Page 20 - Summer 2024

its focus and hit a science fold mirror, angled at
SPACE UPDATE
First Study to examine Environmental Impact of
Satellites
The University of Southampton is leading the
first ever study of the environmental impact
of satellites as they re-enter the Earth’s
atmosphere.
Particles and gases are released as
decommissioned satellites combust on re-entry
and this research aims to assess the impact of
by-products from this combustion on climate
and the environment.
Dr. Minkwan Kim, Associate Professor of
Astronautics at the University of Southampton,
states:
“This topic has never been studied before. The
ablation [burning] process is complex and we
don’t yet fully understand how different materials
behave during re-entry to the atmosphere.
Our project will look at what happens to the
elements that are released, where they go, and
how they might be affecting our planet’s delicate
environmental balance. In theory, the particles
and gases released could be contributing to
ozone depletion and potentially be affecting the
Earth’s ability to regulate solar radiation”.
[ Reference: New Electronics, Vol.57 Issue 6, June 2024, p.44-45 ] to new scientific discoveries about conditions
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University of Surrey pioneers powering of low-
orbit Spacecraft
Scientists at the University of Surrey are
pioneering a new way to power low-orbit
spacecraft.
The thin air at extremely low altitude orbits
requires a different type of spacecraft design
and propulsion that that used by conventional
spacecraft operating in the vacuum of
traditional low Earth orbits.
The technique being devised is one in which
air-breathing electric propulsion harnesses
upper atmospheric air to act as a propellant
for an electric thruster allowing the spacecraft
to maintain orbital altitude through drag-
compensation, removing the need to store
propellant on board. Mission lifetimes therefore
do not need to be limited by propellant capacity.
Dr. Andrea Lucca, Senior Lecturer in Electric
Propulsion at the University of Surrey, comments:
“There are benefits to flying in very low
altitude orbits, like being able to operate Earth
observation at much higher resolutions than
offered at present. It could also mean faster
telecommunications, and it opens the door
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45 degrees and able to rotate to reflect the light
towards various instruments. These instruments
will include spectrographs to identify the
chemical composition of the target object, as
well as its temperature, mass, luminosity and
relative motion. There will also be a polarimeter
to identify the angle of approaching light waves
to identify phenomena such as magnetic fields.
A straight-through port, positioned directly below
the primary mirror will also receive light directly
with no interaction with the science fold mirror.
Here, an imaging camera with a wide field of
view will enable photometry to study brightness,
about conditions in the ionosphere, which could for example from supernovae and gamma-ray
help develop more accurate atmospheric bursts. Alternatively, the straight-through port
models”. may host a polarimeter, as this can yield more
accurate polarimetric measurements.
Postgraduate student Mansur Tisaev explains
more: The ability to switch the light beam towards or
away from the straight-through port in seconds
is crucial to being able to capture fleeting
“We’ve been developing a cathode, or
celestial activity. In order to prevent the light
neutraliser, to work in electrostatic thrusters
beam from being obscured, the focal station’s
operating in the thin air found in ultra-low Earth
mirror must be able to move out of the light path
orbit. By collecting and compressing the gases
rapidly. This mirror is therefore mounted on a
at that altitude, we can create a propellant flow
platform that can move laterally at high speed
that is ionised [transformed into a mix of charged by means of a linear motion system with a
particles] and accelerated using combinations ballscrew actuator.
of electric and magnetic fields, harnessing
electrical power from solar panels”.
The motion system combines a brushless
DC motor with an integrated encoder, and a
Reference: ‘Air-breathing Spacecraft’, New Electronics, Vol.57 Issue6, positioning controller that enables smooth
June 2024, p.44-45 modulation of position and speed. The motion
system is controlled by command signals
New robotic Telescope to capture rapidly
carried via EtherCat, with real-time data
evolving Astronomical Events
exchange operating precision.
In 2003 Liverpool John Moores University
[ Reference: ‘Fast-moving Telescope will capture Cataclysmic
developed the Liverpool Telescope to observe
Events’, Drives and Controls, May 2024, p.38-39 ]
transient astronomical events on the island of
La Palma.
Now, a New Robotic Telescope is being built
jointly by Liverpool John Moores University, the
University of Oviedo in Spain, and the Institute of
Astrophysics of the Canary Islands, which will be
ten times faster and four times more sensitive
with a primary mirror diameter of 4 metres
(double the size of the earlier model).
This fully automated telescope will be able to
operate without staff and provide a 30-second
time-to-target when astronomers around
the world send alerts to it about fast-moving
astronomical phenomena. Instrumentation will
be housed around a focal station whereby light
will travel through the optical system down to
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