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 7

(2 ） Occurrence of mulfunction in comms. and temp control systems (25 April 2002)

Nozomi had been flying without hitches atfer that. However, on 25 April 2002 a mulfunction developped in the comms. and temp control systems and it only became possible to receive beacon signals. At the same time it was no longer possible to control heaters. Because of this the fuel froze and it meant that we were unable to use the main and auxilliary engines.


(3) Operation designed to recover from these troubles

For above reasons we tried recovery operation from 15 May 2002, but we did not get anywhere. For your information, by end August of the same year the use of heat generated from onboard instruments and others led to the frozen fuel reaching the melting temp and it became possible to use the auxilliary engines at the start of September.

Therefore, we attempted the 1st earth swingby on 20 December 2002, the 2nd earth swingby on 19 June 2003 and these were both successful and we were able to put the probe into the Mars transfer orbit.

However, parts of the piping system which were meant to supply fuel to the main engine remained frozen and the main engine remained unusable. The temp change history from late July to end September measued at temp measurement points is shown on the graph I-3-2.

(4) Giving up of hope for Mars circulating orbit insertion (9 December 2003)

It would have been possible to place the probe into the Mars circulating orbit had the main engine recovered from the freeze before insertion into the transfer orbit. We continued recovery operation from 5 July 2003. However, above mentioned function did not come back before 9 December 2003 and the hope of Mars circulating orbit insertion was lost.

For your information, an orbit change to avoid the possibility of collision with Mars (approx. 1% possibility) was conducted during the night of 9 December using the auxilliary engines. Following this operation Nozomi passed the point above Mars surface at approx. 1,000km on 14 December 2003 and it is assumed that Nozomi finally escaped from Mars gravitational field by 16 December 2003.

end of page 7

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