Direct-to-phone satellite messaging

Also known as Direct-to-device satellite, Satellite-to-phone messaging, Direct-to-cell satellite, Supplemental coverage from space

Some phones can now send texts and emergency messages straight to satellites when no mobile tower is in range. Emergency texting on iPhone has been in use since 2022, while broadband-style data to ordinary phones is still at an early stage and rests largely on company-reported figures.

Pilot and early commercialDemonstratedReviewed 21 Oct 2026
AI illustration · Illustrative scene, not a photograph of the specific device or experiment.

In plain language

Most phones connect to ground towers. Where no tower signal reaches, a phone can instead connect to a satellite passing overhead. In November 2022, Apple launched Emergency SOS via satellite on iPhone 14 models in the US and Canada. The feature sends text messages through Globalstar satellites in low Earth orbit when a phone is outside cellular and Wi-Fi coverage, and it is meant for contacting emergency services.

Since then, the aim has been to extend this to ordinary phones and to carry more than emergency text. As reported in June 2025, T-Mobile said its T-Satellite service, which works with Starlink, would start on 23 July 2025 with texts, photos and short audio clips, then offer limited data through selected apps from 1 October 2025. Separately, AST SpaceMobile reports that it achieved peak data speeds of 98.9 megabits per second in international waters in May 2026. The company does not name the handset used. Peak speeds from a single test are not the same as typical speeds, and the company's FAQ does not give the test method.

Technical explanation

The phone-to-satellite link is a mobile network whose base station is in space or on a relay in orbit. The 3GPP Release 17 standard includes NR-NTN for 5G New Radio and IoT-NTN for LTE machine-type communication and narrowband IoT. In NR-NTN, the phone compensates for the delay and Doppler shift caused by satellite motion. It uses its own GNSS position and the satellite's position and velocity, which it receives in broadcast system information. Release 17 also raised the maximum number of HARQ processes from 16 to 32 and added time-based and location-based triggers for conditional handover. Ericsson states that these capabilities are not supported by phone chipsets built to earlier releases, so new devices are needed.

A second approach delivers standard LTE from low Earth orbit to unmodified phones. Ericsson lists the difficulties: delay and Doppler can be compensated for only a single reference point in each beam, distorted random-access preambles may not be detected, HARQ can stall if the round-trip time is too long, and handover is less reliable because signal strength is nearly uniform across a satellite cell. Satellite use of terrestrial mobile spectrum often requires exclusion zones. Ericsson cites supplementary satellite coverage rules for the US (FCC, 2024), Canada (February 2025) and Australia (ACMA guide, date not shown on the page).

AST SpaceMobile's FAQ says the company achieved peak data speeds of 98.9 Mbps in international waters in May 2026. The page lists this result under both its BlueWalker 3 test satellite and its BlueBirds 1-5, without saying which satellite was used. The same FAQ says next-generation BlueBirds will be capable of supporting peak data speeds of up to over 150 Mbps per cell. This is a forward-looking claim, not a test result. The FAQ does not give the test method, device, traffic direction or number of users.

What the evidence says

Each statement is typed by the strength of its evidence and linked to the source that supports it.

Demonstrated Shown in a published experiment, test or shipping product.

Apple's Emergency SOS via satellite became available on iPhone 14 and iPhone 14 Pro in the US and Canada, connecting to Globalstar satellites when the phone is outside cellular and Wi-Fi coverage.

Sources: [1], [2] · Apple newsroom announcement

Apple's satellite SOS is text-based. If local emergency services cannot receive text messages, the request is passed to a relay centre staffed by Apple-trained specialists.

Sources: [1] · Apple newsroom announcement

3GPP Release 17 introduced New Radio NTN and IoT NTN, and phone chipsets based on earlier releases do not support its satellite capabilities.

Sources: [3] · Standardised NTN section

Reported, unverified Stated by a company or team but not independently confirmed.

As reported in June 2025, T-Mobile said its T-Satellite texting service would start on 23 July 2025, with text, photo messages and short audio clips for compatible 4G phones with an unlocked SIM and no special hardware.

Sources: [5] · Launch and services sections · medium confidence

T-Mobile's satellite data is limited to selected apps, which are described as built for low-bandwidth satellite use, and is described as not a replacement for traditional broadband or 5G. No speed figures are given in the reviewed reports.

Sources: [6], [5] · Supported apps and data sections · medium confidence

Ericsson reports that satellite services, smartphones and wearables with IoT-NTN capabilities have been launched commercially, mainly to support emergency messaging, and that 3GPP NTN market adoption remains limited, with few devices supporting these capabilities.

Sources: [3] · Commercial status section · medium confidence

Delivering standard LTE from low Earth orbit to unmodified phones faces random-access failures, HARQ stalling when round-trip time is too long, and less reliable handover, according to Ericsson's analysis.

Sources: [3] · Unmodified 4G LEO section · medium confidence

AST SpaceMobile's FAQ says it achieved peak data speeds of 98.9 Mbps in international waters in May 2026. The FAQ does not name the satellite, handset, test method or traffic direction.

Sources: [4] · Has the technology been proven and BlueBird list · low confidence

Proposed A design or plan that has not yet been built or tested.

AST SpaceMobile says next-generation BlueBird satellites will be capable of supporting peak data speeds of up to over 150 Mbps per cell. This is a forward-looking claim, not a measured result.

Sources: [4] · Data capacity answer · low confidence

Limitations and open problems

  • Apple's Emergency SOS is text-based and for emergencies only. It works only when the phone is outside cellular and Wi-Fi coverage, and users are asked to keep pointing the phone at a satellite.
  • T-Mobile's data service, as reported in September 2025, works only through selected apps, which the June 2025 report describes as built for low-bandwidth satellite use. The reports say it is not a replacement for broadband or 5G, and they give no speed or data caps.
  • The 98.9 Mbps figure from AST SpaceMobile is a company-reported peak. The FAQ gives no test method, device, direction (download or upload), satellite or location beyond international waters.
  • Delivering LTE from low Earth orbit to unmodified phones faces random-access failures, HARQ stalling and weaker handover, according to Ericsson. NR-NTN needs new chipsets and devices, and Ericsson says 3GPP NTN is still at an early stage with limited market adoption.
  • Satellite use of terrestrial mobile spectrum often requires exclusion zones. The regulatory rules in this profile are cited second-hand from Ericsson; the FCC orders themselves were not opened.
  • Coverage areas, supported phones, prices and satellite counts change over time. This profile does not give current 2026 figures for any operator, and T-Mobile's own support and newsroom pages could not be opened.

Possible future uses

Speculative

Ideas, not predictions. None of these has been demonstrated.

  • Satellite messaging as a default fallback for phones in remote farms, mines and shipping lanes where ground networks are absent.
  • Wide-area sensor networks that use satellite IoT links to report from infrastructure far from mobile towers.
  • Disaster response in which satellite links carry alerts and short messages while ground networks are being repaired.

Product concepts: Small satellite text relay for compatible phones

Timeline

  1. Nov 2022Apple's Emergency SOS via satellite becomes available on iPhone 14 models in the US and Canada, using Globalstar satellites. Sources: [1], [2]
  2. 21 Oct 2024T-Mobile press release on its disaster relief efforts after Hurricanes Helene and Milton, cited by Ericsson as an example of satellite connectivity used in emergencies. Sources: [3]
  3. 23 Jul 2025T-Mobile's T-Satellite texting service is scheduled to start in the US, as reported before launch. Sources: [5]
  4. Oct 2025T-Mobile's satellite data through selected apps is scheduled to start on 1 October 2025, as reported in June 2025. A September 2025 report says apps are now working. Sources: [5], [6]
  5. May 2026AST SpaceMobile reports it achieved peak data speeds of 98.9 Mbps in international waters, without naming the satellite. Sources: [4]

Futures this could help bring about

AI illustration
How far away?

Ordinary phones connected by satellite everywhere

Pilots · 4 of 9 steps done

Glossary

Non-terrestrial network (NTN)
A mobile network that uses satellites or high-altitude platforms as relays or base stations.
Low Earth orbit (LEO)
An orbit close to Earth, where satellites move quickly across the sky and many are needed for continuous coverage.
Doppler shift
The change in a radio signal's frequency caused by motion between the satellite and the phone.
Peak data speed
The highest rate reached in a test, which is different from the typical speed users see over time.

Sources

  1. company announcement
    Emergency SOS via satellite made possible by $450M Apple investment
    Apple Newsroom, 10 Nov 2022. Accessed 21 Oct 2026.
  2. news
    Apple Says SOS Via Satellite is Now Available via Globalstar Satellites
    Rachel Jewett. Via Satellite, 15 Nov 2022. Accessed 21 Oct 2026.
  3. review article
    Satellite direct-to-device communication
    S. Song, S. Euler, F. Ghasemifard et al.. Ericsson Technology Review, 11 Dec 2025. Accessed 21 Oct 2026.
  4. company announcement
    AST SpaceMobile FAQs
    AST SpaceMobile, May 2026. Accessed 21 Oct 2026.
  5. news
    T-Mobile and Starlink to launch T-Satellite texting service on July 23, data coming in October
    Darryn John. Drive Tesla Canada, 24 Jun 2025. Accessed 21 Oct 2026.
  6. news
    Starlink Expands T-Mobile Direct-to-Cell Capabilities, Adding Data Support for Popular Apps
    Matt Wilson. Drive Tesla Canada, 8 Sept 2025. Accessed 21 Oct 2026.

Revision history

3 changes since this profile was created.

Changes on 21 Oct 2026
Published on owner instruction (content loop iteration 10)d8d21cd
Sources and claims re-checked against originalsfbb434c
Initial profile drafted from primary sources7e66249