From VCL to Glory: the risk management approach to changing an existing spacecraft configuration

The Glory satellite program is underway at the Orbital Sciences campus in northern Virginia under contract with NASA GSFC. The Glory satellite bus was previously known as the vegetation canopy LIDAR (VCL), a satellite designed to measure the Earth's vegetation coverage, depth, and topography. The Glory program is using this existing NASA asset from the VCL program, which was terminated while the bus was in integration and test (I&T) due to instrument problems. The bus is being revamped for the Glory Science mission, which includes atmospheric aerosol measurements and total solar irradiance monitoring. There are many changes being made to the VCL bus to configure it for the Glory program objectives. The risk management and safety approach to Glory requires extra effort to not only analyze the current work, but all work done in the past under the VCL program. This includes extensive audits of the VCL program hardware and software to ensure safety and compliance with the Glory mission and safety requirements. Risk management is an integral part of any program in order to achieve mission success. In this program, it has special application not only for current program work, but past work as it pertains to the current requirements. To date the Glory team has expended considerable effort in a full component and documentation audit for the VCL program, uncovering situations requiring unique handling for a safe and reliable program. This paper describes the process of risk management in application to the current program that relies on work performed on a previous program. This includes mitigation approaches to newly raised issues and past issues that may have gone unresolved at the close of the VCL program. Using this approach of risk management and lessons learned, the story is told of how an existing bus may be reused while considering the balance of risk and cost and maximizing use of existing hardware.