"In August 2014, NASA completed the review of the SLS program that sets formal cost and schedule baselines and, in doing so, delayed the first test flight to relieve schedule pressure and allow additional time to address design challenges. However, some of the concerns we raised about the cost estimates, mission requirements, and long-term affordability remain. In addition, our ongoing work has found that the three human exploration programs are pursuing inconsistent and unrealistic schedule goals and that the Orion program is facing significant technical and funding issues that may affect NASA's overall schedule for its human exploration programs."
After historic Orion flight, NASA still faces challenges, GAO says, Washington Post
"It took us less than a decade not only to go around the moon but to land on the moon under Apollo," said Rep. Mo Brooks (R-Ala.). Rep. Dana Rohrabacher (R-Calif.) said it could cost at least $10 billion to develop "this monstrous rocket project." Even then, he said, it "won't have a real mission until we go to Mars, which could be two decades or three decades from now, depending on if we can ever get over the technological hurdles we haven't gotten over yet."
At the hearing, Rep. Donna Edwards (D-Md.) asked how much funding would be required to bring the first SLS/Orion mission, called Exploration Mission 1 (EM-1), back to December 2017. "In terms of the technical work, I think we've really probably moved off of December 2017," Gerstenmaier responded, "so I don't think funding will pull us back to that date."