HAPS 101: Stratospheric Satellites – An Introduction for Decision Makers

1. What Are HAPS?

High Altitude Pseudo-Satellites (HAPS) are unmanned aircraft or lighter-than-air platforms that operate in the stratosphere, typically between 18 km and 24 km above sea level. This altitude is above commercial air traffic but below low-Earth orbit satellites.

They are “pseudo-satellites” because they can deliver many of the same capabilities—communications relay, Earth observation, persistent surveillance—without leaving the atmosphere. Unlike satellites, they can be recovered, maintained, and redeployed.

Three main platform types dominate the field:

• Fixed-wing solar aircraft (e.g., Airbus Zephyr, HAPSMobile Sunglider) — ultra-light designs with solar arrays enabling weeks of endurance.

• Aerostatic balloons (e.g., Project Loon heritage) — helium or hydrogen lift, useful for short-term deployments or test missions.

• Airships (e.g., Thales Alenia Stratobus) — large, powered blimps with heavy payload potential for telecom or ISR missions.

2. The Unique Altitude Advantage

Operating in the stratosphere offers distinct advantages:

• Persistent coverage — A single HAPS can provide line-of-sight coverage over a radius of 200–300 km for weeks or months.

• Low latency — Signal paths are shorter than to satellites, meaning quicker response times for telecom and defence applications.

• Flexibility — Unlike satellites locked to orbits, HAPS can be repositioned to respond to events—whether a disaster zone, a major sporting event needing extra connectivity, or a military operation.

• Recoverability — Platforms can land for upgrades, repairs, or payload swaps—reducing lifetime cost and increasing adaptability.

For telecoms, this means the possibility of filling coverage gaps in rural or maritime regions without the expense of dense terrestrial infrastructure or the limitations of LEO/MEO satellite capacity.

3. Key Use Cases for Industry and Government

A. Telecom and ConnectivityHAPS are now a recognised component of non-terrestrial networks (NTNs) under 3GPP’s 5G and upcoming 6G standards. They can deliver:

• Rural 4G/5G coverage where fibre or towers aren’t feasible.

• Maritime and aeronautical broadband.

• Emergency connectivity after disasters.

B. Defence and SecurityFor militaries, persistent Intelligence, Surveillance, and Reconnaissance (ISR) at lower cost than satellites is a major attraction. HAPS can loiter over areas of interest for weeks, integrating electro-optical, infrared, and radar payloads.

C. Environmental MonitoringBecause they can carry advanced sensors and stay in place, HAPS are ideal for tracking deforestation, ice melt, crop health, and pollution at much higher resolution than satellites.

D. Disaster ResponseRapid deployment after earthquakes, hurricanes, or floods can restore comms and provide up-to-date imagery for responders.

4. Current Industry Leaders

• Airbus Zephyr — solar-powered, record-breaking endurance flights, backed by UK MoD and RAF experimentation.

• HAPSMobile Sunglider — SoftBank/AeroVironment project with large wingspan for heavy payload telecom missions.

• Thales Alenia Stratobus — a semi-rigid airship concept focused on telecom and surveillance roles.

The HAPS Alliance—an industry body including SoftBank, Airbus, Loon alumni, and telecom vendors—has been instrumental in driving standardisation and policy engagement.

5. Strategic Benefits for Decision Makers

Telecom operators can integrate HAPS into their RAN (Radio Access Network) to reach customers without major civil works.

Governments can use HAPS to achieve national coverage goals faster than terrestrial rollouts, a point relevant to rural broadband strategies and net-zero initiatives (solar-powered flight = low operational carbon footprint).

Defence agencies gain low-risk, persistent ISR and communications relay without the political complications of satellite overflight.

Commercial enterprises—from mining companies to offshore wind farm operators—could lease HAPS capacity for monitoring and connectivity.

6. The Risks and Unknowns

No emerging technology is without its challenges:

• Technical reliability — Solar array efficiency, battery performance at -70°C, and structural resilience in stratospheric winds remain active engineering hurdles.

• Regulatory ambiguity — Airspace above FL600 is a grey zone; ICAO and national regulators are still shaping frameworks.

• Security — As with satellites, cyber-hardening is essential to prevent hijacking or data interception.

• Economics — The business case is strongest in niche or high-value coverage gaps; scaling to mass-market service needs cost reductions.

7. Why Now?

Three converging trends make this the right time for HAPS to gain momentum:

1. 5G/6G NTN standards explicitly include HAPS—removing the uncertainty of integration into telecom networks.

2. Advances in solar and battery tech make multi-week endurance feasible without mid-mission refuelling.

3. Geopolitical drivers—conflicts, climate events, and global connectivity pledges—create urgent demand for rapid-deploy coverage and ISR platforms.

8. Strategic Questions for Boards and Executives

If you are a telecom CEO, defence procurement head, or infrastructure investor, you should be asking:

• How could HAPS complement our terrestrial and satellite networks?

• What regulatory hurdles must we clear in our jurisdiction?

• Who in the HAPS supply chain is investable, and where are the M&A opportunities?

• What are the resilience benefits versus satellites alone?

• How can we mitigate dependency on foreign-owned platforms?