When Motorola unveiled its Iridium global satellite-based mobile telephony service in the late 1990’s, everything augured well for a revolution in the satellite communications market, only it didn’t happen. Technically, Iridium was very much at the leading edge. The service uses 66 satellites in polar orbits, with 11 in each orbital plane, at an altitude of 780km. Each satellite had 48 down-facing spot beams, arranged into three sectors of 16 beams each. The satellites supported inter-satellite microwave cross-links, operating at 10Mbps.

Iridium’s reception was not overly enthusiastic. Consumers found the Iridium handsets expensive to purchase and use, and the service was available only in a few national markets. The issue was that Iridium faced stony resistance from almost every terrestrial mobile phone provider, and these local providers exerted pressure on national regulatory bodies to deny the regulatory approvals Iridium needed to operate in each national market. This was the major factor behind Iridium’s initial failure. At the time, mobile services were among the few that generated high-margin revenue for the carriage industry, and there was fear that Iridium could operate in a disruptive manner, threatening margins for the incumbent terrestrial providers.

Other negative factors included poor reception quality inside buildings and a service profile that supported only heavily compressed voice (2.4 kbps). Demand was insufficient to recoup the 5 billion dollars invested in Iridium, which then became the largest bankruptcy (at the time) in US history. The billion-dollar system was sold off for a few tens of millions of dollars, and the Iridium service managed to survive, but it left a sour aftertaste, and the enthusiasm for global services based on billion-dollar constellations of low-earth-orbit satellites went quiet for more than a decade.

Thirty years later, the situation has changed. The rich attractions of the mobile service market have been eroded to the extent that mobile services are operating at margins roughly consistent with those of commodity markets, so there is little left for incumbents to defend. At the same time, launch costs to place payloads into low Earth orbit have dropped, and the cost of digital signal processing has decreased while signal processing capabilities have improved.

Starlink is a technically impressive service. Using phased array software-steerable antennae and a 1m terrestrial dish, looking some 340-550 km upward to a constellation of some 10,000 spacecraft, the system can provide Internet access at speeds of some 200 Mbps to almost anywhere on the surface of the earth. Starlink provides a mobile phone service, but there are quite severe restrictions on its signal capabilities. This is due to the unfocused transmission of the mobile device, the limited transmission power and the 350km distance between handset and spacecraft. Reports of available capacity for mobile devices using Starlink are apparently in the range of Kbps, so the service is limited to SMS and location services, and to some extent, voice capability.

Starlink is launching a constellation of 840 satellites to support D2D services. Recent reports suggest that Mbps speeds to mobile devices are possible from these satellites, with up to 17 Mbps downlink and 7 Mbps uplink. The ability to use a mobile device without an antenna is obviously an attractive proposition, and interest in Starlink’s Direct-to-Device (D2D) has been expressed from a number of mobile network operators, including T-Mobile in the USA, KDDI in Japan, One NZ in New Zealand, Optus in Australia and Rogers in Canada.

Amazon LEO is launching some 3,250 spacecraft into slightly higher orbital planes of around 600km, apparently offering a service portfolio similar to that of Starlink. In 2024, Apple invested in Globalstar with a 20% stake and funding for an expansion of its fleet of satellites to support Apple’s Emergency SOS, Messages, Find My, and Roadside Assistance via satellite on iPhone and Apple Watch. It is reported that GlobalStar has allocated some 85% of its network capacity to Apple for this service. In April 2026, Amazon announced the acquisition of Globalstar, enabling Amazon Leo to provide D2D services using the existing Globalstar network and to expand its D2D platform in the near term.

If you want to serve mobile devices in a manner similar to terrestrial networks from a space platform, the basic requirement is to increase signal power and sensitivity. That’s where AST Space Mobile and their spacecraft come into play. This is a spacecraft with a very large antenna, some 223 sqm in size, where the earth-facing side is an array of phased-array units, and the other side is covered with solar panels. AST’s deployment plans for 95 of these spacecraft in orbit. Communication with the satellites uses the Q/V bands. With their large antennae, they intend to operate as a space-based mobile base station providing direct-to-handset 4G and 5G digital services using the 3GPP standards, including LTE on Band 8 at 900 MHz, as well as conventional voice and data services. AST will use a 5 MHz bandwidth allocation, compared to 5G’s 145 MHz.

AST’s commercial model is not a Starlink-style direct retail model, but a wholesale one based on service agreements with local mobile providers. The local mobile provider operates the ground stations and connects the ground stations directly to the terrestrial mobile network. It’s not clear yet whether the AST offering is another run of the Iridium story, but such an outcome is a distinct risk in its focus on the mobile handset market.

It’s an interesting set of market tensions that are at play here. Is there a viable market volume for services to mobile handsets alone that can sustain a dedicated mobile service operator such as AST? Or are terrestrial service platforms already so well established that the only exposed markets are niche ones in remote locations with low subscriber numbers? And are the populations of such niche markets sufficiently large to meet the capital return requirements of the initial investment required to launch multiple LEO D2D services?

Starlink and Amazon Leo have headed in the other direction, driven by the market for competitively priced high-speed data services. It appears that, for these two platforms, D2D mobile services are largely a secondary concern. The service quality available to mobile handsets is lower than users would normally expect from terrestrial 4G and 5G networks due to the physically smaller antenna and lower transmit power used by mobile handsets. Although in isolated remote locations, terrestrial services are not available, so there simply is no comparison to satellite-based D2D. The alternative model is the AST Space Platform approach, where the spacecraft is equipped with a highly specialized antenna designed to support 4G and 5G D2D services but does not provide high-speed data services. There are many dimensions to this story, including access to spectrum, ground stations, inter-satellite relays, wholesale and/or retail models, pricing, launch costs and spacecraft operational lifetimes.

No doubt we will hear more on developments in this new incarnation of the space race in the coming months.