After a few seconds, when the X-15 was safely away, the pilot started its rocket engine.

VOA: special.2010.07.07

The X-15 was the first major investment by the United States in manned space flight technology.

VOA: special.2010.07.07

In the memorial, there is the X-1, the first airplane to fly faster than sound.

VOA: special.2010.07.07

The first proposal for this new research vehicle, the X-15, was made in nineteen fifty-four.

VOA: special.2010.07.07

They felt the X-15 could have continued to provide new information about aviation and space.

VOA: special.2010.07.07

But the story began in the nineteen forties with the X series of experimental aircraft.

VOA: special.2010.07.07

When he is clear of the B-52, he starts the X-15's rocket engine.

VOA: special.2010.07.07

The only tragedy connected with the X-15 program happened in nineteen sixty-seven.

VOA: special.2010.07.07

The X-15 flies high over the sandy wasteland of California's Mojave Desert.

VOA: special.2010.07.07

Then the X-15 pushes over the top of its flight path.

VOA: special.2010.07.07

A few became astronauts. The X-15 program lasted about ten years.

VOA: special.2010.07.07

Today,the X-15 hangs in the Air and Space Museum in Washington,D.C.

VOA: special.2010.07.07

The X-15 set height and speed records greater than those expected.

VOA: special.2010.07.07

At about fifteen thousand meters, the B-52 released the X-15.

VOA: special.2010.07.07