Title: Unlocking the Power of HAPS for Earth Observation

The HAPS Alliance is an industry association of High-Altitude Platform Station (HAPS) industry leaders that include telecommunications, technology, aviation, and aerospace companies, as well as public and educational institutions. United by a vision to address diverse social issues and create new value through the utilization of high-altitude vehicles in the stratosphere, the Alliance is working to accelerate the development and commercial adoption of HAPS technology by promoting and building industry-wide standards, interoperability guidelines and regulatory policies in both the telecommunication and aviation industries.

In addition to connectivity applications to help bridge the digital divide, HAPS is being used for Earth observation. Fitted with Earth observations payloads, HAPS-enabled sophisticated, uncrewed, high altitude long-endurance vehicles, free balloons, and airships are demonstrating in-flight tests how HAPS can deliver high-quality imagery and video continuously the stratosphere. In the future, these HAPS-enabled flights will enable users to deliver real-time situational awareness, gather data around disasters, support effective rescue responses, predict highly accurate weather reports, and more. This presentation will introduce the HAPS Alliance vision for HAPS operations at scale, provide insight into our approach to Earth observation, and share examples of member progress to date. Some actual use cases and tests to be covered will include the following.

HAPS Alliance Member Sceye’s wind-driven lighter-than-air HAPS platform to provide connectivity and Earth observation. Sceye partnered with the EPA to study pollution sources and their impacts on climate and air quality. In a recent connectivity test, Sceye demonstrated the ability to connect with LTE devices up to 120km horizontal distance, demonstrating the large potential that HAPS can offer over terrestrial infrastructures.
HAPS Alliance Member Raven Aerostar demonstrated this year the utility of their free-flying Aerostar balloon in the stratosphere to support firefighting efforts over the Western United States. Raven Aerostar’s Thunderhead Balloon Systems® offers a high state of technical readiness, well-developed balloon manufacturing capability and experienced flight operations crews.
HAPS Alliance Member HAPSMobile, a SoftBank majority-owned joint venture with AeroVironment, achieved a 5 hour and 38-minute flight in the stratosphere with its fixed-wing solar-powered Sunglider aircraft. Using smartphones connected to the Internet through Sunglider’s LTE payload in the stratosphere, and successfully made a video call to HAPSMobile members based in Japan.
HAPS Alliance Member Deutsche Telekom, a SoftBank majority-owned joint venture with AeroVironment, achieved a 5 hour and 38-minute flight in the stratosphere with its fixed-wing solar-powered Sunglider aircraft. Using smartphones connected to the Internet through Sunglider’s LTE payload in the stratosphere, members from Loon and AeroVironment in the US successfully made a video call to HAPSMobile members based in Japan.
HAPS Alliance Member Airbus completed its 2021 Zephyr flight campaign in Arizona to demonstrate how its “Carbon Neutral” Zephyr can remain in the stratosphere for days and months at a time, showing precision and re-tasking flexibility in the stratosphere.

This presentation will also look at other HAPS applications besides Earth observation, developments in the HAPS industry, and the activities of HAPS Alliance member companies.

High Altitude Pseudo-Satellites (HAPS) are unmanned vehicles continuously flying in the Stratosphere or near-Space for months at a time. When equipped with Earth Observation (EO) or Telecommunication payloads, they provide new service possibilities that complement existing satellite and airborne solutions. Like satellites in the 60s and 70s, HAPS technology development requires years of R&D, flight trials and continual investment. However, the HAPS landscape is now changing quickly.

Recent industry achievements demonstrate that HAPS EO services are already operational, reliable and scalable. The last pending frontier for the aerospace industry is being effectively crossed. The high participation in the recent HAPS Alliance Summit demonstrates that expectations on HAPS solutions are growing, not only for the new service provisions but also because HAPS are inherently a green technology, fully aligned with current international commitments towards a sustainable future.

This paper presents Airbus’ successful experience with Zephyr, the company’s persistent fixed-wing heavier-than-air HAPS, applied to Earth Observation. The growing experience in Zephyr EO campaign preparation and execution highlights the operational similarities and differences between HAPS, satellites and airborne platforms. Airbus benefits from its past and present heritage in both fields: air and space. Aircraft tasking, sensor operation and data transfer, processing, analytics and dissemination, are key aspects to provide consistent services to end users.

Building on the two successful Zephyr stratospheric flights in 2021, the paper will share how some of the demonstrated capabilities and advancements will be instrumental to the benefit of environmental applications and to service civil society, among others.

For the wildfires domain, for instance, data from EO satellites is successfully used to assess fire risk, to calculate burnt surfaces and even as an independent, homogeneous means to register fires worldwide. However, current satellites often do not detect fires when they are still small and controllable and do not provide frequent flame progress updates as required by firefighters. A constellation of HAPS adequately deployed over high-risk areas will enable early fire detection and 24/7 persistent monitoring of active fires, complementing or even replacing the current manned daylight-only airborne surveillance.

Similarly, air quality monitoring in and around urban and industrial areas will benefit from the regional coverage of HAPS, their low revisit time and the duration of their missions. The rapid re-tasking and mobilisation of a flying HAPS will contribute to disaster relief activities offering reactivity and significantly better image resolution (GSD) than current satellites. Earth Observation combined with cell phone or radio relay is also a highly valued capability for emergency services acting in remote or not-well-covered areas. Maritime HAPS applications like illegal fishing control or oil spill detection, combining imaging with AIS/VDES processing, will complement what is currently achieved by satellites and aircrafts.

Data captured from HAPS emerge as a new, valuable source in the integrated, multi-layered nature of geospatial data servicing the Earth Observation and Scientific communities, and will definitely contribute to the achievement of ESA’s and EU’s objectives in regards to our “Living Planet” and the UN’s Sustainable Development Goals (SDGs).

Finally, the paper will provide an insight on the path followed by ESA and the HAPS industry towards a first long-duration operational HAPS demonstration in the EU territory.

Poor air quality (AQ) is a health issue in both develop and developing countries, particularly in urban areas. Cities currently encompass most of the population and are foci of air pollution from industries, household heating/cooling, and traffic. Exposure to noxious gases or small particles is statistically and medically proven to cause lung diseases and premature deaths. Cities also account for more than 70% of the anthropogenic CO2 emissions. The Intergovernmental Panel on Climate Change (IPCC) concluded that human-produced greenhouse gases (GHG) such as carbon dioxide, methane and nitrous oxide are inexorably driving the observed increase in Earth's temperatures observed over the past 50 years. The Paris Agreement made the verification and improvement of local GHG emission inventories imperative.

Monitoring emissions and air pollution concentrations over urban areas requires data granularity at the local level, better than that provided by current and planned satellite missions and ground networks: horizontal and vertical resolutions do not always fit the observational requirements to be used in combination with urban and local air quality models. Urban air quality stations have a sparse coverage and local observations suffer from a limited representativeness. Moreover, the stations network density decreases towards suburbs and adjacent rural sites, hampering a citywide instantaneous view of air quality and the attribution of the pollution to its sources. On the other side while satellite observations are suitable to provide AQ information on a global and regional scale, they have limited capability to provide information at urban and local scale. In response to these challenges High Altitude Pseudo Satellites (HAPS), usually unmanned airships or airplanes that operate in the stratosphere at 20km, are a promising complementary alternative for GHG and AQ Earth observation applications.

GMV in collaboration with KNMI, ABB and SCEYE, and funded by the European Space Agency developed a project to analyze how HAPS can provide data to operational AQ and GHG services, such as urban AQ modelling or GHG emission inventories. Synergies with existing or planned satellites have also been taken into account.

Key project objectives included:

- The identification of the air quality and GHG modelling user requirements for high-resolution atmospheric composition data to be provided by HAPS, focusing primarily on NO2 emissions, O3, CO2 and particulate matter.

- The demonstration of the impact a HAPS system can have on improving the status of air quality or GHG modelling in synergy with satellite data. Two HAPS use cases were defined, one for the Great Rotterdam region and the other for Seville metropolitan area. Public entities from both regions having the mandate to monitor urban air quality have been involved as end users, providing concrete requirements and needs to identify the existing technical and scientific opportunities and gaps.

- Definition of the mission requirements for the use cases, including the technical platform and the instrument requirements, preliminary system concepts, air space regulations, geophysical data products and synergies with existing and planned satellite missions.

The user requirements collected, discussions with stakeholders and ESA, and a trade-off analysis (balance completeness to fulfil user needs with mission flexibility and cost effectiveness, technological and scientific readiness) led to develop two HAPS mission concepts: Paris Agreement Monitoring Mission and the Metropolitan Surface AQ Mission.

The HAPS Paris Agreement Monitoring Mission would focus on CO2 and NO2. NO2 is a marker fingerprinting CO2 enhancements related to fossil fuel and biomass burning. The wavelength range of the NO2 instrument would be suitable for monitoring of formaldehyde (HCHO) together with NO2. Combination of CO2 with CO and/or CH4 could be made, depending on the instrument design. Although aerosol measurements are not a principal objective of a CO2 emission monitoring mission, auxiliary aerosol measurements to reduce CO2 measurement uncertainty would provide an aerosol product.

The Metropolitan Surface AQ Mission was selected to have a better understanding of the metropolitan ozone pollution and the processes involved, i.e. the emissions of primary pollutants, the influence of local meteorology such as sea breeze in morning and afternoon, and the photochemical interactions. Particulate Matter (PM10; PM2.5; PM1), especially from (agricultural) waste burning is another main source of air pollution. HAPS-based observations could lead to better insights in, e.g., the regional source locations, temporal variability and particle type characterization. This mission would focus on the NO2, tropospheric ozone and aerosol.

The mission concepts were thoroughly analyzed with the objective to define mission configurations with technical solutions for each of the mission technical components: HAPS fleet, instruments payload and ground segment operations. 42 different configurations were deemed of interest and traced against the 100 technical use requirements. The compliance with the user requirements and the analysis of the challenges faced in the different configurations supported the recommendation of the following three configurations: Ready to Fly Mission Configuration, User-Driven Mission Configuration, and Forward-Looking Mission Configuration.
In interaction with the Agency after analysing the mission concepts and configurations, the consortium partners concluded that on balance the most promising solution to explore as a rapidly available technology demonstrator for the mission objective was a demonstration mission primarily focused on NO2 and restricted to the country of Spain:

- NO2 observations would support both air quality regulation and climate emission control policies in Spain as well as provide a demonstration for other European metropolitan regions;

- Spaceborne observations of NO2 are well established and instruments are available with a high TRL, thus optimally combining technological readiness and scientific readiness. Compared to other atmospheric components a much faster user uptake could be foreseen using existing projects, scientific cooperation and other frameworks such as the Copernicus Atmosphere Monitoring Service (CAMS) and its regional spin-offs (high scientific readiness level);

- A demonstration mission restricted to Spain would prevent potential regulatory issues facing a HAPS demonstration mission in Europe crossing national boundaries, e.g. regarding legislation, and aviation safety;

- Compared to the Rotterdam area, aviation safety is much less of an issue over specific areas in Spain such as around Teruel.

Autonomous Surface Vessels (ASVs) offer a unique range of functional, efficiency and safety benefits over traditional manned vessels, by reducing or removing the need for onboard crew. With advanced shipboard autonomy and teleoperation technologies rapidly approaching market-readiness, a range of vessel systems are already undertaking operational demonstrations for applications including bathymetric surveying, naval mine clearance and commercial shipping. The first step towards achieving robust autonomous navigation in complex maritime environments is maintaining an up-to-date Situational Awareness (SA) picture of vessel surroundings, which covers the perception, comprehension and future state prediction of collision hazards, sea conditions, coastal features and other elements comprising the maritime operating environment.

Furthermore, rising rates of armed conflict, piracy and cyber-attacks constitute a significant threat shipping security, trade and supply chains across the globe, raising further concerns for the safety and security of future uncrewed vessel operations. Developing maritime Situational Awareness (SA) capabilities to a level of sophistication and robustness that facilitates safe vessel navigation and collision-avoidance in a variety of high-risk maritime environments is therefore a major enabler of commercially-viable Harbour to Harbour (H2H) autonomous vessel operations.

“Enhanced Surrounding Awareness and Navigation for Autonomous Vessels” (ESANAV) is a recently-concluded technical and commercial system feasibility study led by DEIMOS UK and performed under the ESA Open Space Innovation Platform (OSIP), which seeks to define the route to addressing these challenges using emerging remote sensing technologies, including High-Altitude Pseudo-Satellites (HAPS), next-generation satellite constellations, high-resolution Earth Observation (EO) payloads, state-of-the-art Computer Vision (CV) algorithms and multi-sensor data fusion architectures.

Fixed-wing High-Altitude Pseudo-Satellites are a particular focus of the study, due to their promise of delivering multi-month stratospheric flight endurances and flexible deployment capabilities highly suited to meeting evolving maritime surveillance needs. When equipped with high-resolution optical and Synthetic Aperture Radar (SAR) imaging payloads, these aircraft are foreseen to be capable of 24/7, real-time monitoring with update intervals consistent with the evolution timescale of maritime environments, including under adverse weather conditions where the utility of shipboard sensor suites is significantly degraded.

In addition to enhancing vessel navigation planning and collision avoidance capabilities, the proposed Situational Awareness services would provide significant value to other vessel monitoring entities including Vessel Traffic Services (VTS), maritime security, and regulatory compliance applications. The successful deployment of low-latency (near-)real-time Earth Observation monitoring capabilities will also open up a wide variety of high-value applications in both maritime and non-maritime domains for better understanding human and natural processes on (sub-)hourly timescales, including smart port and smart city asset optimisation, pollution monitoring, conservation efforts, and disaster response coordination.

At LPS22, we will present the final results of ESANAV system architecture definition, technology trade-off and market analysis activities, share the multi-disciplinary 20-year technical and commercial roadmap that constitutes the ultimate outcome of the study, and highlight the foreseen roles that key maritime, UAV/HAPS and space sector stakeholders can play in realising these exciting next-generation Earth Observation systems and services.

MONICAP (MONItoraggio di Colture Agricole Permanente) project, led by Intecs Solutions in cooperation with the Hypatia Research Consortium and CIRA, aims to develop a sustainable system based on a permanent HAPS tethered platform capable of providing very high spatial resolution thermal, multispectral and hyperspectral images (approximately 450nm to 900nm) over an area ranging from 10 to 50 hectares. The solution is a platform composed of an aerostatic balloon, equipped with aerodynamic elements to contribute to overall lift and stabilisation in windy conditions, tied to a ground station. The payload consists of a hyperspectral sensor, a multispectral sensor, a thermal camera and a visible camera, all moved by means of a gimbal that ensures the referenced pointing of each image acquired and the correct management of the hyperspectral sensor. MONICAP provides useful information to support Variable Rate Agriculture applications such as smart fertilisation, smart irrigation, necessity of using herbicide and phytosanitary treatments (such as information for monitoring of downy mildew infestation, esca disease and flavescence dorée). The platform uses an autonomous electrical generation and storage system, through a weight-optimised generator and accumulator, using flexible, ultra-lightweight cells with an efficiency of over 500W/kg and batteries with a capacity of over 300Wh/kg that power all the on-board instrumentation. The significative advantage of MONICAP is due to the permanent acquisition of images, avoiding also the issues related to the cloud coverage, the very high spatial resolution, which is sub-metric for both multispectral/hyperspectral and thermal sensors, the low latency time in data transfer, the possibility of real-time processing, the high payload capacity, the low cost of the service and high security that a tethered platform entails, which makes the whole solution unique compared to satellite systems and drones. Through the processing of vegetation indices (such as NDVI, NDRE, LAI), temperature data, soil moisture and exploiting machine learning/deep learning algorithms, MONICAP is able to produce estimates of crop yield, provide information on nitrogen management, automatically detect plant diseases due to the presence of pests, detect weeds and infesting plants, provide estimates of crop quality, and autonomously recognise different crops species, combining the best of the two worlds of satellite and UAV technologies. MONICAP therefore aims to demonstrate the full potential that HAPS can offer in creating a Digital Twin of our planet, representing a valuable asset for present analysis and future forecasts, and providing an irreplaceable instrument for decision support when integrated with data from satellites, drones and IoT sensors.

SkyRider is HAPS (High Altitude Pseudo Satellite), lighter-than-air platform flying at an altitude of approximately 20km for weeks to months. It can fly missions up to 6 months with payloads up to 10kg and power consumption of 5kW and it can can keep geostationary position in winds up to 15m/s. SkyRider is designed for the main commercial markets such as Earth observation, navigation, telecommunications etc. It is designed for payloads up to 10 kg, managed both vertical and horizontal maneuvering and long-term station-keeping. Station-keeping is especially important for commercial and scientific Earth Observation applications.
Today, the stratosphere is an unjustly neglected layer of the atmosphere in terms of expanding technological infrastructure. We can talk about the so-called "forgotten height," because there is still no human technology or even infrastructure in the stratosphere. At the same time, the stratosphere has the advantage of an ideal height from the point of view for Earth Observation because aircrafts can never reach this height. Furthermore, at this altitude, there is already a permanent access to energy from the Sun, because otherwise the disturbing effects of the weather are associated with the lower troposphere. In addition, thanks to its low air density, the stratosphere allows HAPS to travel quickly on a global scale.
There seems to be a wide range of user commercial demands for services from the stratosphere. At present, there are occasional attempts for the longest possible stratospheric flight or at least a parabolic flight through the stratosphere. The simplest application today is disposable uncontrolled meteorological balloons, which perform measurements in flight (sometimes up to the stratosphere) and transmit data to the Earth by radio probe. It has been discharged for over 50 years several times a day. Leading global technology companies are trying to take a more sophisticated control of the stratosphere. Generally speaking, the rivalry of different concepts focuses on flight length, horizontal and vertical controllability (propulsion), ground segment quality, robust but lightweight energy system, communication links and especially the ability of station-keeping, ie the ability to "hang" in the stratosphere in defined position above the Earth. Obviously, such a concept will be in great demand once it has been designed and successfully tested. The last criterion of competition is also the cost of production and operation of such a system.