But NASA engineers do not know enough about how the two bits of material on Discovery could affect thermal and aerodynamic forces as the vehicle plunges at 22 times the speed of sound through the atmosphere on re-entry.
But NASA engineers do not know enough about how the two bits of material on Discovery could affect thermal and aerodynamic forces as the vehicle plunges at 22 times the speed of sound through the atmosphere on re-entry.
不过，美国宇航局的工程师们还不能确定，当“发现”号航天飞机以22倍于音速的速度再次经过地球大气层时，机身上的这两块材料会在热量和空气动力方面产生怎样的影响。