# Space Habitat Data Centers--For Future Computing
## 6 Feasibility and Performance Evaluation
### Performance Evaluation and Benefits--Computing-Resource-Related QoS  
The performance evaluation also examines how the use of the proposed SHDCs enhances the quality of service (QoS) for satellite-computing-based applications. The analysis presented in this section is important to demonstrate that the use of the proposed SHDC enhances computing related QoS in the context of space=based computing. In the existing context, i.e., [PERSON] et al. [19], where space edge computing paradigm is used, recourse to terrestrial computing platforms becomes necessary when computing resources aboard space edge computing platforms are exhausted. The existing scenario being considered in this simulation is one in which the use of computing resources aboard space edge computing platforms is infeasible. This arises when all computing resources aboard space edge computing platforms are currently being used for processing data obtained from deployed and in-orbit satellites. Two performance metrics have been examined. These are the computing resource access latency and the amount of accessible computing resources. The parameters used to investigate the compute resource access latency and the associated performance benefits are investigated using the parameters shown in Table 3. In this regard, the simulation discusses the results of performance evaluation from the perspective of accessing the entity hosting the computing resources. In Table 3, the link speed is of the order of gigabits per second and megabits per second. This range of values is considered feasible for realistic satellite communications as seen in [PERSON] et al. [50]. Furthermore, the size of satellite data is of the order of kilobytes and megabytes. This is also considered feasible for satellite applications as seen in [PERSON] et al. [50]. \begin{table}
\begin{tabular}{c l l} \hline \hline
**S/N** & **Parameter** & **Value** \\ \hline
1 & Number of satellites in space segment & 10 \\ \hline
2 & Number of epochs & 15 \\ \hline
3 & Maximum Size of Data–Satellite [1, 2, 3, 4, 5] & [1.48, 1.47, 1.25, 1.33, 1.45] Mbytes \\ \hline
4 & Maximum Size of Data–Satellite [6, 7, 8, 9, 10] & [1.42, 1.47, 1.41, 1.46, 1.33] Mbytes \\ \hline
5 & Minimum Size of Data–Satellite [1, 2, 3, 4, 5] & [1.04, 148.9, 353.6, 317.9, 852.81] Kbytes \\ \hline
6 & Minimum Size of Data–Satellite [6, 7, 8, 9, 10] & [12.37, 82.31, 92.30, 113.00, 6.71] Kbytes \\ \hline
7 & Mean Size of Data–Satellite [1, 2, 3, 4, 5] & [866.37,777.78,567.04,917.37,811.12] Kbytes \\ \hline
8 & Mean Size of Data–Satellite [6,7, 8, 9, 10] & [718,665.93, 920.20, 844.61, 763.45] Kbytes \\ \hline
9 & Maximum Link Speed–Satellite [1, 2, 3, 4, 5] & [2.99, 2.98, 2.92, 2.93, 2.68] Gbps \\ \hline
10 & Maximum Link Speed–Satellite [6, 7, 8, 9, 10] & [2.82, 2.73, 2.69, 2.76, 2.83] Gbps \\ \hline
11 & Minimum Link Speed–Satellite [1, 2, 3, 4, 5] & [380.17, 380.57, 930, 280.8, 124.44] Mbps \\ \hline
12 & Minimum Link Speed–Satellite [6 7 8 9 10] & [32.67, 237.97, 776.48, 107.31,156.90] Mbps \\ \hline
13 & Mean Link Speed–Satellite [1, 2, 3, 4, 5] & [1.47, 1.87, 2.01, 1.69, 1.28] Gbps \\ \hline
14 & Mean Link Speed–Satellite [6, 7, 8, 9, 10] & [1.395, 1.49, 1.26, 1.25, 1.35] Gbps \\ \hline
15 & Altitude–Satellite [1, 2, 3, 4, 5] & [780.5, 791.0, 711.6, 631.04, 766.63] km \\ \hline
16 & Altitude–Satellite [6, 7, 8, 9, 10] & [798.7, 760.4, 614.1, 574.4, 759.9] km \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Compute resource access latency simulation parameters. The compute resource access latency is evaluated for the existing scheme without and with the use of forwarding links. The compute resource access latency (compute platform access latency) for terrestrial data centres, stratosphere-based data centres, and the SHDC without forwarding links is shown in Figure 6. The analysis shows that using HAP computing platforms and SHDC instead of terrestrial computing platforms reduces the compute resource access latency by 11.9% and 33.6% on average, respectively.