 O'Keefe's replacement, Michael D. Griffin, took just two months after his appointment to announce that he disagreed with O'Keefe's decision, and would consider sending a shuttle to repair Hubble.As an engineer, Griffin had previously worked on Hubble's construction, and respected the discoveries the telescope brought to the science community.He agreed with the National Academy of Sciences that a robotic mission was not feasible, and said that in light of the "Return to Flight" changes made following the "Columbia" accident, a shuttle mission to repair Hubble should be reassessed.