Viewing page 57 of 172

This transcription has been completed. Contact us with corrections.

The overall schedules to which all workstations must work are determined through the use of standardized templates. These templates model the process from start to finish, including the time required for each workstation to perform its task as well as when each task must start and finish to deliver the end products on time. The template (fig. 12) has undergone some changes in the last several years, but the major reduction in the time allocated to complete the reconfiguration process for a given flight had not been implemented as of STS 51-L. The first flight for which the "reduced" template was to be used was STS 61-M. Therefore, the full effect of the reduced template on the reconfiguration process had not been felt at the time of the accident.

The reduction in the allocated time was one consequence of the reconfiguration process evolution over several years. The evolution was the result of several factors, including the maturity of the STS, which permitted standardization of some products; a programmatic desire to minimize long lead times in flight preparation; new reconfiguration tools; and the consolidation of the reconfiguration process responsibility into one directorate.

b. The Reconfiguration Process Workstations

(1) Reconfiguration Requirements

The reconfiguration requirements ("Recon") workstation translates requirements from the user community in the areas of telemetry, command, and display into flight-unique reconfiguration formats which are usable by the STS. The products from this workstation include the definition of all the Orbiter cathode-ray tube displays to be used for a particular flight, and the definition and format of all downlinked data and uplinked commands.

(2) Flight Design

The flight design workstation translates user community trajectory requirements such as launch/landing/payload deploy window constraints into a comprehensive flight-unique trajectory definition. This definition must accommodate all requirements, vehicle performance constraints, and basic mass properties for the entire vehicle. The products from this workstation include the ascent, orbit, and entry design parameters which are incorporated into the Orbiter flight software and used for onboard navigation and guidance, and the Mission Control Center (MCC) trajectory display requirements which are incorporated into the flight-unique MCC release and used by the flight controllers for monitoring the vehicle trajectory in real time.

-93-