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Published: 29 June 2023

Space-Based Data Centers and Cooling: Feasibility Analysis via Multi-Criteria and Query Search for Water-Bearing Asteroids Showing Novel Underlying Regular and Symmetric Patterns

,
and
1
Electrical, Electronic and Computer Engineering, Cape Peninsula University of Technology, Bellville 7530, South Africa
2
Electrical and Electronic Engineering Technology, University of Johannesburg, Johannesburg 2092, South Africa
*
Authors to whom correspondence should be addressed.
Symmetry2023, 15(7), 1326;https://doi.org/10.3390/sym15071326
This article belongs to the Section Engineering and Materials
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Abstract

Space-based data centers (SBDCs) are environment-friendly and do not make use of Earth’s water resources for cooling. The cooling of SBDCs can be realized via using water aboard asteroids. The feasibility of this approach requires further consideration and has not received sufficient research attention. The study being presented investigates the existence of water-bearing asteroids whose water resources can potentially be used for cooling the server payloads aboard the SBDC. This is undertaken by executing multi-criteria search queries on the Asterank asteroid database. Data analysis shows that water can be accessed from asteroids at less than 0.26 AU by privately owned space vehicles designed for Earth-to-Mars missions. In addition, the results of data analysis show that there is a regularity and symmetric pattern among different asteroids. This arises as asteroids with different identities have the same near-Earth distance and upcoming approaches.

1. Introduction

Data centers have been recognized as having a significant water footprint []. This high-water footprint can be reduced by siting data centers in space. Space-based data centers enable the low-latency transfer of low-Earth-orbiting satellites. These data centers can also be cooled using water from asteroids. The discussion in [] investigates the feasibility of using water aboard asteroids for cooling space-based data centers. This is undertaken by analyzing asteroid data from asteroid databases. An example of a suitable asteroid database is the Asterank database []. The information in the Asterank asteroid database has been compiled with the aim of making a case for the commercial appeal of asteroid mining [,].
The study and the data analysis conducted in [] have not considered the execution of multiple criteria searches on the Asterank database. The conduction of a multi-criteria search query is helpful in obtaining data, information, and insights on the suitability of different asteroids for use in the potential mining of water to cool space-based data centers.
The study being presented focuses on identifying suitable asteroids when different criteria are considered. The suitable asteroids are those that have water and are suited for cool space-based data centers hosted in a space habitat environment. The criteria are cost-effectiveness, profitability, and upcoming approaches from 2023 onward. Accessibility by privately owned space vehicles is also considered in the analysis and identification of suitable asteroids. The motivation here is to identify the cost-effective and easily approachable asteroids that have water content and potential accessibility by privately owned space vehicles. This rationale has not been addressed in [] but is considered in the study being presented. In addition, the presented study opines that space habitat-hosted data centers (in outer space) will be used by private cloud-computing organizations.
The Asterank database has been considered for use in the search in the proposed study. This can be found in the study presented in [,,,,]. The discussion in Ridgway [] recognizes the evolution of the use of data in the domain of astronomy. In this regard, the Asterank database has been identified as an example of a database suitable for providing data enabling the use of asteroid-related data for purposes involving probable commercial intents. In addition, the discussions of Jensen [], Crawford et al. [], Dahl et al. [], and Pasko [] recognize the suitability of using the data aboard the Asterank database in research. The discussion in Dahl et al. [] notes that the Asterank database was acquired by Planetary Resources. Prior to this acquisition, the Asterank database was populated by data derived from observations conducted by the Jet Propulsion Laboratory’s Small-Body Database and Minor Planet Center []. The Jet Propulsion Laboratory and the Minor Planet Center are recognized as leading research centers in space sciences. Hence, the use of the data found in the Asterank database for research purposes is credible.
Research Contribution:
The presented study addresses the use of non-terrestrial computing platform entities with a focus on space-based data centers. The use of the space-based data center is recognized to be beneficial because of its non-reliance on Earth’s water resources. In addition, the use of space-based data centers is environment-friendly. The use of space-based data centers hosting computing payload, i.e., servers, requires cooling. However, additional research is required to investigate the suitability of using asteroid water resourcesdue to the necessity of cooling the servers that constitute the computing payload in the space-based data center. The water aboard asteroids has been identified to be a suitable coolant for the space-based data center. However, the feasibility of using the water aboard asteroids for this purpose requires additional consideration in research. The presented study considers the search for suitable asteroids using different search conditions. Each of these conditions constitutes a criterion in a multi-criteria approach. The criteria consider factors such as cost-effectiveness, near-access date, and near-access distance.
The study proposes the use of water to cool space-based data centers. The concerned data centers are aboard space habitats. The space habitat is solar powered, has a cooling system, and processing facilities enabling the processing of water obtained from asteroids and then using this for cooling. However, the cooling process and associated processing require the availability of water from the asteroid. The study presented is set in the context of conducting analysis to identify suitable asteroids.
The presented study conducts an analysis of the upcoming approaches (future dates). The upcoming approaches and associated future dates are for asteroids that are deemed to be commercially viable and have water content. In addition, information on asteroids with upcoming passes and water-bearing status is also presented in the study and data analysis. In addition, the study also examines the feasibility of using the distance to the Earth at an upcoming approach to determine the ability of privately owned space vehicles to visit identified asteroids. This extends the research in [] by investigating the viability of using high-profit asteroids to obtain water for cooling space-based data centers. Furthermore, the presented study examines the effectiveness of using another search approach instead of the Asterank database approach presented in [] with regard to determining the potential of obtaining water from an asteroid.
In addition, the study being presented significantly extends the research in []. The research work presented in [] focuses on how the use of space-based data centers has the capacity to reduce latency associated with data transfer. In [], the data transfer is performed in the context of transmitting data from big data space applications (alongside satellites) to data centers for storage and processing. However, the research here significantly extends [] by focusing on the cooling of the computing platform, i.e., space-based data center.
The investigation of the suitability of the research is conducted using the quantitative research approach. The focus is on the numerical parameters that describe the suitability of an asteroid as being capable of providing water for the intended cooling of space-based data centers. This arises because of the important role that parameters and data such as near-Earth access date, i.e., epoch, distance, and estimated profitability, play in determining the suitability of identified asteroids.
The rest of the study is organized as follows. Section 2 presents the background work. Section 3 presents data on asteroids that are deemed most profitable. In this case, the concerned asteroids have water content. It presents data and discusses information on asteroids with recently upcoming epochs of near-Earth passes of water-bearing asteroids. The estimated profit associated with each asteroid is also presented. Section 4 discusses the water-access feasibility from a space vehicle capability perspective. Section 5 is the conclusion.

3. Data on Profitable Water-Bearing Asteroids

The information and data on asteroids having water are presented in this section. The water found aboard asteroids is used in cooling the server payload aboard space habitats. Space habitats have been used to host the server payload constituting the space-based data centers. Space habitats have been used because they have the capability to support human living in space. They provide support for protecting humans from radiation arising from space environments. Hence, they are suitable for hosting servers and computing payloads in the outer space environment. The use of friendly and radiation-resistance habitats has been found to be suitable for hosting humans, as seen in [,,,,]. Therefore, space habitats can support servers and computing payloads in a manner that overcomes the effects and challenges arising from space weather and radiation. Furthermore, the space habitat will be powered via onboard solar panels.
Yarlagadda [] notes that there has been a significant advance and progress in mining water from asteroids. The advances provide a thrust for the consideration of using water aboard asteroids in the proposed computing application. A similar application perspective is found in []. The notion in [] and [] is that it is technologically feasible to mine water from asteroids.
The proposed use of asteroid water for cooling space-based data centers occurs in a manner such that a space vehicle is deployed to the water-bearing asteroid. The deployed space vehicle mines water and supplies the water to the space-based data center for cooling its payload. In addition, the space habitat-based data center also incorporates a cooling subsystem whose details are like those in existing work [].
The search query has been executed by selecting the most valuable as the search criterion in the query menu option. All the listed asteroids have estimated values and profits that exceed $100 t. The information on the asteroids and their approaches, as found in the Asterank database, is presented in Table 1.
Table 1. Highly Profitable Water-Bearing Asteroids with Profits exceeding ($100 trillion).
From Table 1, there is a small number of P-type asteroids that bear more water in comparison to other elements. This inference has been reached because P-type asteroids have been deemed to comprise water in the Asterank database.
In addition, it can also be noted that the access dates for all types of asteroids concerned lie in past epochs, i.e., between the years 2001 and 2006. However, it is important to ascertain the number of asteroids with a water content that have a near-Earth pass at an upcoming epoch. The concerned data are extracted by executing a non-automated search for asteroids with future scheduled upcoming passes and later verifying their water-bearing status. The concerned asteroids are those with upcoming near-Earth status from the year 2023 and onward. The associated data in this case are presented in Table 2. In accessing the information on the data presented in Table 2, it is noted that the information in the column on the asteroid type is empty for some of these asteroids. Hence, the resources aboard the listed asteroids have not been presented. Nevertheless, these asteroids are potential water-bearing asteroids. Therefore, they have been listed in the results of the data analysis. Furthermore, the data presented in Table 2 show a regular and symmetric pattern in the number of near-Earth approaches. Some of the asteroids such as 1999 CG9 and 2010 TW54 have a similar number of near-Earth approaches (exceeding 10) and near-Earth years in the years 2023–2073.
Table 2. List of potential water-bearing asteroids with upcoming approaches from 2023 onwards.
In Table 2, the information on the number of near-Earth approaches has been obtained from the Asterank database.
From the information in Table 2, up to 20 asteroids have near-access periods lying onward from the year 2023. Two of these asteroids, i.e., the 3671 Dionysus 1984 KD and 3833 Calingasta 1971 SC, are found to have water content. The passes indicated for the 3671 Dionysus 1984 KD are (1) 3 September 2023—distance of 0.483 astronomical units (AU), (2) 19 May 2059—distance of 0.316 AU, (3) 29 May 2072—distance of 0.147 AU, (4) 18 June 2085—0.028 AU, (5) 15 August 2098—0.276 AU, (6) 23 May 2134—0.264 AU, (7) 23 June 2147—0.047 AU, (8) 30 August 2160—0.376 AU, (9) 25 May 2183—0.236 AU, and (10) 22 July 2196—0.167 AU.
In Table 2, the cases where the water-bearing asteroids are indicated as being not available do not necessarily imply the non-availability of water. Asteroid characterization is deemed incomplete as the information on the asteroid type is not available in the Asterank database. In addition, the 3833 Calingasta 1971 SC and 3671 Dionysus 1984 KD that are identified to have water content have estimated profits of $2.15 t and $304.03 b, respectively.
Furthermore, the study also examines the feasibility of conducting the search using the queries ‘closest approaching’ and ‘most accessible’ and presents data on a list of water-bearing asteroids. However, these search queries have not been used. They do not directly depict the cost-effectiveness of the concerned asteroid. The data analysis also recognizes the importance of cost-effectiveness in accessing water-bearing asteroids. However, the most suitable query considered for obtaining water from asteroids is using the search for finding the most cost-effective water-bearing asteroids. The concerned search is executed by using the search query ‘most cost effective’. The names, values, and estimated profits alongside the associated profits are in Table 3.
Table 3. Identity and Details of most cost-effective Asteroids.
In a manner such as the data presented in Table 2, there is a similarity in the approach epochs across multiple epochs. For example, the asteroids 175706 1996 FG3, 308635 2005 YU55, and 136793 1997 AQ 18 have their near-Earth approaches exceeding 10 and spanning the years in the range 2027–2177.
In Table 3, the information on the profit in ($) has been obtained from the Asterank database. The Asterank database is a credible source of data suitable for research, as seen in [,,,,].
The data in Table 3 present the asteroids that have water and are most cost-effective for space-mining applications. There are 26 asteroids with known upcoming approach dates. The accessed data from the Asterank asteroid database also show that the recognized asteroids have appreciable profitability and a number of upcoming approaches. The asteroids 3671 Dionysus 1984 KD and 3833 Calingasta 1971 SC identified from Table 2 are also identified to be among the most cost-effective water-bearing asteroids. Hence, the analysis, whose results are presented in Table 3, is beneficial in confirming the status of these asteroids.

4. Feasibility of Water Access Aboard Asteroids—Space Vehicle Capability Perspective

The presented study also extends [] by evaluating the feasibility of visiting and sojourning to an asteroid by a given space vehicle. Different types of space vehicles that can be used for space mining, i.e., accessing resources aboard asteroids, are Landers [] and Spacecraft []. Vehicles that can travel from Earth to Mars can be used in visiting asteroids and executing water-mining processes. The distance from Earth to Mars is given as 78,340,000 km and 0.52 astronomical units (AU). In this case, privately owned space vehicles have been considered. The use of water to cool space-based data centers is envisioned as a private sector-led industry. Examples of suitable private space vehicles are Starship Spacecraft (SpaceX) [,], Blue Moon (Blue Origin) [], Boeing Starliner Spacecraft [], and SpaceShipTwo Spacecraft [].
The SpaceX Starship spacecraft is designed to service satellites in Earth’s orbit and execute missions to the Moon and Mars []. As seen in [], the space Starship can also convey cargo exceeding 100,000 kg. It is recognized that the Blue Moon lander, Starliner spacecraft, and SpaceShipTwo spacecraft are designed for missions to the low-Earth orbit and the Moon. These are not suitable for asteroid access as the maximum distance they can travel is 0.0025 AU which is significantly less than 0.52 AU (Earth to Mars distance). Furthermore, the data in [] show the increased focus of the private sector on Lunar-based missions.
The data showing the identification of profitable water-bearing asteroids with the access dates and corresponding distance in astronomical units are presented in Table 4. The asteroids in Table 4 are those for which the travel distance is 0.26 AU. The distance of 0.26 AU has been considered because the suitable space vehicle is assumed to have 50% travel distance efficiency. In addition, the estimated profit of the concerned asteroids is presented. This case is performed by selecting the search criterion ‘most cost effective’.
Table 4. List of most cost-effective asteroids accessible by privately owned vehicles.
Analyzed data in Table 4 show that certain asteroids have orbital mechanisms with symmetric patterns enabling the realization of the same access distance across different access dates. The concerned distance in this case is 0.122 AU for asteroids 14402 1991 DB (25 March 2128) and 3288 Seleucus 1982 DV (30 April 2156). This is also observed for the distance of 0.121. In this case, the asteroids demonstrating the symmetric pattern are 308635 2005 YU 55 (31 October 2036) and 11066 Sigurd 1992 CC1 (9 September 2091).
The data presented in Table 4 are an inexhaustive list of asteroids with suitable water resources. The information in Table 4 has been obtained from the Asterank database due to its suitability for the concerned research, as seen in [,,,,]. In addition, the access dates, distance, and profit associated with each asteroid are also presented.
The data presented in Table 4 show that 20 asteroids are deemed to be cost-effective and capable of providing access to water. In addition, the near-Earth approach in all cases falls short of 0.26 AU. Therefore, the proposed approach of accessing water from asteroids for cooling space-based data centers is feasible due to the availability of water-bearing asteroids and privately owned space vehicles.
The discussion in the presented study has presented an analysis of the suitability of using water aboard asteroids to cool space-based data centers. The discussion in the study recognizes existing work showing that water is a composition of asteroids [,,,,,,,]. The focus of the study is the use of this insight on asteroid composition to evaluate the feasibility of an asteroid water-cooled space-based data center application. In this regard, a central repository such as the Asterank database has been recognized and serves as the source of the asteroid data. The Asterank database has been accessed as the main repository for accessing asteroid-related data. The analysis has focused on identifying water-bearing asteroids with high profit when mined, as seen in Table 1. The results in the case show that there are 41 suitable water-bearing asteroids. In addition, the feasibility of asteroids with future access periods from the year 2023 is also considered. In this case, 24 asteroids have been identified and are shown in Table 2. The consideration is important and has been undertaken because some asteroids have near-Earth access periods in the years prior to 2022. Further refining the list of suitable asteroids focuses on identifying the most cost-effective asteroids. In this case, the concerned asteroids are those that have water suitable for potentially cooling space-based data centers. In this case, the procedures show the list of asteroids presented in Table 3. The number of asteroids in this case also exceeds 20. Ease of access is considered as an important criterion in the results presented in Table 4. In this case, a threshold near-Earth distance is considered. This threshold distance is chosen to be 0.26 AU. This is undertaken considering the ease of access by privately owned space vehicles. The results of the analysis consider that there are advances in privately owned space vehicle capabilities. The results of the analysis, as presented in Table 1, Table 2, Table 3 and Table 4, show that there is a feasibility of asteroids that can potentially provide water for cooling space-based data centers.

5. Conclusions

Advances in computing and the need to process increasing amounts of data from deployed data-acquiring satellites necessitate the provisioning of computing assets. The use of space-based data centers enables the low-latency transfer of satellite data for storage and processing. Space-based data centers host server payloads and use water aboard asteroids for cooling. The discussion in this study presents an analysis of data on the water-bearing status of asteroids. The analysis has been conducted with the aim of investigating the suitability of asteroids as having water resources suitable for use in the cooling of the space-based data center. This was conducted while considering the near-access distances and associated dates. It is found that up to 20 water-bearing asteroids with a near-Earth distance that is less than 0.26 AU and with appreciable profitability can be found from the analysis in the Asterank database. The data are obtained from Asterank, an asteroid database developed by Planetary Resources, and which uses data from the Jet Propulsion Laboratory Small-Body Database which is driven by observation-related data from NASA. The data obtained and analyzed show that it is feasible for privately owned space vehicles to access water-bearing asteroids while executing a single trip of less than 0.26 AU. In addition, the analysis of the presented data shows that there is a symmetric pattern among different asteroids with regard to the near-access dates. In this case, the identified asteroids have the same near-Earth approach distance, signifying that there is a similarity in their orbits as they approach the Earth on their different near-Earth approach dates. The discussion in the presented study has focused on determining the feasibility of using water-bearing asteroids for cooling space-based data centers. The use of privately owned space vehicles has been identified to be crucial for accessing water-bearing asteroids. This study has identified the existence of feasible water-bearing asteroids. Future work will focus on examining how advances in privately owned space vehicles enable the realization of the proposed water-cooled space-based data centers. In addition, the design of a network architecture considers the ease for accessing the water resources aboard suitable asteroids. Furthermore, the viability of using water-bearing asteroids for the purposes of cooling space-based data centers will also be examined. This will be performed by examining evolving data found aboard asteroid resource databases such as Asterank. The study presented also invokes the need to develop technological solutions for asteroid mineralogy and mining. In this case, asteroid mineralogy involves the conducting of a search for water and the liquefaction of water for the intended cooling. In this regard, it is important to design asteroid-specific techniques capable of mining water from diverse types of water-bearing asteroids.

Author Contributions

A.P., conceptualization, writing—original draft preparation, visualization; A.A., methodology, resources, supervision, project administration, writing—reviewing and editing; K.O., supervision, project administration, writing—reviewing and editing. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding, and The APC was funded by the Cape Peninsula University of Technology and the University of Johannesburg.

Data Availability Statement

All utilized data can be accessed on the Asterank Database.

Acknowledgments

The support of the Cape Peninsula University of Technology and University of Johannesburg is acknowledged.

Conflicts of Interest

The authors declare no conflict of interest.

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