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A report suggesting that SpaceX plans to seek government clearance for launching a colossal satellite computing array has all the makings of a space moonshot. A more constructive view of such an ambition would take it for what it really is an extremely complicated challenge in terms of systems engineering. To put the company’s plans in perspective, it is not only about the number of space vehicles to be launched. Rather, it is about whether SpaceX will be able to develop all the necessary aspects including launch cadence, spacecraft thermal control, laser networking, and mass manufacturing in unison.
SpaceX is known to be developing its next-generation Starlink satellites, however, this time they appear to have a completely different mission. While Starlink is expected to continue providing high-speed internet services, this time the payload would serve other purposes. Namely, the reported concept suggests a new mission launching thousands of orbiting AI compute nodes using solar panels and powerful laser-based inter-satellite communication channels. One particular type of the spacecraft mentioned was AI Sat Mini, implying that the technology would imply a series of identical or highly similar orbiters.
Such a mission, in contrast to previous ones by SpaceX, would be extremely challenging as far as space technology is concerned. In fact, terrestrial computing centers are characterized by multiple advantages in terms of powering up and cooling down computers. Orbital computing centers, however, should consider much more factors as far as power supply and energy efficiency are concerned. As a result, they require much better and more sophisticated thermal control technologies.
Speaking of space vehicles’ power supply, they require designing a proper structure to maximize the efficiency of solar panel usage and thermal radiation rejection. According to NASA’s guidelines, there are several challenges associated with this aspect of small satellite design. Firstly, limited availability of surface area poses limitations to both the amount of electricity produced and heat emitted. Secondly, the high energy density means that a considerable portion of the spacecraft body would have to be devoted to energy storage and transfer.
The second challenge is related to space vehicle networking as well as to the spacecraft itself. The proposed concept implies using a laser-based communication channel, which implies much higher energy requirements compared to RF communication. Therefore, the space vehicles should possess reliable and efficient attitude control systems, powerful power generators and optical equipment. What is especially challenging is the continuously changing nature of a laser network topology due to constantly changing geometrical location of the satellites.
As a result, one should understand that SpaceX’s proposal does not primarily represent a satellite program. This is a spacecraft program with a focus on networking. Therefore, one needs to develop and integrate a number of technologies including avionics and attitude control technologies. However, while the networking is essential for successful deployment, the launch is indispensable for this task to begin with. SpaceX has linked its plans for launching advanced satellites to the success of its Starship program.
Starship is believed to become SpaceX’s next-generation heavy launch vehicle with a capacity comparable to the famous Saturn rocket. Furthermore, reports suggest that this is the only vehicle which SpaceX expects to deliver larger spacecraft to orbit in the near future. Therefore, any delay in delivering Starship to orbit could postpone plans concerning orbital compute as well. In addition, launching a complex compute satellite would be expensive.
Moreover, to launch a constellation of thousands of such space vehicles, SpaceX would need to establish a factory which would be capable of producing thousands of spacecraft of similar type. That is to say, SpaceX should make sure that manufacturing process would be fast and inexpensive. Therefore, the company would need to build its own factory as opposed to modifying existing plants.
This aspect is crucial since the history shows that SpaceX’s deployment efforts were not fruitless. The ability to iterate through design and test numerous prototypes is important. This approach would be the one needed to retire the risks and build the initial fleet of satellites. Thus, it will be crucial to develop the prototypes that would allow proving energy balance, thermal stability, and optical communications reliability.
From a US perspective, the involvement of FCC is significant, however, it represents just the tip of the iceberg. In fact, the key challenge to the development of orbital compute would be the technological maturity of American infrastructure to support launch operations, spacecraft assembly and networking. This breakthrough would imply that the US industry would finally gain capabilities to design a completely new payload type.
By David Whitaker – Associate editor for aerospace and drone systems; translates flight systems and UAV developments into accessible technical stories.
