Space Technology Special Report - September 2024 - 8

Microelectronics
precise MEMS-based accelerometer,
the CAS291, will be used for the
first time to measure the level of
microgravity inside the LEO satellite.
The data will be used to assess
the impact of microgravity on the
effective manufacture, in the ultravacuum
conditions of space, of
advanced materials such as alloys,
proteins and semiconductors.
In LEO applications such as the
ForgeStar program, space, weight,
and power are critical constraints,
given the compact size of the CubeSat
which will require lower power, highly
sensitive accelerometers to accurately
measure low gravitational forces. The
CAS291 is supplied as a small (10.4
× 6.7 × 2.7 mm), surface-mounted
package in both flat and orthogonal
variations, enabling acceleration to
be measured on all required axis. It is
able to measure linear acceleration by
using a silicon MEMS detector, forming
an orthogonal pair of sprung masses.
Each mass provides the moving plate
of a variable capacitor formed by an
array of interlaced 'fingers'. When
linear acceleration occurs, it results
in a change of capacitance which is
measured by demodulation of the
square wave excitation. This structure
yields a robust design, enabling the
CAS290 Accelerometer Proof Mass CofG
10.40
Pads for factory use only
X
(D)
Y
+ve
13
(A) = 3.10
(B) = 0.95
(C) = 3.15
(D) = 0.90
(E) = 1.60
All dimensions in millimeters
Silicon Sensing's CAS290 Series. (Image: Silicon Sensing Systems)
8 SEPTEMBER 2024
SPACE TECHNOLOGY SPECIAL REPORT
(B)
Y
Y
(A)
12 34 56
CL
X +ve
C.G. 18677
14
4× (R0.20)
15
7 89 10 11 12
6×0.50
(0.90P×9=8.10)
16
6×(2.30)
(E)
CL
(C)
2.7
Silicon Sensing's CAS291 orthogonal
accelerometer. (Image: Silicon Sensing
Systems)
CAS accelerometer series to measure
a wide range of gravitational forces
ranging from ±0.85g to ±96g.
Dr. Mark Marshall, Chief Engineer,
Silicon Sensing concludes: " This is an
ambitious research program to which
our accelerometer will make a critical
contribution. Over a relatively short term,
we believe ForgeStar will bring about real
progress towards successful manufacture
in space - and to achieving the related
performance and environmental
benefits that will stem from that. "
As the ForgeStar program
advances, the collaboration
between Space Forge and Silicon
Sensing stands as a testament to
the transformative potential of
MEMS technology. The successful
integration of the CAS291
accelerometer into the CubeSat
platform not only underscores the
versatility and precision of modern
MEMS devices but also paves the way
for groundbreaking advancements
in space manufacturing. The ability
to produce high-quality materials
in the microgravity environment
of space could revolutionize
various industries on Earth.
Looking ahead, the continued
development of MEMS technology
will likely unlock new possibilities
for space exploration and utilization,
ensuring that projects like ForgeStar
remain at the forefront of scientific
and technological progress. As the
boundaries of what is achievable in
space continue to expand, the role
of precise, reliable, and compact
sensors will be crucial in realizing the
full potential of this environment.
This article was written by Dr. Mark
Marshall, Chief Engineer, Silicon
Sensing Systems Ltd., (Devon, U.K.).
For more information, visit
www.siliconsensing.com.
X
6.70
8×(0.30) 8×(3.05)
http://www.siliconsensing.com
Space Technology Special Report - September 2024

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