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 9

(what follows follows directly from the last para on the last page)

For this reason a command was sent (18:20 UTC on the same day) to the oxidiser gas system latching valve LV2 to open it (schematic II-1-1) which is instaled as a non-reversible valve in the pusher gas piping system for the oxidiser tank. As a result we obtained following information and we concluded that the propulsion system returned to normal.

・ We obtained confirmation that the status of LV2 was open (schematic II-1-4).

・ Accelometer detected a vibration which seemed to have come from the functioning of the LV2 valve and the gas flow following it (schematic II-1-5)

・ It was confirmed that the oxidiser tank pressure recovered 15.1kgf/cm (1.48MPa) (schematic Ⅱ－１－ 2（1.48MPa）４)

(about this reference number, I am utterly unsure and we will have to wait until tommorrow if above is right. This is a result of my copy/paste and 1.48MPa sneaked into this reference and it ought ot be immdeiately after the kgf and I cut this out and put it in the right place as you can see here. However, if I cut out (1.48MPa) from the reference I will be left with a ridiculous ref number. It cannot be 24, and I suspect that it is actually 4, but there is no easy way for me to find out without losing what I have done by now)



(3) Grasping the events from the telemetry data

1) Telemetry data analysis

Analysis of the telemetry data relating to the propulsion system obtained during the period immediately after TMI indicated what follows.

a) Attitude change (at the time of the latching valve beeing open)


・Attitude change so that OME points in the velocity increase direction and a spinup (10 to 25 rpm) for securing attitude stability for when OME functions, both of these were activated by the RCS engines


・ A series of sequence until liquid and gas system latching valves (LV6, LV5, and LV2) indicator indicated open status were normally executed.


Functioning of OME

・The pressure of the oxidiser tank continued to fall without staying constant throughout the period in which OME burnt, from 14.6kgf/cm (1.43MPa) to 7.1kgf/cm (0.70MPa) at the time of OME stopage (schematic 2II-1-6).

(this makes me think above might have been 2II-1-4, P)


・ Acceleration also decreased from 0.97m/s to 0.76m/s (schematic II-1-7, 22) (again, unsure about this 22, P)


・ Integrated value of acceleration did not reach the required value of velocity increase. However, the duration of OME firing reached the maximum operational 397.5 seconds for safety and the firing was automatically terminated. It meant that there was a shortfall of 100m/s against the required value of 423.22m/s as the reached value was 327.1m/s.



c) Attitude change (at the time of latching valve close)

end of page 9

P