Herbert William Schnopper, former director of the Danish Space Research Institute and senior astrophysicist at the Center for Astrophysics | Harvard & Smithsonian (CfA), died on 1 April 2019 from Alzheimer’s disease at age 86.
Born of immigrant parents in New York City, Schnopper received a BS in physics from Rensselaer Polytechnic Institute in 1954 and a PhD in physics from Cornell University in 1962. After a stint as a senior scientist at the Jet Propulsion Laboratory, he briefly returned to Cornell to teach and continue his earlier atomic physics research on multiple excitation and ionization by x rays of inner atomic shells using innovative high resolution spectroscopic techniques. During this time, he served as a captain in the Army reserve.
Beginning in 1966, Schnopper spent 12 years at MIT, first as an assistant professor and then associate professor. It was at MIT where Schnopper turned his sights and expertise toward the stars and developed a range of innovative x-ray imaging and spectroscopic and polarimetric concepts that would initially fly aboard sounding rockets and then on a variety of satellites. In particular, he designed the rotating modulation collimator aboard NASA’s SAS 3 satellite, which was an advanced method for locating x-ray sources with high precision. He also designed the focal plane x-ray spectrometer that flew aboard the Einstein satellite. He was also one of the original co-investigators for the follow-up to the Einstein satellite, the Chandra X-ray Observatory. Some of his other x-ray spectrometer concepts were adopted by several groups involved with studying the properties of magnetically confined laboratory plasmas, such as those at MIT’s Alcator and Princeton’s PLT tokamaks in the US and similar facilities in Europe.
Perhaps more importantly, Schnopper originated the concept of the Bragg crystal polarimeter, an instrument that opened up a new window of x-ray astronomy and astrophysics. It made it possible to learn more about plasma emission processes and the geometry of exotic cosmic objects such as supernova remnants, neutron stars, pulsars, and black holes. His instrumental ideas for spaceborne polarimeters were first adopted by the group at Columbia University in early sounding rocket flights and then aboard NASA’s OSO 8 spacecraft. Today there are many groups actively pursuing soft and hard x-ray polarimetry.
In 1980, after spending two years at the CfA, Schnopper became the director of the Danish Space Research Institute (DSRI) in Copenhagen. At that time, the DSRI was in the middle of analyzing data from the successful HEAO-3 Cosmic Ray Isotope Spectrometer. Since it was clear that after HEAO-3, further progress in cosmic ray research would require instruments far beyond the means available of the DSRI, Schnopper defined a new research direction for the astrophysical research at the institute. DSRI soon became a center for developing x-ray spectroscopy applications for x-ray astronomy.
After an initial tour of all the astronomical observatories and space research facilities in the Nordic countries, Schnopper started in-house developments of x-ray instrumentation on several fronts. He initiated work on imaging gas proportional detectors and on thin-foil grazing incidence x-ray telescopes. He wanted the institute to become a major player in European x-ray spectroscopy missions.
Schnopper became a member of the ESA Horizons 2000 Survey Committee and was among the founders of the XMM (now XMM-Newton) studies in the 1980s. The XMM study group opted for an x-ray mirror technology based on electro-formed nickel shells, as this offered better angular resolution than was possible with the early thin-foil concepts. Consequently, Schnopper found a new possibility for flying the thin foil mirrors by joining the Russian Spectrum X-Gamma project proposed by the Space Research Institute of the Russian Academy of Sciences in Moscow. Unfortunately, Spectrum X-Gamma ran into severe financial difficulties following the collapse of the Soviet Union, and in the end the project had to be given up.
DSRI subsequently became involved in the ESA INTEGRAL project, where Schnopper organized the JEM-X collaboration for an x-ray monitor instrument involving six different European countries. Eventually this instrument was selected for flight and has been successfully operating in space for more than 17 years.
Schnopper decided to leave his post as director of the DSRI in September 1996. His legacy is clearly felt by the work being carried out today at the Danish Technical Institute for Space, with the institute’s strong position in multilayer x-ray optics (NuSTAR, ATHENA) and advanced x-ray detectors.
Returning to the US in 1998, Schnopper joined an interdisciplinary program in x-ray spectroscopy, polarimetry, and imaging at the CfA. There he continued developing his concept for thin-foil optics, this time fabricated with a special type of plastic. He continued to collaborate with colleagues in Europe on x-ray astronomy satellite concepts. He had a special relationship with the Università degli Studi di Palermo, Dipartimento di Scienze Fisiche ed Astronomiche in Palermo, Italy, and together they made the first successful demonstration of the plastic optics.
Schnopper was married twice, the second time to Patricia (Pat) Griffith, just before he took the directorship of the DSRI. Their overseas experiences were exciting, fulfilling times, and whenever they had the opportunity, they returned to their favorite spot on Earth, Deer Isle, Maine. They owned a piece of coastline where they built a special retreat that overlooked a beautiful Atlantic Ocean cove. Sadly, their time together was short as Pat passed away in 1986 and is survived by her daughters, Patti and Rachel, and sons, James and Joe, who acknowledged that their mother’s happiest years were those spent with Herb in Denmark and Deer Isle.
An excellent teacher, lecturer, adviser, and mentor, his legacy of innovation and creativity carries on in his many students. He was not impressed by titles or rank; it didn’t matter whether one had a high school degree or a PhD. He would hire those with good ideas and a strong work ethic, even if it meant he would have to buck the system to get them on board. In an anecdote from Pat’s son Joe, Schnopper commented about an MIT student’s thesis that had been classified secret, preventing publication: “With mock indignation and a dry smile, he remarked that classified research represented the Antithesis of a Thesis.”
His memory is honored by colleagues Niels Jørgen Westergaard, Niels Lund, Marco Barbera, and Rashid Sunyaev, is fondly remembered by Bert Singer and Angela Kimbert, and is cherished by close friends Kay Gunter, Eric Silver, and Marjorie Randell-Silver.
