John P. Doty wrote: > Joerg wrote: >> Totally OT here, quick question since you seem to be quite the expert on >> this: Do you know some sort of main distributor or clearing house for >> space-rated parts? Or is the only way to just piece it all together like >> usual, via individual quotes from companies such as Solitron? >> >> > > I don't know of any shortcuts. If you have a customer who insists on > "space qualified" parts, you need to talk to them. Everybody has their > own rules. If you're dealing with somebody with a lot of rules, you'll > need a parts specialist to deal with them. This is more like lawyering > than engineering. >
Yes, that's what it looks like to me. > From an engineering perspective, "space qualified" is almost > meaningless, since "space" is neither an environment nor an application, > but a wide range of them. If the part that best fits your requirements > is in stock at Digi-Key, use that. I've flown a lot of these with great > success. "Space qualified" parts tend to fragile, obsolete junk that > behaves unpredictably in actual applications. But they've been blessed > by the priesthood. > That's what I have seen a lot, older parts from obsolete parts dealers. Don't want to rely on that because when the pot is empty the meal is going to be over. > Regardless: > > Understand the mission. > Understand the environment. > Understand the physics of the interaction of the environment with the > technology. > Understand the requirements. > Agree. I understand the concerns about rad-hard and common failure mechanisms. Understanding the mission will hopefully be achieved after the next meeting. Where I'll have a whole lot of questions ;-) > In depth, not in the shallow, sloppy way that too many "designers" think > adequate. There are no cribsheets, and "space qualified" is no guarantee > of anything, except maybe on paper. God is in the details. > God is in heaven, much farther than this craft can go but still near enough for me ;-) > Don't torque your parts selection around to solve issues better > addressed at the system level. Not every part needs to be immune to > radiation-induced upset, for example. > That's what I am planning to do. Keep it as simple as possible, prototype with Digikey parts and then take a hard look to see which ones could be critical. Then I'll sit down with the customer. But it might be a back-to-the-wall situation because they in turn will be bound by agreements. Of course, there always comes a point where it's "either we modify a requirement or we can't do it". Thanks for the insight, John, I appreciate that. -- Regards, Joerg http://www.analogconsultants.com/ _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
