50 Years of the European Satellite ESRO-2B (Iris)

The IRIS satellite in orbit around the Earth. Above: the occasion 'ESRO-2B' and the years '1968' and '2018'. Below the satellite, the inscription 'IRIS' (International Radiation Investigation Satellite). The country code 'BE', the mint master's mark of Ingrid Herzele and the Utrecht mint mark round off the lower portion of the design. The initials LL of designer Luc Luycx appear beneath the globe.

ESRO-2B, later known as IRIS, was the second research satellite of the European Space Research Organisation and was launched by NASA on 17 May 1968 aboard a Scout rocket from Vandenberg Air Force Base in California. Its main task was to measure cosmic radiation and high-energy solar particles in Earth orbit — data that was fundamental to understanding space physics and the radiation environment in low Earth orbit. ESRO, the precursor organisation to today's ESA, founded in 1964 by ten European states, used the satellite as early proof that Europe was technically capable of carrying out independent space missions. Belgium had been a member of ESRO from the outset and contributed to its programmes both scientifically and financially.

The launch of ESRO-2B marked an important moment in the history of European space cooperation: for the first time, the European partner nations succeeded in transmitting reliable measurement data from orbit using a jointly developed scientific satellite. Belgium, which had been involved in space research early on through institutes such as the Belgian Institute for Space Aeronomy (BIRA-IASB), remains an active ESA partner to this day. With the issue of a Belgian 2-euro commemorative coin in 2018, the country marked the 50th anniversary of this launch and its role in a project that laid the groundwork for Europe's later space infrastructure.