The first European satellites

The first European satellites, the first satellites of the European Space Research Organisation (ESRO), a pair of satellites that formed the basis of ESRO’s scientific program, concentrated on solar and cosmic radiation and its interaction with Earth. ESRO-1A was launched on October 3, 1968 and re-entered on June 26, 1970; ESRO-1B was launched on October 1, 1969 and re-entered on November 23, 1969. ESRO-1B, the fourth successfully launched ESRO satellite, had been put into a lower circular orbit to provide complementary measurements for ESRO-1A, but this was lower than planned which meant that re-entry was inevitable after only a few weeks.

ESRO-1A (Aurorae) and ESRO-1B (Boreas), the first European satellites, were designed to study how the auroral zones responded to geomagnetic and solar activity. They could make direct measurements as these high-energy charged particles plunged from the outer magnetosphere into the atmosphere. They would investigate the fine structure of aurora borealis and correlate studies on auroral particles, auroral luminosity, ionospheric composition and heating effects.

The main ESRO-1 program was a joint venture between NASA and ESRO. For ESRO-1A, NASA had provided the Scout launch vehicle (ELV), as well as the launch facilities at the Western Test Range, Vandenberg Air Force Base, California. For ESRO-1B, the launch vehicle (ELV) was purchased by ESRO from NASA. ESRO-1B carried eight experiments from four countries (Denmark, Norway, Sweden, and the United Kingdom). Progressive switch-on of the experiments took place quickly and was completed within seven days of launch.

The experiments were conceived as complementary from the outset of the programme and by covering a wide range of effects were intended to produce more comprehensive and meaningful information than would have been obtained had they been orbited separately. This policy had been fruitfully rewarded by the operation of ESRO-1A.

Europe in outer space

The European Launcher Development Organisation (ELDO)

The European Space Agency is an intergovernmental organisation dedicated to the exploration of outer space. It was established in 1975 and headquartered in Paris. One of its two ancestors is the European Launcher Development Organisation (ELDO). The European Launcher Development Organisation (ELDO) is a former European space research organisation. It was first developed in order to establish a satellite launch vehicle for Europe. The three-stage rocket developed was named Europa, after the mythical Greek god. Overall, there were ten launches that occurred under ELDO’s funding. Initially, the launch site was in Woomera, Australia, but was later moved to the French site Kourou, in French Guiana. The program was created to replace the Blue Streak Missile Program after its cancellation in 1960. In 1974, after an unsuccessful satellite launch, the program was merged with the European Space Research Organisation (ESRO) to form the European Space Agency (ESA).

The European Space Research Organisation (ESRO)

The European Space Research Organisation (ESRO) was an international organisation founded by European States with the intention of jointly pursuing scientific research in outer space. It was founded in 1964. Between 1964 and 1975, ESRO developed eight small scientific satellites launched by NASA and started the realisation of seven others. Towards the end of its existence, the European Space Research Organisation had expanded its field of intervention to include space applications in the field of telecommunications and meteorology. ESRO has also carried out space-related studies by launching sounding rockets. Following a general overhaul of the European Space Program decided in 1973, the European Space Research Organisation was merged with ELDO to form the European Space Agency (ESA) in 1975.

The European Space Research and Technology Centre (ESTEC)

The European Space Research and Technology Centre (ESTEC), located in Noordwijk (the Netherlands), was founded in 1968. The centre was to be the core of the European Space Research Organisation (ESRO). Its responsibilities included the engineering and testing of satellites and their payloads, the integration of scientific instruments in these payloads, and making arrangements for their launch. In some cases member States were to produce the scientific instruments for ESRO or produce them as part of their own national effort and compensate ESTEC for its service. In practice, national organisations simply used ESTEC as a service organisation and left it to pay for their efforts from the ESRO budget.

The first European satellites

The ESRO-1 mission and its payload were first outlined in 1963 at scientific meetings at the COPERS (the European Preparatory Commission for Space Research), the forerunner of ESRO. ESRO put out a call for tenders in 1964 for the design, development and manufacture of the two ESRO-1 satellites. In April 1965, the contract was awarded to Laboratoire Central de Télécommunications, Paris, as prime contractor in association with Contraves AG, Zurich, and Bell Telephone Manufacturing Company, Antwerp. The design of the spacecraft was under the authority of ESRO.

The basic form of each satellite was a small cylinder with a diameter of eighty centimetres and a height of ninety-three centimetres, which fitted snugly into the fairing of the Scout launch vehicle. They were non-stabilised satellites carrying very simple experiments designed to measure the radiation environment around the spacecraft. They represented the direct satellite descendants of the experience gained with earlier sounding rocket experiments.

ESRO-1A (Aurorae), developed by the European Space Research Organisation, was a eighty kilograms, cylindrically shaped, solar-cell-powered spacecraft instrumented with seven scientific experiments chosen to measure a comprehensive range of auroral effects. The measurements include auroral luminosity, ionospheric composition and temperature, and the flux, type and energy spectra of trapped and precipitated energetic particles. The spacecraft was placed in a Low Polar Orbit (LPO) with its axis of symmetry magnetically aligned along the Earth’s field. It had operated satisfactorily for eighteen months, except for the tape recorder which failed after seven months.

ESRO-1B (Boreas) conducted correlative studies with the identical satellite ESRO-1A (Aurorae); its experiments were: 1. Trapped and Precipitated Electron Flux and Energy Spectra; 2. High Latitude Particle Electrostatic Analyser; 3. Trapped and Precipitated Proton Spectra; 4. Pitch Angle Distribution of Electrons and Protons; 5. Flux and Energy Spectra of Solar Protons; 6. Auroral Photometers; 7. Langmuir Probe; and 8. Ion Composition and Temperature.

The first ESRO satellites were the basis of the scientific exploration that ESA inherited from ESRO. These small pioneers enabled ESA to build on the experience of the ESRO programmes and paved the way for the scientific missions that were to take place over the next fifty years.