Risk reduction - pretty well explained above. Experimentation - Standard definition. Trying out stuff. Concept-of-operations development - take the experiments and turn them into instructions and procedures for normal operations. Think of it as production compared to experimentation being dev. (concept of operations is a standard document describing the 'how' of something, typically in a tech-agnostic way)

Basically they are using this vehicle to figure out how to do this stuff with future vehicles in a scaled-up way.