Space X is a great program and I'm all for it. But I'm concerned that when NASA outsources its systems and vehicles to THAT extent, it will only exist as a feeble shadow of its former self and will accordingly shift an excess of its responsibility, accountability, and liability to said contractors.
One significant difference is that DOD does not design ships, aircraft or vehicles. They lay out the specifications and the companies competing for the contract submit their designs.
NASA took a different course with the Shuttle Program. NASA engineers design the systems and then let contracts for the parts.
When Challenger exploded, NASA may have been able to point to Thiokol for its faulty O-rings, but NASA was itself ultimately responsible for astronaut safety and mission completion.
NASA got equal blame on that O-ring failure as the manufacturer. From the Senate investigation:
We also agree that the failure of the joint was due to a faulty design, and that neither NASA nor Thiokol fully understood the operation of the joint prior to the accident. Further, the joint test and certification programs were inadequate, and neither NASA nor Thiokol responded adequately to available warning signs that the joint design was defective.
The investigation also found that :
the Committee confirms that the safety, reliability, and quality assurance programs within
NASA were grossly inadequate, but in addition recommends that NASA review its risk management activities to define a complete risk management program.
The second part is a huge blackeye for NASA. They were called unsafe for the Senate!!
The War College did a case study on the Challenger mishap to demonstrate the danger of group think when decisions are made.