What explosion had an altitude of 539 km?
CREATE TABLE table_148578_1 (explosion VARCHAR, altitude__km_ VARCHAR)
SELECT explosion FROM table_148578_1 WHERE altitude__km_ = "539"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_148578_1 (explosion VARCHAR, altitude__km_ VARCHAR) Question: What explosion had an altitude of 539 km? [/INST] SELECT explosion FROM table_148578_1 WHERE altitude__km_ = "539" </s>