Relay 2, although principally a communications satellite, carried particle experiments designed to map the trapped radiation belt. The spin axis orientation had a right ascension of about 130 deg and a declination of about -60 deg. Accurate spin axis orientation information was not available. The initial spin rate was about 173 rpm. Relay 2, physically similar to Relay 1, had on board two transmitters, one of which was used for PCM telemetry (the sequence requiring about 1 s). Design changes in this satellite improved its performance to the point where response to spurious commands was essentially eliminated. One of the two onboard transponders operated normally until November 20, 1966. From that time until its failure on January 20, 1967, it required a longer time than normal to come on. The other transponder continued to operate until June 9, 1967, when it too failed to operate normally.