seen with neutrons is around 20 times greater than with ionization chambers; in 1951, he found that the time variations are much greater as well. He had recognized the potential of neutrons and lower energy cosmic ray particles for exploring the causes of the time variations. That year he also invented the neutron monitor to fulfill the need for a stable ground-based neutron detector. In doing so, he established neutron monitor stations at various locations including Huancayo, Peru; Mexico City, Mexico; Sacramento Peak, New Mexico; Climax, Colorado; and Chicago, Illinois. In 1954 and 1955, Simpson explored the global and time variations of cosmic rays at these neutron monitor stations around the world. In 1956, a giant cosmic ray flare provided the first direct glimpse of composition of interplanetary space. At this point, the scientific community surrounding cosmic rays and solar activity had grown large. Simpson was one of 12 scientists responsible for organizing and coordinating the International Geophysical Year (1957–58), helping to make it a huge success. At the end of 1957, after the launch of Sputnik by the Soviet Union, Simpson, realizing the necessity for the US to send instruments into space, outlined the scientific situation and his plans for such activity to University Chancellor Lawrence Kimpton. Kimpton granted Simpson $5,000 to get the project off the ground, and partnered with Peter Meyer to develop small lightweight particle detectors suited for the space environment. Simpson's first particle detector was launched in 1958 on the spacecraft Pioneer 2. In 1962, Simpson and Professor Peter Meyer established the Laboratory for Astrophysics and Space Research (LASR) which was built within the Enrico Fermi Institute at the University of Chicago. NASA contributed towards the laboratory and funded a building for LASR, which was completed in 1964. In the laboratory, instrument development and space research were consolidated under one roof, along with theoretical research connected with the results of the ongoing research and space experiments. In 1965, Simpson, along with his students and co-workers, built the first cosmic ray detectors to visit Mars. It also became the first to visit Jupiter (in 1973), Mercury (1974) and Saturn (1979). Jupiter's mission detected the relativistic (3-30 MeV) electron population the planet was emitting for the first time; electrons were observed within the Jovian magnetosphere and then escaping at distances of at least 1 AU. Simpson's detection in 1974 is what first established that the magnetic fields