Tell me the launch date/time for payload of gsat-4
CREATE TABLE "launch_history" (
  "flight" text,
  "launch_date_time_utc" text,
  "variant" text,
  "launch_pad" text,
  "payload" text,
  "payload_mass" text
);
SELECT "launch_date_time_utc" FROM "launch_history" WHERE "payload"='gsat-4';