Secret Space Plane Lands After Two Years in Orbit
This is What's Trending Today....
That is the sound of the United States Air Force's unmanned spacecraft landing at the Kennedy Space Center in Florida over the weekend.
The United States Department of Defense posted a video of the landing on YouTube.
The Air Force's X-37B spacecraft passed over the state of Florida early in the morning Sunday.
It made a different sound then. It created a "sonic boom." That is the noise caused by something traveling faster than the speed of sound – or 1,225 kilometers per hour.
The sonic boom served as a surprising alarm clock for some Floridians. They took to Twitter to express their shock and describe the loud noise.
One person said she thought someone had crashed into her garage.
The X-37B was first used in 2010. Each time it goes on a mission, it stays in space and orbits the Earth many times. In its first mission, it stayed in space for about six months. Its second mission was close to a year, and its third mission was close to two years.
On Sunday, the plane ended its fourth mission about two weeks short of two years.
So, what does the plane do when it is in space?
No one really knows. It is classified. That means only certain military members are permitted to know about its mission.
The Air Force can only publicly say that the plane helps them see how new devices perform while in space for a long time.
The website Space.com reported that the Air Force was happy with the mission. The long trip did not result in any problems.
The Air Force is planning to continue launching and landing the space plane from Florida.
And that's what's Trending Today.
I'm Dan Friedell.
1.result in 导致；结果是
The breakdown of law and order could result in killing on a massive scale.
2.sonic boom 音爆
The new aircraft creates a sonic boom.
3.close to 接近
I was close to tears with frustration, but I held back.
4.unmanned spacecraft 无人驾驶飞机
The unmanned spacecraft carries an infrared telescope.
1.The Air Force's X-37B spacecraft passed over the state of Florida early in the morning Sunday.
pass over 忽略；经过
She claimed she was repeatedly passed over for promotion.
He largely passed over the government's record.
2.One person said she thought someone had crashed into her garage.
crash into 闯入；撞到
She noticed a car crash into a big tree nearby.
I crash into this inexhaustible knowledge sea.
当时飞机发出了一种特殊的声音，它产生了音爆 。音爆是指飞行速度超过声速或超过每小时1225公里所产生的噪音 。
一些佛罗里达州居民被音爆声惊醒 。他们在推特上表示受到惊吓，还描述了这一巨大的噪音 。
2010年，X-37B空天飞机首次投入使用 。每次执行任务时都会在太空绕地球轨道运行多次 。首次执行任务时，它在太空停留了约6个月，第二次任务停留的时间接近一年，第三次任务停留的时间接近两年 。
无人知晓，这是军事机密 。也就说只有指定的军官知悉任务内容 。
Space.com网站报道称，美国空军对这次任务非常满意 。这次长途飞行一切顺利 。