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 8

Ⅱ．Trying to clarify the causes of mulfunction in the fuel supply system

１．How mulfunction occurred

(1) Outline of the propulsion system

Nozomi's propulsive system was meant for insertion into Mars transfer orbit before reaching Mars, orbital changes for insertion into Mars circulating orbit, and pointing the antenna towards the earth once in Martian orbit and consisted of the Orbit Maneuvre Engine (OME) with a 500N class dual liquid thruster and the Reaction Control System (RCS) with single liquid thrusters for atitude and orbit control.


Nozomi's propulsion system and main specs are listed with the schematic II-1-1 and the table II-1-1.

Nozomi's piping system was typical satellite propulsion system and its OME engine produced propulsion by burning the hydrazine from the fuel tank with NTO. In so doing the fuel and the oxidiser are pushed out by the helium gas into the engine. Both hydrazine and NTO are liquid and are highly reactive when mixed together with self-igniting capability and for that reason the engine does not have a special ignition mechanism as such.

(2) About the operation at the time of insertion into Mars transfer orbit

Nozomi was launched by an M-V 3 solid fuel rocket on 4 July 1999 and went through various orbital adjestments. During the unseen period (tracking station unable to see the satellite in line of sight) on 20 December of the same year an automatic control was executed to put the satellite into the Trans Mars Orbit (TMI).

It was during this sequence that the orbital change by the OME did not attain the required velocity increase. Time sequence of this event is shown on the schematic II-1-2.

1) Status at the time of TMI

According to the US JPL flash report issued around 12:00 (UTC) on 20 December 1999 there was a shortfall of velocity by some 100m/s against the required delta V of 423.22m/s

2) Operation during the visible period immediately after TMI

(part of what follows actually spills out onto page 9, but I am translating the whole paragraph for ease of reading)

The visible operation immdeiately after the TMI (around 17:00 on 20 December (UTC)) indicated that the onborad intergrated value was 327.1m/s as the velocity increase, close to JPL flash report. At the same time the pressure sensoer P4 indicated that the pressure of the oxidiser tank alone showed an abnormal value of 8.3kgf/cm (0.8MPa). (Schematic II-1-3)

end of page 8

P