The recent mention of the work by Kozai and Lidov and it's relation to AO-13 stimulated a number of long dormant memories. I've always been in awe of Dr. Victor Kudielka, OE1VKW who, using 80286 (?) technology, was able to apply their work to predict the demise of AO-13.

Prior to launch I don't think any of us had considered the possibility that asymmetries in the shape of the earth could cause fluctuations in the eccentricity of AO-13's final orbit that would, without affecting the spacecraft's total energy, lower the perigee to the point where re-entry would occur.

Which leads me to wonder about Victor's status these days. I can't find any reference to him post 2013. Any info would be appreciated.

73, Martin, k2ubc

On Wed, Feb 28, 2018 at 8:00 AM, Robert McGwier rwmcgwier@gmail.com wrote:

Yes, AO 13.

On Tue, Feb 27, 2018 at 1:09 PM Gregory Beat w9gb@icloud.com wrote:

...

Jeopardy question?

Oscar 13, AO-13

greg, w9gb

=== Subject: [amsat-bb] Yoshihide Kozai

The long scientific life of Kozai ended recently with his death at ~90 years old

Kozai and Lidov proposed a mechanism for why the Luna 3 probe decayed

into

...

the Earth's atmosphere when everyone believed it would last "forever".

This same mechanism describes the death of which amateur spacecraft?

Bob N4HY

Sent from iPad Air

-- Bob McGwier Founder, Federated Wireless, Inc Founder and Technical Advisor, HawkEye 360, Inc Research Professor Virginia Tech Chief Scientist: The Ted and Karyn Hume Center for National Security and Technology Senior Member IEEE, Facebook: N4HYBob, ARS: N4HY Faculty Advisor Virginia Tech Amateur Radio Assn, Trustee K4KDJ Member of PVRC (Roanoke-Blacksburg), TAPR, life member of ARRL and AMSAT, NRVR.ORG (Rocketry) _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb