Jeffrey Alan Hoffman, Ph.D. (born November 2, 1944) is an American former NASA astronaut and currently a professor of aeronautics and astronautics at MIT.
Hoffman's original research interests were in high-energy astrophysics, specifically cosmic gamma ray and x-ray astronomy. His doctoral work at Harvard University was the design, construction, testing, and flight of a balloon-borne, low-energy, gamma ray telescope.
Krishnaswami Kasturirangan received his Doctorate Degree in Experimental High Energy Astronomy in 1971, working at the Physical Research Laboratory, Ahmedabad.
As an Astrophysicist, Dr. Kasturirangan's research interests include high energy X-ray and gamma ray astronomy as well as optical astronomy. Using balloon observation, he studied cosmic X-rays in the 20-200 keV range and the secondary background properties of X-ray astronomical telescopes.
Walter H. G. Lewin, (Walter Lewin) is currently a professor of physics at the Massachusetts Institute of Technology (MIT). He earned his Ph.D. degree in nuclear physics in 1965 at the Delft University of Technology in the Netherlands.
He joined an X-ray astronomy group at MIT and conducted all-sky balloon surveys with George W. Clark. Through the late seventies, there were about twenty successful balloon flights. These balloon surveys led to the discovery of five new X-ray sources, which doubled the number known at the time. Furthermore, some of these X-ray sources were found to be varying, and some were X-ray flares. The rockets used by other researchers could not have discovered that the X-ray sources varied because they were only in the air for a few minutes, whereas the balloons could be in the air for many hours. The surveys also resulted in the discovery of GX 1+4, which was the first slowly rotating X-ray pulsar found.
Herbert Friedman was an American pioneer in the application of sounding rockets to solar physics, aeronomy, and X-ray astronomy. Friedman served as superintendent of the Atmosphere and Astrophysics Division at the US Naval Research Laboratory after World War II and helped to acquire German V-2 rockets for use as sounding rockets. Later on his group made use of Aerobee and Viking rockets and Rockoons. Over his career at NRL, his group discovered some 30 X-ray sources, usually designated with an XR- preface.
Riccardo Giacconi received a degree from the University of Milan before moving to the US to pursue a career in astrophysics research.
Giacconi worked on the instrumentation for X-ray astronomy, from rocket-borne detectors in the late 1950s and early 1960s, through to Uhuru, the first orbiting X-ray astronomy satellite, the Einstein Observatory, the first fully imaging X-ray telescope put into space, and the Chandra X-ray Observatory which was launched in 1999 and is still in operation. Giacconi was awarded the Nobel Prize in Physics in 2002 "for pioneering contributions to astrophysics, which have led to the discovery of cosmic X-ray sources".
Herbert Gursky was the Superintendent of the Naval Research Laboratory's Space Science Division and Chief Scientist of the E.O. Hulburt Center for Space Research. Dr. Gursky's research activities concentrated in the area of X-ray astronomy. He was the Principal Investigator for NASA sponsored space programs on the Astronomical Netherlands Satellite and the 1st High Energy Astrophysics Observatory (HEAO-1) satellite.
Dr. Gursky is best known as a member of the group that made the discovery of cosmic x-ray sources in 1961, his work with sounding rockets (he actually launched the June 12, 1962, rocket) that culminated in the optical identification of the bright X-ray source Scorpius X-1 in 1966, and later Cygnus X-1, his work on clusters of galaxies and the diffuse X-ray background from the Uhuru satellite and the discovery of X-ray bursters on the Astronomical Netherlands Satellite.