Development of an Air-Bearing Fan for Space Extravehicular Activity (EVA) Suit Ventilation

AiResearch has demonstrated a high-speed axial fan that can be used for space extravehicular activity (EVA) suit ventilation. The fan provides variable flow for the suit in a lightweight, compact design. It combines fine-scale aerodynamics with air bearings and a two-pole toothless permanent magnet motor. The fan has demonstrated quiet, vibration-free operation satisfying performance requirements in a small package: 0.31 l (18.9 cu in.) in volume, 7.8 cm (7 in.) in length, with a weight under 0.9 kg (1.98 lb).

This paper describes the fan and control design and discusses test results. The fan accommodates desired changes in the ventilation flow rate by allowing the astronaut to vary fan speed, achieving over a two-to-one range in flow rate. The development program tested the fan at flow rates ranging from 99 to 225 l/min (3.5 to 8 acfm) at operating pressures from 0.414 to 1.586 bar (6.0 to 23 psia) with pressure rises of 0.5 to 2.49 kPa (2.0 to 10 in. H₂O). The input powers ranged form 12.4 to 42 W.

The air bearing fan was developed under Prime Contract NAS9 179000 from Johnson Space Center and Subcontract 0200122973 from Lockheed Engineering Sciences Company for the preprototype portable life support system ventilation loop.