The X-15 was a hypersonic aircraft. It was part of the experimental project of x conducted by NASA with the U.S air force, Navy and North American Aviation. The X-15 set world records for speed and altitude. It went 4,250 mph and 354,200 feet high to investigate all aspects of hypersonic flight. These flights, which were conducted from 1959 to 1968, gained information that contributed to the development of Mercury, Gemini and Apollo piloted space flight programs like the space shuttle program.
There were three X-15s (manufactured by North American Aviation) which flew 199 flights. Scott Crossfield was the first person to fly the X-15 on June 8th 1959. Later on October 24th,1969 William H. Dana was the pilot who made the last flight of the X-15. All the X-15s had an XLR-11 engine, but the X-15 to had an XLR 99 Engine with the thrust of 57000 pounds. Pete Knight from the Air Force set the world record.
The X-15 had a wingspan of 22 ft and consumed large amounts of fuel, so it needed to be launched from a B-52 aircraft at a height of 45000 ft. On the 15th of November Captain Michael Adams was launched in the X-15 3 which featured in adaptive control panel. An electrical disturbance distracted him and slightly degraded the control of the aircraft. Then Adams took the plane to 266,000 feet. At 230000 ft, encountering rapidly dynamic pressures, the X-15 entered Mach 5 spin. After some basic aerodynamic stability the plane recovered and was in a dive at Mach 4.7. It broke up into pieces and hit Johannesburg. And this sadly was the reason they stopped the X-15 flights.
There have been many fast planes but none as fast as the X-15. Since the X-15 flies so fast the aerodynamic heating is very high. This means the plane could burn up if not made with the right materials. Space shuttles use ceramic tiles to keep it safe from the atmosphere during re-entry. But, ceramic tiles are heavy. Weight is one of the main things that affect speed. The X-15 is also rocket powered, which makes it heavier. There is a air breathing engine called the scram jet. But the problem is that it can’t start on it’s own. Some aircrafts(like the X-430) need to be launched from a high altitude and need a lot assistance.
These are the technical difficulties the X-15 faced. But there were many more different reasons. NASA needed billions of dollars to buy a rocket engine or make new spaceships. The government has stopped paying NASA for the space travel. They think that money should be used on other stuff because of this NASA cannot build more X-15s or space shuttles.