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


(3) Nozomi's design philosophy

Nozomi was designed to be launched in 1997 and its development and manufacturing spanned the four years starting in 1993. Its development was based on the following points.

① It should carry world first class instruments which can expect maximum returns.

② In order to maximise its scientific returns Nozomi should be designed to be proactively international.

③ Most reliable engineering technologies should be employed to secure its mission.

④ In manufacturing the probe only reliable and trustworthy parts and instruments should be procured.

⑤ Since the launching rocket is to be an M-V type the maximum weight of the probe should be kept within 530kg (later increased to 540kg thanks to the improvement of the rocket capability).

With respect to the points 1 and 2 above we are pleased to note that overseas groups were providing 4 instruments, ultrahigh stable resonator, image compression chips with world top class obervational capabilities.

In addition, all the data obtained by its mission was, ultimately, to be made available to all scientists across the world.

About the point 3 above, we adopted the dual liquid propulsion system because we concluded that aerocapture (note 3) and electric propulsion system (note 4) were still technically unreliable.

About the point 4 above, the valves that were right for the Nozomi specs were not produced by domestic manufacturers. This meant that we would have to use overseas parts with restrictions on the provision of technical indformation. For this reason, we decided that we should be sufficiently careful in order to ensure that they met our requirements in terms of reliability through quality assurance tests and related tests and inspections.

About the point 5 above, we reflected this weight limitation in our probe design (to be discussed later) and reduction of the weight of the probe was concretely put into action.


(Note 3) Aerocapture

This is a technique by which atmospheric pressure resistance is used to reduce the velocity of the probe for orbit insertion. This will allow a very large amount of reduction in fuel consumption. However, in the case of Mars the precision required for deviation from an optimum height is about 5km and is quite chaleenging. In addition, the target height will also vary according to the state of the Mars atmosphere at the time of velocity reduction and also the probe must be protected against heat.

（Note 4) Electrical propulsion

Artificially produced plasma is accelerated by high voltage and released into space for propulsion

End of page 4

(I am trying to be as accurate as possible in my translation. However, if anybody has any questions or require further clarification I will be very pleased to re-translate the bits in question. P)