The sky’s not the limit

Since 2017, Pierluigi Silvestrin has been head of the Future Systems Department (also known as the Φ Department) in the Earth Observation (EO) Programs Directorate of the European Space Agency (ESA). Previously, he led the Future Missions Division and the Mission and System Studies Section, which are part of the Φ Department and located at the ESA center in Noordwijk, the Netherlands, together with the Φ-lab Division and the Copernicus Space Office at ESA's center in Frascati, Italy. He has been involved with defining EO missions and architectures for 32 years, including nearly all Earth Explorers and Copernicus Sentinels — as well as meteorological missions for the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT), with original contributions successfully deployed in orbit.

Silvestrin was a plenary speaker at SPIE Remote Sensing 2021, where he gave an overview of current and future missions of the ESA's Earth Observation Programs.

What are some of your responsibilities at ESA?

My responsibilities include leading the department of ESA that is tasked to perform preparatory activities for future EO programs, i.e., studies and developments on future EO architectures, missions — both research and operational oriented — and related instruments. The department is also responsible for future EO technologies programs, including investigations of new domains in EO, such as applications of artificial intelligence for EO, and for supporting European EO industries in order to strengthen their global competitiveness. The latter is the aim of a dedicated program based on co-funded projects proposed by industries.

What are some of the short-term and long-term plans for the future of EO programs at ESA? What are some of the strategic goals of these programs?

Alongside the continued operations and data exploitation of research and operational EO missions in orbit — for instance, Aeolus, SMOS, Swarm, CryoSat-2, the Copernicus Sentinels — the short-term plan includes the completion of several satellite projects leading to their launch in a few years. These include the Earth Explorer missions Biomass, FLEX, and FORUM; the small Scout missions HydroGNSS and CubeMAP; and various other missions for ESA's partners, namely new meteorological missions for EUMETSAT and the global-monitoring missions for the European Union EO program Copernicus.

The long-term plans include renewed efforts to extend and enhance those mission lines in order to meet the challenges of better understanding planet Earth, with new Earth Explorer and Scout research missions providing entirely new measurements, e.g., bistatic radar data over ocean, land, and ice surfaces. This incorporates continuous monitoring of climate variables and other parameters that are delivering societal benefits. The latter also includes increasingly commercial aspects, e.g., developing added-value products from imagery in all spectral regions. Improving the ability to apply the EO data in new ways so as to meet new needs is also an effort that is continuously increasing.

The strategic goals could be summarized in one sentence: to understand and monitor Earth from space for all kinds of societal benefits, from basic knowledge of the planet to continuous EO monitoring for all sorts of applications — weather forecasts, climate, food, water — including the survival of humanity and nature in current climate and biodiversity emergencies.

Pierluigi Silvestrin explains how ESA's Earth Observation Future Systems Department is structured to harness innovation to develop future systems. (Click on image to see interview) Credit: ESA

What are some of the new missions ESA is developing?

Two new missions in the design phase are the Earth Explorers — Harmony and Far-infrared Outgoing Radiation Understanding and Monitoring (FORUM). Harmony aims to study small-scale processes for Earth system models by observing displacements in the ocean, solid Earth, and the cryosphere, as well as providing data to better understand ocean sub-mesoscale circulation patterns, ice dynamics and mass balance, 3D deformation fields in land topography, and the ocean-atmosphere boundary layer. Harmony uses two passive receiving satellites to realize bistatic Synthetic Aperture Radar (SAR) imaging, flying in a symmetric formation with Copernicus Sentinel-1 SAR (the radar illuminator), with a ~250 km baseline for along- and cross-track interferometry. This will provide measurements of 3D Doppler and backscatter parameters. Harmony also includes a Thermal Infrared Imager observing a wide area around the bistatic scattering zone.

The FORUM satellite, whose project is now moving into the development phase, will provide unique spectrometric data on the Earth's outgoing energy, filling a measurement gap in the spectral far-infrared (FIR) with FIR observations below 400 cm-1. The observed radiative signatures will provide information on the variability in water vapor, greenhouse gases, cloud, and surface properties, so as to improve climate models.

Your professional work includes such technologies and areas as sensors, satellites, ground operations, data exploitation, and services for institutions, businesses, and citizens. What is your favorite aspect (or aspects) of the work that you do?

The aspects that I most enjoy in my work are the development of new observing techniques and of related applications in concert with users, typically Earth scientists. The possibility to link a better knowledge of the Earth system from EO, helping to preserve it, with evolutions in technologies — for instance new detectors using novel materials or new processing algorithms, just to mention two among many — is especially rewarding.

What originally drew you to Earth observation? Was it an interest in the planet, or an interest in the related technologies — or both?

I started working in EO following a technological interest in the area of special satellite platforms and sensors used for gravity measurements. My interest in the many other technologies applied in EO and in their numerous applications quickly followed, fueled by increasing concern about the impacts of human activities on the Earth system. I am convinced there is no real limit to matching high tech in space with the desire and need to observe the Earth, our living planet.