I don't think there is much difference when you look at ALL the failed and operational sats. BTW, FO-29 is inoperative, HO-68 was both FM and linear, and you forgot DO-64 in recently failed transponders. AO-27 is 17? years old.

Satellites come and go. I still miss SO-35, RS-10/11, RS-12/13, FO-20, UO-14, SO-41, AO-10, and of course AO-40. The point is we have to continue to build and launch new ones, and use what we have at the moment. "Love the one you're with" for those who remember the song.

Looking in the near term, we have P3E, Kiwisat, Fox-1 and -2, UKube, FunCube, Turksat-3U, the planned SA-AMSAT cubes, and others that need our support to get to orbit.

73, Drew KO4MA

-----Original Message-----

From: zach hillerson qstick333@yahoo.com Sent: Nov 29, 2011 10:48 AM To: "amsat-bb@amsat.org" amsat-bb@amsat.org Subject: [amsat-bb] satellite durability fm vs. linears

Serious question regarding satellite durability.  It seems with HO68, SO67, and now AO51, the FM satellites are quickly going away.  It also seems that the older linear counterparts such as AO7, VO52 and FO29 all seem to continue working properly.

Is there a design issue with the FM birds that limits the useful lifespan or is it purely random luck?  Usage rates, etc... play a role?

It seems to happen far too often (even with a small sample size) to be a fluke.

Zach N4ERZ _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb