Tribute to an Interstellar Pioneer: Icarus Shepherd Probes

Recently it was announced that one of the pioneers behind interstellar research, Dr Les Shepherd, had passed away. Les was a pioneer of atomic rockets (with Val Cleaver in 1949), interstellar flight (with his seminal 1952 paper) and international co-operation in the pursuit of space, being one of the founders of the International Astronautical Federation (IAF) in 1950. He served as Chairman of the British Interplanetary Society from 1957-1960 and again later as President from 1965 – 1967. He also served as President of the IAF in 1957, 1962. Les was one of the people behind the formation of the International Academy of Astronautics (IAA) in 1959. When he died Les had been a member of the BIS for 77 years, the longest ever serving member – an amazing record. If only our space probes could survive that long. Paul Gilster recently ran two tremendous blog articles in tribute to this great man. Dr Claudio Maccone’s recollections are especially moving: and here is the British Interplanetary Society’s own tribute: In a recently published Spaceflight magazine article (Spaceflight, 54, 1, January 2012) I briefly discussed Les Shepherd and said the following: Members of the British Interplanetary Society are no strangers to the problem of interstellar flight. The first academic paper on the subject, ‘Interstellar Flight’, was published by one of the founding members Dr Les Shepherd in a 1952 issue of the Journal of the British Interplanetary Society (JBIS). This is a paper that is not well cited in the interstellar community but it should be, because it was the first. The author considers the distance, time, energy, exhaust velocities, accelerations, possible fuels, mass ratio, the effect of interstellar matter, relativistic speeds. In this paper Shepherd states: “There does not appear to be any fundamental reason why human communities should not be transported to planets around neighbouring stars, always assuming that such planets can be discovered. However, it may transpire that the time of transit from one system to another is so great that many generations must live and die in space, in order that a group may eventually reach the given destination. There is no reason why interstellar exploration should not proceed along such lines, though it is quite natural that we should hope for something better”. In Icarus we have thought of a good way to pay tribute to Les Shepherd and came across a comment by one of the Centuri Dreams readers (ljk) who suggesting renaming Icarus after Dr Shepherd. Well, we’re not quite going to do that, but something very similar. Above shows a schematic of the Daedalus sub-probes. For Project Icarus, we have not yet determined the specific type of sub-probes we will use and this is still an issue under design discussion. For this reasons its important to keep our characterisation of the sub-probes generic. But in tribute to a pioneer, we have decided to give them the name “Shepherd Probes” to describe the entire class of completely autonomous sub-probes designed to be distributed into a target system from an interstellar vessel. Rest In Peace Dr Les Shepherd (1918-2012) and thank you for your contribution to a peaceful human future in space. Kelvin Long Vice President (Europe) Icarus Interstellar