In a late update to the STS-135 mission: the PSSC-2 picosatellite, ejected from Atlantis after it undocked from ISS, reentered on December 8.
(I haven't seen this mentioned in the forum, apologies if I missed something).
I looked at the orbital decay over time and it appears that they fired one of the quartet of tiny onboard solid motors at 1530 UTC on Nov 4, raising the apogee by 10 km, which seems to have delayed reentry by about 4 days
(i.e., the orbit returned to its previous altitude by Nov
. The other three motors were probably left unused.