IEEE Electrification - December 2020 - 9

CubeSats
Satellites are an emerging
technology currently employed in many unique applications, such as space science
and exploration, high-speed
Internet, ship and airplane
tracking, and so on (Bouwmeester et al. 2010 and Aoudeche et al. 2018). Nevertheless,
satellites require a knotty
design and are burdened by
tradeoffs, which are very
disingenuous to balance in
this specific application.
Among those are the spacecraft development time and
price, including launch. To
overcome the deficiencies of
the aforementioned satellites, small satellites such as
nanosatellites and picosatellites, known as CubeSats,
have been proposed and
developed to mitigate from
the previously cited burdens,
resulting in different spacecraft classes, as listed in
Table 1. This class of satellite orbits in the low-Earth
orbit (LEO) and are, therefore, able to perform most
of the tasks associated with
larger satellites. Moreover,
they orbit in low orbits of other
planets like Mars (Komarek
et al. 2013).
CubeSats are modular
and scalable, where the
basic unit weights 1.33 kg or
less and occupies an area of
10 cm # 10 cm # 10 cm. This
modular structure enables a larger satellite with higherlevel capabilities, while maintaining its advantageous
simple structure and design. The need for such a smallscale satellite began to be evident as a result of research
and investigations done at Stanford University's Space
System Development Laboratory in 1998. The first CubeSats were a pair of PicoSats tied together by a short wire
launched from OPAL Launch System on 8 February 2000.
With the developments of more miniaturized components, CubeSats continued to evolve even more than
before, as depicted in Figure 1 (Kulu 2020).
The EPS is one of the main composites of satellites and
works on power generation, storage, delivery, and conditioning. Without any of these, satellites would be out of

service and could cause the failure of the whole space mission. The EPS of satellites has attracted great attention from
researchers due to the number of stringent requirements,
such as its limited weight and space, impossibility of repair,
wide range of temperatures, and severe radiation environment. These requirements can be fulfilled by using sophisticated control methods to create a robust, resilient design
of the EPS.
Lee et al. 2013 presented the design and management
of satellite power systems, wherein they investigated the
demand, characteristics, management, and design needed
to meet the required goals of the satellite power supply.
This study followed an actual nanosatellite by demonstrating some effective solutions as a case study. Lim et al.
2018 presented a modular EPS architecture for LEO satellites. The main idea is modularization to make the EPS
reusable for a variety of missions with a minimal redesign.
In this context, the energy generation and storage subsystems are modularized and the objectives of the modularization are accomplished with no compromise on power
stability and efficiency. Furthermore, for a case study of
the CubeSat KySat-2, calculations were performed for
determining the overall efficiency of the system, where
the efficiency is 71.07% when all the payloads were connected to the modular EPS.
In 2019, Djebko et al. presented a model-based fault
detection and diagnosis for the power supply of the
SONAT triple-cube nanosatellite. In this study, for the
abnormal behavior of the components, a generic, modelbased diagnosis system is presented, which detects the
abnormality to take countermeasures earlier. The
observed data of the components and the housekeeping
data are analyzed through simulation, and the expected
behavior of the component is then attained. The experimental results show that this fault-detection system
detects the abnormality, which is not predictable by
telemetry data only.
Pang et al. 2015 identified a robust scheduling and
design of a nanosatellite swarm based on bandwidth

TABLE 1. A classification of spacecraft with

mass and manufacturing time. Classification
by Bugryniec (2016).
Type

Mass (kg)

Manufacturing
Time (Years)

Large satellite

>1,000

Medium satellite

500 -1,000

Minisatellite

100 -500

Microsatellite

10 -100

Nanosatellite

1-10

Picosatellite

0.1-1

Femtosatellite

<0.1

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IEEE Electrification - December 2020

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