We still have some live left for NO-84 (PSAT), Cat ID 40654.
Based on past experience, when an amateur satellite’s drag rises above the 0.01 magnitude, the satellite is usually getting close to reentry. Some have climbed back up for a while. But, as a rule of thumb, 0.01 drag is the point I start watching a satellite’s drag. Almost all amateur satellites have a mean motion of at least 16 when they decay.
The current TLE shows NO-84 (PSAT), Cat ID 40654, with a drag of 0.00320060 and a mean motion of 15.99945301. Getting close.
For example, here are the drag values for a few satellites the day they deorbited:
SAT Cat ID drag Mean Motion
==================================================
NEPALISAT1 44331 0.04661449 16.30483242
RAVAANA 44329 0.04382427 16.28919678
UGUISU 44330 0.06186538 16.33294840
CP9 44360 0.01594744 16.12399308
TW-1C 40926 0.05243455 16.31196197
MO-105 44832 0.11453400 16.41416157
MO-106 44830 0.14504533 16.46538413
ENDURO SAT ONE 43551 0.12819970 16.45548142
EQUISAT 43552 0.10316869 16.43170683
SWAMPSAT 45115 0.19123998 16.36852634
PWSAT 2 43814 0.25888781 16.21683976
Per above, several have hung on for another order of magnitude of
drag. It would be very difficult to estimate a deorbit time based solely on drag. But, all have had a mean motion in excess of 16 when they decayed.
Ray Hoad
WA5QGD
AMSAT-NA Orbital Elements Manager
From: Robert Bruninga [mailto:[email protected]]
Sent: Wednesday, December 1, 2021 14:48
To: amsat bb <[email protected]>
Cc: Robert Bruninga <[email protected]>
Subject: [AMSAT-BB] APRS satellite Lifetimes?
Joe, KM1P reminded us of the decay of NO-84 soon.
It woiuld be nice to get an assessment of the remaining lifetimes of the
remaining APRS satellites listed on http://aprs.org/sats.html
Since I retired (and health issues),, I wont be building any replacements
and have not been paying attention.
Joe wanna take a crack at it?
Bob
On Wed, Dec 1, 2021 at 11:05 AM Joseph B. Fitzgerald wrote:
>
> There is a non Russian object threatening NO-84, specifically the earth's
> atmosphere. Mean motion is now dangerously close to 16! Time for a
> Chicken Little contest?
>
> de KM1P Joe