What Time elapsed has both the Launched of 15 October 1997 and the Closest approach of 24 June 1999?
CREATE TABLE "1990s" (
  "spacecraft" text,
  "destination" text,
  "launched" text,
  "closest_approach" text,
  "time_elapsed" text
);
SELECT "time_elapsed" FROM "1990s" WHERE "launched"='15 october 1997' AND "closest_approach"='24 june 1999';