A spokesman for SpaceX, John Taylor, said the company already has a plan in place to fix the potential cracking issue. "We have qualified our engines to be robust to turbine wheel cracks," Taylor said. "However, we are modifying the design to avoid them altogether. This will be part of the final design iteration on Falcon 9." This final variant of the Falcon 9 booster, named Block 5, is being designed for optimal safety and easier return for potential reuse. According to company founder Elon Musk, it could fly by the end of this year.
The new report also cites other problems with the commercial crew development efforts by SpaceX and Boeing. The latter company, for example, may be having difficulty with ensuring the reliability of its parachute systems to bring crews safely back to a land-based landing.
Spacex and Boeing are struggling to meet NASA's mission requirement for a loss-of-crew probability of 1-in-270. NASA has previously acknowledged this issue, citing the challenge of dealing with micrometeoroid and orbital debris