美国发射4颗卫星研究神秘磁重联现象

美国东部时间3月12日22时44分，一枚火箭搭载4颗卫星从佛罗里达的Cape Canaveral Air Force Base（卡纳维拉尔角空军基地）发射升空。这4颗卫星将组成金字塔状编队飞行，用于研究磁重联现象。磁重联是科学家迄今知之甚少的神秘领域之一。

美国国家航空航天局（NASA）这项"磁层多尺度"（Magnetospheric Multiscale，MMS）任务耗资11亿美元，由4颗直径11英尺（约3.3米）、高4英尺（约1.2米）的八角形小卫星组成。据介绍，每个MMS天文台设有25个传感器，其对磁相互作用数据的采集速度比任何先前的任务提高了100倍，足以在磁重联事件发生时进行观察和探测。

NASA研究人员指出，磁重联通常伴随着巨大的能量释放。磁重联被认为是太阳耀斑等活动的成因，磁重联密切影响着空间气候。这些强烈爆发产生的某些物质可能会使得人造卫星受到破坏，导致地球上的输电网络和通信网络出现异常。

科学家们认为，对磁重联更好的认识能促进生产更好更清洁的能源，因为磁约束是实现可控聚变反应堆的主流方案之一。

英文原文：

Launch Begins MMS Mission in Spectacular Fashion

Four octagonal disc-shaped spacecraft are flying in a loose formation above Earth following a brilliant, thundering launch from Florida that lit up the Cape Canaveral region for miles late Thursday night. The spacecraft make up the Magnetospheric MultiScale mission which is set to decipher interactions within magnetic fields that cause tremendous amounts of energy to be released when the fields reconnect.

A United Launch Alliance Atlas V lifted the four spacecraft into orbit with the help of solid-fueled boosters that joined with the RD-180 main engine on the first stage to produce 1.5 million pounds of thrust at liftoff. The four spacecraft deployed separately beginning about an hour-and-a-half after the 10:44 p.m. EDT liftoff. It took about 15 minutes to deploy all four, each flying free five minutes after the previous one.

"It was a picture-perfect launch and the flight went well and everyone's cheering," said Omar Baez, NASA launch director for MMS. "You can't ask for anything more. This was a really hard mission to put together and the team really made it look easy, but it's not."

The four spacecraft will fly in a pyramid formation through space to take unprecedented measurements of magnetic reconnection phenomenon as it occurs in different areas of Earth's magnetosphere. The spacecraft will fly the first phase of the mission in an elliptical orbit of 1,600 miles above Earth to reach out more than 43,000 miles from the planet. After a year-and-a-half in that orbit, the MMS formation will take its orbit out to 95,000 miles, almost halfway to the moon.

"This evening unfolded essentially perfectly for us," said Craig Tooley, program manager for MMS. "As we separated them in turn, we talked to them and they are all healthy and we're headed into our mission."

Researchers theorize that the principles of magnetic reconnection and the energy release they generate are a significant force throughout the universe including the acceleration of ultra-high-energy cosmic rays. Reconnection is also thought to be a factor in solar flares and other conditions of space weather that can disrupt satellite electronics above Earth and some devices on the planet.

"Everything to do with space weather starts with reconnection," said Jim Burch, principal investigator for MMS from Southwest Research Institute. "The MMS mission will conduct a definitive experiment in space that will finally allow us to understand how magnetic reconnection works. A fundamental question is why and how does magnetic reconnection take place. With MMS we will be able to study the region where