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Autonomous vehicles (AVs) have already driven millions of miles on public roads, but even the simplest scenarios have not been certified for safety. Current methodologies for the verification of AV’s decision and control systems attempt to divorce the lower level, short-term trajectory planning and trajectory tracking functions from the behavioral rules-based framework that governs mid-term actions. Such analysis is typically predicated on the discretization of the state space and has several limitations. First, it requires that a conservative buffer be added around obstacles such that many feasible plans are classified as unsafe. Second, the discretized controllers modeled in this analysis require several refinement steps before being implementable on an actual AV, and typically do not allow the specification of comfort-related properties on the trajectories. Consumer-ready AVs use motion planning algorithms that generate smooth trajectories.

Automobiles are becoming ever more complex as advanced safety features are integrated into the vehicle platform. As the pace of integration and complexity of new features rises, it is becoming increasingly difficult for system engineers to assess the impact of new additions on vehicle safety and performance. In response to this challenge, a new approach for analyzing multiple control systems as an extension to the Systems Theoretic Process Analysis (STPA) framework has been developed. The new approach meets the growing need of system engineers to analyze integrated control systems, that may or may not have been developed in a coordinated manner, and assess them for safety and performance. The new approach identifies unsafe combinations of control actions, from one or more control systems, that could lead to an accident. For example, independent controllers for Auto Hold, Engine Idle Stop, and Adaptive Cruise Control may interfere with each other in certain situations.

This paper reports on the Thermal Control System (TCS) of the AMS-02 (Alpha Magnetic Spectrometer). AMS-02 will be installed on the International Space Station (ISS) Starboard segment of the Truss in 2005, where it will acquire data for at least three years. The AMS-02 payload has a mass of about 6700 kg, a power budget of 2kW and consists of 5 different instruments, with their associated electronic equipment. Analytical integration of the AMS-02 thermal mathematical model is described in the paper, together with the main thermal design features. Stringent temperature stability requirements have been satisfied, providing a stable thermal environment that allows for easier calibration of the detectors. The overall thermal design uses a combination of standard and innovative concepts to fit specific instruments needs.

This paper details the analysis and design of the Temporary Sleep Station (TeSS) environmental control system for International Space Station (ISS). The TeSS will provide crewmembers with a private and personal space, to accommodate sleeping, donning and doffing of clothing, personal communication and performance of recreational activities. The need for privacy to accommodate these activities requires adequate ventilation inside the TeSS. This study considers whether temperature, carbon dioxide, and humidity remain within crew comfort and safety levels for various expected operating scenarios. Evaluation of these scenarios required the use and integration of various simulation codes. An approach was adapted for this study, whereby results from a particular code were integrated with other codes when necessary.

Engineers at the Johnson Space Center (JSC) are using innovative strategies to design the TCS for the Bio-regenerative Planetary Life Support Systems Test Complex (BIO-Plex), a regenerative advanced life support system ground test bed. This paper provides a current description of the BIO-Plex TCS design, testing objectives, analyses, descriptions of the TCS test articles expected to be tested in the BIO-Plex, and forward work regarding TCS. The TCS has been divided into some subsystems identified as permanent “infrastructure” for the BIO-Plex and others that are “test articles” that may change from one test to the next. The infrastructure subsystems are the Heating, Ventilation and Air-Conditioning (HVAC), the Crew Chambers Internal Thermal Control Subsystem (CC ITCS), the Biomass Production Chamber Internal Thermal Control Subsystem (BPC ITCS), the Waste Heat Distribution Subsystem (WHDS) and the External Thermal Control Subsystem (ETCS).

A SINDA/FLUINT model was developed for performing the thermal analysis of the compressible gaseous nitrogen (GN2) flow of X-38 pressure control system (PCS). The purpose of this analysis is to predict the thermal performance of X-38 PCS for the first mission phase, and to ensure that the GN2 pressure in tank stays above 1000 psi and the GN2 temperature in tank stays above −65°F during a real mission phase. The model simulations of the X-38 PCS have been conducted with the flowrates of the first mission phase for different ambient and GN2 temperatures with/without heating the GN2 tank wall. The predicted results show that the GN2 pressures and temperatures fulfill the requirements and limitations of the X-38 pressure control system without heating the GN2 tank wall. The electrical heaters on the GN2 tank exterior may be eliminated.