TPADS (National Aeronautics and Space Administration)

Specialized fast-time stand alone tool for NASA Technology Portfolio Assessment used to quantify the benefits of their environmental technology programs

NASA has a portfolio of technologies to improve fuel efficiency, reduce emissions, and reduce noise, and understands the benefits of these particular technologies on a per-flight basis, but quantifying the potential benefits system-wide is a challenge. Modeling system-level environmental performance requires time-consuming data preparation and models with long computational run times. A fast-response screening tool was needed to perform these calculations quickly and easily. The TPADS project included a number of project disciplines including; tool development, development of analytical foundations for the tool and the analysis of NASA’s technology portfolio and system-wide benefits under a number of analysis assumptions.

The objective of the project was to provide a tool NASA can use to quantify the benefits of their environmental technology programs. The project required pulling together data from multiple sources including:

  • Model forecasted passenger demand out to 2050 nn Validated and adjusted forecasted demand against expected airport and airspace capacities
  • Modeling the environmental performance of future aircraft
  • Building a future fleet of aircraft based on expected fleet turnover and the availability of the various NASAinitiated technologies
  • Modelling the changes in the NAS due to changes in fuel price (number of flights, aircraft size, passenger throughput) nn Assessing the impacts of each NASA technology in isolation, and combined
  • Computing total fuel, NOx, and noise impacts as each of these factors are varied nn Complete the requirements above in a tool that is easy to use, computes results quickly, and is easily shared among many users

Metron Aviation developed a fast-computation tool allowing the user to explore the system wide benefits of various NASA NextGen technologies. The rapid assessment tool, developed in Excel, utilizes data pre-computed data from high-fidelity tools (NIRS) for fuel burn, NOx, and noise exposure. The user can quickly assess the potential impacts of various technologies without time-consuming data preparation and lengthy computer processing times associated with high-fidelity tools. The tool models the performance of these future aircraft on forecasted passenger demand out to 2050.

The tool also integrates the Airline Network Evolution Model (ANEM) developed by George Mason University where ANEM models airline changes in routes served (number of flights, aircraft size) in response to changes in fuel price. In TPADS, the user can vary the price of jet fuel and the underlying flight schedules are modified based on ANEM. Changes in total fuel, NOx, and noise exposure are calculated.

Within TPADS, Metron Aviation developed an original fastcomputational noise methodology for computing the number of people exposed to significant aircraft noise (65 and 55 dB DNL) based on pre-computed model runs from NIRS. TPADS varies the effective noise reduction level of the fleet based on the assumed scheduled insertion of noise-reducing technologies in the fleet, weighted by the contributions of each aircraft class to total noise. The TPADS tool also models future aircraft performance relative to baseline fuel, NOx, and noise performance, where aircraft performance was modified based on the expected improvements from the various NASA technologies. The approach included an original analysis of expected trends in engine size, and overall pressure ratios (OPR) being key drivers of NOx production. For future fleet modeling, TPADS uses combined data on historical fleet turn-over and expected availability of NASA technology to build an appropriate fleet mix to model fuel, NOx, and noise for each forecast year out to 2050, preparing today’s skies for tomorrow.