Choosing Between Skylo and Iridium

Blues offers non-terrestrial network (NTN) connectivity on two different satellite networks, Skylo and Iridium, across multiple hardware products. Choosing the right network depends on your product design, where your devices will operate, and how much sky view they'll have.

This guide explains the trade-offs so you can pick confidently.

Hardware Options

Skylo is available in two form factors, while Iridium is offered as a single paired satellite module:

• Notecard for Skylo is an all-in-one module that combines cellular (LTE-M, NB-IoT, GPRS), WiFi, and Skylo NTN on a single Notecard. No separate Starnote required.
• Starnote for Skylo is a companion board that pairs with an existing Notecard (Cellular, Cell+WiFi, or WiFi) to add Skylo NTN.
• Starnote for Iridium is a companion board that pairs with an existing Notecard (Cellular, Cell+WiFi, or WiFi) to add Iridium network coverage.

At a Glance

How the Networks Differ

Skylo: Fixed in the Sky Relative to Your Device

Skylo delivers NTN connectivity over geostationary satellites parked roughly 22,000 miles above the equator. Because these satellites don't move relative to the ground, a Skylo device either has line-of-sight to the satellite or it doesn't.

In practice, this makes Skylo more reliable in situations where sky view is partial. Devices mounted near buildings, inside window sills, on narrow streets, or under light tree cover can often sustain a connection as long as the view toward the equator is unobstructed. If you're in the northern hemisphere, that means an unobstructed view to the south; in the southern hemisphere, to the north.

The trade-off is coverage geography. Skylo is available in a growing set of supported regions, but it is not global, and coverage is not uniform worldwide. Consult Skylo's coverage map to confirm your deployment regions are supported, especially if you're planning a multi-country fleet.

Iridium: A Global Constellation in Constant Motion

Iridium's LEO constellation orbits much closer to Earth and is in constant motion, so the set of satellites visible from any given location changes continuously. Any satellite that's in view at a given moment is usually at an angle, not directly overhead. You can get a sense of this motion at iridiumwhere.com.

Because satellites are moving and often low on the horizon, Iridium generally requires a more open view of the sky than Skylo. A device tucked against a wall or under heavy cover may have to wait for a well-positioned satellite to pass before a link establishes.

Iridium's biggest advantage is reach: it provides connectivity anywhere on Earth, including open oceans, polar regions, and the most remote parts of any continent.

Deciding Factors

Where Will the Device Operate?

• Inside a Skylo-covered region, on land: Skylo (via Notecard for Skylo or Starnote for Skylo) is typically the better default. It tends to connect faster and works well in partial sky-view scenarios.
• At sea, at the poles, or in regions outside Skylo coverage: Starnote for Iridium is the only option.
• Mixed or unknown deployment geography: If some of your fleet will ship to regions Skylo doesn't cover, Iridium provides a single consistent answer.

How Much Sky Can the Antenna See?

• Limited sky view (urban environments, window-mounted, under light foliage, narrow streets): Skylo's fixed overhead satellites are usually easier to acquire as long as the equatorial direction is unobstructed.
• Open sky in multiple directions: Either network performs well, but Iridium benefits most from a wide, clear view.

Hardware Form Factor

• Notecard for Skylo integrates cellular, WiFi, and Skylo NTN on a single Notecard, so there's no companion board or second UART link to manage. Best for new designs where Skylo is the chosen network.
• Starnote for Skylo uses a Notecarrier XS and is offered in two variants: one with onboard Ignion antennas, and one with two u.FL connectors (SAT for the included Skylo-certified LTE-capable antenna and GPS for a passive GPS/GNSS antenna). Both antennas must be placed outdoors with a clear view of the sky. Best for adding Skylo NTN to an existing Notecard deployment.
• Starnote for Iridium uses a Notecarrier XI and has a single u.FL connector for the included Iridium-certified antenna, which handles both satellite and GPS/GNSS. The antenna must be installed outdoors with a clear view of the sky.