NASA anticipates initiating a full and open competition for the advanced booster system in FY2015 with award anticipated in FY2016 and hardware delivery in the FY2019 timeframe. The 130-metric-ton, evolved SLS is slated for completion following the 2021 test flight.
There are other cost estimates that go as high as $62.5 billion to build and operate SLS through 2015. The $38 billion estimate to 2025 has been criticized as unrealistic. Just a simple projection of maintaining $3 billion per year to 2032 is $63 billion. Given the history of this kind of rocket development costs to 2032 are more likely to be $120-250 billion and there would be delays to 2035-2045.