CREATE TABLE table_31681 ("Flight" TEXT, "Launch date/time  ( UTC ) " TEXT, "Variant" TEXT, "Launch Pad" TEXT, "Payload" TEXT, "Payload Mass" TEXT)

Tell me the launch date/time for payload of gsat-4
SELECT "Launch date/time (UTC)" FROM table_31681 WHERE "Payload" = 'gsat-4'
SELECT "Launch date/time (UTC)" FROM "table_31681" WHERE "Payload" = 'gsat-4'