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June 2020
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
them perfect candidates for education and training, particu-
larly for student research groups. The F’SATI program at the
Cape Peninsula University of Technology is a postgraduate
program in satellite systems engineering that focuses on the
development of Cubesats. This initiative enabled students
to acquire hands-on technical skills in satellite engineering
and to undertake innovative research in the development of
Cubesats. The program was funded by the Department of
Science and Innovation (DSI), the National Research Foun-
dation (NRF) and the South African National Space Agency.
Three Cubesats have been successfully launched from the
program to date, including ZACube-01 and ZACube-02.
ZACube-1 is an IU Cubesat (“U” refers to a 100x100x-
113.5mm cube) that carries an HF beacon transmitter for
ionospheric tomography as its primary payload for monitor-
ing space weather. The payload was developed jointly with
scientists at SANSA Science in Hermanus and consists of a
simple radio transmitter. It emits a 14 MHz beacon signal
received on the ground to characterize the electron density
for the zone of the ionosphere traversed by the Cubesat. The
data was used to validate and improve the International
Reference Ionosphere model and to characterize the iono-
spheric radar for the Super Dual Auroral Radar Network
(SuperDARN) (van Zyl et al. 2013). ZACube-01 also carries
onboard a very low-resolution camera to capture pictures
of the earth. Launched on December 27, 2018, ZACube-2 is
a 3U Cubesat carrying an automatic identification system
(AIS) as its primary payload and an additional ocean color
and fire detection imager (Zaidi and van Zyl 2017, Zaidi et
al. 2018). The K-line and reference infrared camera channels
constitute a secondary payload. The AIS is used for detecting
and tracking ship movement in the South African territorial
waters in support of maritime domain awareness. The K-line
and reference camera channels are used for wildfire detec-
tion and monitoring.
Recent Activities
In 2017, two South African Cubesats, ZA-AeroSat and
nSight-1 were launched from the International Space Station
(ISS) as part of ESA’s QB50 project for upper tropospheric
modeling research. ZA-AeroSat 3U Cubesat was jointly de-
veloped by Stellenbosch University, Cape Peninsula Univer-
sity of Technology and CubeSpace. The satellite was used to
showcase passive Cubesat aerodynamic stabilization using
its four communication antennas as aerodynamic feathers,
but the Cubesat was only semi-operational due to weak
signal issues.
nSight-1 is a 2Us Cubesat built by a private South African
company, Space Commercial Services. It carries onboard
IPEX (Flux-Φ-Probe Experiment) scientific instrument that
collects atmospheric oxygen data in the lower thermosphere.
nSight-1 also carries an additional RGB (Red, Green and
Blue) multispectral earth observation imager as a secondary
payload that captures images to support remote sensing
applications (Mhangara et al. 2020).
The maturity of Cubesats as a space platform to support
operational earth observation data has gained the attention
of the South African space industry. The last decade has
witnessed an increased number of South African companies
participating in the development of Cubesats, namely Space
Commercial Service, NewSpace Systems, Simera Technology
Group, CubeSpace, Spaceteq and Amaya. Most of the com-
panies are collaborating with universities that have satellite
engineering capability, such as Cape Peninsula University
of Technology and Stellenbosch University,as innovation
partners.
Emerging Cubesat Remote
Sensing Applications
Cubesats are progressively transforming the space science
and technology landscape in South Africa. The four South Af-
rican Cubesats launched in the last decade demonstrate the
feasibility of using nanosatellites as operational platforms
to support earth observation applications for socio-economic
benefit. It is evident from the review of the Cubesats that
imagers were only added as secondary payloads piggy-back-
ing on funded scientific experiments that were the primary
missions. An analysis of the images produced by n-Sight-1
nanosatellite and the infrared imager in ZACube-2 shows the
feasibility of using Cubesats for operational remote sensing
applications as a means of complementing data from current
missions such as Landsat 8 and Sentinel-2.
In a recent study, Mhangara et al. (2020) analyzed nSight-1
and observed that the images are valuable for a multitude
of remote sensing applications. Some of the identified uses
included geological mapping, geomorphological analysis,
extraction of surface water bodies, agricultural field demar-
cation and crop mapping, ship detection, vegetation assess-
ments, differentiation of urbanized areas and other land
use and land cover applications. The visual interpretation
of n-Sight-1 imagery showed the images were suitable for a
range of applications. Land use and land cover types dis-
cernable from nSight-1 imagery include agricultural fields,
surface water bodies and geomorphological and structural
geology features as illustrated in Figure 1, Figure 2 and
Figure 3, respectively.
The infrared sensor onboard ZACube-2 is an invaluable tool
for fire monitoring. The novelty of this imager is that it is
capable of detecting the characteristic potassium spectral
emissions of burning vegetation biomass using the near-in-
frared spectral channel and is valuable in identifying ocean
color. Figure 4 displays an infrared image acquired by this
sensor.
The practical value of the automatic identification system
onboard ZACube-2 is maritime surveillance. AIS data from
ZACube-2 is already being used for ocean vessel detection in
South African Exclusive Economic Zone (EEZ) in support of
a government oceans economy program known as Operations
