• 1958 - Doctorate in law and joined the German Federal Ministry of the Interior as an administrator
• 1962 - Legal Advisor for COPERS and later ESRO
• 1964 - Assistant Director for International and Legal Affairs for ESRO and later ESA, from 1974 Assistant Director for International and Legal Affairs
• 1979 - left ESA to administer a research programme in the Federal Ministry of the Interior in Bonn
• 1980-1983 - Developed a nuclear energy programme at the International Atomic Energy Agency in Vienna
• 1984 - Directed UNESCO’s office for Operational Activities in Paris.

In 1962 Kaltenecker joined the Secretariat of COPERS, with responsibility for legal affairs and on the establishment of ESRO in 1964 became its Legal Advisor, dealing with many of the crises of the early years over contracts and member states' responsibilities. In 1974, during the creation of ESA, he became Assistant Director for International and Legal Affairs, supervising offices in Paris and Washington and developing relations with non-member states and international organisations. He was closely involved in negotiations for collaboration between ESA and other countries, including the Ariane programme and the NASA-ESA Spacelab programme.

• 1967 – Graduated in physics from the Technical University of Munich, PhD at the University of Bochum
• 1960s – Space research projects at the Max-Planck Institute for Extraterrestrial Physics in Garching, visiting scientist at the Space Sciences laboratory in Berkeley, California
• 1975-1990 – joined the Spacelab Phase C/D project team at ERNO Raumfahrttechnik GmbH, becoming General Manager of ERNO in 1987
• 1990-1993 – Director for Space Programmes at the German Aerospace Research Establishment (DLR)
• 1993-1997 – Worked for STN Atlas Electronik with responsibility for corporate development and technology research and development
• 1997-2007 – ESA Director of Industrial Matters and Technology Programmes (1997-2004); Director of Resources Management (2004-2007)

After the merger between ERNO and MBB, Kappler was appointed General Manager of ERNO, whose main activities were Ariane 4 production, Ariane 5 upper stage development, EURECA, DFS Kopernikus and Columbus Phase B. 

Kappler was appointed Director of Industrial Matters and Technology Programmes by the ESA Council in March 1997, and took up duty on 1 June 1997. He became Director of Resources Management in 2004 and left ESA at the end of April 2007. 

• 1952-1966 – Worked for ICEM, the Intergovernmental Committee for European Migration (which went on to become today’s International Organization for Migration (IOM) in 1989) with a period as Head of Mission in Brazil.
• 1950s-60s – also worked in South America for the UN Food and Agriculture Organization (FAO)
• 1967-1978 – Appointed as Secretary to the ESRO Council and Head of the Director General’s Office, a position that in the early 1970s became Head of the Director General’s Cabinet
• Left ESA on his retirement in May 1978

• Undertook studies at ETH Zürich, the Swiss Federal Institute of Technology in Zürich
• 1966-1967 - First Director of ESTEC for ESRO, came from a background in Swiss industry

• 1936 - Doctorate in Physics, Habilitation in Heidelberg
• 1931-1946 – worked in Berlin, first at AEG’s research institute (1931-1932) and then at Telefunken (1932-46) becoming Director of Telefunken's High Vacuum Development Section
• 1946-1950 – Moved to Paris, worked in the research centre of the Compagnie Génerale de Télégraphe Sans Fil, leading a research group in microwave tubes
• 1950-1952 - National Electronics Institute in Madrid
• 1952-1967 - returned to Germany to work for Siemens and Halske AG in Munich.  Appointed Director of their research laboratory in 1959.
• 1968-1971 -Director of ESTEC
• Taught at University of Munich, University of Madrid, Technical University of Stockholm and Chalmers University of Gotherburg

From 1968 to 1971 Kleen was the Director of ESTEC, the European Space Technology Centre in Noordwijk, the Netherlands.  His drive to introduce reliable and state-of-the-art technology laid the groundwork for the successful launch of several satellites by ESA after his retirement.

• 1987 – Doctor of Medicine degree from the University of Amsterdam
• 1987-1988 – Officer of the Royal Netherlands Air Force Medical Corps
• 1989-1999 – Worked for the Research and Development department of the Netherlands Aerospace Medical Centre in Soesterberg
• 1999 – Joined the ESA Astronaut Corps, ESA Astronaut on two missions between 2004 and 2012

During his time at the Netherlands Aerospace Medical Centre Kuipers was involved in the physiological ESA experiments for space missions, including the Spacelab-D2 mission in 1993, the EuroMir-95 mission and the LMS Spacelab mission in 1996.

In July 1999, Kuipers joined the ESA’s Astronaut Corps and was assigned to ESTEC, continuing his work on microgravity experiments.

During Soyuz missions Soyuz 6S and 7S to the International Space Station he supported ESA's ground team from the Russian Control Centre as Crew Interface Coordinator and was also backup for ESA astronaut Pedro Duque’s mission in October 2003.

In 2002, Kuipers was assigned as a Flight Engineer for a Soyuz flight to the International Space Station on the DELTA mission, which took place in April 2004 and where he performed 21 experiments in human physiology, biology, technology and education.

From 2007, he trained as backup to ESA astronaut Frank De Winne for Europe’s second long-duration spaceflight to the International Space Station : from May 2009, Kuipers was assigned to Eurocom duties at the Columbus Control Centre and EAC in support of De Winne’s six-month mission.

He was later assigned to Expedition 30/31, a long-duration mission to the International Space Station called PromISSe, launched in December 2011 from Baikonur Cosmodrome in Kazakhstan. During his mission, he took part in around 50 experiments covering a wide range of disciplines and returned to Earth in July 2012.