Too Heavy to Fly Clean

Decarbonizing commercial aviation — responsible for ~3% of global CO₂ emissions — requires all-electric or hybrid-electric propulsion for the workhorse single-aisle aircraft segment (150–200 passengers, Boeing 737 / Airbus A320 class). Current electric motor and power electronics technology achieves roughly 5–7 kW/kg at the system level. ARPA-E's ASCEND program identifies 12 kW/kg at 93%+ efficiency as the minimum threshold for a viable 150-passenger electric aircraft. This 2× improvement over state-of-the-art cannot be achieved by incremental improvements to existing motor topologies — it requires fundamental advances in motor design, thermal management, and power electronics integration.

Aviation accounts for approximately 900 million tons of CO₂ annually and is one of the hardest sectors to decarbonize. Single-aisle aircraft represent ~60% of the global commercial fleet and ~45% of aviation fuel consumption. Sustainable aviation fuels (SAF) address emissions but face feedstock constraints and cost 2–5× more than jet fuel. Battery-electric flight is energy-limited by battery specific energy (~250 Wh/kg for Li-ion vs. ~12,000 Wh/kg for jet fuel), but for short-haul routes (500–1,000 miles), high-power-density electric propulsion could enable hybrid architectures using smaller, lighter fuel loads. Without the powertrain breakthrough, the aviation industry has no credible pathway to net-zero for its largest fleet segment.

Existing high-power-density motors (e.g., those used in Formula E racing or aerospace actuators) achieve impressive specific power but sacrifice efficiency or thermal endurance. Superconducting motors offer very high power density but require cryogenic cooling systems that add weight and complexity. Conventional motor topologies (permanent magnet synchronous, induction) are approaching theoretical limits at their current operating temperatures. The motor, its drive electronics, and thermal management system are typically designed by separate teams, leading to sub-optimal integration — thermal management alone can consume 30–40% of the total powertrain weight. GE Aerospace and others have demonstrated MW-class motors, but none at the required specific power with integrated drives.

ASCEND's approach of co-designing the motor, drive electronics, and thermal management as a single synergistically cooled system could eliminate the weight penalty of separate cooling loops. Advances in wide-bandgap semiconductors (SiC, GaN) enable higher switching frequencies and operating temperatures in the drive, reducing passive component sizes. Novel motor topologies (axial flux, transverse flux) and direct-drive architectures could reduce mechanical transmission losses. Additive manufacturing of motor components with integrated cooling channels represents a fabrication breakthrough that enables geometries impossible with conventional manufacturing.

A team could model the thermal-electromagnetic co-design of a motor segment, optimizing winding geometry and cooling channel placement simultaneously using multi-physics simulation. Alternatively, a team could benchmark emerging wide-bandgap power electronics for aviation duty cycles and identify the thermal derating factors that limit real-world performance. Electrical engineering, aerospace engineering, and thermal science skills are most relevant.