[svlug] open source avionics in Ares I

Rick Kwan kwanrj03 at comcast.net
Sat Jan 5 17:36:07 PST 2008

Hi all,

Following a tip to the article cited below, I managed to engage a
few aerospace computing professionals across the country on what this
may mean.

Title:  NASA Will Tinker With Open-Source Rocket for Return to Moon
Author:  Alex Hutchinson
Date:  Dec. 12, 2007
URL:  http://www.popularmechanics.com/science/air_space/4236758.html

When I asked about it, we were told the rationale is that NASA's
Constellation is a roughly a 30 year program.  Ares I is a launch
vehicle which would put humans into orbit.  The Ares I team wants to
ensure that the avionics code is maintainable even if a particular
vendor goes out of business.  (This decision only applies to Ares I,
not Constellation in general.)

Reactions of my colleagues have ranged from curiosity and skepticism
to "government use rights" do pretty much the same thing.  Frankly, we
still don't have all the specifics; we expect that one of the folks has
access and will straighten us out.  I've been pondering OSS avionics
with human life at stake in my own free time for a couple of years.
I sent the following two points to my friends today.

1. The OSS community likes to say "given enough eyeballs, all
problems are shallow" or something to that effect.  This is how
projects like Linux, Apache, and other keep the quality up.  It also
assumes that the eyeballs understand the problem space.  It seems to
me, the narrower the problem space, the harder it is to find qualified
eyeballs.  Part of why device drivers are so hard is because device
behavior is often not well understood.  (Conversely, the OSS community
loves manufacturers that open their hardware interface specs.  A
similar thing would have to happen for OSS avionics.)

2.  Sweat equity.  In the strictest sense, OSS source code only needs
to be delivered to the software's users.  However, it does provide a
context and good starting point for the uninitiated.  Individual
developers will often develop their expertise in an area by studying
someone else's source code.  (Of course, this comes as no surprise,
since that's how software maintenance works.)  Lots of OSS projects
have readers that the project originators are completely unaware of.
But it certainly works a lot better when there are forums, FAQs, etc.
Before I get into the next round of discussion, I'd like to give people
here a chance to shoot me down, or elaborate further.

Last year, the group published a set of guidelines for the use of
commercial off-the-shelf software in mission critical systems (specifically
in aerospace).  Naturally, I asked how OSS fit in the picture.  We didn't
answer that in the current edition. But there is a very strong likelihood
that we'll do it this time.

--Rick Kwan

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