## 3 Mission Analysis
### Orbital Parameters LEO Design and Selection  
The choice of orbit parameters depends on the application used in the nanosatellite in LEO. The second criterion of the orbit is the launching opportunity because most of the nanosatellite performs a technological demonstration. An additional criterion is the constellation design that should be considered for the choice. The number of nanosatellites according to their approximate orbits after launch is presented in Figure 6.  
According to Figure 6, it is obvious that a significant number of nanosatellites are launched into a 450 km circular orbit. A circular orbit with a 400-500 km interval is considered in the study presented in this paper. The main missions' requirements are the minimum revisit time, response time for 100% of coverage, sufficient access duration to uplink data, and low cost for every mission. The most appropriate orbit for the proposed missions is the LEO, which can be around 400 km of altitude. Based on these requirements, the continuous monitoring of AIS and fire detection over some regions of developing and emerging countries should be guaranteed as the main objectives of the proposed missions. For example, the two main areas of focus are the coverage provided by the AIS mission in the South China Sea, which can be helpful \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Acceptable** & **Desired** \\ \hline
**Access duration for AIS** & 7.5 min & More than 8 min \\ \hline
**Access duration for Fire** & 7.5 min & More than 8 min \\
**Detection** & 2 h & Less than 1 h \\ \hline
**Revisit time for Fire** & 3 h & Less than 1 h \\
**Detection** & 2 h & Less than 1 h \\ \hline
**Response time for AIS** & 2 h & Less than 1 h \\ \hline
**Response time for Fire** & 3 h & Less than 1 h \\
**Detection** & 3 h & Less than 1 h \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Threshold performance requirements for IoST based on AIS and fire detection. Figure 6: Nanosatellite number vs orbit parameters [38]. for many emerging and developing countries (maritime silk route), and the fire detection mission scheduled to cover forest areas in mainland China. Several designs of nanosatellite constellations dedicated to Earth coverage are conceivable; nevertheless, they are unlike in coverage duration and revisit time. Each of the cases of studies was obtained by calculations from the developed model based on the literature [39] and verified by using Analytical Graphics Inc.'s Satellite Toolkit (STK), Inc. The analysis focused on three parameters: revisit time, access duration, and response time for 100% of coverage. The constraints that must be taken into consideration while choosing the orbital elements for a successful mission analysis include the type of space mission, the various types of the constellation, and the potential for the launch to cross various orbits. Deploying nanosatellites to suitable orbits can be challenging due to their restricted launch capabilities, which force them to be transported into orbit as an afterthought aboard bigger spacecraft. An extensive orbital study based on the actual launch opportunity is necessary to decide whether a launch is appropriate for the constellation. Therefore, the circular orbit of 400 km of altitude is taken into consideration based on the available launch opportunity after numerous iterations using the trial and error method to select the ideal orbit parameters. Then, it is necessary to incline the orbit to 49 degrees to approach the southeast of the Chinese mainland, located between 110-129\({}^{\circ}\) east longitude and 29-48\({}^{\circ}\) north latitude, where forests are present [40], and the South China Sea, located between 107-114\({}^{\circ}\) east longitude and 4-17\({}^{\circ}\) north latitude, where ship navigation is extremely congested. This covers the majority of the forest areas and navigation areas in eastern and southern China.