SES O3b and O3b mPOWER show how medium Earth orbit can support broadband transport. Their useful comparison with LEO systems involves footprint, tracking, configurable beams and service performance, rather than satellite count alone.
Reviewed October 30, 2026. Dates distinguish operating services, launch announcements and future plans. Published capacity figures describe their stated configuration; they are not guaranteed performance for every terminal.
Contents
Executive Summary
The table separates the service, orbit and technical distinctions used throughout this note.
Topic | Summary |
|---|---|
Orbit | MEO, approximately 8,000 km |
Generations | Original O3b and second-generation O3b mPOWER |
Service | Broadband transport for enterprise, mobility, government and backhaul |
September 2026 milestone | Final three mPOWER satellites launched; commissioning is a separate step |
Why MEO for Broadband ?
O3b occupies the middle ground between low and geostationary orbit. A higher orbit covers a wider region per satellite, but increases path length. The engineering question is how to balance that geometry with terminal throughput and tracking.
Orbit and the ground terminal
SES places O3b mPOWER at approximately 8,000 km in medium Earth orbit. Satellites move relative to a ground terminal, so the terminal and network must manage tracking and transitions between usable spacecraft. [1]
For scale, an idealized vertical ground-to-satellite-to-ground path at 8,000 km takes about 53 milliseconds in free space. A round trip takes about 107 milliseconds before adding slant range, processing and terrestrial routing. This calculation uses distance divided by the speed of light; it is not an SES service-latency measurement.
A larger footprint can reduce how often the network changes satellites compared with a lower orbit. It does not remove antenna tracking or make every point on Earth equally well served. The service footprint, minimum elevation and gateway design still limit a real connection.
From fixed capacity to configurable beams
The O3b mPOWER design uses software-controlled capacity and electronically generated beams. SES contrasts this with the smaller set of mechanically steerable user beams on the original O3b satellites. The improvement concerns resource placement, not unlimited total power. [1]
A network can direct capacity toward a ship, an island gateway or a government site as demand changes. However, bandwidth, transmit power and terminal capability remain finite. Allocating more resources to one service may reduce resources available elsewhere; beam flexibility is a scheduling capability rather than new spectrum.
Figure 1. Rows compare functional roles or dated states. Boxes are explanatory and are not a measured traffic trace.
Deployment, Service and Practical Limits
A broadband constellation should be described with both its launch state and its commercial-service state. A spacecraft can be successfully launched yet still need orbit raising, testing and network integration before it contributes customer capacity.
Original O3b and mPOWER milestones
SES identifies the original O3b system as a 20-satellite constellation and mPOWER as a 13-satellite system. Its September 13, 2026 release announces the launch of mPOWER satellites 11, 12 and 13, joining ten already operating spacecraft. [1] [2]
That wording distinguishes launched from operational. This note does not assume that all thirteen were in commercial service immediately after the final launch. O3b mPOWER had already begun commercial service in April 2024, so deployment expansion and service operation overlap. [3]
RF and network design questions
O3b is a Ka-band broadband system. A complete deployment needs the exact licensed uplink and downlink assignments, terminal antenna specification and link budget. The broad Ka-band name alone is insufficient to configure a carrier. [4]
Rain attenuation can reduce margin at these frequencies. Adaptive coding and modulation can maintain connectivity by reducing useful rate, while site diversity can reduce dependence on one weather-affected gateway. The resulting availability depends on the actual RF and network design, not simply the constellation name.
Comparison item | What to check |
|---|---|
Latency | Measured round-trip application delay, not only orbital propagation |
Throughput | Committed rate, peak rate, contention and terminal limit |
Mobility | Tracking, handover continuity and installation constraints |
Availability | Rain margin, gateway diversity and service coverage |
O3b is primarily a broadband transport network for equipped sites and platforms. Backhauling a cellular base station through it does not make ordinary phones direct O3b terminals. The base station can serve phones terrestrially while its backhaul crosses the satellite link.
Reference
Primary sources used for this note are listed below. Any limited source review is identified explicitly; general engineering explanations and illustrative calculations are not vendor performance measurements.
[1] SES MEO overview : Original O3b / mPOWER comparison and orbit.
[2] SES final-three launch announcement : September 13, 2026.
[3] SES commercial-service announcement : February 27, 2025; identifies April 2024 service start.
[4] O3b mPOWER: Technology : SES technical explanation of MEO and Ka-band; current deployment status uses the separate 2026 announcement.