Transponder built from parts of a Hubble K7C Stellar Assessment Array
The Hubble K7C Stellar Assessment Array was a model of solar array used by the Federation on solar research vessels in the 23rd century.
In 2259, Lieutenant jg Montgomery Scott cannibalized the Hubble K7C Stellar Assessment Array on the USS Stardiver to construct a transponder, which he used to escape the notice of hostile Gorn vessels. (SNW: "Hegemony")