NASA recently selected 15 visionary ideas for its NIAC (NASA Innovative Advanced Concepts) program which develops concepts to transform future missions. Chosen from companies and institutions across the United States, the 2025 Phase I awardees represent a wide range of aerospace concepts. The combined award for the 2025 concepts is a maximum of $2.625M in grants to evaluate technologies that could enable future aerospace missions.

Among the selected projects is Hy2PASS (Hydrogen Hybrid Power for Aviation Sustainable Systems), led by Phillip Ansell, University of Illinois, Urbana. The purpose of this program is to demonstrate the merits of hydrogen hybrid fuel cell/gas turbine engine power systems for sustainable commercial transport aircraft design and mission-optimized performance.

The focus is on the specific architecture of hybridization, how it changes the fundamental elements of the aircraft integration, and how these holistic design changes can be leveraged to result simultaneously in large reductions in mission energy required while practically introducing a zero-emissions solution.

Artist concept highlighting the novel approach proposed by the 2025 NIAC awarded selection of Hydrogen Hybrid Power for Aviation Sustainable Systems (Hy2PASS). NASA/Phillip Ansel

Instead of combining electrical power between a fuel cell stack and hydrogen turbogenerator or combining mechanical power between a fuel cell-driven motor coupled to turbine spool, this architecture will feature hybridization through air handling.

The fuel cell is used to power an electrically driven compressor which supplies the oxygen supply to the fuel cell cathode, as well as the burner of the gas turbine, removing the need for a core compressor stages in the thermal engine.

The mechanical uncoupling of the compressor from the turbine allows the compressor to be operated fully independently from the turbine stages, which in turn allows the compressor to be operated at variable overall pressure ratios.

This Hy2PASS system enables new performance capabilities for aircraft, which can be used for new mission-optimized aircraft architectures.