GALLIUM ARSENIDE SOLAR CELLS ON UNMANNED AERIAL VEHICLES AND THEIR IMPLICATION IN THE MILITARY

Sarah Wielgosz | Michael Lincoln | Keai Yao

Unmanned Aerial Vehicles and the SBXC Ethics and Sustainability How Solar Cells Work Sailplane • Solar cells convert sunlight to electricity using • Unmanned aerial vehicles (UAVs) are any type of • Military drones allow for precision targeting that semiconductor materials aircraft that does not have an onboard human pilot minimizes casualties in theory • Photons from sunlight strike the semiconductor. If • They are used for purposes such as photography, • Due to the nature of the job, this is not always the the photon has a high enough energy of impact, it search and rescue missions, and in the military case. Strikes are sometimes conducted on targets that excites an electron • The Naval Research Laboratory modified the fit the profile of an enemy. Thus, civilian casualties • The electron travels across a gap in the company RnR’s model SBXC Sailplane with GaAs still occur, though the aim is to minimize them semiconductor to a region where its energy is solar cells from Alta Devices • On military drones, or drones of any kind, solar captured (shown below) • Flight time increased from 4 hours with only battery panels would be sustainable by replacing batteries • Solar cells have a maximum power to 11.2 hours with GaAs solar cells (wing with that are made from toxic chemicals, which harm the theoretical energy efficiency Alta Devices cells shown to right) environment upon disposal by polluting water and of 33.5% • Alta Devices’ solar cells were the soil • Solar energy is a popular easiest to attach to the sailplane • In a broader sense, solar panels are sustainable source of renewable energy compared to other cells because they provide clean energy and replace harmful nonrenewable energy sources, such as fossil Gallium Arsenide Solar Cells Application to Drones in the Military fuels • To minimize the negative effects in drone warfare, one needs to think sustainably, seeing through a broad • They are made using the semiconductor gallium • Drones in the military are used in intelligence, viewpoint that acknowledges the positive and arsenide (GaAs) surveillance, and reconnaissance missions to gather negative consequences that actions have across all • GaAs solar cells are advantageous compared to more information about the enemy. They are also people, society, and future generations traditional silicon solar cells for many reasons: weaponized with missiles • Lightweight – they do not weight UAVs down • With, single junction GaAs solar cells on weaponized • Flexible – they are easy to affix to UAVs drones, drones will be able to fly for longer periods of • Energy efficient – they generate higher amounts of time or carry larger payloads (i.e. missiles) Image showing the energy compared to silicon solar cells • Operators can survey situations for extended periods modified SBXC • Weather resistant – they are less susceptible to of time, thus ensuring they have the right target sailplane damage from wind and ultraviolet radiation • Current development on resupply drones may allow constructed by the • Alta Devices, a California based future drones to bring supplies to Naval Research company focused on producing troops on the dangerous front lines Laboratory solar panels, developed a GaAs • GaAs solar cells would allow such solar cell with a record 29.1% drones to carry more supplies a efficiency (shown to the right) farther distance