Klaus Torkar was one of the most influential researchers at the Institute of Space Research of the Austrian Academy of Sciences for decades. He passed away peacefully on March 17, 2024.
Immediately after completing his electrical engineering/electronics diploma, Dr. Torkar began his career at the Institute of Space Research of the Austrian Academy of Sciences in 1975. In his diploma thesis, he dealt with software development (with punch cards!) for early rocket experiments at the Graz University of Technology. In addition to experiments with rockets, he also worked on experiments with balloons and, at the same time, began to familiarize himself with the topics of plasma physics, ionospheric physics and the physics of the upper atmosphere. Based on this subject area, he completed his viva at the end of 1977 and was awarded his doctorate at the beginning of 1978.
A new chapter in Klaus Torkar's career began with "Spacelab". Spacelab was a laboratory project coordinated by the ESA that was integrated into the cargo bay of a space shuttle. The IWF was involved in the magnetometer and the particle spectrometer. The two devices were intended to measure the effects of artificially generated electron and ion beams on the space shuttle's environment. Dr. Torkar was interested in data evaluation and came into contact with the so-called "active experiments", which were based on artificial particle beams. Similar devices were used in Russian and Scandinavian rocket experiments, in which Klaus Torkar was involved due to his related topic of his diploma thesis. In 1989, he successfully completed his habilitation thesis on the subject of "Active Experiments" and became a university lecturer with a teaching license for experimental space research.
At this point, Austria had already been a full member of ESA for two years, which focused scientific interest on the Sun's influence on the Earth's environment. ESA was planning the CLUSTER project, in which four satellites of the same type were to orbit the Earth in formation to study the Earth's magnetosphere. Dr. Rudolf Schmidt, CLUSTER Project Scientist and former colleague of Klaus Torkar from his time at IWF Graz, proposed an instrument with ion emitters to control the electrical potential difference between the satellites and their surroundings. Similar concepts for potential control, which were intended to improve the measurement accuracy of other instruments on a satellite, had been discussed since the early 1980s and had already been tested in other missions such as GEOTAIL, AUSTROMIR or INTERBALL - also with participation from Graz. The Seibersdorf Research Center at that time had suitable ion emitters in its portfolio and the IWF, particularly Klaus Torkar, had plenty of experience with "active experiments". The instrument ASPOC - Active Spacecraft Potential Control - was accepted for CLUSTER and built under the technical leadership of Dr. Torkar with Austrian, Norwegian and Dutch participation.
Despite the early end of CLUSTER - the four satellites crashed into the South American jungle following the explosion of the Ariane 5 rocket on its first flight 50 seconds after launch - ASPOC became a success story in the long term. Under Klaus Torkar's project management, the IWF, together with international partners, built variants of the device for the EQUATOR-S mission carried out by the Max Planck Institute for Extraterrestrial Physics, for CLUSTER II, for the European-Chinese Double Star project and finally eight ASPOC flight models for the NASA Magnetospheric Multiscale mission, which, similar to the European CLUSTER II mission, measures the Earth's magnetosphere with four identical satellites, but at higher cadence. The CLUSTER II mission ends in 2024 - the last ASPOC emitter retired from service in 2008 - but on MMS, the most advanced ASPOC variants are still working largely flawlessly 10 years after the start of the mission.
In CLUSTER II, Dr. Torkar took over the leadership of ASPOC as Principal Investigator from Prof. Willibald Riedler; in MMS, he was Principal Investigator from the beginning. Dr. Torkar's intensive involvement with potential control made him a proven and internationally highly respected expert on the effects of electrical charging of satellites and the measures to control it. Until shortly before his death, Dr. Torkar was still in active exchange with colleagues at the IWF, which testifies to his deep attachment to this research topic.
Klaus Torkar also left his mark on two other IWF instrument participations. As PI of MIDAS (Micro Imaging Dust Analysis System) for the ROSETTA mission to the comet Churyumov-Gerasimenko, he was primarily responsible for the development of the instrument, whose measurement principle is based on atomic force microscopy for characterizing comet dust particles. The challenging mission, not only due to its long duration, attracted significant international attention when it arrived at the comet in 2014 and brought the IWF considerable media coverage. Klaus Torkar being already retired around that time, it was his successors who could reap the rewards.
The same applies to the last new development under Dr. Torkar's leadership, the ion spectrometer PICAM (Planetary Ion Camera). Klaus Torkar was the Co-Principal Investigator of this measuring device, which was built as part of the SERENA instrument package under Italian leadership for the ESA BepiColombo mission to Mercury.
The start of the PICAM was also not a straightforward one. The original design proved to be too unreliable. The teams involved were from Germany, France, Ireland, Hungary, and Austria, and they only realized the difficulties arising from the complicated mechanical and electrical design and the extreme thermal requirements when the prototype was built. Thanks to Klaus Torkar's tenacity and outstanding commitment, the most severe problems were overcome when he retired in 2014. His successors ultimately convinced ESA to approve PICAM as part of the mission and install it on the Mercury Planetary Orbiter. Today, two years before the actual start of the scientific mission phase at Mercury and after measurements during the flight in interplanetary space and during the flybys of Earth, Venus and Mercury, as well as after three software updates, PICAM is fully functional and has already provided the data for several scientific publications.
His numerous project participations are a hallmark of Klaus Torkar's scientific excellence. They have also made him an expert on the shortest connecting routes between gates and many other secrets at airports worldwide. Colleagues traveling with him have benefited from these special skills many times.
Klaus Torkar published 40 papers as the first author, almost 30 in peer-reviewed journals, and a further 240 scientific articles as a co-author.
He was a scientist, engineer, and manager with personnel responsibility all rolled into one. Thus, he had a decisive influence on the Space Research Institute at the Austrian Academy of Sciences and the people who had the privilege to work with him.
Rest in peace!
