Complex sentence: He worked his last mission as FIDO in 1981, when he was on console during the second Shuttle launch (STS-2); however, by that point his responsibilities in the Flight Dynamics Branch were largely managerial.
Split into simpler sentences: He worked his last mission as FIDO in 1981, when he was on console during the second Shuttle launch (STS-2). By that point, however, his responsibilities in the Flight Dynamics Branch were largely managerial.