Насчет test sockets вы правы, а спутники-носители - это supporting carriers, которые служат для автоматической установки микросхем в эти тестовые разъемы и переноса их обратно

Carrier and carrier system for flatpack integrated circuits
https://www.freepatentsonline.com/5109981.html
It is not possible, however, to adapt these configurations to carriers for integrated circuits in flatpack packages. A central rectangular or square ceramic body and terminals emanating from each side of the ceramic body in the plane of the body characterize integrated circuits in flatpack packages. Whereas in a PGA carrier, the terminals are accessible from the bottom of the carrier, the flatpack configuration requires accessibility from the top of the carrier. As a result, if a PGA carrier transports its chip "on top" of a supporting structure, a carrier for a flatpack integrated circuit carries the integrated circuit below the supporting carrier structure. Automated production lines typically move the carriers along a route in a line. The PGA system requires the carrier to move transversely to the line so it nests within the removal tool. Such transverse motion can complicate the production line and reduce production throughput involving flatpack components.