[LEO Warring States Period ②] Does AST SpaceMobile's 'Strongest Satellite' Surpass SpaceX!? | Latest Technology in 5 Minutes
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SpaceX is currently running far ahead in the development of communication satellite constellations centered on LEO (Low Earth Orbit), a topic that has no shortage of discussion lately.
This is the second installment of a series titled 'LEO Warring States Period,' which focuses on satellite constellation projects other than SpaceX.
(Click here for the first article, which includes the current status of SpaceX.)
This time, we are looking at AST SpaceMobile, which is also attracting significant attention from investors.
🤔 What is AST SpaceMobile?
AST SpaceMobile (Ticker: $ASTS) is the name of the company. It is an emerging company founded in 2017 and only recently listed on the NASDAQ in 2021.
Planned number of satellites: Approximately 90 (Target by the end of 2027)
Number of satellites launched: 6 (BlueBird 1-6)
Service launch: Scheduled for the first half of 2026 (Rakuten's service launch is targeted for Q4 2026)
The business involves providing satellite communication services for smartphones, putting it in direct competition with Starlink Mobile, which has already started its service.
May 2017: Company established as AST & Science LLC
April 2019: Launched the first test satellite 'BlueWalker 1'
April 2021: AST SpaceMobile established through a SPAC business combination and listed on the NASDAQ
September 2022: Launched the second test satellite 'BlueWalker 3'
April 2023: Successfully conducted the world's first two-way voice call using BlueWalker 3 with an unmodified commercial smartphone
September 2024: Launched commercial satellites 'BlueBird 1-5' on a SpaceX Falcon 9
December 2025: Launched 'BlueBird 6', the next-generation commercial satellite (Block 2)
In 2020, they also received investment from Rakuten in Japan and formed a strategic partnership. In April 2025, it was announced as the 'Rakuten Strongest Satellite Service', and it also made headlines for successfully conducting the first domestic demonstration test of video calls using a commercial smartphone.
Looking at it this way, AST SpaceMobile's business seems to be going quite smoothly.
In fact, although there is a 1-2 year delay relative to the plan, I think it can be called 'smooth' in the field of space development.
⚔️ Going Head-to-Head with SpaceX in Smartphone Connectivity
The satellite communication service for smartphones that AST SpaceMobile aims to provide is the same as SpaceX's Starlink Mobile (formerly Starlink DTC) in that
existing smartphones can be used as-is. However, the communication speeds are completely different.
Starlink Mobile's communication speed is said to be limited to about 4 Mbps, making it primarily for text messaging and emergency contact.
On the other hand, AST SpaceMobile achieved a maximum downlink speed of 21 Mbps in demonstration tests with BlueWalker 3.
For the next-generation satellite 'BlueBird Block-2' which will be the mainstay in actual operation, they are aiming for a maximum downlink speed of 120 Mbps. This is a level where most things, such as video streaming and online gaming, can be enjoyed comfortably.
It means it will no longer be a 'backup' for when something happens, but a service that can be used daily.
Why exactly is there such a difference?
💪 The 'Ultimate Satellite' Created by an Unconventional Appearance
When it comes to AST SpaceMobile's satellites, attention is drawn above all to their bizarre appearance.
When people think of artificial satellites, they generally imagine solar panels (solar paddles) like wings attached to both sides of the main body.
However, AST SpaceMobile's satellites look like flying carpets, or rather, tatami mats??.
In fact, each of the tile-like parts that form this 'tatami' appearance is a unit that combines a solar paddle and a phased array antenna, supplying power generated by sunlight directly to the antenna.
In other words, the entire satellite is a giant deployable antenna. This enables broadband communication even with the weak signals of a smartphone.
Furthermore, the next-generation satellite 'BlueBird Block-2' has significantly increased in size.
The first-generation satellite was about 8 meters square (64㎡), but the next-generation satellite will be about 15 meters square (223㎡).
With a size roughly equivalent to one tennis court, the communication capacity will be expanded by 10 times.
BlueBird's orbital altitude is about 700 km, slightly higher than Starlink Mobile.
With the powerful communication capability of this large antenna, it is possible to cover a wider area from a higher position with just a single satellite.
The range is 3000 km in diameter... you might not get a clear picture of that, but it's enough to cover the entire Japanese archipelago from Hokkaido to Ishigaki Island in Okinawa.
With this, it is said that the entire world can be covered with just about 90 Block-2 satellites.
They are taking a strategy of elite few, which is the exact opposite of Starlink, which is just increasing the number of satellites.
🛰️ The Mechanism is Also Different from Starlink Mobile
AST SpaceMobile's satellites overwhelm Starlink Mobile with antenna power, but that's not the only difference. In fact, there is also a major difference in the communication mechanism.
💫 What is AST SpaceMobile's Bent-Pipe Method?
As explained in a previous article, Starlink Mobile's satellites themselves act as base stations.
This is called a 'regenerative relay method,' and AST SpaceMobile uses a method called the 'bent-pipe method'.
Why is it called a bent-pipe? Because it is just a path for data.
In other words, the base station is on the ground, and the satellite simply reflects the radio waves from the ground back to the ground.
Of course, it doesn't just reflect them as they are; it changes the frequency of the radio waves and amplifies the signals, but the point is whether the base station is on the satellite or on the ground.
💫 What are the benefits of the bent-pipe method?
The question is, which one is actually better?
The advantage of the bent-pipe method is, above all, that the satellite structure is simple.
Since the satellite is just a path for radio waves, all the functions required as a base station for connecting to smartphones can be installed on the ground.
The functions of the satellite itself are very simple, so it can be realized at a low cost, and there is less risk of trouble or failure.
This is also convenient for smartphone carriers preparing ground-side equipment, as they can use their existing ground network infrastructure as is.
Furthermore, even if the smartphone's communication standard evolves from 4G to 5G and then to 6G, the satellite can still be used by simply updating the ground stations
. It really is all pros.
On the other hand, the regenerative relay method adopted by Starlink Mobile requires the satellite itself to function as a base station, which results in a structure that places a heavy burden on the satellite side.
High-performance satellites are expensive and have a high risk of failure, and if a satellite fails in space, maintenance is almost impossible.
When a new communication standard is introduced, existing satellites cannot be used, so it is necessary to develop and launch new satellites. As you can see, it inevitably becomes high-cost.
😫 Of course, there are weaknesses too
Based on what we've covered so far, it might seem like AST SpaceMobile is superior to Starlink Mobile in every way, but of course, there are weaknesses.
💫 High communication latency
The biggest disadvantage of the bent-pipe method is likely the high communication latency.
Before a smartphone can connect to a base station and communicate, many steps such as "establishing a wireless connection," "authentication," "encryption," and "securing a communication path" are required, involving 10 to 20 exchanges.
In the bent-pipe method, these exchanges must be sent and received via the satellite to the ground station every time.
Compared to the regenerative relay method where the satellite itself acts as a base station, the communication path is simply doubled, which increases communication latency, and it may have an impact on applications where real-time performance is important.
💫 Cannot be used in areas where ground stations cannot be installed
Also, because of that, a ground station is always required in an area where the satellite can communicate. Not being able to support ISL (Inter-Satellite Link) is also a disadvantage.
Starlink Mobile, which adopts the regenerative relay method, can use ISL to, in an extreme case, communicate even if the ground station is on the other side of the earth.
On the other hand, with the bent-pipe method, communication cannot be established unless there is always a ground station within the area covered by the satellite.
Therefore, usage is limited in places where it is difficult to install base stations over a wide area, such as on the ocean or in polar regions.
📡 Overwhelming SpaceX with a network partnered with telecommunications companies
Despite that, AST SpaceMobile, as mentioned above, leverages its compatibility with telecommunications operators and, even before the service has started, is expanding its network of partnerships with telecommunications operators in each country.
Including major shareholder Rakuten, it has partnered with over 50 companies worldwide, such as AT&T (USA), Verizon (USA), Vodafone Group (Europe, etc.), and Orange (France).
The potential customer base reaches over 1.5 billion people worldwide, overwhelming Starlink Mobile.
In Japan, attention is focused on Starlink Mobile because the three major companies, au, Docomo, and SoftBank, have partnered with it, but globally, AST SpaceMobile is in a favorable position.
That is why, with the service launch imminent, it is attracting significant attention from investors around the world.
📝 Summary
So, that concludes the second installment of the 'LEO Warring States Period' series, featuring an explanation of AST SpaceMobile. While the service has yet to launch and remains an unknown quantity, it is attracting even more anticipation than SpaceX for satellite communication services aimed at smartphones.
On the other hand, SpaceX is not just sitting idly by. The next-generation Starlink Mobile V2 has been announced, which is said to achieve communication speeds of 150 Mbps, surpassing AST SpaceMobile.
Who will ultimately seize hegemony in satellite communication services for smartphones?
Or will a dark horse third force emerge?
Stay tuned for future developments.