Tech Briefs Magazine - March 2022 - 51

ing in plausible ways. This " model-driven
dynamic deception " is much more
realistic than a static decoy, a more common
tool that is quickly recognized by
experienced cyberattackers.
Shadow Figment spans two worlds
that years ago were independent but
are now intertwined - the cyber world
and the physical world - with elaborate
structures that rely on complex industrial
control systems. Physical systems are
so complex and immense that the number
of potential targets - valves, controls,
pumps, sensors, chillers, and so on
- is boundless. Thousands of devices
work in concert to bring uninterrupted
electricity, clean water, and comfortable
working conditions. False readings fed
into a system maliciously could cause
electricity to shut down, drive up the
temperature in a building to uncomfortable
or unsafe levels, or change the
concentration of chemicals added to a
water supply.
Shadow Figment creates interactive
clones of such a system, in all their complexity,
in ways that experienced operators
and cyber criminals would expect.
For example, if a hacker turns off a fan
in a server room in the artificial world,
Shadow Figment responds by signaling
that air movement has slowed and the
temperature is rising. If a hacker changes
a setting to a water boiler, the system
adjusts the water flow rate accordingly.
Shadow Figment has far-reaching applications
in government and private
sectors, from city municipalities and
utilities, to banking institutions, manufacturing,
and health providers.
For more information, contact Tom Rickey
at tom.rickey@pnnl.gov; 509-375-3732.
Simulations Provide Understanding of Spacecraft
Landing Dynamics
The simulations provide insight on the models needed to simulate a full-scale landing event.
University of Michigan, Ann Arbor, MI
F
uture spacecraft bound for the Moon
or beyond will benefit from high-powered
computer simulations that model
the particulate mayhem set in motion by
rocket thruster-powered landings. During
descent, exhaust plumes fluidize surface
soil and dust, forming craters and buffeting
the lander with coarse, abrasive particles.
This action presents a host of variables that
can jeopardize a landing. A current understanding
of those millions of interactions is
based on data that is, in some cases, 40 to 50
years old. Much of the available data used
in the design stage, including for the Mars
2020 mission, is based on Apollo-era data.
Landing-relevant data is very difficult to
generate because such an ex periment cannot
be run on Earth. Existing mathematical
models break down in these more extreme
conditions when particles approach
supersonic speeds. The new numerical
algorithms enable such simulations.
The team is developing physics-based
models that can be incorporated into
codes used by NASA to help predict what
will happen when a spacecraft attempts
to land millions of miles from home.
These include " messy turbulent flows "
and simulating the behavior of fluids
made of two phases of matter - in this
case, solid particles suspended in a gas.
Apollo-era landings showed that disturbed
surface material can spread up to
half a mile, posing hazards not only to
the lander itself, but also for neighboring
vehicles or landing sites. Despite advances
made in the years since, landings
remain fraught with potential hazards.
Eight years ago, a wind sensor on the
Curiosity rover was damaged during its
Mars landing. As NASA moves toward
new crewed missions under the Artemis
Program, this work becomes more vital.
Not only do humans onboard raise the
stakes, they mean larger payloads and
subsequently, stronger exhaust plumes
interacting with the planet's surface.
The team uses models - best guesses
based on all available data - to provide
a framework NASA can use to better predict
how different designs will impact
the ground and the landing and adjust.
Watch the simulation on Tech Briefs TV
Simulation showing shock waves (black/white) and wakes (color) past solid particles in a fluid flow.
(Photo: Capecelatro Research Group, Michigan Engineering)
Tech Briefs, March 2022
www.techbriefs.com
at www.techbriefs.com/tv/mars-landing. For
more information, contact Jim Lynch at
lynchja@umich.edu.
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Tech Briefs Magazine - March 2022

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