# Survey on Unmanned Aerial Vehicle for Mars Exploration: Deployment Use Case
## 2 Space Exploration through Different Methods/Vehicles
### Space Exploration through UAVs
#### 2.1.2 Venus UAVs  
Venus certainly has an Earth-like air pressure, which implies that the flight power needed is smaller than other planets. Thus, the analysis has also been performed on UAVs that can fly in the atmosphere of Venus. The incredibly slow rate of rotation of Venus results in a very long solar day. This means that the ground speed needed to stay at the sub-solar point for an aircraft is incredibly slow, at the equator just 13.4 km/h [35]. In article [36], a solar-powered aircraft system has been proposed for Venus exploration. Large aircraft are more powerful than tiny aircraft. As the flight of an aircraft with a wing area of 1-2 square meters is feasible, building larger and more efficient aircraft is also possible.  
Article [35] suggested the notion of a small solar-powered UAV floating over Venus' cloud cover. The design was carried out based on the Pioneer-Venus small atmospheric probe scale to reduce the mission expenses. It was supposed that the UAV would fit inside the probe aeroshell. In article [37], a study was carried out to determine the feasibility of using an aircraft as a long-duration flight platform inside the atmosphere of Venus. The power plant for the vehicle had to be capable of working for prolonged periods to accomplish a long-range flight. A solar energy control system using a photovoltaic array as the main power source was analysed to assess their flight altitude range in order to do this. This study was conducted for a station-keeping mission in which the vehicle had to sustain a flight over a ground area. This requires that the vehicle, at a given altitude, is able to travel faster than the wind speed. This study was also carried out to determine the altitude range and maximum length of a vehicle not necessary to operate the station at a given site. The findings of the study indicate that inside some areas of Venus' atmosphere, each type of flight vehicle and power device is capable of flying. The aircraft is a functional framework for both station-keeping and non-station-keeping activities.  
In [38], the authors consider using a cycloidal blade system to construct a stopped-rotor cyclo-copter vehicle during a mission to Venus as a means of supplying lift and propulsive thrust and in conjunction with a stopped rotor system. This stopped-rotor cyclo-copter would fly for experimental investigation at all atmospheric depths of Venus and land on the Earth. In RotCFD, three conceptual reference models of varying stopped-rotor cyclo-copter yaw angles are tested, and a hovering cyclo-rotor model for comparison with the recent literature work and groundbreaking testing future projects. Table 2 shows the comparison between the parameters of various Venus UAVs.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**References** & **UAV** & **Power Supply** & **Range (km)** & **Endurance** & **Mass (kg)** & **Wingspan (m)** \\ \hline
[18] (1975-1982) &
\begin{tabular}{c} Mini-Sniffer \\ Aircraft \\ \end{tabular} & - & 70 & 1 h & 75.7 & 6.7 \\ \hline
[19] (1978) & Astroplane & - & 10,000 & & 300 & 21 \\ \hline
[5,25] (1998) & MAGE & - & 1800 & 3 h & 135 & 9.75 \\ \hline
[26] (1999) & Canyon Flyer & - & - & 15 min & 20 & 2.2 \\ \hline  & \
\begin{tabular}{c} 1. ARES-1 \\ Aeroplane \\ \end{tabular} &
\begin{tabular}{c} Li/MnO\({}_{2}\) batteries for \\ electrical power \\ \end{tabular} & - & - & & \\ \cline{2-6}  & 2. ARES-2 & & & 175 & 6.25 \\ \hline
[27,28] (2008) & ExoFly-DelFly 2 & Solar & 10 & 12 min & 0.02 & 0.35 \\ \hline
[29, 30, 31, 32] (2014) & Mars Helicopter & Solar & - & 1.5 min & 1.8 & - \\ \hline
[33,34] (2017) & Marsbee & - & - & - & \(2.14\times 10^{-4}\) & - \\ \hline \hline \end{tabular}
\end{table}
Table 1: Comparison in the parameters of various Mars UAVs.