What was the altitude of the event on 1962-07-09?
CREATE TABLE "list_of_artificial_radiation_belts" (
  "explosion" text,
  "location" text,
  "date" text,
  "yield_approximate" text,
  "altitude_km" text,
  "nation_of_origin" text
);
SELECT "altitude_km" FROM "list_of_artificial_radiation_belts" WHERE "date"='1962-07-09';