Starlink and Airships

There is lot of excitement and curiosity globally around ‘Starlink’, the ambitious project of Elon Musk, the founder of SpaceX, which plans to offer broadband services to customers with its massive internet-from-space initiative.
Starlink aims to provide high-speed, low-cost internet access to everyone through satellite communication and provide coverage to the remotest parts of the world, which remain isolated and disconnected due to non-existent internet infrastructure set-up in these areas.

With a mission to achieve this objective, SpaceX has already launched its first batch of Low-Earth-Orbit (LEO) satellites into the orbit in May 2019. There would be thousands of LEO satellites that the organization plans to send to space in the future, which would orbit in a circular low earth orbit at about 500 kilometres altitude in a high-inclination orbit for a planned six to twelve month duration.

SpaceX intends to provide broadband internet connectivity to underserved areas of the planet, as well as provide competitively priced service to urban areas. The company has stated that the positive cash flow from selling satellite internet services would be necessary to fund their Mars plans.

Though satellite communication could provide wider global coverage, the chances of connectivity getting interrupted due to bad/cloudy weather conditions are quite high. This would mean increased latency and disrupted network issues. Satellite internet connections use microwave radio frequencies that travel in straight lines and cannot pass through solid objects. Weather affects the air between the antenna and the satellite and moisture reduces the signal. Solid objects can block satellite internet systems, so systems in tropical areas need to be constantly checked for trees growing into the path. Some trees can grow 20 to 30 feet in just a few months and what once seemed to be a clear path could become blocked.

This interruption can be greatly reduced by establishing a strong aerial infrastructure set-up somewhere between the satellites and the end users. This set-up could be in the form of airships/tethered aerostats, which are Lighter-Than-Air aircraft, deployed somewhere at an altitude of 20 kilometres or more than 65000 feet in the sky. These airships would operate as mobile towers in the sky, converting the satellite network into mobile network through the help of techno-enabled support systems. An LEO satellite sits approximately 35 times closer to the earth than a geostationary one, but still would be 50 to 100 times higher than the airship stationed in the stratosphere. These air mobile towers would serve as an effective terminal between the satellites and ground systems, increase network efficiency and thus become the backbone of a new kind of aerial internet infrastructure.

The mobile phones, we use, do not have the functionality to support satellite internet, which means SpaceX expects all the users to replace their existing mobile handsets to an instrument which would be compatible with their satellite network. This is quite an unrealistic expectation and could pose a real challenge for the organization to achieve its goal.

SpaceX’s plans include setting up millions of ground stations that would be used by customers of the starlink satellite internet service. These stations would rely on a flat-panel, phased array system to transmit and receive signals in the ku-band to and from the starlink constellation. However, setting up this kind of an infrastructure would require huge investment and might become a major obstacle in the organization’s endeavour to provide a low-cost internet service to remote areas.

Starlink plans to have a pizza-box sized phased-array antenna, which is again an expensive proposition. The expensive part is all the digital phase control circuits that are needed to actively steer the antenna beam. Large part of population may not be able to afford such an expensive antenna and though the antenna’s size would be of a pizza-box, it still cannot be expected that users carry it everywhere along with them.

This problem can be solved by considering the cost benefits that the techno-enabled airship towers can offer by converting the satellite network into a mobile network and also minimize the difficulties for a user to switch from one network to another.

Since airships would stay at an elevated altitude, they would be able to offer a much wider coverage. Wireless coverage from one autonomous aerostat could be equivalent to more than 15 cell towers. Using latest technologies of ML, AI and IOT, these aerostats can operate autonomously and require significantly less infrastructure to get up and running, the cost to deploy them would be about 60% less than that of setting up cell phone towers and would be much lesser than the cost of setting up millions of ground stations and antennas for satellite internet.

With Space X’s goal to provide internet connections to people in rural and remote areas of the world and also have a competitive edge in pricing in urban areas, deploying airships as mobile towers could be a game-changer and expedite the journey of provision of affordable internet to everyone.