Re: NASA orbit simulation software

Derek Lyons wrote:
Pat Flannery <flanner@xxxxxxxxxx> wrote:
So the various centers have workforces that know their particular software very well indeed.
But like I said, this means that there is a real problem with exchanging data between the centers as the people at the other center aren't going to know how the data was arrived at if it was derived from software that they are unfamiliar with.

Orbital parameters have a fixed format - how they were arrived at is
irrelevant.

References, please?

My own experiences in various software systems suggest that while there may be an abstract "fixed format", a dozen different programs will have at least ten different formats.

In the early days, for any kind of data set, it isn't at all clear what the best fixed-format should be. Build a dozen different programs, compare the results, and you know enough to kill-off half the formats. Build another dozen different programs and you begin to see commonalities. Build another dozen programs and it begins to make sense to talk about standards. Build another dozen and it begins to make sense to enlist a standards organization (IEEE, ANSI, etc.) to start creating standard. After a few years, it becomes clear how to build gateways between formats. After another few years, folks standardize on a single format.

An on-topic example, what's the best launch configuration? Single Stage to Orbit has lots of advantages -- it's just not easy to build. Multiple stages? History now demonstrate that works, but there are complications like staging. Parallel launch? The Sputnik launchers demonstrate this works, but as payloads increase this gets complex. Hybrid parallel like the Space Shuttle -- that works most of the time, but we have to acknowledge the final flights of Challenger and Columbia. Serial stages (e.g., Saturn V) work, but with much complexity for "staging".

Summary: the idea that there is an initially obvious "fixed format" is flawed. The fixed format will become evident only as we try a bunch of different things.


<long irrelevant anecdote snipped.>

yah, well, this is Usenet...
--
Kevin Willoughby kevinwilloughby@xxxxxxxxxxxxxxx

It doesn't take many trips in Air Force One
to spoil you. -- Ronald Reagan

.

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