Tech Briefs Magazine - August 2022 - 41

space for maximum articulation. If not
allowed separate rotation, the line of action
through a universal joint and hinge
acts effectively as another linkage. This
leads to a much more complex and uncontrollable
structure, especially when
considering multiple dimensions.
Comprising the Multi-Link Spherical
Joint, a spherical shell encases the cupped
ends of each six possible attachments and
allows each of those attachments to be independently
controlled and rotated without
inhibiting the motion of the others.
To do this, each link is precisely limited to
15 degrees of rotation off the link centerline,
thus allowing a total of 30 degrees of
rotation for each link. The shell-and-cup
structure can handle the loads of linear
actuators that may be used to control and
vary the geometry of a truss system utilizing
the new joint technology.
The calculated operating load that the
truss system must handle can be used to
scale the size of the joint, further allowing
customization of any potential truss
system. Additionally, the incorporated
linear actuators can be controlled and
powered by wiring routed through the
joint without putting undo stress on the
wires during operation. This innovative
joint technology enables more efficient
deployment and precise operation of articulating
structures.
This technology can be key for creating
a deployable, variable geometry truss system,
with a compact form factor that can
reduce payload volume within the confines
of a launch or other transport vehicle.
Typically, flexible truss systems rely on
joints where each of the links do not rotate
around the same point, creating instability
in the joints and the entire structure.
The Multi-Link Spherical Joint removes
those instabilities, allowing for a durable
and adaptable technology with multiple
space and terrestrial applications.
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/
MSC-TOPS-109.
Self-Aligning Poppet
Testing has shown that NASA's poppet reduces leakage rates of traditional aerospace
cryogenic valves by three orders of magnitude.
Marshall Space Flight Center, Huntsville, AL
A
s NASA plans for manned missions
to Mars, efforts are being made to
identify technologies that must be improved
to make such trips feasible. Without
improvements in valve technologies,
propellant and commodity losses will
likely make long-duration space missions
infeasible. Engineers at NASA's Marshall
Space Flight Center have developed a
self-aligning poppet for low leakage
valves a seat alignment technology that
eliminates the need to precisely control
interfaces between poppet sealing surfaces
and the valve seat seal.
Cryogenic valve leakage is often a result
of misalignment and the seat seal not being
perpendicular relative to the poppet.
Conventional valve designs attempt to
control alignment through tight tolerances
across several mechanical interfaces,
bolted or welded joints, machined part
surfaces, etc. However, because such tight
tolerances are difficult to maintain, leakage
remains an issue. Traditional poppets
are not self-aligning, and thus require
large forces to crush the poppet and seat
together to overcome misalignment and
create a tight seal. In contrast, NASAs
poppet valve self-aligns the poppet to the
valve seat to minimize leakage.
Once the poppet and seat are precisely
self-aligned, careful seat crush is provided.
Owing to this unique design, the invention
substantially reduces the energy required
to make a tight seal reducing size, weight,
Tech Briefs, August 2022
Renderings of a 3 " low leakage relief valve using NASA's self-aligning poppet technology. The arrow
in the cross-sectional view (right) marks the poppet head. (Image: NASA)
and power requirements relative to traditional
valves. Testing at MSFC showed that
NASA's poppet reduces leakage rates of
traditional aerospace cryogenic valves
(~1000 SCIM) by three orders of magnitude,
resulting in leakage rates suitable for
long-duration space missions (~1 SCIM).
NASA's self-aligning poppet was originally
targeted for aerospace cryogenic
valve systems, especially for long-duration
manned space missions making the invention
an attractive solution for aerospace
valve vendors. The invention may
also be used in the petrochemical or other
industries that require sealing to prewww.techbriefs.com
vent
critical or hazardous chemicals from
leaking into the environment. Generally,
the invention may be suitable for any application
requiring low-leak and/or long
duration storage of expensive or limited
resource commodities (e.g., cryogenic
gases, natural gas, nuclear engines, etc).
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/
MFS-TOPS-116.
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Tech Briefs Magazine - August 2022

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