New information on the identity of BRICSat, NO-83 has been been received from Nico Janssen, PA0DLO.
Nico (with the help of Jan, PEOSAT) came up with an ingenious way of making the tight-lipped BRICSat tell us which object it really is. See excerpt from Nico's email to me below.
From Nico Janssen, PA0DLO -
To be able to receive downlink signals from BRICSat, I asked Jan, PE0SAT, to assist by transmitting PSK31 signals to this satellite on the 10 m uplink, hoping the downlink would switch on. And this worked. But since the power system in this satellite is very weak, there is not enough power available for longer transmissions. So when an uplink signal is received, the downlink transmitter switches on but then switches off after a fraction of a second. The only thing you see in the downlink is a very short blip. And this repeats with every PSK31 transmission in the uplink.
Interestingly, these tests only worked during passes of ULTRASat 2, not ULTRASat 3 or any other ULTRASat... So now we have to conclude that BRICSat, NO 83, is actually object 90721, ULTRASat 2.
Therefore, the AMSAT distribution will begin using the ULTRASAT-2 TLEs for BRICSat, NO-83.
Thanks to Nico, PA0DLO and Jan, PEOSAT for a really great bit of detective work.