美国航天局准备星期四发射两个无人月球探测器。这次发射距离上次人类登月将近40年。
美国航天局的重力恢复与内部实验室计划，又称“圣杯”号月球探测器将首先环绕月球轨道飞行，然后在月球表面着陆。这次使命将对月球内部从核心到表明的内部构造进行测绘，包括人类从未探索过的月球暗面。
星期二，美国航天局公布了显示美国航天局此前登月任务痕迹的高清照片。有照片显示阿波罗17号释放的月球车在月球表面留下的轮胎痕迹。
美国航天局将在11月发射火星探测器。预计探测器将需要两年时间抵达火星。
The U.S. space agency is preparing for Thursday's launch of two unmanned spacecraft to the moon, nearly forty years after man last walked on the moon.
NASA's Gravity Recovery and Interior Laboratory, or GRAIL, mission spacecraft will orbit the moon before landing on the lunar surface.
The mission will map the moon from its core to its surface, including the far side of the moon which humans have never explored.
Tuesday, NASA released high resolution photographs showing the remnants of the space agency's previous lunar visits. The photos show tire tracks from the Apollo 17 lunar rover.
In November, NASA will launch a spacecraft bound for Mars. The flight to Mars is expected to last two years.