Starship communication system

We know that the primary use of Starship in near term will be the launch of Starlink satellites. But FCC authority to test Starlink terminals on Starship provides clues about about the future of the communication infrastructure on the Starship.

I have argued before that even though Starlink required a perfect storm of technologies coming together, the main driver was really low cost phase array terminal. But this is not revolutionary for ground segment, it also simplifies the design of the space segment communication terminals a great deal. 

Why is that? Well, the space antenna, especially in deep space, requires very precise attitude control, which often can be at odds with other requirements (such as overheating or overcooling, addressed through rotation) or insolation requirements for solar panels. Also, antenna pointing also might require mechanical stresses or excessive use of attitude control thrusters. 

How does flat phased array antennas help? Main benefit is they use electricity for beam pointing, providing much more attitude control freedom. Also, such antenna can fit the shape of the airframe, which means it can be mounted on the surface of the spacecraft without the protective shell (fairing). 

But in Starship case, there is additional benefit related to the huge size of the spacecraft. This enables seamless integration of very large phased array antennas, even consisting of several antennas that can be combined into a single antenna (providing narrower beam, higher signal to noise ratio) or splitting them into several separate antennas (providing a network hub/repeater capability). 

Enabling Starship with Starlink capability would simplify communication connectivity anywhere in LEO. Essentially Starship from the start will be able to communicate with at least 100Mbits during all mission phases with marginal cost.

If Starship will have Starlink antennas and it will work reliably in LEO...should HLS use anything different? Well, satellites can be easily deployed around the Moon too. There is one problem related to magnetorquers for attitude control which cannot be used around the Moon.

Furthermore, the space segment Starlink antennas on Starship can also be used in deep space missions. There having multiple Starlink antennas can be used to construct larger (virtual) aperture, leading to better pointing precision and total radiated power. Direct communication to the Starlink satellites will probably be out of the question (even at lunar distances the signal is five to six orders of magnitude weaker), but nothing stops SpaceX or NASA to use large ground based antennas for this purpose. Although some upgrades would be required since NASA Deep Space Network does not support Ku-band (which was initially used), but it does work with Ka-band (which Starlink is licenced to use by FCC). 

Using Starlink terminals for both LEO and deep space missions on Starship greatly simplifies the communication infrastructure, since existing Starlink satellites could be used as intermediate relay satellites without much modification. For example, each Mars mission could "drop-off" few relay Starlink satellites during Hoffman transfer phase of the mission. Effectively that would build a "Starlink" mesh network of relay nodes that would orbit between Earth and Mars. True value of such network would be communication resiliency (since there would be multiple paths between Earth and Mars at any moment) and redundancy coupled with store-and-forward type of networking even with current type of Starlink satellite hardware. 

Although deep space communication will not be a significant revenue capability for Starlink for decades to come, its inclusion to Starship will make space communication much cheaper and easy to build through standardization. Which means that we might see Dishy McFlatface become ubiquitous throughout the inner solar system.