Before revision: In 1975, the X-24B aircraft was dropped from a Balls 8 at an altitude of 45,000 feet above the Mojave Desert, and then ignited rocket engines to increase speed and propel it to 60,000 feet .
After revision: In 1975, the X-24B aircraft was dropped from a Balls 8 at an altitude of above the Mojave Desert, and then ignited rocket engines to increase speed and propel it to .