NASA could miss an important deadline for a test launch of its Space Launch System (SLS) because it is not on path to reach a December 2017 test flight at the required confidence level of 70 percent, a key performance metric, according the Government Accountability Office (GAO).
GAO said Wednesday in a report (GAO-14-631) NASA has not established an executable business case that matches the SLS program’s cost and schedule resources, which GAO calls a best practice for establishing a successful acquisition program. NASA uses a calculation known as “joint cost and schedule confidence level” to estimate the probable success of a program meeting its cost and schedule targets, GAO said.
NASA policy usually requires a 70 percent confidence level, GAO said, for a program to proceed with final design and fabrication. GAO said its work on best practices has shown that programs that do not establish an executable business case that matches requirements or customer needs to resources, such as schedule and funding, are at increased risk of schedule and cost growth. Any confidence level approved by the decision authority at less than 70 percent must be justified or documented.
GAO said SLS is on target to achieve goals for design drawing release and mass and is expected to meet necessary documentation requirements for its critical design review (CDR). However, GAO said the development schedule of the core stage, which drives the overall program schedule, is aggressive and substantial amounts of schedule that the program reserved to resolve unanticipated issues is already threatened.
GAO also noted, according the program’s risk analysis, NASA’s funding plan for SLS may be $400 million short of what the program needs to launch by 2017. If the agency determines the current funding plan for SLS is insufficient to match requirements to resources for the 2017 flight test at the 70 percent confidence level, NASA’s options for matching requirements to resources are largely limited to increasing program funding, delaying the schedule or accepting a reduced confidence level for the initial flight test. Increasing program funding or delaying the schedule could have “dramatic effects” on other programs as SLS makes up about nine percent of NASA’s annual budget, according to GAO.
NASA told GAO it understands the recommendation of developing an executable business case based on matching requirements and resources to reach 70 percent confidence and concurs with its intent. The agency said plans are in place to adjust schedule and minimize costs if either funding levels decrease or technical problems arise as delaying SLS development schedule or diverting funding from other priorities to satisfy a confidence level could jeopardize these goals and result in increased costs.
NASA engineers on July 17 installed an RS-25 engine on a test stand at the agency’s Stennis Space Center in Mississippi, a step NASA says is crucial toward preparing to test parts of SLS. Engineers at Stennis will perform developmental and flight certification testing of the RS-25, four of which will power the SLS core stage. RS-25 is a modified version of the space shuttle main engine that powered missions into space from 1981 to 2011.
SLS is NASA’s advanced, heavy lift launch vehicle intended for deep space exploration to destinations including an asteroid and Mars. SLS will carry the Orion multi-purpose crew vehicle as well as important cargo, equipment and science experiments. Orion is scheduled to carry up to four astronauts beyond low earth orbit (LEO) on long-duration, deep space mission and include both crew and service modules and a launch abort system to significantly increase crew safety.