Winter 2013
Warwick University Satellite
Project: Winter 2013
Newsletter
WUSAT
The WUSAT project aims to build and launch a
CubeSat, a 10cm cube satellite, into low Earth
orbit. This year’s team is working on designing
and manufacturing a prototype CubeSat,
which will be launched into the stratosphere
on a weather balloon for testing. The project
website (www.warwick.ac.uk/cubesat) is
continually updated with the latest news and
sponsors.
Progress
The project is now rapidly evolving; the team
are in the process of designing the finer details
of the prototype and organising the balloon
launch. Since the previous newsletter, a fit
chassis has been ordered and manufactured
(see photo on right). The prototype chassis
has been submitted for manufacture. On the
electronics side, Arduino boards have been
delivered, and the team is working on
designing printed circuit boards (PCBs) for
them, as well as working on the
communication and power systems. Small
cameras, 30mm across, have also been
purchased for the balloon launch, although
they will need to be insulated in order to work
at high altitude and low temperatures.
Balloon Launch
The balloon launch has been scheduled for
around the end of term (mid-March); suitable
balloons and parachutes have been selected
with suppliers in mind. The final selection will
depend on the approximate weight of the
whole system, as the ascent and descent rate
are important in terms of minimising the risk
of landing in the sea. Contact has been made
The completed
fit chassis,
currently being
used to identify
the best way to
utilise the
space within
the CubeSat.
with an amateur high altitude ballooning
society, UKHAS, on the matter of launch site.
It has been recommended not to launch from
Warwick University due to its proximity to
Birmingham and Coventry airports. Instead, a
launch site in Shropshire has been chosen.
Industrial Links
WUSAT maintains contact with many
companies, for example a few weeks ago
National Instruments delivered a training
course on LabVIEW, which we have chosen to
use for the base station software. This allows
us to view the data from the CubeSat in realtime.
The communication system has been ordered
from RS Components and the electronics team
are working towards PCB designs for Lyncolec
to manufacture. Contact has also been made
with local firms with regards to manufacturing
the chassis, due to begin shortly.
Electronics
On the programming side, progress has been
made in obtaining images from the cameras
and designing the mezzanine PCB for the
Arduino board. The key strategy is to get the
board manufactured by Lyncolec as soon as
Winter 2013
possible, with the design allowing for changes
in functionality later on.
It has been decided to use a high powered
xbee transceiver module in the satellite, which
will make use of an external patch antenna.
Despite not fitting within the size
requirements of the CubeSat specification, it
was decided that this would be the best
compromise in order to recover as much data
as possible from the launch as there is a
possibility of not retrieving the satellite upon
landing. A further xbee transceiver with a high
gain antenna will be used for the base station,
which will allow us to directly interface with
LabVIEW software supplied by NI for the base
station data processing.
Having established the power requirement for
the CubeSat payload and comms system, the
A diagram of how
the CubeSat may
look: chassis
surrounded by
insulation and
inside, a camera,
Arduino
microcontroller
boards, batteries
and a payload.
battery type of choice will be a Li-ion battery
available through RS Components. Four such
batteries will provide power to the payload for
3 times the duration of the estimated balloon
flight time (1.5hrs). Due to the flight’s short
duration, the CubeSat will primarily depend
on the battery and will not need solar cells to
provide sufficient power. However, some solar
cells will still be mounted on the structure for
testing purposes.
Mechanical
The CubeSat’s chassis has been designed and
modelled within SolidWorks. The twin design
goals of weight minimisation and interior
volume maximisation have resulted in a
chassis composed of six milled aluminium
panels, held together by a single fixing in each
corner of the frame. In line with the
mechanical
specification,
this
design
emphasises simplicity of assembly, allowing
easy access to the satellite’s electronics and
payload.
Finite element drop test simulations have
been carried out to ensure the body can
withstand impact velocities of up to 15m/s.
This gives a safety factor of 2, as the decent
rate is expected to be at most 7.5m/s. Initial
tests showed excessive (greater than yield)
stress in panel corners and diagonal struts.
Therefore, a design study within SolidWorks is
currently being conducted to find the optimal
panel pattern.
The thermal housing has been designed and
will consist of an interlocking jigsaw-like
design.
The design will enable simple
manufacture and easy disassembly once the
CubeSat is recovered. The material used for
the thermal housing will be Polystyrene,
chosen for its strength and thermal
properties.
The team with the recently completed poster
about the project, available to view from the
website.