英语听力：自然百科 行星旅行指南：火星 Mars—10

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I can just picture being there in a vehicle this type and looking back at earth in the distance and deciding to go AVA and BM boots on the surface in 10 minutes with which just being a remarkable¹ breakthrough. 

 

Astronauts can cover more ground by living in the vehicle for weeks at a time. Stepping outside when they want to and back inside at the first sign of danger. Mars does not have a powerful magnetic field the way earth does. So there is radiation from the sun, also cosmic rays that are gonna penetrate² through space suits.  

 

An astronaut might get a 30 minute warning of an incoming solar storm. But less predictable is the risk of being hit by a meteorite³. Recent estimates based on fresh equator counts suggests that up to 200 new holes are blasted into the surface of Mars each year, and even the Martian moons are not guaranteed to stay in place. The days of Phobos are numbered. Possibly in asteroid⁴ that once stray too close, the moon is trapped in a gravitational embrace. Every passing century sees a drop of 6 feet closer to death. In about 50 million years, its fall is expected to be complete. 

 

The aftermath if anyone is around to see it, could be Mars with a bright ring of moon dust to rival Saturn’s.  But events like this are not your real danger; it’s the day to day exposure to the cold, dry Martian environment that will make a long stay tricky⁵.

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