苏联，美国阿婆罗， 中国嫦娥落月器都是用一个大的可调发动机降落。 

这学生说用多个小的，省钱。 

the basic design for Chandrayaan Descent propulsion system was based on a master student thesis from MIT in 2004. "Lunar descent using sequential engine shutdownThe notion of sequential engine shutdown is introduced and its application to lunar descent is motivated. The concept calls for the utilization of multiple fixed thrust engines in place of a single continuously throttleable engine."

印度用的就是这个理念。 不摔就怪了。