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 17

5) Temporary immobility (or solidification) by material growth (or some kind of crystal formation?)

If there had been residual water inside the propulsion system it could have been possible that the reaction of fuel and oxidiser led to the formation of ammonium nitrate. However, this possibility has been discarded as extremely low for the following reasons.


・ dryness at the time of propellant filling was very good (condensation temperature being minus 55 degrees C or below)


・ Had there been a mixing with fuel the check valve upstream would have caused mulfunction


・ It would have shown up in a short span of time (a few days)


(3) Result of estimating for the causes of mulfunction

If we are to summarise what we have been talking about so far, we think that the causes of LV2 mulfunction are due to, as shown in 1) of (2), the fact that the valve was susceptive to increased sliding friction of the plug given that the valving was powered by the differential pressure by the seperate inner piece and the plug

and also the fact that the sliding surface caused a fletching wear leading to corrosion by the oxidiser environment, further leading to an inceased sliding friction.

That is to say that the multiplier effect by these two factors was the most likely cause of the failure.

end of page 17

P