Bridging the gap between human and automated procedure execution

Procedures are a fundamental product used by NASA flight controllers and crew to operate space systems. Procedures are often complex and repetitive, taking operators hours to perform. Standard practice today is to manually create scripts to automate procedures. This process is laborious, error-prone, and inflexible. NASA's Exploration Technology Development Project (ETDP) is investing in advanced technology designed to improve operations for the Constellation Program, which oversees the creation of the next generation of human spaceflight vehicles. Under this project, NASA has developed technology for creating human-readable procedures, as well as for automating the execution of these procedures in a way that permits the crew to maintain a fine degree of control over the level and extent of the automation. The Procedure Representation Language (PRL) is a language for specifying spacecraft procedures, primarily for display to humans who are responsible for all commanding and decision-making. The Plan Execution Interchange Language (PLEXIL) represents plans for automatic execution, and has been demonstrated on applications ranging from planetary analog drills and surface robots to rotorcraft control. We describe the automated translation from PRL to PLEXIL and how the result provides an effective means to execute procedures under the desired level of automation. We highlight the resulting capability using examples derived from the International Space Station.