ALT Hugh McCann for Ireland signs the Act while the cameras look on (pic: ESA ECSR)

ALT Practical arrangements for the day, 30 May 1975 (pic ESA ECSR)

ALT ESA circular letter announcing that the ESA Convention had been signed 30 May and that ESA was operating from 31 May 1975.

ALT Michel Bourély standing with paper in hand at the Conference of Plenipotentiaries, 30 May 1975. With Swedish and Swiss delegates

ALT Gaston Geens chairing the first ESA Ministerial Council in 1977. Other notable figures identifiable are Director General Roy Gibson, head of French delegation Michel Bignier and Harry Atkinson, UK delegation.

ALT March 1974 – Alexander Hocker speaking at the '10 Years of ESRO' anniversary party in the main corridor at ESTEC in the Netherlands.

ALT ESA Astronaut Thomas Pesquet is standing on the steps at the base of the launch tower, waving to well-wishers before he boards the rocket that will take him to the International Space Station.

ALT A camera on the mobile launcher shows the rocket and spacecraft lifting off as umbilical arms swing away to provide a clean path for the rocket’s ascent. The ESA and NASA logos can be clearly seen on the rocket's white fairing. (Photo: NASA/Chris Coleman, Kevin Davis).

ALT A photograph of the Portuguese flag against a blue background. It is a vertically divided green-red national flag with a coat of arms centred on the line between the two colours.

ALT cover of the Blue Book produced by COPERS (the initial eight-year programme of ESRO)

ALT ESRO flag and HEOS-A model

ALT Cover of document with ELDO job descriptions

ALT A cartoon showing the Philae lander on the surface of Comet 67P. The character of Philae is wearing a yellow safety helmet with a lamp on it and is planting an ESA flag on the surface of the comet. The Rosetta spacecraft is shown in the upper left hand corner of the image.

ALT Ariane 3 flight V11 carrying the Marecs B2 satellite lifts off from the launch pad into the night sky. The smoke and flames from the rocket can be clearly seen as it clears the launch pad.

ALT The picture shows an artist's impression of Venus Express orbiting the planet Venus. The spacecraft is the shape of a cube and is a golden colour. Two solar panels extend outwards on two sides, the light of the sun is reflected on the panels. Venus can partially be seen in the background, in the top right-hand corner of the image. The surface of the planet is a beige colour.

ALT The launch of the Metop-C satellite into the night sky. The flames from the rocket's engines light up the launch pad as it lifts of.

ALT Black and white photo of Pierre Auger and Hermann Bondi visiting ESTEC on 6 September 1967.