[Namaste-dev] Software Defined Radio - Mars Lander daily software changes

grayg ralphsnyder wgrayg at mountain.net
Tue Jun 10 20:22:28 PDT 2008

I just read an article about the Mars Lander mission which helped me 
think about some things :

The data relay satellite orbiting Mars has a 'safe mode' that it goes 
into when some fault occurs or by other causes such as excessive 
radiation.  It stops what is was doing until it receives new 
instructions.  Do all satellites have this feature ?  I think it would 
be a good idea for us especially since the radio software may be updated 
for improvements, features, etc. and there may be a point where things 
'crash' and some kind of 'watch dog timer' will be needed to 'reset' the 
satellite systems.  The safe mode program would be encoded in hardware 
so the satellite could always be communicated with / through in its 
'base mode.'  If during some disaster-emergency situation the satellite 
got into this 'base mode', the ground stations should be able to fall 
back to their 'base operation mode.'  With this at least the satellite 
would remain useful and not frustrate the system's users.  There would 
have to be some mechanisms to allow the ground stations to know which 
mode the satellite was operating in - or what 'level' of software it was 
at - related to features, etc.

NASA's team of about 30 engineering and programmers change between 1000 
and 1500 lines of code each day.  This is for fine tuning the lander's 
operation to help make sure every minute and action give valuable 
results.  How well the collaborative effort works considering the 
requirements to 'get it right' each day/code change is interesting.  
Collaborative projects like Mozilla and Open Office, for example, show 
that good results can be gotten.  Of course, the repercussions for a 
screw up with the Mars Lander can be more of a disaster ... or is the 
'how bad is the disaster' in the eye of the beholder ?  So with our 
project, that is going to take a bit of management work, coordination 
and executive decision making.  What kind of team will it take ?  Will 
the entire team / labor to get this done be voluntarily or will part of 
it be paid by 'investors, etc.' ?

And "... the developers, who used the C programming language to build 
their own software for a Linux operating system."  What kind of program 
language / etc is typically used for a satellite, in particular one of 
the kind we are looking at ?

grayg - KC8SVT

The article :
"NASA: 'Extreme programming' controls Mars Lander robot
Engineers send code 170 million miles through space daily in search for 
life on Mars
By Sharon Gaudin"


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