SSTL and Oxford Space
Systems complete development of an advanced
deployable SAR Antenna Payload
19 Jul 2022
Oxford Space Systems (OSS) and
Surrey Satellite Technology Ltd (SSTL) have
completed the build of an innovative deployable
Synthetic Aperture Radar (SAR) antenna payload for
the next generation of high-performance low-cost
Earth Observation radar small satellite missions.
The new SAR payload, which comprises of a highly
stowage-efficient deployable antenna from OSS and a
high bandwidth radar instrument and RF system from
SSTL, has been exclusively designed in the UK,
supported by a grant from the UK Space Agency's
National Space Technology Programme.
OSS has developed an innovative
Cassegrain reflector antenna with a metal mesh
surface known as the “Wrapped Rib” antenna, a 3m
diameter parabolic reflector which stows into a
small volume, making the architecture compatible
with ~150kg spacecraft. Operating at high frequency,
the Wrapped Rib antenna is the ideal solution for
low-cost, high resolution SAR missions using SSTL’s
CarbSAR platform. The project successfully
demonstrated deployment of the main reflector ribs
and secondary reflector mast with a subsequent RF
test of the system’s performance.
Sean Sutcliffe, Chief Executive
of Oxford Space Systems said:
“We are delighted with the outcome of this
collaboration with SSTL and UKSA. The highly
innovative OSS Wrapped Rib Antenna, combined with
SSTL’s digital and RF electronics provides a compact
SAR payload for smallsat missions and we are already
seeing strong international customer interest for
this product”.
Andrew Haslehurst, Chief
Technology Officer of SSTL, said:
“SSTL pioneered the development of small satellites
from the early 80’s combining initiative
technologies with a different approach enabling
smallsat missions. Embedding the
SAR electronics directly into our core avionics
simplifies the architecture, combined with the
impressive stowage volume of the Wrapped Rib has
enabled SSTL to develop a very capable CarbSAR
product providing high resolution X-band SAR imaging
capabilities day, night and whatever the weather”.
Surveillance, Change detection
and “big data” analytics applications are driving
interest in spaceborne SAR data, to support
day/night and all-weather imaging at a rate faster
than what can be achieved with any individual
satellite. This drives demand for much smaller radar
satellites that can be launched within a limited
launch volume in groups, however it is still
desirable to retain a large antenna for better
quality imagery. Having a large, scalable, stowable
and lightweight, reflector antenna provides a number
of benefits in designing small radar satellites for
particular applications. A reflector antenna can
also significantly simplify the radar electronics,
making it ideal for implementing radar on much
smaller spacecraft such as SSTL’s CarbSAR platform.
The funding grant from the UK
Space Agency's National Space Technology Programme
has enabled OSS and SSTL to mature the technology in
readiness for a potential demonstration mission next
year.
Dr Paul Bate, Chief Executive
of the UK Space Agency, said: “The UK
has been a pioneer in the small satellite market and
is at the forefront of Earth observation technology
and antenna design and development for this class of
spacecraft. We’re backing companies like Oxford
Space Systems and SSTL to deliver new space
capabilities that will help us tackle challenges,
including disaster monitoring, urban planning and
transport management.
“Our support for this exciting
partnership shows how we are working to catalyse
investment into the thriving space sector and
provide valuable services to a global community.”
The innovative antenna
developed by Oxford Space Systems has a 3m diameter
deployable reflector but there are very few
facilities available that can accommodate such a
large antenna for RF testing measurement.
Oxford Space Systems is working
in collaboration with QuadSAT to use a drone-based
measurement system to overcome the challenges of
testing such a large reflector diameter. Drones
offer unparalleled flexibility and portability for
outdoor antenna measurements, which is especially
convenient to assess the performance of large
aperture systems. Earlier in April 2022, this drone
measurement approach was used for the first time on
the 3m EM version of the Wrapped Rib antenna.
Carlo Rizzo, CCO, QuadSAT,
commented: “With this project, Oxford Space Systems
is making high-performance, low-cost earth
observation attainable. We wanted to ensure our UAS
system could remove the complexity normally
associated with testing large space deployable
antennas which are subject to gravitational effects.
As well as being able to test and verify the antenna
is performing as expected, we have proven the
system’s ability to test large antennas, either
before deployment or on an ongoing basis.”
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