Small satellites shouldn't add to the problem of space debris since they are relatively easy to deorbit.
小卫星相比较而言容易脱轨，但也不应该增加空间碎片问题。
2
To keep people on the ground safe, it's best to deorbit a spacecraft with a strong burn of propellant, to slow it down at the right time.
为确保地面上人的安全，最好的方法是以一个强大的推进器燃烧来使宇宙飞船脱轨，在正确的时间使其慢下来。
3
It's evaluated for every area I and every chunk from a given spacecraft. If the sum total exceeds.0001-i.e., a 1 in 10,000 chance of a single casualty-that craft requires a controlled deorbit.