Every few years, satellite connectivity re‑enters the spotlight with headlines promising the end of terrestrial networks. Low Earth orbit (LEO) constellations and reusable rockets have fuelled claims that satellites could one day replace fibre entirely.
This article examines whether that’s feasible.
While satellite technology has improved dramatically, the idea that it could replace fibre‑based ground networks is fundamentally flawed. The two technologies serve very different purposes—and when it comes to scale, performance, reliability, and economics, fibre remains unmatched.
Understanding why requires looking beyond marketing narratives and examining the physical, architectural, and operational realities of networks.
- Physics still favours fibre
Ultimately networking is governed by physics. The speed of light in glass, and therefore in fibre‑optic cables, is approximately 2/3 the speed of light in a vacuum, offering extremely low latency, minimal signal degradation across long distances, and predictability.
Satellite connectivity, even with LEO constellations, cannot escape the issues resulting from a lack of these benefits. If nothing else, signals must travel up to space and back down.
Even under ideal conditions, round‑trip latency for LEO satellites is higher and more variable than terrestrial fibre. For time critical applications such as voice and video, microseconds matter—fibre consistently wins.
- Capacity and scalability: fibre has no real ceiling
A single fibre can carry tens of terabits per second. Capacity upgrades often require little more than minor equipment changes at each end.
Satellite systems, by contrast, are constrained by finite spectrum allocations, orbital congestion, and power constraints on spacecraft.
Each satellite must serve thousands of users simultaneously. As demand grows, per‑user performance drops unless massive new constellations are launched—at extraordinary cost.
This is why satellite networks perform best in low‑density scenarios. Fibre thrives in high‑density ones. Cities, data centres, mobile backhaul, and national infrastructure quickly outgrow satellite capacity models, and then some.
- Economics: fibre gets cheaper, satellites don’t
Fibre has a high upfront cost, but once deployed, its economics improve:
- Fibre lifespan is measured in decades (30-50 years)
- Capability is upgraded without replacing the cable
- Ongoing cost per bit continues to fall
Satellite networks invert that model:
- Satellites have a comparatively limited lifespan (often 5–10 years)
- Entire constellations must be replenished
- Launch, insurance, and space debris mitigation add cost
This is why hyperscalers, carriers, and governments continue to pour capital into fibre—even when satellite options exist.
- Reliability, resilience, and operational control
Ground‑based fibre networks are not immune to failure, but they are:
- Easier to monitor
- Quicker to repair
- More controllable end‑to‑end
Satellite networks introduce new failure domains:
- Space weather and solar activity
- Inter‑satellite handover instability
- Terminal alignment and environmental obstruction
For critical infrastructure—healthcare, emergency services, transport, energy grids, and of course Research and Education—predictability and ownership matter. Fibre allows operators to design redundancy, ring topologies, and fast‑reroute mechanisms with deterministic behaviour.
Satellite remains, by definition, shared and probabilistic.
- Security and regulatory constraints
Fibre networks operate entirely within national or privately controlled boundaries. This makes them easier to secure, regulate, and audit.
Satellite traffic often traverses international airspace, depends on foreign‑owned infrastructure, and raises complex sovereignty and compliance questions.
For governments and other regulated industries, these constraints alone rule out satellite as a primary transport medium.
- “Last Resort” vs “Last Mile”
Satellite excels where fibre cannot practically reach:
- Remote communities
- Offshore platforms
- Disaster recovery scenarios
- Temporary connectivity
This does not make it a replacement for fibre—it makes it complimentary.
Confusing “coverage” with “capability” leads to unrealistic expectations. Fibre is deployed where people live and work at scale. Satellite serves best where fibre is impossible or uneconomic.
Even mobile networks—often cited as satellite alternatives—depend heavily on fibre for backhaul. The wireless edge still terminates into glass.
- No cloud without fibre
Every major cloud provider is fundamentally a fibre operator, from data centre interconnects to subsea cables spanning continents.
Satellite plays almost no role in core cloud interconnect. The reason is simple: cloud architectures demand enormous, predictable, east‑west traffic flows that satellite cannot sustain.
If fibre was replaceable, hyperscalers would already be replacing it, but they’re not. Quite the opposite – they’re adding more.
Conclusion: horses for courses
Satellite technology is impressive, valuable, and increasingly important—but it is not a substitute for fibre networks on the ground.
Fibre wins on:
- Latency
- Capacity
- Cost at scale
- Reliability
- Security
- Longevity
- Sovereignty
Satellite wins on:
- Reach
- Speed of deployment
- Resilience in extreme scenarios
The future of networks is hybrid, not hierarchical. Satellites will continue to extend connectivity to the edges, but the backbone—economically, technically, and physically—will remain fibre.
Glass in the ground is not a legacy technology. It’s the one thing every network, including Janet, still depends on.