Tech Briefs Magazine - December 2022 - 20

Aeronautics
Federal Aviation Administration (FAA)
or other private or public governing
bodies, from one or more AAM vehicles
in flight, and from weather sources.
Potential users of this technology include
the AAM industry, city planners/
departments of transportation, Vertiport
developers, as well as electric vertical
take off and landing (eVTOL) vehicle
manufacturers and designers.
NASA is actively seeking licensees to
commercialize this technology. Please
contact NASA's Licensing Concierge at
Agency-Patent-Licensing@mail.nasa.gov
or call at 202-358-7432 to initiate licensing
discussions. For more information, visit
https://technology.nasa.gov/patent/
TOP2-298.
3D-Printed Catalysts Propel Hypersonic Flight
The catalysts could prevent overheating in hypersonic aircraft and aid thermal management
across industries.
RMIT University, Melbourne, Australia
U
ltra-efficient catalysts were developed
that are cost-effective to make and
simple to scale. The 3D-printed catalysts
could potentially be used to in future to
power hypersonic flight while simultaneously
cooling the system.
Only a few experimental planes have
reached hypersonic speed (defined as
above Mach 5 - over 6,100 km an hour
or 1.7 km per second). Many challenges
remain in the development of hypersonic
air travel such as the extreme heat levels.
Using fuel as a coolant was one of the
most promising experimental ap proaches
to the overheating problem. Fuels that
can absorb heat while powering an aircraft
are a key focus but they rely on
heat-consuming chemical reactions that
need highly efficient catalysts.
The heat exchangers where the fuel
comes in contact with the catalysts must be
as small as possible, because of the tight
volume and weight constraints in hypersonic
aircraft. To make the new catalysts,
the team 3D printed tiny heat exchangers
made of metal alloys and coated them with
synthetic minerals known as zeolites. The
researchers then replicated at lab scale the
extreme temperatures and pressures experienced
by the fuel at hypersonic speeds to
test the functionality of their design. When
the 3D-printed structures heat up, some of
the metal moves into the zeolite framework
- a process crucial to the unprecedented
efficiency of the new catalysts.
The next steps for the research team include
optimizing the 3D-printed catalysts
by studying them with X-ray synchrotron
techniques and other in-depth analysis
methods. The researchers also hope to extend
potential applications of the work into
air pollution control for vehicles and miniature
devices to improve indoor air quality
- especially important in managing airborne
respiratory viruses like COVID-19.
For more information, contact the media
team at news@rmit.edu.au; +61 439
704 077.
A range of experimental designs for the 3D-printed
catalysts. (Image: RMIT University)
Solid Electrolyte-Based Microthrusters for Precision Propulsion
A simple, efficient design for highly controllable in-space propulsion.
Jet Propulsion Lab, Pasadena, CA
R
esearchers at NASA's Jet Propulsion
Laboratory (JPL) are developing a novel
microthruster that could provide easy-tocontrol
propulsion during spaceflight.
Using solid silver as the fuel source, this
innovative microthruster provides thrust
via electrospray without heating the fuel
reservoir or transporting liquid metals.
Instead of transporting a molten metal,
this design transports metal ions via a
solid electrolyte film.
NASA's need for highly controllable
microscale thrusters for in-space propulsion
prompted the development of this
20
innovative concept. Because it is easier
to control currents and voltages than
chemical reactions, aerospace engineers
have been exploring electrospray-based
microthrusters.
Traditional designs use capillary forces
to transport molten metal from a fuel
reservoir across a substrate to the tip of
an electrospray emitter. The emission
creates a plume that provides a small
amount of thrust. Such designs pose several
challenges, including having to heat
the fuel reservoir and the substrate, successfully
control the molten metal, and
www.techbriefs.com
construct appropriate and consistent
emitter tip geometry.
JPL's concept addresses the limitations
of other microthruster designs. As
shown in the image, the JPL design uses
a simple, container-free reservoir of solid
silver. A covalently bonded chalcogenide
solid electrolyte film transports
the silver ions to the emitter tip via an
applied electric field, creating the thrust
plume. (This same approach has been
used to transport silver ions between
electrodes in low-power, nonvolatile
memory systems.)
Tech Briefs, December 2022
https://technology.nasa.gov/patent/TOP2-298 http://www.techbriefs.com
Tech Briefs Magazine - December 2022

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