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#SpaceWatchGL Op’ed: HAPs – A Future Complement to Satellite

Aquila, courtesy Facebook

The satellite industry has long been renowned for its unique ability to deliver connectivity to remote regions of the world, making communications accessible where they previously weren’t available. However, there is a technology that is being trialled by some of the world’s biggest tech companies that promises to enable telecommunications networks with a re-usable platform that can form telecommunications networks where there is little or no access. That is the High Altitude Platform. In this article, satellite internet provider, BusinessCom Networks finds out more.

These unmanned airships or balloons are positioned around 20km above the Earth, in the stratosphere, and are used for communications or remote sensing purposes. The interest of Google and Facebook in the development of these platforms has re-ignited interest in whether these platforms have a future and whether they could complement satellite technology in the connectivity stakes.

HAPs are typically drones or air balloons that stay in place, or continually pass over a region that requires a service for extended periods of time. Most use solar panels for power, driving propellers to keep them in place. Others, such as Google’s Project Loon follow air currents, and autonomously raise and lower themselves to follow atmospheric currents back to a target location. They connect to an earth station and relay internet and cellular services to the ground in areas where other service options aren’t available. HAPs can offer services when normal operations are knocked out by storms or deliver services in deep valleys where standard GEO satellites can’t be seen. They can be put in place to support first responders or provide information to soldiers on the ground. There are many potential applications for these platforms.

Pros and Cons

The two biggest projects that have recently been taking up the most column inches are Project Loon, now a subsidiary of Alphabet and Facebook’s Aquila.

Facebook announced in June that after four years, it is abandoning its plans to build a fleet of HAPs based on drone technology that was intended to offer internet access to remote locations. Facebook’s Aquila named after the astronomical constellation, the Eagle, planned to use gigantic solar-powered drones to beam internet to the ground.  Facebook’s team in Bridgewater in the UK, led the design, development and testing for the new platform. It was designed to stay in the air for months at a time. The idea was to create a 50 km communications zone into which they would transmit a signal that would be received by small towers on the ground and converted to either Wi-Fi or LTE cellular services for smartphone users on the ground.

Loon, photo courtesy Doug Caldwell and WikimediaCommons

There were two challenges and areas of development.  On the one hand, they needed to develop an aircraft that was light enough, yet strong enough to carry solar panels, batteries, and RF electronics, and keep it aloft for extended periods of time.  They also worked on critical millimetre-wave (MMW) technology which was to be used for point-to-point connectivity between the HAPs and earth stations connected to the backbone, as well as being used to relay and beam services to users below.  It is in this area that their advances will certainly continue to contribute to the industry.  High frequency MMW delivers high bandwidth.  Facebook’s team tested a point-to-point link that broke a record, reaching nearly 20 Gbps over a 13 km path. This is enough capacity to stream nearly 1000 ultra HD videos at the same time. Additional testing pushed the technology forward as they demonstrated an ability to communicate at 40 Gbps in both directions with a circling Cessna, 7 km away. They also developed and demonstrated a super-fast switching system to route around links that have lost line-of- sight connectivity.

Facebook looked at the development going on by others in the aerospace industry and decided to drop future efforts on their own aircraft.  They will continue to support the development and operation of HAPs, particularly on the data side, where their technology has contributed to the industry in a meaningful way.

Google’s Project Loon, now a subsidiary of Alphabet, like Aquila, is aiming to provide internet access to rural and remote areas. Loon uses high altitude balloons to create a wireless 4G-LTE network that enables users to gain access to the internet using antennas that are fixed onto their residences. The signal travels from one balloon to another and then to a ground-based station that is connected to an ISP, and then onto the internet. The balloons are manoeuvred by adjusting their altitude using wind data provided by NOAA.  Loon is aiming to improve communications in underserved areas and to re-establish communications in the event of natural disasters. In 2017, Loon proved itself by providing emergency communications over Puerto Rico after Hurricane Maria. It’s not the only HAP that has had success. Others such as Worldview Enterprises and Raven Aerostar have demonstrated the effectiveness of balloons for communications, remote sensing and adventure tourism applications.

On the other hand, there have been some less publicly shared problems. Headlines include:

“Kenyan farmer threatens Google with lawsuit for balloon crash;”

“Worldview test balloon blast costs $200K in property damage;”

“Raven Aerostar balloon crashes into frozen Wolf Lake Weyauwega at speeds exceeding 113 km/hr.”

Northern Sky Research (NSR) anticipates that with as many as 5 balloon accidents in a 15-month period, there will be stricter regulations coming, which may shrink investment and slow development of these platforms.

ESA Eyes HAPs as Missing Link

The European Space Agency (ESA) is currently looking into the ways in which HAPs may complement satellite platforms, enabling precise monitoring and surveillance, high bandwidth communications or to act as a back-up to existing satellite navigation services. This potential has been investigated by ESA for some time and the agency eventually hopes to bring the domains together. The maturation of technologies used in HAPs such as solar cells, miniaturised avionics and lightweight batteries lend themselves to the scaling up of HAP platforms. HAPs could present a valuable means of establishing applications that complement ESA’s satellites whilst accelerating space technologies though HAP flight testing.

Future for HAPs

What does all this mean for the future of HAPs?  It seems to be going through a normal growth cycle.  New technology encounters a few bumps that need to be worked out. New players come in and then exit after realising that this is not their key area of expertise.  However, the business opportunity continues to justify ongoing development.  Are HAPs a short-term solution that will be limited by next generation LEO satellites?  Perhaps to some extent, but LEO deployment will not be instantaneous, and the window is likely to be open long enough to justify the effort. There will always be niche applications for which HAPs will be the best solution.  Stay tuned.

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