An automated flight safety decision process enables a flight vehicle itself to make real-time decisions on if/when/where/how to safely abort a mission or terminate the flight. It can serve as an advisor to mission flight control and the flight crew, a backup in case of a breakdown in communications or other elements of the infrastructure, and a fully autonomous onboard capability that is insensitive to any potential infrastructure breakdown.

The feasibility of automating the flight safety decision process was verified with the successful completion of AFSS Phase I (see Research and Technology 2000/2001 Report for details). Wallops Flight Facility (WFF) is providing funding for Phase II of AFSS under a Defense Micro-Electronics Agency (DMEA) contract. WFF and KSC are jointly managing Phase II in order to leverage work completed on Phase I and provide synergism to obtain a prototype AFSS.

The representative Expendable Launch Vehicle (ELV) mission chosen for this phase of AFSS is the Kodiak Star Athena I. The mission rules identified in the flight safety plan for this mission are representative of the rules for other classes of ELV’s.

Phase II is broken into two primary components. The first one is software development and the subsequent verification and demonstration of the software. Lockheed Martin in Huntsville, Alabama, is performing this under the DMEA contract. The configuration for performing this task is shown in figure 1.

The objective of testing the AFSS software is to verify and demonstrate that it works as designed and implements flight termination limits properly. The software emulation of the human-in-the-loop system performance will also be verified at this stage. Once this is accomplished successfully, then the incorporation of the software into a flight computer will proceed. Figure 2 shows the configuration to be utilized in the laboratory for verifying the software will perform satisfactorily on a flight computer.

The AFSS Flight Computer Configuration is partitioned into 3 sections:

1. Global Positioning System (GPS) Section: This includes two GPS units, a GPS constellation simulator, trajectory simulation files for driving the constellation simulator, and a capability for simulating anomalous trajectories on one or both GPS data streams.
2. Flight Computer Section: This includes the flight prototype computer with operating system (OS) software, any support computer and software needed for configuring the flight computer OS for AFSS and for compiling and loading the AFSS software and limits data onto the flight computer, along with compatible interface ports.
3. AFSS Development Support Equipment (DSE) Section: This includes the computer on which the AFSS algorithms are developed and coded, the software for the real-time AFSS graphic display, and the AFSS algorithm code and limits data to be supplied to the flight computer support computer.

All elements verified in the software development configuration will be rechecked to ensure operational capability on the flight computer. In addition, a valuation of effectiveness and responsiveness will be performed at this time.

The AFSS concept for range safety offers many advantages. It provides global coverage and supports both the ascent and return-to-Earth flight phases. It improves safety by ensuring a comprehensive decision process predicated upon complete knowledge of the vehicle state and abort capabilities. Furthermore, it improves safety and reduces operations cost by eliminating dependence on radar and other dedicated assets.

Contacts: B.A. Ferrell (Bobby.Ferrell@ksc.nasa.gov), YA-D7, (321) 867-6678; and Dr. J.C. Simpson, YA-D7, (321) 867-6937
Participating Organizations: Wallops Flight Facility (J. Hickman, W. Powell, M. Patterson, J. Lanzi, and B. Bull), Lockheed Martin (S. Haley), and YA-D2 (S.A. Santuro)