In Memoriam

ICTP is mourning the passing of Sandro Marie Radicella, former head of ICTP's Telecommunications/ICT for Development Laboratory (T/ICT4D). Director Atish Dabholkar led staff in observing a minute of silence to honour the longterm Centre scientist.

Under Radicella's guidance, ICTP became one of the world's leading organisations in making ionospheric science and wireless-communication technology available to developing countries. For several decades Radicella organized and carried out colleges, schools and workshops in aeronomy, space sciences and telecommunications, training thousands of young scientists and university professors from developing countries. As an example of his work, in the early 1990s, Radicella established ICTP's programme on Academic Computer Networking in Developing Countries, organizing a pilot project in Nigeria to strengthen Internet access at universities there. Today, Nigeria has about 140 universities, all of which have benefitted from the residual technical expertise that this project introduced to the country.

Radicella’s academic and scientific journey began at the Universidad Nacional de Tucumán in Argentina, where he earned his degree in physics. He served as a university professor and created research groups in Tucumán, La Plata and San Juan. He was principal researcher for Argentina’s National Scientific and Technical Research Council (CONICET). In Argentina he organized and directed for 20 years the National Program of Radiopropagation (PRONARP).

But it was his commitment to global collaboration that truly defined his legacy. In 1989, he joined ICTP to launch a vital initiative: organizing a series of schools, colleges, and training workshops for scientists and engineers from developing nations. By 1990, he took the lead in establishing the Aeronomy and Radiopropagation Laboratory (ARPL), which later expanded into the T/ICT4D. 

For three decades, from 1990 to 2020, he guided this group, bridging deep scientific research with practical applications like space weather studies, GNSS navigation, and wireless networks for underserved regions. He initiated the International Reference Ionosphere (IRI) Task Force Activity (ITFA) meetings at ICTP following the IRI Workshop in 1993 and continued them annually until 2004. These activities contributed substantially to several important improvements of the IRI model electron density characterization.

His collaborative spirit with colleagues from the University of Graz led to the development of  a family of ionospheric models, most notably the NeQuick ionospheric electron density model, which became a cornerstone for global navigation satellite systems; one version based on it was officially adopted by the European Space Agency for ionospheric corrections in the Galileo, the European GNSS constellation. 

He has received Doctorate Honoris Causa degrees from the University of Bucharest (Romania) in 2001, Obafemi Awolowo University (Nigeria) in 2005, and the National University of Tucumán (Argentina) in 2019.

Beyond these technical triumphs, Radicella's greatest achievement was his dedication to nurturing talent. He trained generations of scientists across Africa, Latin America, and Asia in space weather, radiocommunications, and open-access technologies. This led to a 2009 partnership agreement between ICTP and Boston College, represented by Pat Doherty, to help developing countries, particularly in Africa, to develop a local sustainable workforce in ionospheric and radiopropagation science. The impact was a substantial increase in the international scientific contribution of African scientists and the development of university curricula, earning Radicella and Doherty the affectionate titles "Papa Africa" and "Mama Africa" from their African colleagues.

In recognition of his profound impact, Radicella was a recipient of ICTP's 2019 Spirit of Abdus Salam Award for his dedication in fostering research in ionospheric physics, radio science and its applications in digital communications throughout the developing world.

After retiring from ICTP, he continued working and mentoring students, affiliated as a visiting scholar at Boston College and since 2013 as Lifetime Honorary Professor at the Universidad Complutense de Madrid, Spain.

Former ICTP Director Fernando Quevedo fondly recalled Radicella as a driving force behind many of the ICTP initiatives to support African scientists. "I had the greatest respect for him as an educator, researcher and dear friend. Interacting with him I learned how important ICTP has been not only to support basic sciences but also applied subjects with direct impact in the developing world. I would not exaggerate to say that essentially all the activities on the applied section of ICTP would not have existed without Sandro's permanent support for their initiatives and the younger scientists and engineers that work at ICTP and the many visitors. He will be very much missed."

Remembrances

In the 1995, I attended his radio propagation course at ICTP, starting our long-term scientific collaboration. Driven by Professor Radicella, ICTP and China Research Institute of Radiowave Propagation (CRIRP) established stable partnership, focusing on joint research of the ionospheric model. He organized long-term training courses for developing countries and hosted young researchers from CRIRP cultivating a cohort of outstanding young scientists for our institute. Professor Radicella devoted himself to ionospheric and radiopropagation research and talent training for developing countries. We mourn his passing and send sincere condolences to his family, students and colleagues.

Weimin Zhen
China Research Institute of Radiowave Propagation

Sandro was a truly wonderful human being who helped so many people, both in science and in life. He was in exactly the right place at ICTP, where he supported countless colleagues, particularly scientists from developing countries and especially from Africa. I have wonderful memories of the very productive and enjoyable times we shared during the IRI Task Force Activity (ITFA) meetings at ICTP. Sandro was the driving force behind these meetings, bringing together scientists from developed and developing countries, who came to the ITFA with their data, models, and ideas to work together. Sandro will be greatly missed by all of us. We will always remember his kindness, his enthusiasm, and his commitment to helping others.

Dieter and Roxana Bilitza (US)

My first introduction to him was in 2019, and ever since, I have been deeply inspired by his work and his remarkable contributions to the ionospheric community. Dr. Radicella is one of the names we have always mentioned to our students as an example of excellence and dedication. I last had the opportunity to meet him in 2025, and his talk on interdisciplinary collaboration profoundly influenced me. It encouraged me to think beyond the limited scope of my own work and to appreciate the importance of looking at scientific challenges from broader perspectives.

Bushra Gul (Pakistan)

I will always remain deeply grateful to him for giving me my first opportunity to see the research world beyond India @ ICTP School in 2006. He truly motivated/guided me to pursue ionospheric research. His generosity and encouraging nature has left an everlasting impression on me. What I remember most fondly is that he would often invite us for coffee, and the warmth extended during that time was truly special, and remains among my most cherished memories of him. Even he brought sweaters for me thinking of the peak Italian winters. I feel privileged to have known him, pursue research under his supervision, and profoundly grateful for everything and his kind blessings. I will always remember him with immense respect, gratitude, and warmth. It is very difficult to accept that he is no longer with us.

Navin Parihar (India)

Professor Radicella was not only my supervisor and mentor; he was also a father figure and a guide in my life. His advice was never limited to academic or scientific matters. He cared about us as people, and his kindness, generosity, patience, and willingness to help touched my life in so many ways.

Melessew Nigussie (Ethiopia)

It is with deepest sorrow that I heard of Professor Radicella's passing. I worked under Professor Radicella for more than eight years in 1990s, and he was both a mentor and a father figure to me. I will always be grateful for his guidance and kindness.

Man-Lian (CAS, China, former ICTP researcher)

I remember most his generosity of spirit and the way he made people feel welcome and valued. His faith was also an important part of his life, and I remember it as something that gave him strength and guided the way he related to others. Although many years have passed since we first met, the impression he left on me has remained. I feel fortunate to have crossed paths with him at such an important time in my life and career.

Carlo Scotto (INGV)

Professor Radicella was my PhD supervisor, and a second father and I feel deeply fortunate to have had the opportunity to learn from him and work with him. He had an important influence on my academic, professional and personal journey, and I will always be grateful for his guidance, knowledge, encouragement, and support. The greatest way I can express my gratitude to him is by carrying his teachings with me and trying to put them into practice in my own life.

Claudia Paparini

When I visited ICTP for the SCOSTEP/PRESTO workshop in 2023, Sandro was very kind to me.  I remember his warm smile. During these SCOSTEP workshops, I see his NeQuick model of the ionosphere has been widely used by the community, particularly in developing countries, to help understanding the dynamic variation of the ionosphere. It is truly sad that he has passed away.

Kazuo Shiokawa, President, Scientific Committee on Solar-Terrestrial Physics (SCOSTEP)

He was a great scientist and an exquisite person. We bonded immediately upon meeting decades ago, Prof. Radicella at the ICTP and I at the INAF-Astronomical Observatory of Trieste. Over the years, we collaborated to strengthen the field of Space Weather: Prof. Radicella focusing on the ionospheric physics and I on solar physics. His scientific and personal legacy will endure through the people who knew him and will always remember him.

Mauro Messerotti (INAF)

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With thanks to Yenca Migoya-Orue, a researcher in ICTP's Science, Technology and Innovation section and a former student of Radicella's, for her generous contributions to this article.