
NASA chief: Apollo engineers who criticize SLS don't grok modern rocketry, Ars Technica
"Although the SLS rocket does indeed use modern manufacturing processes and sophisticated computer simulations, it is in many ways based on technology from the 1970s. For its initial boost, the SLS will use solid-rocket boosters based on those that performed the same function for the shuttle. The rocket will be powered by four space shuttle main engines, which NASA began developing as far back as 1969. Bolden then reiterated that Kraft knew more than him about rockets, but he again qualified this praise: "I have the advantage of a team around me that he didn't have," he said. "You have to remember. Most of us forget. I have a very mature leadership team. When Dr. Kraft was in mission control, and when he led the Johnson Space Center, we went to the Moon. Most of the people were 20 years old. They didn't know anything."
Bolden asked about Chris Kraft quote that "SLS operating expenses will eat NASA alive". Asked why existing launchers can't be used
— NASA Watch (@NASAWatch) March 15, 2016