By Paul Struhsaker

CTO of Carnegie Labs & Contributing Analyst, Tirias Research

There has been a great deal of press covering Google’s LOON and Facebook’s AQUILA high-altitude communications demonstration projects to provide broadband access to rural and underserved customers, however, that is not the entire story. If and when the LOON and AQUILA systems reach commercial operations, they will be competing with next generation satellite systems from ViaSat, Iridium, and OneWeb which are fully funded and moving to launch and deployment.

COMMUNICATIONS FOR THE UNDERSERVED

More than half of the world’s population is underserved by the internet. [i] These potential users are either too remote or lack affordable internet infrastructure.  A number of companies are creating or upgrading systems to directly address these underserved users.  In the near term ( 2 to 5years),  competitive solutions will begin deployment addressing those underserved.  In general, these systems fall into two categories:

• Satellite platforms: Low Earth Orbit (LEO) or Geostationary Orbit (GEO)
• High altitude platforms: balloons, dirigibles, or high altitude autonomous planes

Satellites operate form 700Km(LEO) to 42,000 Km (GEO) above the earth.  The lower the orbit, the more satellites are required to provide coverage of the earth’s surface. LEO systems have anywhere from 40 to over 600 satellites in their earth coverage constellation. GEO satellites require just three satellites for the equivalent coverage of the earth. In both cases, the satellites are expensive to launch and have a roughly 15-year service life in orbit.

By contrast, high altitude platforms, dirigibles, balloons or autonomous planes operate at an altitude of 20Km to 30Km, which is roughly 5Km above standard aircraft cruising altitudes. At these altitudes, the air is very thin so there is a tradeoff in weight and power generation vs the size of the platform needed to keep the system aloft. Unlike satellites that have short periods of time blocked from the sun, high altitude platforms can spend up to 12 hours blocked from sunlight every day. The communications footprint of each high altitude platform is roughly 80Km to 100Km in diameter.  To put that into perspective, 1000 to 2000 platforms would be needed to cover the lower 48 continental United States as opposed to just one GEO satellite or 5 to 15 LEO satellites.  These systems have at most 100 days of flight operations before they must return for maintenance.  High altitude platforms require significant launch operations to maintain coverage. As an example, Google’s LOON system would require 22 launches per day to maintain coverage over the continental United States.   

Both systems must deal with rain and cloud cover losses.  This limits their up and down RF links to frequencies below ~40 GHz due to fading. One advantage of high altitude systems is that the radio link can be designed to use cellular 4G-LTE, which can operate directly with standard cell phones. Google (LOON ) and SpaceData are testing prototypes for this direct usage model. For optimized data throughput, a majority of solutions work with a specialized radio link and use a bridge/access point to distribute data and services to the end user.

SATELLITE SYSTEMS:

Satellite systems have been in use since the 1960’s.  These systems have been plagued by very high costs for both service fees and end user equipment.  However, this is about to change.  Significant technology improvements and entirely new satellite systems are being launched over the next few years.  Let’s briefly review three upcoming systems from Viasat, WebOne, and Iridium:

ViaSat3 system

ViaSat is about to launch three geostationary (GEO)  VisaSat 3 satellites that will deliver 1Tera bps per satellite and 3Tbps system capacity. To put that into perspective, that is more capacity in a single satellite than in all of the satellites that have ever been launched to date combined. The company is already financially successful providing nearly 700,000 users with its Excede broadband service in North America. [ii]  The next generation of Excede will supply 100Mbps residential service.  In addition, the system also supports aircraft~1 to 10 Mbps and up to 1 Gbps to high-speed terminals for ships or ground services.

OneWeb

WebOne is privately funded Low Earth Orbit (LOE) satellite system consisting of 648 satellites on 20 orbital planes.   The major backers are Richard Branson's Virgin Group and Europe’s Airbus Group along with Qualcomm and other investors. [iii] The OneWeb system will use micro satellites weighting 150-175 kilograms and is expected to begin launching in 2018. Operations are expected begin in 2019.   The satellites will fly in orbits about 1,200 kilometers (745 miles) above Earth.

The network will provide more than 10 Tbps with each satellite delivering ~ 16 Gbps. The system is designed to use a bridge or access point using beam steering array antennas to support fixed buildings (schools, hospitals, emergency services, etc. ) and backhaul for remote cellular microcells. Smaller portable terminals are also contemplated for airplanes and vehicles . These terminals are designed to deliver up to 50 Mbps.

Iridium

Iridium is launching an upgrade this year called ”Iridium Next” based on a 66 satellite LEO constellation orbiting at 750Km above the earth. [iv]   Each Iridium satellite can provide ~3Mbps of voice and data with a system capacity of ~200 Mbps.  Iridium Next does not provide the massive capacity of the Viasat 3 or OneWeb , but it can support simple and inexpensive satellite phones and small internet bridges to end users.

HIGH ALTITUDE SYSTEMS:

Balloon, dirigibles and airplanes have been used as radar and communications platforms since the early 20th century. The new generation of platforms, such as Loon, is driven by miniaturization of electronics, improvements in solar technology, improved battery density and better construction materials. The combination of these technology improvements has allowed Google, Facebook, and balloon communications pioneer Space Data to deliver a “poor man’s satellite” high altitude communications platform. Despite these improvements, however, questions remain about the ability to create a profitable and sustainable communications operation using such high altitude platforms.

Let’s look at three of the major players: Space Data, Google’s Loon, and Facebook’s Aquila:

Space Data

Space Data is an early innovator of high altitude weather balloon communications technology having operated systems for the better part of a decade.  The company specializes in lofting communications packages of less than 12 lbs attached to a large latex balloon. Holding to these weight restrictions, there are no FAA rules or waivers needed to launch. Depending on the communications payload, flights last between two and seven days. Solar cells are not used due to both weight limitations and the lack of any rigid surface facing the sun. [v]

Space Data has launched communications packages in 900 MHz unlicensed bands and UHF bands for military and boarder security. It has performed successful experimental flight tests in 2.4GHz and 5.x GHz WiFI, GSM cellular, and an LTE cellular package.  Each balloon platform has up to a 640 Km diameter area of coverage.  Roughly 38 platforms would be needed to cover the continental United States and deliver roughly 200 Mbps across the coverage area using a WiFi link.

Google’s Project Loon

Project Loon is a variation of the high altitude balloon system pioneered by Space Data. Loon will be a much larger and heavier platform, powered by solar cells (100W) and is designed to stay aloft for roughly 100 days. Loon’s balloon envelopes are made from sheets of polyethylene plastic, and they measure 15 meters wide by 12 meters tall when fully inflated. The electronics include LI-Ion batteries, balloon to balloon cross links, ground link, and micro LTE BTS for direct communications with user LTE phones. [vi]

Each balloon platform provides an 80 KM area of coverage. Roughly 2,400 platforms would be needed to cover the continental United States.  In this configuration, the system would deliver 112Gbps based on roughly 45 Mbps of delivery per platform.

The project is in the early stages of development. There is no committed date for commercial deployment.

Facebook’s Aquila

Solar power flight is not new. Since 2003, NASA developed a series of experimental solar planes to under project Helios. They were built to develop the technologies that would allow long-term, high-altitude aircraft to serve as "atmospheric satellites" which would perform atmospheric research tasks as well as serve as communications platforms. [vii]

Facebook’s Aquilla project builds on the Helios project solar powered concept to provide a high-altitude, long duration flight platform based on advances in carbon fiber materials, improved Li-Ion battery technology and solar cell technology. The platform is a mono wing design (like a B-2 bomber) with a wingspan of a Boeing 737 passenger jet (~120 ft / 40m) weighing between 400 and 500 Kg.  Half of the platform weight will be taken up by Li-Ion batteries that provide propulsion and communications power during the night.  Like balloon based systems, the platform will drift between 20Km to 30K in altitude and is designed for roughly a 90-day flight duration.

Each Aguilla platform provides 100Km area of coverage. Roughly 1,100 platforms would be needed to cover the continental United States and would deliver 1,100 Gbps based on the ~1 Gbpsclaimed to be delivered by each platform.

The project is in the early stages of development. There is no committed date for commercial deployment.

CONCLUSIONS

Satellite companies are committed, funded, and moving to deploy an impressive array of technology upgrades to economically reach the nearly half of the earth’s population that is unserved and underserved. With no committed deployment dates and the massive scale of deployment needed for wide scale coverage, high altitude systems seem destined to provide only short to mid-term communications in limited areas until low cost terrestrial systems replace them. Unless there is acceleration in development and commitment to wide scale deployment, high altitude systems will lose “the race to space.”

[i] https://www.qualcomm.com/invention/research/projects/oneweb

[ii] https://www.viasat.com/products/high-capacity-satellites

[iii] http://oneweb.world/

[iv] https://www.iridium.com/network/iridiumnext

[v] http://www.spacedata.net/

[vi] https://www.google.com/loon/

[vii] https://www.nasa.gov/centers/dryden/history/pastprojects/Helios/#.V6EYcmgrJeU