# Space Habitat Data Centers--For Future Computing
## 4 Proposed Solution
### Proposed Solution--SHDC Access to Computing Resources  
Inter-communication between SHDCs becomes necessary when SHDCs are in the range of space vehicles or other SHDCs have insufficient computing resources as described in C3-C5. This can be addressed by increasing SHDC computing capability or launching more SHDCs. Let \(\theta\) be the set of SHDCs.  
\[\theta=\left\{\theta_{1},\theta_{2},\theta_{3},\ldots,\theta_{J}\right\} \tag{15}\]  
The computing capability and idle computing resources of the _jth_ SHDC, \(\theta_{j},\ \theta_{j}\ \epsilon\ \theta\) is denoted \(\mathrm{C_{1}}\big{(}\theta_{j}\big{)}\) and \(\mathrm{C_{1}}\big{(}\theta_{j}\,,t_{y}\big{)}\), respectively. The mean of the idle computing resources is determined and sharedwith other SHDCs. The mean idle computing resource available on each SHDC is determined over a given duration. The \((j+1)\)_th_ SHDC \(\theta_{j+1}\), \(\theta_{j+1}\)\(\epsilon\)\(\theta\) is most suitable for data processing if  
\[\max\left(\sum_{y=1}^{Y}C_{I}\Big{(}\theta_{1},t_{y}\Big{)},\ \ldots,\sum_{y=1}^{Y}C_{I}\Big{(} \theta_{j}\,,t_{y}\Big{)}.\sum_{y=1}^{Y}C_{I}\Big{(}\theta_{j+1},t_{y}\Big{)} \right)=\sum_{y=1}^{Y}C_{I}\Big{(}\theta_{j+1},t_{y}\Big{)} \tag{16}\]  
The process of accessing computing resources in an SHDC network is shown in Figure 2. If the SHDC does not have sufficient computing resources, the workload is fragmented and processed in a distributed manner in a SHDC network.  
Figure 1: Relations between space habitat data centre, satellites, and the terrestrial segment.  
Figure 2: Steps in executing workload received from terrestrial ground station gateways (TSGWs) or space-based in low Earth orbit (LEO) satellites.  
The SHDC intended for use in Figure 2 is hosted in an international computing space station with provider-specific interfaces (PSIs). In addition, the SHDC is located in the low Earth orbit. However, it is sited at an altitude that is higher than that of the targeted small satellite networks being considered. The PSIs enable computing platform service providers to host data centres in the space habitat. The CLS, SCS, and CCS are present in each SHDC. PSIs are attached to the international computing space station via space computing nodes (SCNs). The role of PSIs, SCNs, and computing and algorithm execution entities is shown in Figure 3. Each data centre comprises a PSI through which subscribers' access computing services via the CCS. Figure 3 has 8 PSIs. The concerned PSIs is given as PSI \(x,\ x=\{1,2,3,4,5,6,7,8\}\) and are attached to the subsystem monitoring chambers via the SCNs. SCNs host sensors and enable data transfer from the PSI to the subsystem monitoring chambers.  
The architecture also shows sub-components supporting SHDC functioning. These are the living space for data centre engineers, store, and subsystem monitoring chambers. The subsystem monitoring chamber hosts components that monitor data centre performance and water availability for SHDC cooling. The store hosts the spare sub-systems and devices. It is allocated to different organizations and can be replenished by trips to the SHDC. Each PSI communicates with ground-based entities and satellites via the CCS. The SHDC's computing payload is operated by the engineers in the living space. The engineers execute maintenance procedures in a manner similar to terrestrial data centres.