chances of the thrusters also working?
They always said with shuttle that redesigning/mods always risked making the issue bigger, so I'd go with better QA.
A well design integrated fuel system may have saved these two missions. For example, looking at the Soyuz spacecraft prop system, there are capabilities for completing entire missions missing the main engine.
6 August 2012 - FOD, clogged line. Chances of the thrusters also working?
Well do we know what's going on at Khrunichev? For some reason the Fregat upper stage build by Lavochikin, which uses an engine with more or less the same parts and design, never had any in flight failures since its first flight in 2000 (and only one small ground processing issue that led to a slightly off course mission in 2009). Why? QA issues? Or just that a space tug with a pump fed engine that must work for 9 hours + is just difficult to work with high reliability?
You forgot about Lavochikin's work with Phobos Grunt.
Have we even seen Soyuz 2.1v yet? I know it hasn't launched but has it been seen in public?
Aerospace in Russia is hitting a wall it seems.Soviet technology has lasted quite a while but now it's all starting to break down and lack of new investments are showing through.I voted for better QA but that's because Proton is on the way out anyway.Angara with a hydrolox upper stage is where Russia wants to go. Getting that right is important. If it makes it through development. Have we even seen Soyuz 2.1v yet? I know it hasn't launched but has it been seen in public?