Comment Competition to the rescue. (Score 1) 65
Need a prize approach in a set of objectives are listed and variable-level prize rewarded based on ranking. Get it done first, and you get $$$, with second getting $. Finally, upon successful return of Up to 1/2 of the samples, they get $ 3B/1B. Finally, limit this to 2-3 groups register for this.
With this approach, it will likely have SX and BO as entities, but it may also produce a 3rd group. This way, a great deal of infrastructure gets quickly developed and will be reused later for Martian/lunar/asteroids missions.