The X-15 was a NASA experimental rocket powered aircraft (launched from a parent B-52) that could reach the Karman line. Questions should be related to its upper atmosphere operations. Questions about its function as an aircraft should be asked on Aviation.SE
The X-15 was an experimental aircraft operated by NASA that set numerous speed and altitude records, including two that exceeded the Karman line (100km). This project, and other similar experimental planes like it, is why the Air Force set its astronaut badge at 50 miles(80km).
The X-15 required a modified B-52 to carry it to 13.7km for release, at which point it would ignite its rocket engine.
Questions should be related to its operations as a virtual spacecraft near the Karman line. Questions about all other aircraft operations (including its carrier B-52s) should be asked on Avation.SE