Nozomi in perspective, Revisiting the causes of failure Options

[pandaneko]

http://www.mext.go.jp/b_menu/shingi/uchuu/...ts/04061101.pdf

Above pdf file will be translated for aspiring students in aeronautics, control engineering etc. so that in future lay people like me will be able to enjoy planetary scenes and events without worrying about failures.

The overall title is "Looking into the causes of failure and trying to find the right measures to take for the future with respect to the 18th scientific satellite (PLANET-B ) not inserted into Mars orbit as planned" and it is dated 21 May 2004.

This file is very much detailed at 1.1 megabytes and the number of pages is about 40, I think. In addition, I will be translating 3 more files after this particular file. They will be;

1. ISAS file with views and comments on the failure
2. Another ISAS file, a newsletter written out in a series of 4 individual letters.
3. JAXA file, which is a press release and it is a very concise document with just sufficient details.

Re concise link making I tried a few times, but I simply failed and all the links will be fully pasted out as required.

Pandaneko

[pandaneko]

http://www.mext.go.jp/b_menu/shingi/uchuu/...ts/04061101.pdf

above for ease of reference

page 75

Table IV-2-2 Means for seperating out failure causes and their characteristics

(This is a C3R6 regular matrix inluding the headers in row 1)

C1R1: Failure cause seperation means
C2R1: Meritts
C3R1: Demeritts

C1R2: Resistances
C1R3: Fuses
C1R4: Relays and limtter circuits
C1R5: FET switches and limitter circuits
C1R6: Ideal redundancies

C2R2: system is easy and repetitive activations are possible.

C2R3: Setting up is easy.

C2R4: Repetitive activations are possible.

also, cancelling of latching up is possible.

There is a possibility to save components from temporary shortciruiting.

C2R5: Repetitive activation is possible.

There is no limit to the number of activation.

also, cancelling of latching up is possible. There is a possibility to save components from temporary shortciruiting.

It is very easy to set the system to OFF side without fail at the time of power on.

C2R6: It is possible to accept, at least once and perfectly as well, every possible failure mode.

C3R2: Need heat resistance at times of short circuiting.

Given voltage drop we may find it difficutlt to use this as "load current" may fluctuate.

C3R3: Once activated it will remain in the same state forever.

We need to check anti-vivration characteristics at launch times.

Action possible region is generally fairly narrow in that it will function without being affected by a sudden surge etc, with a current which will not affect other devices.

C3R4: Composition is very complex.

Relaying system itself needs watching out for failures and there is a limitation on the number of possible actions that can be taken.

If the relay system is of a "latch type" it may not improve the situation if:

1. there is another breaker downstream and
2. response speed upstream is slow

C3R5: Composition is very complex.

We need to allow for:

1. some extent of voltage drop
2. some extent of heat generation

C3R6: Impact on heavy resources is largest (I have no idea what they are talking about, P)

If we want to introduce cross-redundancies it will lead to the system getting very complicated and we will have to be extremely careful in design and verification.

We will need to evaluate its usefulness against the failure rate of similar redundant systems if:

1. the vulnerability against failure is very localised and/or

2. if the failure rate in question is very low in the first place.

end of page 75

P