The Magnetically Enhanced Electrolysis (MEE) Experiment

Abstract

Water electrolysis is a key technology for oxygen and hydrogen production in space, finding application in environmental control and life support systems, propulsion technologies, and high-density energy storage devices. However, the management of multiphase flows in microgravity is complicated due to the absence of buoyancy. Diamagnetic buoyancy can be induced by means of permanent magnets to remove and collect gas bubbles and simplify current oxygen generation architectures. Ultimately, this could lead to a new generation of electrolytic cells with minimum or no moving parts. The Magnetically Enhanced Electrolysis (MEE) experiment seeks to evaluate this approach by testing a technology demonstrator onboard Blue Origin’s New Shepard suborbital rocket. Preliminary drop tower results exemplify the effectivity of this method.

Full text

The Magnetically Enhanced Electrolysis (MEE) Experiment
Á. Romero-Calvoa, C. Nogalesb, K. Billingsc, W. Westc, H. Schaubd
a: School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA
b: Department of Electrical, Computer, and Energy Engineering, University of Colorado Boulder, Boulder, CO
c: Electrochemical Technology Group, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA
d: Department of Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO
Summary
Water electrolysis is a key technology for oxygen
and hydrogen production in space, finding
application in environmental control and life
support systems, propulsion technologies, and
high-density energy storage devices. However, the
management of multiphase flows in microgravity is
complicated due to the absence of buoyancy.
Diamagnetic buoyancy can be induced by means
of permanent magnets to remove and collect gas
bubbles and simplify current oxygen generation
architectures. Ultimately, this could lead to a new
generation of electrolytic cells with minimum or no
moving parts. The Magnetically Enhanced
Electrolysis (MEE) experiment seeks to evaluate
this approach by testing a technology
demonstrator onboard Blue Origin’s New Shepard
suborbital rocket. Preliminary drop tower results
exemplify the effectivity of this method.
Experimental Setup
The MEE setup, depicted in Fig. 1, is designed to
study the (i) bubble life-cycle dynamics and (ii)
magnetic electrolysis performance. Formatted as
a 0.5 kg 2U structure, it is composed of magnetic
and non-magnetic electrolytic cells, with the latter
serving as a control unit. Two block magnets are
used to induce the detachment, collection, and
coalescence of hydrogen and oxygen bubbles. The
system is monitored during the ~3 min New
Shepard microgravity flight by a small camera and
a potentiostat implemented in a Raspberry Pi.
Results & Discussion
Prior to the suborbital campaign, the magnetic cell
was exposed to 4.7 s of microgravity conditions at
ZARM’s drop tower in Bremen, Germany. The
recording, shown in Fig. 2, demonstrates that
magnets can effectively detach and collect gas
bubbles in microgravity. Bubble trajectories are
driven by the diamagnetic and Lorentz forces, with
the first producing well-defined trajectories and the
second inducing an helicoidal motion. This
observation determines the operational strategy of
the experiment onboard Blue Origin’s NS-23 flight.
Figure 1: Experimental setup of the MEE experiment.
The NS-23 suffered a booster failure that
prevented the collection of microgravity data.
Luckily, the experiment operated as expected and
survived the flight thanks to the capsule launch
escape system. A future New Shepard mission will
test the long-term performance of the MEE
experiment and assess whether diamagnetic
buoyancy can, as indicated by preliminary results,
simplify microgravity electrolysis cell design.
Figure 2: Gas bubble dynamics in microgravity.