Re: [amsat-bb] eagle costs

["Luc Leblanc (VE2DWE)" <luclebla@xxxxxxxxxxxxxxxxx>]

On 5 Sep 2004 at 17:54, Diane Bruce wrote:

> On Sun, Sep 05, 2004 at 07:52:30PM -0000, John B. Stephensen wrote:
> > The rocket engine explosion on AO-40 had nothing to do with the complexity of
> > the electronics or the number of transponders.
> 
> Minor nit. I certainly would not say that or imply that.
> 
>        It was caused by human error on
> > the ground.
> 



 the valve(s) simply refused to open. We had such a problem before during the test phase of the s/c, and one 
of the helium valves was repaired as a consequence. All the indications are that we ran again into this type 
of problem - which may be caused by the age of the components we are using. We then executed multiple open 
and close commands, which eventually got the helium flowing. But it was also noted that the helium flow was 
almost an order of magnitude less than required. Still we build up pressure in the tank to nominal and then 
programmed the s/c to perform the burn on Monday evening.  

This time the burn started properly, but there were some anomalies in the telemetry indicating that the burn 
did not stop at the programmed time but lasted about 3 minutes longer. Thus we achieve an orbit with about 
60,000 km apogee altitude. For our ultimate plans this is no problem, we would have used the electric 
propulsion anyway to further increase the apogee. James Miller had written a data collection program for IHU-
2, thus we have a very detailed account of all the events of this burn. A detailed analysis is under way, but 
we have already some first indications of the nature of the problem and also possible ways to cure it or at 
least to cope with it, provided that the motor was not damaged by this event.  

During the next days we will investigate this matter in detail. If we have a real problem with the 400 N 
propulsion system, we may need to change our strategy for achieving a useful final orbit. But it may also 
mean only that we have to observe a number of boundary conditions during the following burns and that the 
situation may have no impact on the mission goals.  

For the next days no attitude changes are planned, thus we will be able to start to investigate the problem 
with the 70cm TX. During these tests we will find out if we can operationally plan on using the 70cm TX or 
not. So we are living exiting times.  

Finally we would like to express our compliments and our appreciation to the command stations for the superb 
job they are doing. Each day they are facing new difficulties requiring a very large amount of time and 
dedication. They are doing a SUPER job.  

Karl Meinzer , DJ4ZC, AMSAT-DL President  
Robin Haighton , VE3FRH, AMSAT-NA President 
 


> It is just as possible the valve in question failed in flight.
> 
> I'd be curious why you conclude it was soley a ground station error,
> or do you also consider the possibility of the valve in question
> not being rejected for the final flight as human error?.


Just to pointed out the following part...

 We had such a problem before during the test phase of the s/c, and one of the helium valves was repaired as 
a consequence. All the indications are that we ran again into this type of problem - which may be caused by 
the age of the components we are using.

THE AGE OF THE COMPONENTS WE ARE USING  Is this can be the ultimate explanation regarding the cascade of 
failures aboard AO-40? When some folks ask for A KISS sats (as i am) it is with the AO-40 saga in mind. Some 
also answered back regarding "EAGLE COSTS" VS KISS SATS  "That Most of these arguments are moot."

I read a lot of rethorics but bear in mind the cost of loosing AO-40 FAR EXCEED any rethorics regarding cost 
breakdown...  When we say put something simple without bell and whistles it also implied  the human error 
factor and design short cuts as USING OLD AGE components lets say 2nd hands stuff when building our sats.

"The transponder packages are almost in the noise compared to all of the other costs." It is true if we cut 
on the components quality eg: valve and batteries and guess what else... Valves nearly destroy  AO-40 and 
batteries killed it at the end added to some human errors we end up with a complete loss of a multi millions 
investment. I hardly believe the transponder packages are "ALMOST IN THE NOISE" if we extend a bit the 
definition of a transponder package we can look at all the parts inside a sat as the real package... when we 
ask for something simple it is to prevent the castatrophic AO-40 saga of failures.

To concluded UO-11 batteries are still working after 20 years.  Wihthout any ISO numbers on amateur satellite 
construction it is why some are saying make our next sat in a way to expect a life span over 3 years. 
Considering our past experience and a well documented chronic batteries problem could be if we concentrate 
more on the X-ponder and on some simple and proven hardware we can afterwards think about skyrocketing our 
techcs dreams on the high speed modems and 20 ghz wide band and laser kits and so and so...

We rely actually (called it a set back eg:HEO) to 10 minutes sats when our newbies will have to invest in a 
costly doppler and tracking systems to be able to afford their first sat QSO'S? Or they will have to find 
another pair of hands to manually for 10 minutes play with their knobs and switches.

Yes i'm complaining but lets say AO-51 NEVER EXPERIENCE any failures yet. I hope he will be there for more 
than 3 years and it is actually with 2 others LEO our cubesat fleet. They will be joinned soon by other Borg 
cubes and they all have their place in space naturally. When some express their concerns about COSTS they 
probably have in mind their donations and investments knowing for a big chunck of our membership their 
satellite fever represent a big investment and for some it is often a budget item...

We know all the efforts and workload the construction and control teams are doing but at the user end the 
ultimate one i believe? some efforts should also be made to listen on what they wants. Communicate first to 
be able to experiment after. Trying to reverse the order will not be a solution.

A comment from the gallery! 

 
Luc Leblanc VE2DWE
Coordonnateur AMSAT pour le Québec
Quebec AMSAT coordinator
AMSAT MEMBER (33583)
Sites web sites: www.qsl.net/ve2dwe
                          www.sorel-tracy.qc.ca/~luclebla

P.O. Box 341
Sorel-Tracy  QC.
Canada
J3P 5N6
----
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