http://www.engineeringchallenges.org/cms/7126/7622.aspx
The central feature of the SLS architecture is that the propulsion hardware and terrain sensors are placed high above the rover during touchdown. As a result, their operation is uninterrupted during the entire landing sequence. One important result of this feature is that the velocity control of the whole system is improved, and, therefore, the rover touches down at lower velocity. Thus, there is no last-meter free fall associated with engine cutoff, and, because dust kick-up is minimal, the radar antennas can continue to operate even while the rover is being set down on the surface.
... asi tak nějak - možná najdete lepší popis celého problému - a omlouvám se za překlepy