Marsden served in
France during
World War I as a
Royal Engineer in a special sound-ranging section and was awarded the
Military Cross in the
1919 King's Birthday Honours. In 1922 Marsden turned from his research and position as Professor of Physics to bureaucracy. He was appointed Assistant Director of Education before accepting the position of Secretary of New Zealand's new
Department of Scientific and Industrial Research (DSIR) in 1926. The new Department's focus was on assisting primary industries, and Marsden worked to organise research particularly in the area of
agriculture. During the War he worked on
radar research, setting up a team to develop the radar equipment for use in the Pacific. Marsden also used his scientific connections to form a team of young New Zealand scientists who would participate in the American Manhattan Project developing the nuclear bomb, and initiated the search for uranium, the raw material needed for nuclear projects, in New Zealand. Marsden had a post-war vision of a nuclear New Zealand, with scientists working on research using local nuclear reactors, and developing connections with the British nuclear energy and weapons program. While this vision was not fully realised, in 1946 he established a team of scientists to carry out research into atomic energy and the application of nuclear science to problems in agriculture, health, and industry. Ties between Marsden and the scientific community in Britain remained strong, and in 1947 he became the DSIR's scientific liaison officer in
London. Marsden retired in 1954 and returned to Wellington, where he continued to work and travel extensively, serving on a number of committees and conducting research into environmental radioactivity. As his studies turned to the impact of fallout from radioactive bombs, Marsden came to oppose testing and the development of nuclear weapons. While Marsden had a significant role in establishing and encouraging nuclear science in New Zealand, this role of speaking out against nuclear weapons development and testing - which he only did after the British nuclear testing program was complete - is less known. In 1966, the same year France began testing nuclear bombs in the Pacific, Marsden suffered a stroke after which he used a wheelchair. He later died at his home in Lowry Bay,
Lower Hutt on the shores of Wellington Harbour in 1970. ==Family life==