What potential complications might the robot encounter on an asteroid?

We will perform a slow-motion (10 cm/s) touch-and-go maneuver to grab a sample of Bennu. We will then open a bottle of high-pressure nitrogen gas to agitate the regolith and collect it in a large air filter. We worry about sending too much material up towards the spacecraft, potentially coating our optical surfaces with dust and damaging important components. We have learned that in order to model this process we will have to invent some new physics to describe an expanding gas in a micro-gravity environment interacting with regolith grains. Our results to date suggest that all the equipment necessary for the return journey home is safe. We may add a protective cover to one of the lidar (laser ranging) instruments to protect it from damage – in case a second attempt is needed.