Question: Where was the landing site when the duration on the lunar surface was 21:31?
SQL: SELECT "Lunar landing site" FROM "2-1558077-8" WHERE "Duration on lunar surface" = '21:31';

Question: Who were the crew for the Falcon?
SQL: SELECT "Crew" FROM "2-1558077-8" WHERE "Lunar lander" = 'Falcon';

Question: What is the average number of EVA for the Orion?
SQL: SELECT AVG("Number of s EVA") FROM "2-1558077-8" WHERE "Lunar lander" = 'Orion';