A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Space Science » Technology
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

Operating systems used in spacecraft?



 
 
Thread Tools Display Modes
  #11  
Old October 27th 03, 08:09 PM
someguy
external usenet poster
 
Posts: n/a
Default Operating systems used in spacecraft?

"Greg" wrote in
...
Richard Kaiser wrote in message

. ..
I would try google on FlightLinux to see if its status is
on the web. It may be hosts on sourceforge.org, look there
too. If FlightLinux does fly it will probable be in an
amature radio or university built satelite.


I'm a big fan of open source etc. But even i would be very carful
using it any of these applications. The problem is that too many
people have writen the softwear. Some parts are writen very well, some
are not. As you say, licence fees for these things are petty cash.

It's not licence fee problems that makes people attracted by open source
software. When using operating systems in particular you need to have access to
the source code for debuging strange system behaviour. Anyone tried to do fault
injection testing of fault tolerant computer without acess to the OS source
code? It is a nightmare when the system dies, you don't know why and have no
post mortem analysis possibilities. This fact for instance make the open source
OS RTEMS a more suitable choice in space applications than for instance VxWorks
(although I think Wind River has now realised the hard facts and makes the
source available to licensees).

Having access to the source code also simplifies additional testing on the
product, something that definitely improves the quality of the final system.


This begs the question-- perhaps a little OT. How is flight softwear,
flight tested?


In-flight testing is not the best criteria to "qualify" a product (look at for
instance the first Ariane5 failure where a "flight-proven" software from Ariane4
was reused in a new application without proper system testing). Instead adequate
design rules combined with carful testing both at module, software product and
integrated system level guaratees a much more reliable function than showing
that your software has flown once or twice.

--
someguy

  #12  
Old October 28th 03, 12:47 AM
Greg
external usenet poster
 
Posts: n/a
Default Operating systems used in spacecraft?

And this is different from closed-source software... how, exactly?

I assumed that any FAA approved OS would have to document every line
of code? Much like all FAA approved hardware.

Otherwise my experience has been very good for some open source
products (linux kernel ie without X11). Better support, easy to find
out absolute limits etc While we have most commercial software will
claim a lot more than they can deliver.

greg
  #13  
Old October 28th 03, 12:58 AM
Greg
external usenet poster
 
Posts: n/a
Default Operating systems used in spacecraft?

Kevin Willoughby wrote in message ...
In article , gewi001
@phy.auckland.ac.nz says...
This begs the question-- perhaps a little OT. How is flight [software],
flight tested?


Very carefully....
:-)

In ordinary commercial software, the standard estimate is that a
software product spends half of its budget during the testing phase.
Apollo and Shuttle flight software spends 90% of its budget on quality
assurance.


Only half? Most projects i work on its a lot higher. I guess you could
call it scope creep. But really it all still comes down to total cost
of ownership.
  #14  
Old October 28th 03, 05:54 AM
Michael J Wise
external usenet poster
 
Posts: n/a
Default Operating systems used in spacecraft?

Henry Spencer wrote:

There are two possible answers.


[Blink]

3) Redundant CPUs, one of which is running a different operating system,
so if the other two get frotzed by Yet Another Windows Exploit in deep
space, the Penguin can Save The Day. Or the Mac, as the case may be.

There are always more possible answers.

Aloha mai Nai`a.
--
"Please have your Internet License http://kapu.net/~mjwise/
and Usenet Registration handy..."

  #15  
Old October 29th 03, 10:47 PM
Adam Przybyla
external usenet poster
 
Posts: n/a
Default Operating systems used in spacecraft?

Grem wrote:
Which operating system/systems are used in spacecrafts? Has FlightLinux
been implemented yet; and if not how far in the testing are they? Any
information on these topics would be greatly appreciated.

... well, there is many open source aplication/systems in space,
for example SSTL use RTEMS in his satellites. Flightlinux project was finished,
but try to look at: ipinspace.gsfc.nasa.gov. there are also rumours about ST-7
(some technology from flight linux will be used). European use open source
in Galileo Project (small costs) too. Sorry for my english. Some interesting pages:
http://www.rocketforge.org/ or http://www.polsek.org.pl/ (polish only/english version
in progress) Regards
Adam Przybyla

  #16  
Old October 30th 03, 09:32 PM
Henry Spencer
external usenet poster
 
Posts: n/a
Default Operating systems used in spacecraft?

In article ,
Michael J Wise wrote:
There are two possible answers.


3) Redundant CPUs, one of which is running a different operating system,
so if the other two get frotzed by Yet Another Windows Exploit in deep
space, the Penguin can Save The Day. Or the Mac, as the case may be.


Only if the Windows machine(s) haven't already fired the pyros, left the
gas valves open, pointed the camera at the Sun, etc. (Clementine's R3081
running C and VxWorks couldn't save the spacecraft when the antique 1750,
that NRL had insisted on putting in, went berserk due to a software bug
and left the thrusters on.)

Yes, you can put in safeguards against such things... but if there is no
way for a software malfunction to wreck the mission, then you don't *need*
the extra computer at all -- you can rely on doing a reload from the
ground if things go wrong. So in essence you're back to my answer #1,
running the new experimental stuff as a secondary payload that is not
crucial to mission success.
--
MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer
pointing, 10 Sept; first science, early Oct; all well. |
  #17  
Old October 31st 03, 01:57 AM
Derek Lyons
external usenet poster
 
Posts: n/a
Default Operating systems used in spacecraft?

"someguy" wrote:
It's not licence fee problems that makes people attracted by open source
software. When using operating systems in particular you need to have access to
the source code for debuging strange system behaviour.


While that may be indeed what attracts some to Open Source, I suspect
politics accounts for most of the interest in it.

D.
--
The STS-107 Columbia Loss FAQ can be found
at the following URLs:

Text-Only Version:
http://www.io.com/~o_m/columbia_loss_faq.html

Enhanced HTML Version:
http://www.io.com/~o_m/columbia_loss_faq_x.html

Corrections, comments, and additions should be
e-mailed to , as well as posted to
sci.space.history and sci.space.shuttle for
discussion.
  #18  
Old November 1st 03, 09:18 PM
Christopher M. Jones
external usenet poster
 
Posts: n/a
Default Operating systems used in spacecraft?

Michael J Wise wrote:
Henry Spencer wrote:

There are two possible answers.


[Blink]

3) Redundant CPUs, one of which is running a different operating system,
so if the other two get frotzed by Yet Another Windows Exploit in deep
space, the Penguin can Save The Day. Or the Mac, as the case may be.


You obviously have no idea how complex and difficult such a thing
would be in practice. It's hard enough doing realtime control with
one software / hardware system, it would be much more than twice as
difficult with two different systems that had to mesh together and
somehow magically share control and hand-off or assume control between
each other when the other doesn't work right. "Nightmare" seems like
a good enough first approximation for the problem, though it is not
remotely sufficiently pungent a description to get across how
difficult it would actually be. The Space Shuttle uses different
control systems which back each other up but the software is very,
very closely related to each other (the backup is a stripped down
version of the original) and it all runs on the same hardware.
  #19  
Old November 5th 03, 11:32 AM
Jan C. Vorbrüggen
external usenet poster
 
Posts: n/a
Default Operating systems used in spacecraft?

You obviously have no idea how complex and difficult such a thing
would be in practice. It's hard enough doing realtime control with
one software / hardware system, it would be much more than twice as
difficult with two different systems that had to mesh together and
somehow magically share control and hand-off or assume control between
each other when the other doesn't work right. "Nightmare" seems like
a good enough first approximation for the problem, though it is not
remotely sufficiently pungent a description to get across how
difficult it would actually be.


...yet all fliy-by-wire aircraft, and especially those from Airbus, do
it every day.

The Space Shuttle uses different
control systems which back each other up but the software is very,
very closely related to each other (the backup is a stripped down
version of the original) and it all runs on the same hardware.


That is not the case - the BFS is completely indepedant, in software
development, tools and history - from PASS. Same hardware, though -
and manual switchover.

Jan
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Decision on the Soyuz TMA-4 spacecraft prelaunch processing Jacques van Oene Space Station 0 April 1st 04 01:12 PM
Voyager Spacecraft Approaching Solar System's Final Frontier Ron Baalke Science 0 November 5th 03 07:56 PM
Soyuz TMA-3 manned spacecraft launch to the ISS Jacques van Oene Space Station 0 October 21st 03 09:39 AM
The Final Day on Galileo Ron Baalke Science 0 September 19th 03 07:32 PM
BAE Systems Microprocessors Enroute To Mars Ron Baalke Technology 0 July 29th 03 10:40 PM


All times are GMT +1. The time now is 01:37 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.