ELI5: Explain Like I'm 5

Boeing X-51

The Boeing X-51 is a special type of experimental aircraft that can go really, really fast! It's a special type of airplane that is made to go super fast and do cool things that other planes can't do.

The X-51 is unique because it doesn't use normal jet engines to fly, but instead it uses something called a scramjet. A scramjet is like a super, duper fast rocket engine that can go much faster than normal planes.

The X-51 was created to test out this new technology and see how fast and efficient it could be. It was made to go so fast that it could reach speeds up to Mach 5, which is over 3,800 mph! That's like traveling from one side of the United States to the other in less than an hour!

Scientists and engineers used a special airplane to launch the X-51 really high up into the sky, and then the X-51 would take over by using its own scramjet engine. It only took a few minutes to reach its top speed before running out of fuel and landing in the ocean.

Even though the X-51 was only used for a short amount of time, it helped scientists gather important information about how scramjet engines work and how fast planes can go. Who knows, maybe one day we'll have passenger planes that can travel at amazing speeds, thanks to the X-51 and other experiments like it!