Dec. 1, 2003

Green Hills did not lose Pathfinder job

I read with interest your October story on the complexities of space flight. Your article, "Spacecraft Systems Integrators Struggle With Increasing Complexity of Rad-hard Computers," gave an overview of some of the unique challenges of space flight. It went to great lengths to include comments from several contributors to the Mars Rover Missions, Orbiter and Spirit, which launched into space this past June.

Green Hills Software's comments — among others — were included and while the coverage was very comprehensive, there was one misstatement in the article that must be clarified. The inaccurate statement I refer to reads: "The only change between the Pathfinder and Rover Missions was a change from Green Hills' INTEGRITY RTOS to Wind River's VxWorks RTOS."

Just to be clear, there was no change to the RTOS from Pathfinder to Spirit/Orbiter, and VxWorks did not replace Green Hills' INTEGRITY. In fact, to my knowledge, our INTEGRITY RTOS has never been replaced by Wind River's VxWorks — but the opposite occurs frequently.

The statement should have said the difference between the two missions was the version of compiler used. While Green Hills' compiler was used with great success to recompile the VxWorks RTOS during both missions, the Mars Rover's more complex mission required additional compiler optimizations to improve size and speed of both the application and kernel. Recompiling VxWorks with the Green Hills compilers provided improvement to the RTOS' size and performance allowing this mission to take place as planned. At the same time, recompiling VxWorks rather than changing RTOSes allowed for a cost and time savings.

Green Hills Software is proud of the role our products played in keeping this mission on time and on budget. I want to be sure your readers — and our potential customers — understand the facts of this project.

We appreciate you contacting us about our involvement in the military and aerospace industry and look forward to many more discussions in the future.

Lynn Robinson
marketing communications manager
Green Hills Software Inc

Manned space flight can be made safer

I read with interest your editorial in the October 2003 issue of Military & Aerospace Electronics entitled "End of the line for manned space travel?"

I do not agree with your assessment. I believe that the recent Chinese space shot will attest to that.

I believe that space travel can be made safer even in this day and age by supplying our astronauts with artificial gravity with some sort of spinning mechanism on the International Space Station (ISS) currently in orbit.

The problem with the U.S. space program is that there are no real goals. President Kennedy got the whole nation enthused to put a man on the moon and several after that. What happened after that was a complete travesty of letting that achievement go to waste, letting all of those experienced engineers, astronauts, etc. go to waste with no clear follow-on plans to build a moon base and perhaps mine the moon for minerals, etc.

There is also that military goal of capturing the "high" ground from which to do DOD research, etc.

I believe that the Chinese probably have a "plan" for their future in space both around the Earth and the moon ... with future military plans. Otherwise they would not spend so much money on a process where they could simply buy rides to the ISS for very little comparative outlay of money. The Chinese are too smart to simply spend several billion dollars for prestige alone.

Michael E. Keller
ASTE Executive Director
Sr. Staff Engineer
The MITRE Corporation
Bedford, Mass.

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