Libyan Cubesat for monitoring desertification and deforestation

Asem ELARABI , Akram ELKASEH , Abdurrahim ABUGHUFA ), Said BEN RABHA , Ahmed TURKMAN , Mahdi
ALAYEB
)
The Libyan Center for Remote Sensing and Space Science, Tripoli, Libya.
asemelarabi@gmail.com

Desertification is one of the main problems threatening the Libyan agriculture. The major environmental hazard in
this area is sand encroachment from the south direction towards the north directions. Deforestation is another
important threat of agriculture in Libya, especially in the recent years, with no lawful authority to control the chaotic
deforestation process, huge areas of forests are threatened to become unorganized farms, houses and buildings. By
building our own Cube-Sat , its images could be used to observe and monitor deforestation, desertification, and to
control the uncontrolled increasing violation of green lands and illegal buildings.

In our mission, we are planning to develop and fabricate a cube-sat –initially called “LCRSat-I” – to monitor the
agricultural cover of Libyan lands. The satellite mission aimed at monitoring and assessing of desertification in
southern Libyan land, deforestation in the north, and random build houses and buildings. In addition, it will be used
to investigating the potential use of remote sensing and GIS in assessing and monitoring sand encroachment and
vegetation degradation as desertification indicators in the semi-arid environment. These valuable data will help the
government to initiate platform data bases which can be used in the development of Libya infrastructure.

Key Words: Cubesat, Desertification, Deforestation, Monitoring.

Introduction × 10cm cube which would be accepted on the major launch

platforms. Simplification of the satellite’s infrastructure makes
Since its project began at California Polytechic State it possible to design and produce a workable satellite at low
University (Cal Poly) in 1990 , cubesat capabilities in earth cost.
observation and near earth environment monitoring are rapidly
progressing. Cubesat can be designed, built, launched and
operated by a small team in a fraction of time and with a low
magnitude of cost. In addition, the standardization of the
launcher interface and deployer (P-POD) has helped the
Cubsat to receive general acceptance as the de facto standard
The number of new satellite developers such as universities
and small business companies has increased.
Desertification and deforestation are natural phenomena
which can affect the agriculture. In Libya, the active sand
storms hit from south to north direction are the major
environmental hazard. Additionally, forests, farms and Although the primary mission of the Cubesat Program was
agricultural areas at the cost have been rapidly destroyed by educational and to provide access to space for small payloads,
people in the recent years. dozens of Cubesats with different interesting based missions
The achievements in novel space technology applications will have been lunched into low earth orbit.
be used for earth environmental monitoring such as Fig. 1. Single unit Cubesat “Goliat model” .
monitoring the agricultural cover lands, and remote sensing
desertification and deforestation effects. Valuable processed Cubesat novel missions such as research and development,
data can be achieved by imaging areas of interest from the astronomy ), earth observation and remote sensing have been
space. very successfully completed.
Earth imaging is a commonly quoted objective for a Cubsat
. Cubesats mission, typically achieved using a CMOS camera and
without any complex lensing system .
A Cubesat is a type of nanosatellite that usually has a size As smaller and more powerful cameras become available, the
of one, two, or three blocks, each block being a 10cm × 10cm resolution of images taken from Cubesats will only improve.
Also, with smaller components and sensors that allow the including the following:
satellite to change its orientation the images be targeted at 1. The unjust use of private land and cutting down trees
specific locations, making them more relevant for earth around the main cities in the cost.
observation and remote sensing ). 2. Haphazard construction in farmland.
3. Razing forests and windbreaks, this leads to open orifices
wind.
Desertification and Deforestation in Libya 4. Excessive pumping of water from shallow wells, which
resulted in soil salinization in coastal areas, has reached salt
Desertification is one of the most serious problems facing water creep.
the world in general, and particularly the African continent. At Figure (2) shows deforestation in south east part of Tripoli.
the global level, is exposed to about 30% of the Earth's surface The dark green areas in the images show the forest and green
at risk of desertification affecting the lives of millions of lands. The images show the drastic change in the forest area at
people in the world. the region within a short period of 14 years, images show that
It is estimated that an area of land, which graduated annually desertification is also taken place at the bottom right side of
from the scope of agriculture as a result of the process of the picture.
desertification, approximately 50,000 km and the proportion Other images from Landsat satellite with a pixel resolution of
of land desertification-prone 40% of the land area and are 30 m is shown in figure ( ). Top image was taken in in 1989
home to more than a billion people. and bottom image was taken in 2003.
Actions and activities that lead to deforestation, as a result of
logging to the use of wood in construction and industrial
purposes, or as a result of burning trees or remove them for
the exploitation of forest land to increase the area of arable
land and other development objectives. Deforestation also
leads to reduced soil stabilization thereby increasing
desertification.

Fig. . Landsat images of Tripoli: top image at 1989 and bottom image
at 2003.
If we compare what is inside the two images, we will see a
clear deforestation due to the unjust use of private land and
cutting down trees in many regions. Randomly built houses
were fabricated after green-lands and forest were destroyed by
human being.
Fig. . Landsat images of south east Tripoli: top image at 1989 and
bottom image at 2003. . LCRsat-I Satellite Subsystems Overview

In Libya, desertification and deforestation are main According to the specification, a standard Cubesat satellite
environmental hazards that facing the government. As most of is 10 cm cube weighing at most kilogram. Currently, up to
the land is covered with big SAHARA, both factors can affect three such cubes may be combined and thus creating a single
the agriculture sector immediately. satellite of dimensions 10cm × 10cm × 30cm with mass of 3
There are natural and human factors that play a major role in kg.
the raise of desertification and deforestation in the Libya, LCRsat-I will be within the standard specification and the
configurations of ground segment, space segment and . . Attitude Determination and Control System
launching methods that would be most cost-effective will be The ADCS system is the most crucial system in the sense
identified. that any spacecraft or instrument has to be oriented towards a
specific target and toward the ground station while keeping
. Ground Station and Antenna the orbit parameters in certain limits. This can be achieved
A basic ground station consists of hardware and software to using sensors for acquiring spacecraft attitude and position as
transmit and receive data reliably. The ground station includes well as orientation and after performing on board calculation
transmit and receive antennas, a computer programmed with or receiving commands from the ground the spacecraft makes
orbital-prediction software compatible with the hardware, and use of actuators to achieve the desired trajectories.
transceiver to transmit and receive data. The most common sensors used in ADCS are: the sun sensor,
With the radio band determined to be in the amateur band, the Earth sensor, star track, magneto-meters, gyroscopes, and
ground station antennas will be chosen to be a GPS.
commercial-of-the-shelf rotator VHF and UHF antennas with Attitude control can be performed passively using magnets
high gain. and gravity gradient, or actively performed by a control
mechanism such as gas thrusters, three-axis magnetic torque
. . Power Supply Subsystem coils, or by momentum /reaction/inertial wheels.
The main functions for the power system are provision, To date Commercial Cubesat ADCS modules are available
storage, distribution and control of power to other satellite from the market including sensors, actuators and processors,
subsystems such as RF communication, Attitude Determine such modules as the ones from ClydeSpace company will be
and Control system (ADCS), image processing, deployable used in LCRsat-I Cubesat.
mechanism actuation. Power budget must ensure that the
payload and all Cubesat subsystems have the power they need . . Optical Payload
during the lifetime of the satellite. The satellite power systems To fulfill the photography mission of LCRsat-I, a small
include electrical power system, battery assemblies, and commercial camera is used. Optical payload consists of
deployable solar cells. commercially available high resolution single lens reflex
The Electrical Power System (EPS) is responsible for gathering camera lens, processor and memory. For typical satellite
power from solar panels, storing into batteries and distributing orbiting at around 700 km altitude, the expected equivalent
it for whole system. LCRsat-I will be orbiting in Low Earth area in a 3 mega pixel image is a 50 × 70 km. The expected
orbit (500km – 700km) in such a way that it will be in eclipse pixel resolution is tens of meters for a camera consists of a
during about 30% of the orbital period. Part of the captured 2048× 1536 matrix of pixels, enabling the identification of
solar energy must be kept in a battery in order to return it to the geographical features and even a large construction at the
subsystems during the eclipse. EPS has to control, distribute ground.
and regulate power for subsystems and to balance power
requirements and generation during eclipse and sun phase.
There will be five sides covered with solar cells, two solar cells
per side of the satellite that are connected serial and different
sides are connected parallel to each other. Two Lithium ion
rechargeable batteries connected in series will be used as a
second source of power.

. . Communication
The primary goal of the communication subsystem is to
provide a link to relay data findings and send commands to
and from the Cubesat. Analog digital data collected by the
sensors and payload must be relayed to the ground station via
the telemetry system.
Command and uplink portion is another aspect of the
communication subsystem. All incoming signals from the
ground will be received by the antenna, encoded, and Fig. 1. Commercial camera on board for Cubesat .
processed, errant signals will be discarded.
A transceiver is a single board housing both a transmitter and Similar high resolution satellite camera with interface board
receiver circuit. The transceiver converts data from the on works at visible light spectrum and accessible high accuracy
board computer (OBC) into a form that can be sent to ground will be used to image the extent of sand encroachment and the
stations via a carrier signal. The most common Transceivers vegetation deterioration during satellite life time.
for CubeSats operate in both the UHF and VHF bands. This
allows the use of the VHF band for downlink and UHF band LCRsat-I will use a modified commercial of the shelf structure
for uplink or vice-versa. consists of a 1U skeletonized aluminum cage. Thermal
A commercially available high speed data rate ISIS UHF / subsystem maintains the satellite temperature within
VHF transceiver will be used in our satellite. acceptable limits.
Thermal control subsystems can be used actively and Osaraetin, I., Retherford, L., Scarito, M., Nanosatellite for earth
passively, active systems such as heat pumps, electric heaters environmental monitoring: The MicroMAS project. Microwave
Radiometry and Remote Sensing of the Environment, IEEE. 2012,
or coolers, have the capacity to turn on and off to adjust the ISBN: 978- - -
temperature of the satellite subsystems, whereas passive . “Student satellite to be launched” BBC news:
systems such as blankets, thermal coatings, bare fixed in place http://news.bbc.co.uk/2/hi/uk_news/england/leicestershire/7
and heat is transferred through a natural process. Passive 453497.stm.
thermal control will be used in our satellite.
Testing will be performed to meet all launch provider
requirements as well as any additional requirements deemed
necessary to ensure the safety of the Cubesats. Comprehensive
test facility include thermal vacuum chamber and high power
shaker will be built, and LCRsat-I will undergo the random
vibration, thermal vacuum bake out, and shock tests.

. Conclusion

The use of space technologies in earth observation has a

good impact on agriculture and an environmental protection.
Using the satellite is possible to obtain information and
images from space help to establish a database on
desertification and forests in areas of interest.
Design, manufacture, test, and launch of a Cubesat satellite
with a high resolution camera is not impossible task. This
satellite gathers information and depicts satellite images from
the space, and helps the government and the people to protect
the land and forests in our country.

9. Others

The final total budget for LCRsat-I space and ground

segments still need to be finalized.

Acknowledgments

The team would like to thank LCRSSS and the National

Authority for Scientific Research for their support.

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