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 57

Table II-2-5 FTA for LV2 mulfunction

First of all, notations belows this table.

Cross: not possible
Triangle: small possibility
Single circle: medium possibility
Double circle: large possibility

Top row headers go like:

C1R1: suspected reason
C2R1: judgement
C3R1: reason for judgement
C4R1: operational judgement

Since C1 has subcolumns I will have to de descriptive in some cases.

C1R2: mulfunction with the monitoring device

C1 leftmost subcolumn R3 to R10: mulfunction in device area (best I can translate, I am afraid..., P)

C1 righthand subcolumn R3: mulfunction with the inner piece

C1 righthand subcolumn's left subcolumn R4 to R10: mulfunction in valving action

C1 righthand subcolumn's right subcolumn's rows (and there are many and I will hereafter use R numbers only, P)

above's R4: expansion due to incompatible plug materials

above's R5: bad sliding of the plug

above's R6: plug glitching into valve opening area

above's R7: plug misallignment

above's R8: glitching of (or by) foreign material

above's R9: clearance change at sliding setion due to valve temp. change

above's R10: temporary solidification due to crystal formation (such as nitric ammonia)

(hereafter entries become regular, P)

C3R2: monitor is healthy because open/close sensor indicated that the rod for sensor moved in the same direction as the inner piece in response to the open/close command.

C3R3: inner piece movement is considered to be normal because there was a stroke large enough to change the open/close status monitor and also latching had been secured.

C3R4: mulfunction due to expansion is not possible because of the metal jacket at the sealing section and the jacket itself is resistant to NTO.

C3R5: it is thought that because the valve and the plug are independent and are activated by a differential pressure the valve body surface got roughed up by fletching wear and led to corrosion in NTO environment.

C3R6: it is thought that the valve was slightly opened during TMI. However, in this mulfunction mode the slight opening of the valve is difficult to take place.

C3R7: this must be due to bad manufacturing, but the ground tests did not give any indication.

C3R8: this possibility is low because we used a finer filter than the minimum diametrical clearance.

C3R9: the valve had functioned properly in similar environment in flight.

C3R10: propellant was charged (or injected) after dryness confirmation. Also, this phenomenon should have shown up within a few days.

(now the last column, P)

C4R5: we will leave the valve LV2 in open state because we think that slidability will worsen as time goes by.

C4R6: we will leave the valve LV2 in open state because closing it may lead to the same mulfunction with a high possibility.

C4R7: we will leave the valve LV2 in open state because closing it may lead to the same mulfunction.

C4R8: repetition of mulfunction is thought to be low in possibility because it was accidental and also the foreign material must by now have been carried downstream.

C4R10: we will leave LV2 open as closing it may lead to repetition.

(outside the table there are 5 character strings giving the degree of suspicion as the candidate for causing mulfunction. These sit side by side to Rows 5, 6, 7, 8, and 10 and carry a numerical value of 1 to 5 respectively.)

end of page 57

P