LEO has received a lot of attention recently, which is understandable given its potential to deliver high data bandwidth and low latency connectivity for next generation services. While investment used to be more directed toward GEO and MEO, according to McKinsey & Company, approximately 60 to 70% of space-company funding is now directed at activities in LEO.
With the planned further expansion of mega constellations in LEO over the coming years by companies such as SpaceX and OneWeb, does it spell the decline or even the death of GEO, as some would predict? Or, can GEO stay relevant and cement its role in this new environment?
The Rise Of LEO
Consider why LEO is growing in popularity... as mentioned, one of the primary benefits of LEO satellites is low latency, a result of their close proximity to the Earth. Low latency is particularly important for applications needing real time data transfer such as autonomous vehicles, tracking, voice and video communications, and online gaming.
Another reason that LEO satellites have become more popular in recent years is due to the increasing availability of launch services and the decreasing cost of satellite components. This has made it easier for smaller companies and startups to enter the satellite industry and develop their own LEO satellite constellations.
Increased activity in LEO is, however, not without challenges. As more objects are launched, the volume of orbital space debris and space traffic is increasing — this is impacting on the sustainability and safety of space operations across all orbits. To manage these challenges and reduce the risk of collisions, the industry needs more effective space situational awareness and space traffic management systems.
Another challenge of increased space activity in LEO is the allocation of frequency spectrum for communications and other purposes. The frequency spectrum is a limited resource, and as more satellites are launched into LEO, the demand for frequency spectrum increases. This can lead to congestion and interference, which can affect the quality of communications and other services.
Non-geosynchronous (NGSO) satellites and their corresponding ground stations are also more complex than GEO satellites. LEO satellites are continually having to switch teleports and ground stations need to be able to track satellites and facilitate a seamless handover from one teleport to the next. This is a highly dynamic operation that increases the probability of error which, in turn, increases the risk of interference.
GEO Vs. LEO
GEO satellites orbit at an altitude of approximately 36,000 kilometres above the Earth’s equator and remain stationary, relative to the planet’s surface. In contrast, LEO satellites orbit at an altitude of approximately 2,000 kilometres or less and circle the Earth far faster, completing one orbit in about 90 minutes.
One of the primary advantages of GEO satellites arises from their distance from the Earth, and that is their ability to provide continuous coverage over a large geographic area. This makes them particularly useful for broadcasting television signals.
While LEO satellites can also provide such services, they must be in constant motion, meaning that they can only provide coverage for a limited period of time before passing out of range. Therefore, huge mega constellations are required if LEO is to provide continuous coverage, and to do this is costly.
GEO, on the other hand, is able to provide wide ranging coverage where it is needed, using fewer satellites. Another advantage of GEO satellites is their longevity. By being stationary relative to the Earth’s surface, they are subject to less wear and tear than LEO satellites, which must constantly adjust their orbits to avoid collisions with other satellites and debris. This equates to GEO satellites having a longer operational lifespan and they require less maintenance, making them a more cost-effective option over the long term.
Added to that, GEO systems are also less power hungry than LEO and terminals are less expensive. Furthermore, GEO satellites are capable of providing high-speed data as well as cost-effective connectivity — this makes them ideal for connecting remote regions with limited terrestrial infrastructure. In fact, many developing countries rely on GEO satellites to provide internet connectivity and support critical services such as disaster response and healthcare.
While LEO may offer lower latency and equally high speeds, GEO is highly cost effective and, therefore, may well be preferable for many, particularly where there isn’t the ability or willingness to pay the premium price that LEO carries.
There has been a lot of well marketed hype building around LEO and it’s not surprising that some people see it is the silver bullet that will provide seamless connectivity to the world, replacing GEO in the process. However, as with most things that promise to be everything to everyone, we should question if LEO might in fact be overrated.
Rather than jumping on the bandwagon and shouting about LEO replacing GEO, a more sensible approach would be to recognize the many solid and long-term advantages that GEO offers,and understand that the two are not mutually exclusive.
Innovation In GEO
Just as technology has advanced for LEO, there are also important developments in GEO. Software defined payloads are becoming increasingly popular as they allow operators to provide a newfound level of flexibility. With software defined platforms, coverage, power and spectrum can all be assigned in order to meet customer demand. This is a much more efficient way of working, over time, and will also likely lead to reduced costs for end users.
There is also a trend toward a multi-orbit environment, where operators use both LEO and GEO/MEO to provide a flexible service to meet customers’ needs. Last year, Intelsat and OneWeb partnered to bring their respective GEO and LEO satellite systems together to create a multi-orbit solution to provide a connectivity solution for the aviation community. After all, end users don’t care how their connectivity is provided, so whether it uses LEO, GEO or a combination of the two, doesn’t matter to them. They just want a well performing, reliable service that provides the coverage they need.
GEO is — without a doubt — going to play a leading role in the future of satellite connectivity for a long time to come. As satellite technology continues to evolve, it’s likely there will be an increasing mix of LEO and GEO satellites both being used, with each technology playing a critical role in the global communications network.
Author Nimrod Kapon, the Founder and Chief Executive Officer of Oasis Networks, possesses extensive experience within diverse fields addressing telecom systems, from analog voice carriers, asynchronous data networks, voice networks, fiber, SDH and SONET, wireless, and satellite. He is a field engineer by training and orientation as well as a GVF qualified examiner.