Question: What was the altitude of the explosion Hardtack Teak?
SQL: SELECT "Altitude (km)" FROM "1-148578-1" WHERE "Explosion" = 'Hardtack Teak';

Question: What was the altitude of the event on 1962-07-09?
SQL: SELECT "Altitude (km)" FROM "1-148578-1" WHERE "Date" = '1962-07-09';

Question: What was the altitude of the yield of 1.4 megatons?
SQL: SELECT "Altitude (km)" FROM "1-148578-1" WHERE "Yield (approximate)" = '1.4 megatons';

Question: What was the yield of the K-4 explosion?
SQL: SELECT "Yield (approximate)" FROM "1-148578-1" WHERE "Explosion" = 'K-4';

Question: What explosion had an altitude of 539 km?
SQL: SELECT "Explosion" FROM "1-148578-1" WHERE "Altitude (km)" = '539';