CREATE TABLE table_37866 ("orbit" TEXT, "center-to-center distance" TEXT, "altitude above the Earth's surface" TEXT, "Orbital period" TEXT, "specific orbital energy" TEXT)

specific orbital energy of 0.5 mj/kg is what altitude above the earth's surface?
SELECT "altitude above the Earth's surface" FROM table_37866 WHERE "specific orbital energy" = '−0.5 mj/kg'
SELECT "altitude above the Earth's surface" FROM "table_37866" WHERE "specific orbital energy" = '−0.5 mj/kg'