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Re: ARISS Operations



  Thank you for sharing your experience and ideas re ARISS, they're
greatly appreciated!

  My sole experience in orbital packet work is with MIR, and I'm a little
rusty on the whole thing. I'm very much the new kid on the block as far as
ARISS is concerned and had no idea what to expect, so you've cleared up a
number of issues which were very murky to me.

  One positive thing about it is that I've had time to get my packet gear
back on the air and checked, and to read up on the ARISS operating
procedure.

  Anyway, it helps just to hear some news. Thanks again!

	73,
	Steve, N0RLB


On Thu, 27 Feb 2003, Frank H. Bauer wrote:

> All,
>
> 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.
>
> 73,
>
> Frank Bauer, KA3HDO
>
> ----


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