"NASA spokesmen Dwayne Brown and Dave Steitz confirmed via email that NASA terminated the agreement with B612. Steitz explained that B612 had not met an important milestone in the SAA -- starting Sentinel's development -- and NASA therefore terminated the agreement because "due to limited resources, NASA can no longer afford to reserve funds" to support the project. "NASA believes it is in the best interest of both parties to terminate this agreement but remains open to future opportunities to collaborate with the B612 Foundation," he added."
Keith's note: This certainly sucks. Odd that NASA gave up this easily. Curiously NASA is promoting a #JourneyToMars program with a fantasy budget and rockets whose launch dates slip year after year. But wait: B612 was going to pay for the spacecraft. NASA only had to use it.
If you read the actual Space Act Agreement between NASA and B612 these two articles pretty much rive everything else:
"ARTICLE 3. GATES Four Gates are identified that constitute milestones in the determination of the benefit to NASA from the Sentinel Mission. In the event that the Sentinel Mission does not fulfill a Gate, NASA will assess the impact thereof to the NASA benefit from the Sentinel Mission to determine whether or not to proceed with this Agreement. Any follow-on agreements or modifications agreed to by the Parties in the course of implementing the Sentinel Mission as described herein shall be fully incorporated in this Agreement and shall constitute a modification of this Agreement in Accordance with ARTICLE 24 Modifications.
ARTICLE 6. FINANCIAL OBLIGATIONS There will be no transfer of funds between the Parties under this Agreement and each Party will fund its own participation. All activities under or pursuant to this Agreement are subject to the availability of funds, and no provision of this Agreement shall be interpreted to require obligation or payment of funds in violation of the Anti-Deficiency Act,(31 U.S.C. § 1341)."
So B612 pays for, builds, launches, and operates Sentinel - and all NASA needs to do is provides the things needed to use it, collect data etc. NASA can walk away from this agreement at any time and B612 does not get a penny from NASA. I can tell you that there are others (i.e. traditional space mission vendors like APL, JPL, etc.) who tell people that they'd be building a spacecraft like Sentinel (but paid for by NASA) if it were not for the fact that NASA keeps saying "No, no we'll just use Sentinel".