He was a good student and went to college when he was just 15 years old.
VOA: special.2009.01.16
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
One of them,the Apollo-11, traveled to the moon just seven months after the last X-15 flight.
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
When he is clear of the B-52, he starts the X-15's rocket engine.
VOA: special.2010.07.07
From under the plane's right wing, the black sharp-nosed X-15 drops free.
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
应用推荐