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 76

Table IV-2-3 Concrete examples of failure seperation methods

(Inside the top horizontally oblong square says):

Large characters and those enclosed inside ovals are the points of improvements made with Nozomi

(However, I do not find any large characters on this page and next. There are, however, characters shown in red toegther with lines in red as you will see)

(There are two system outlines on this and next page, one on left and the other on right)

(One on left here says): Nozomi's system outline : current

(the only other characters for translation here is inside the top of 3 boxes next to TCI and it says): "Pressure monitor".

(the other one on right here says): Nozomi's system outline with improvement plan (1): Protective resisters in case of Black Box failure.

(the only other characters for translation here is inside the top of 3 boxes next to TCI and it says): "Pressure monitor".

end of page 76

Page 77 (system outline continuued)

(One on left here says): Nozomi's system outline with improvement plan (2): Protective resisters in addtion to switching between CI and PSU ( as indicated by vertically long square in red) + 1 kg in weight ( and the characters in this square says):

"Power control motherboard (within TCI)"

(the only other characters for translation here is inside the top of 3 boxes next to TCI and it says): "Pressure monitor".

(the other one on right here says): Nozomi's system outline with improvement plan (3): Protective resisters in addition to individual power source for every device (+ 3 kg in weight)

(characters in the square above LVDT next to TCI-2 box in red says): "Pressure monitor".

end of page 77

P

[pandaneko]

end of page 77

I now realise that I have effectively come to the end of translation work for this particular document. There are some more pages including pages 79 to 81 which are glossary pages in English and Japanese and very useful for any future correction work.

However, just glancing at these pages I note with satisfaction that I have not made fatal mistakes in the choice of my wordings.

Other pages are irrelevant to the story of this failure and need not be translated.

For now I may take up to 10 days of break in view of the inevitable events coming up over the next 2 weeks or so. However, it does not mean that I will not be able to grab time to do what remains to be done even during this period. It is just inpredictable.

When I resume the first document will be the JAXA press release summing up the causes of failure.

P

[pandaneko]

When I resume the first document will be the JAXA press release summing up the causes of failure.

What follows is the press release. I will provide link info and any other info later. Also, I am not exactly sure if this will be useful and I may not be able to complete translation of the whole of this release this evening and in which case I will continue tommorrow on with the rest. Here, we go as follows.

About abandoning insertion of Nozomi into Mars circular orbit

10 December 2003, JAXA

We reported on above subject to Space Activities Comission (SAC) held today as follows.

1. Current status

1. Mars probe Nozomi (launched July 1999) (fig. 1) developped a mulfunction in the fuel supply system at the time of leaving the earth gravitational fields (20 December 1999) (mulfunction history shown in seperate paper 1) and we had to change the original orbital plan and the arrival had to be changed from October 2000 to December 2003.


• 1st Japanese Mars probe launched by ISAS, carrying instruments from Sweden, Germany, US and Canada, also in cooperation with France.

• Launched by M-V 3 solid fuel rocket on 4 July 1998 from Uchinoura Space Observation Centre of ISAS in Kagoshima prfecture.


• Main objectives: Interaction between Solar winds and upper utmosphere of Mars

(Martian magnetosphere, atmosphere, plasma composition, satellites)

• Nozomi has been in its final approach into Mars since June of this year. EAT is 14 December.


Fig. 1 Outline of Mars probe Nozomi (Planet


2. A mulfunction developped in April 2002 in the comms. and thermal protection systems, resulting in minimum amount of communication in addition to incapability to perform temperature control. The mulfucntion here refers to thoes events as shown in Fig. 2 whereby part of the series of the circuits meant to supply power from common sources of power to components developped short circuiting.


Fig. 2 Nozomi power supply, schematic outline

3. May 2002 we tried to stablise probe temp. by turning on instruments. Also, we made a restoration work by trying to burn out the short circuiting sections by directing currents. However, this operation resulted in total loss of communiction capability.

4. July 2002 we kept trying to recover comms. for two months based on the findings of trouble shootings and achieved a minimum level of communication capability.

5. August 2002 fuel temp. reached that of fuel defreezing temp. This was due to the decreasing distance between the probe and the Sun and also the heat generated by the instruments on board. From here on we managed to control fuel temp. by keeping the right probe orientation.

6. June 2003 we managed to insert Nozomi, using the bare minimum communication means, into its final transer orbit.

7. July 2003 we needed precise orbital determination and firing of the main engine. This meant that we had to restore thermal contorl system and the work began as required. Unfortunately, this work yet again led to the total loss of comms.

8. From July 2003 to today (December) we have been trying to burn out the short circuiting sections by directing currents to there, and this meant that the number of times we turned on the common power source reached 1.3 times 10,000,000,000.

We also tried to rewrite the ROMs on board in order to exclude the possibility of the onboard computers going bad to no effects. Based on this we returned the ROMs to their initial values and continued with "continous ON" operation, but there is no prospect of recovery on the night of 9 December.


9. All this made us persuade that insertion into Mars orbit was no longer possible and we began the process of work required to make sure Nozomi will avoid collision into Mars on the night of 9 December in accordance with an international agreenment (collision probability is less than 0. 1% as required)

For your reference current orbital plan with insertion in mind is shown in Fig. 3 and that of fly-by is shown in Fig. 4. As you can see from Fig. 3 continuing with the current orbital plan with a fly-by will mean just a slight acceleration by Mars gravity and lead to a clser approach to Mars.


NOTE) COSPAR planetatry protection policy and moral obligation to observe its policy



Fig. 3 Nozoni's original orbit

Fig. 4 Nozomi's Mars orbiting plan and its fly-by orbit


(This will continue, not by very much, though)

P