"The deterioration in portfolio performance was the result of nine [out] of the 17 projects in development experiencing cost or schedule growth," a press release summarizing the report stated.
NASA expects cost growth for the Orion crew capsule, which is being built to carry astronauts to Mars, but does not have a current cost estimate, the release said.
The Space Launch System, a giant rocket being built to carry the Orion into deep space, has been subject of aggressive schedules with insufficient funding and allowances for delays, the release noted.
In addition, the James Webb space telescope is encountering delays because the integration of various spacecraft elements taking is longer than expected, the release said.
The average launch delay for the entire NASA portfolio of major projects was 12 months, the highest delay GAO has reported in its ten years of assessing major NASA projects, the release concluded.