When talking about spaceflight launch vehicles used by NASA, it is frequently pointed out how the older style "cost plus" contract model let vendors take advantage of US taxpayers by delivering subpar final solutions with astronomically high costs, all while guaranteeing a healthy profit for the vendor. Vendors deserve lots of the blame, but not all of it, and here we see why:
“We don’t have a lot of opportunities to force specific design changes beyond what they had originally proposed,” he said. “There are very few opportunities for us to essentially force them to provide the telemetry and instrumentation that we may want to have.”
This NASA official wants something from the vendor that was not agreed to when the vendor and NASA signed the contract. He wants to force the vendor to do it anyway (implicitly also wants it for free). However, this isn't a "cost plus" contract. Instead its a fixed service contract where the vendor will provide the outcome contracted (in this case landing astronauts on the moon), but the vendor has the freedom to design and deliver the method to reach that outcome themselves irrespective of NASA's late add-on desires.
That was particularly true for the HLS contracts, he said, where cryogenic fluid management is a means to an end, transporting astronauts to and from the lunar surface using a services contract. “The service is to deliver crew to the moon. It’s not to deliver a cryogenic fluid management system that we can validate,” he said.
We've seen vendors feet held to the fire to deliver on these fixed bid contract for spaceflight, and now we see how its keeping NASA from being a bad actor too.