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 72

Fig. III-2-3 Bus system voltage and current at the time of flares

(The only caption here is indicated by red lines and it says):

No change is seen in the portions indicated (by lines in red)

end of page 72

page 73

Table III-2-1 Accidental failure probability in space use by component types (quality assured level at class S)

(This is a C4 R many matrix. The only captions to be translated are):

C3R1: How many years before accident? or Accident every how many years?

C4R1: Occurrence rate of short cicuiting mode (for information only)

Note: FIT is the number of failures in 10 to the power of 9 years

end of page 72

Page 73

Table IV-2-1 Measures to be taken for the cause candidates which this time have been rated low (With Nozomi measures have been taken)

(This is an easy C2R6 matrix.)

C1R1: Cause candidates
C2R1: Measures to be taken

C1R2: total dose
C2R2: choose components which are most approapriate for the environment in use

*: initial sign of total dose is a small increase in current and this itself will not easily lead to "lost functions". We must therefore ensure that current limitters will not react prematurely.

C1R3: single event upset (SEU)
C2R3:

1. regular patroling and provision of refreshening function
2. triple redundancy for important registers
3. robust control logic (eg. automatic discovery of imvalid data)

C1R4: latch up
C2R4: choose radiation hardened components

C1R5: charging up
C2R5: Get rid of conductive layers which are not earthed

C1R6: high voltage discharge
C2R6:

1. isolation of vulnerable systems (eg. surrounding by secondary ground, primary and secondary isolation)
2. installation of imprinted voltage variables

end of page 73

P