COTS Content in a Critical Manned Space Application

Todd Smithgall

United Space Alliance, LLC
Houston, TX

Abstract

The Space Shuttle cockpit has recently been upgraded from four monochromatic CRTs and mechanical instruments to 11 modern, color, flat-panel electronic displays. The completed upgrade improves the reliability and visibility of the cockpit display system, but does not directly improve the functionality of the man-machine interface.

The Cockpit Avionics Upgrade (CAU) project makes essential improvements to both the Command (human input) and Display (information output) functions, providing the Space Shuttle with a new and superior user interface. Advantages include improved crew situational awareness as well as greatly streamlined cockpit task execution. Questions such as "Where am I?", "Where am I going?", "What is the condition of the vehicle?", and "What action do I need to take?" are answered quickly and concisely without significant procedural or mental effort. The result is that the Space Shuttle crew can make real-time decisions and take required action much more quickly and more confidently as compared to the older CRT system. Dependency on ground control calls is greatly reduced. Human capacity is reserved for high-level mission- and flight-critical decision making, rather than expended on low-level data collection and integration tasks.

Commercial Off-the-Shelf (COTS) technology is applied where appropriate, after first being qualified for the space environment. COTS technology is not a panacea, and deployment must be undertaken with extreme attention to design detail and environmental factors. For CAU, the COTS technology appears only at the component level, and then only after each component type has been evaluated against traditional MIL / Space screens. Further, all components are controlled by lot and date code. All lots are subjected to destructive physical analysis. All individual components are subjected to dynamic functional test before entering the hardware production flow. Certain components have been rejected on these grounds, while others have been repackaged, both with associated design impacts. Obviously, these steps do not define a low-cost parts program. Rather, COTS technology is being employed in CAU as necessary to meet key performance and functionality goals, within the larger constraints of existing Shuttle thermal and power budgets, hardware footprint, and system uptime requirements.

Likewise, the top-level system must be made perfectly safe against spurious or erroneous outputs (characterized as Data Pollution), not only during normal operation, but during power-up, power-down, power-transient and general hardware and software failure conditions. While CAU is a command and display system, not directly engaged in Space Shuttle flight control, it does directly interface to the legacy flight control & systems control General Purpose Computers (GPCs). Since the Space Shuttle is a 100% fly-by-wire vehicle, upsetting these GPCs through some improperly controlled CAU interface is unacceptable.

The CAU man-machine interface design and COTS technology adaptation not only directly improve Space Shuttle safety, but also demonstrate new capabilities required for more autonomous manned deep-space and interplanetary manned missions of the future.

 

2004 MAPLD International Conference Home Page