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ARISS Operations


I saw yesterday's e-mail traffic on the SAREX reflector and I thought I 
would clarify some items.

First, it is good to see that this reflector is still active.  For a while 
there, I only thought that Dave Larsen, Arthur Rowe and I were the only 
members of this reflector (hi hi).

Let's talk about the packet hardware.  I would not characterize the packet 
system as being "radiation fried."  It is true that the packet system has 
been down for a very long time.  If you all noticed, we did experience a 
similar, but not as lengthy packet down-period with another crew 
expedition.  That expedition, I believe, did not fully understand the APRS 
uses of the packet hardware and the system kept getting shut off.  It is my 
belief that this is the same problem we are experiencing with this 
crew.  What defends this theory is that we have made several requests to 
turn the packet system on through the Mission Control Center (not an easy 
thing to do for a secondary activity).  Each time, the packet system was 
reactivated and within an orbit, it was gone again.  If you haven't seen 
this packet resource, take a look at:  http://www.ariss.net/ and scroll 
down to the bottom to see the APRS packet ops.

We are working with the Mission ops folks to get the packet reactivated 
again and to make sure it stays on.  Stay tuned.

Those of you that know me pretty good know that I am an Aerospace Engineer 
that has also served on several failure investigation boards.  If you want 
my technical opinion of  the anomalies we have seen with the packet system, 
I really do not think they are radiation or Single Event Effects 
related.  A radiation issue would, most likely, cause the packet module to 
cease from operating when the susceptible part hits its radiation 
threshold.  If the packet system never turns on again, then radiation could 
be the issue.  But as you have probably deduced, I think it is an 
operations concern.  I do not think that the funnies many have you have 
seen with the packet messaging are single event effects (SEE/SEU) related 
either.  If that happened, the system would lock up or a bit flip (or many 
bit flips) would occur.  These would be random events.  But we see very 
consistent events (like the disappearing and reappearing of messages).  My 
conjecture is that this is a software bug, not an SEE/SEU.  Now that I have 
stated my conjecture, I am sure that many others will provide their own 
thoughts and ideas.  But these are my opinions based on my Aerospace 
experience and my experience with this set of hardware.

Regarding ARISS ops---as some have stated, some crews get excited about 
amateur radio and others don't.  Just like some people like amateur radio 
and others don't.  Just like some people like APRS, SSTV, Voice ops, CW, 
Contests, Field Day, and others don't.  Personally, I am grateful that the 
international space agencies are allowing us on-board.  We have gotten 
antenna feedthroughs, space on-board the crowded ISS, up-mass on Shuttles 
and Progress launch vehicles to fly our hardware and extremely valuable 
crew time.  These items clearly represent millions of dollars of space 
agency costs.  The ARISS-developed hardware complement costs pales in 
comparison to the space agency costs for allowing us on-board.  Every 
minute our equipment is on the air should be considered a blessing.

This past month has been a tough one due to the Columbia tragedy.  From an 
ops perspective, ARISS is just getting back on-line with a couple of school 
group contacts.  Please bear with us on the packet issue.  We will continue 
to work this as hard as possible while making sure we don't overstep our 
bounds with the space agencies and become thorns in their sides.

It is good to see that Don Petit is enjoying something that is inspiring to 
him while he is on ISS.  Just like amateur radio inspires all of us.


Frank Bauer, KA3HDO

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