Integration of Triple Junction Solar Panels
in Nanosatellite Power Systems
Ali Alqaraghuli, John L. Crassidis, PhD.
Department of Mechanical and Aerospace Engineering, University at Buffalo
There are various bits of rock and dust in space,
originated mostly from comets. In the 21st century, most
of the space debris is a result of satellite wreckage due to
failure in mission or collision with another satellite. There
are also nonfunctional satellites floating in orbit.
To prevent satellites from colliding in the future, and
protect existing satellites from space debris, the
University at Buffalo Nanosatellite Laboratory in
partnership with the Air Force Research Laboratory have
released two sister missions:
• Glint Analyzing Data Observation Satellite (GLADOS)
• Spectrometry Observation for Reflectivity Analysis
The data collecting device for GLADOS will be two visible
and near IR Cameras, while SORA uses a spectrometer.
The GLADOS prototype is shown below:
GLADOS is a shoe-box-
sized satellite, the two
cameras are also shown
in the picture. These
cameras record and
gather data from the light
reflecting off space debris,
also known as glint testing
Dr. Crassidis’ ‘Glint
Triple-Junction Solar Panels provide a broader range of
accepted wavelengths due to the three layers, and
therefore have the ability to support a more efficient
recharging system for lithium ion battery in Nanosatellite
Triple-Junction Solar Panels will be used for
the following reasons:
• Multiple junctions allow for a broader wavelength
tolerance, therefore more of the sunrays can be used to
transfer solar radiation into electrical current.
• Use of three different semiconducting materials allows
three different p-n junctions, which allows cell to be
• Theoretically, infinite junction solar panels have a
theoretical efficiency of around 84%, vs. a maximum
theoretical of 34% for single junction solar panels.
Visible light can be broken into a large array of
wavelengths represented by a different color. In a
theoretical infinite junction solar cell, all wavelength ranges
would transform solar radiation into electrical current.
Breakdown of the Solar Cells
• 26.8% Efficiency
• Up to 31 cm2 size
• Integral Bypass Diode Protection
• Transparent Insertion into Existing Systems
• Varying extreme environmental tolerance
• Three semiconductor layers, as each layer is
populated with holes of varying sizes to suite the
Research Methods Results and Conclusion
It was found that two of the three layers are activated
by infrared wavelengths, rather than visible light.
The following values are the spike wavelengths for
each one of the semiconductor layers:
A. AlInGAP: 520 nm wavelength
B. GaAs: 740 nm wavelength
C. InGaAs: 940 nm wavelength
Figure 10, 11, 12: LED power and wavelength ranges
John L. Crassidis, Ph.D., Dept. of Mechanical and Aerospace Eng.
Mara Boardman, Chief Engineer, UB Nanosatellite Laboratory
Rohan Kuriakose, Jiazhe Chen, Dept. of Electrical Engineering
The Collegiate Science and Technology Entry Program (CSTEP)
Throughout the electronic age, space vehicles have shaped
our modern civilization and created a more connected world.
Satellites are now designed to perform serious duties while
hosting smaller structures. However, with smaller satellites,
smaller solar cells need to be implemented, which can cause
a dilemma in the case of recharging the vehicle’s battery. For
a cell to maintain high efficiency at a small size, it must have
multiple junctions. For the purposes of the University at
Buffalo Nanosatellite Laboratories’ (UBNL) Space Debris
sister satellites, triple junction solar cells can provide reliable
and renewable power to small satellites to guarantee data
and command handling, in addition
to recovering power lost to tumbling.
Figure 1: Glados Integration
GLADOS will be powered
using the solar panels
integrated by UBNL, they
are formed of triple-
junction solar cells, which
will be responsible for
recharging of Lithium
Polymer battery, This
battery was chosen based
on the space environment.
Figure 3: Newtonian Visible Light Prism
Figure 4:ITJ Solar Cell Figure 5: Cell Material
Before the integration of the solar panels onto the satellite,
three tests must be performed:
1. Spectroscopy Test:
Before launching the solar panels into space, they must be
tested on ground to verify whether they can tolerate the given
wavelength ranges in the sheet. It is important to activate all
three junctions at the same time, or else leakage current can
end up harming the cells which would cause the entire
satellite power system to fail. This can be done easily using
an array of LEDs. A schematic and an assembly of LED
arrays is visualized below.
2. Environmental Chamber Test:
Following testing the full activation of three layers, the cells
must be tested for surviving the conditions through the
atmosphere and outer space, meaning extremely hot and cold
temperatures. This is done using an environmental chamber
similar to the one shown below.
Figure 6: LED Array Design via Diptrace Software
Figure 7: Printed Circuit Board Figure 8: Uniform LED Array
Figure 9: SE-300
SE-300 Thermal Chamber:
MOOG is responsible for
performing the Environmental
Chamber Test. The panels would
go into the chamber and use a
prototype for structural support.
The LED array designed above
would be facing the screen from
the outside. This is due to the
LEDs intolerance of the heating
range for the chamber, as well as
the change in light emission for
the LEDs that take place with
changes in temperature.
Guter, Wolfgang, et al. "Current-matched triple-junction solar cell reaching 41.1%
conversion efficiency under concentrated sunlight." Applied Physics Letters 94.22 (2009):
SpectroLab, a Boeing company, for providing most of the graphs in solar cell datasheet.