Aerospace & Defense Technology - August 2024 - 30

RF & Microwave Technology
an Data Relay System (EDRS) to provide high bandwidth capability
to LEO satellites and airborne platforms by means of
optical communications via the EDRS-A and EDRS-C geostationary
satellites and ground stations in Europe.
Proliferated Commercial Satellite Constellations
Starlink, an ambitious project initiated by SpaceX, has
made notable strides in its mission to provide high-speed
internet to every corner of the globe. As of July 2023, 4,487
Starlink satellites are operating in low Earth orbit, with the
newest versions of the satellites networked to each other
with lasers. SpaceX anticipates the total number of satellites
in the Starlink network to grow to between 12,000 and
42,000 eventually.
SpaceX founder Elon Musk tweeted last year, " Laser links
in orbit can reduce long-distance latency by as much as 50%,
due to higher speed of light in vacuum & shorter path than
undersea fiber. "
The Starlink project is groundbreaking and transformative,
but it is not without competition. One of the biggest competitors
is OneWeb, a UK-based company that also aims to build a
satellite network for global broadband service. Another formidable
rival is Amazon's Project Kuiper, which plans to deploy
over 3,000 satellites for similar purposes.
Two Part Adhesive with
LOW THERMAL RESISTANCE
EP30TC Epoxy Passes NASA Low Outgassing Tests
Exceptionally low thermal resistance
7-10 x 10-6
K*m2
/W
Superb thermal conductivity
18-20 BTU*in/ft2
*hr*°F
Ultra thin bond lines
5-15 microns
Furthermore, China's state-run space agency is also working
on a global broadband service called Tianlink. Each of these
competitors brings unique strategies and resources to the table,
thereby contributing to an increasingly dynamic and competitive
landscape in satellite-based internet services.
Aiming the Narrow Laser Beam
All these developments depend on the remarkable quality of
laser light - the extraordinarily straight and narrow beam of
light that can be focused on a distant target, transmitting data
at incredible speeds and low latency, with minimal signal loss
due to beam divergence.
And yet, it is the narrowness of the laser that makes it so
difficult to acquire and maintain a line-of-sight link over distances
of thousands of kilometers.
Aiming the transmitter and receiver is challenging due to the
extreme precision required and because the system must quickly
and smoothly adjust as the host satellites and spacecraft
move at high velocity in different directions relative to each
other and to ground stations. And the high-precision components
must reliably stand up to the rigorous demands of space
launches and the harsh space environment.
Fast steering mirrors require precision position data to rapidly
adjust mirror position, which is usually actuated by electromagnetic
voice coils. Extremely sensitive sensors can
accurately measure the mirror position with extremely fine
resolution in the sub-micron range.
The system is designed so that the performance of the sensors
remains unaffected by the severe temperature fluctuations
in the space environment. As shown in Figure 1, electronically
matched sensors, using eddy current technology, are positioned
in pairs on opposite sides of the pivot point of the mirror
and equidistant from this point.
The sensor-to-target relationship is such that as the target
moves away from one sensor, it simultaneously moves towards
the other an equal amount. The two pairs of sensors are positioned
in two axes set perpendicularly to provide precise x-y
tilt/tip position data. Operating in differential mode, the sensors
eliminate or reduce common mode effects, such as piston
action, and signal noise.
Taking Aim at the Future
Kaman Precision Products, through its Measuring line of
business, developed its line of differential position measuring
systems over 30 years ago. Kaman has continually refined
the performance capabilities of these renowned products to
meet the increasing requirements of the space and defense
markets. The product line now boasts three exceptional
products including the KD-5100 family, with over 100krad
TID capability and a rich 3-decades space heritage including
the Mars 2020 Rover, as well as its COTS version, the
DIT5200L, a low noise, affordable LEO-capable system, and
our new digital KD-5690 system.
Hackensack, NJ 07601 USA * +1.201.343.8983 * main@masterbond.com
www.masterbond.com
30
This article was written by Rick Williams, Senior Manager,
Business Development, Kaman Precision Products (Middletown,
CT). For more information, visit www.kaman.com.
mobilityengineeringtech.com
Aerospace & Defense Technology, August 2024
http://info.hotims.com/86258-724 http://www.kaman.com https://mobilityengineeringtech.com
Aerospace & Defense Technology - August 2024

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