Just to "echo" what others have been saying: AO51, R.I.P. And a hearty thank-you to the Control Team for giving us so many many happy and proud hours!
I am a new ham, licensed less than two years, and worked John K8YSE via AO-51 with my little HT and an Arrow maybe six weeks after passing my Tech. A few months later after another test my first QSO signing "slash AG" was again on that bird, with Patrick WD9EWK.
Since that time, mostly from my home QTH driveway, but also at club special events, on the beach at Cape May, New Jersey, even the shores of Lake Champlain, I remember working at least some of the other great satellite operators whose posts are seen here from time to time. The furthest DX I worked was Ivan YY6IEA in Venezuela. I frequently tried, but never successfully worked, Drew KO4MA.
And I guess it also emphasizes that, not only do we have to continue to hone our technical skills to continue with the fleet that we still do have, but moreover that we really do have to continue to support (i.e., give money to) AMSAT and Fox. Good luck guys!
Best wishes to all of the community of amateur satellite operators!
73, Bob. KC2WYH