The Voyager mission 41 years after: Limits of the Solar System and Echoes from the Galaxy



Humanity’s farthest and longest-lived spacecraft, Voyager 1 and 2, achieve 40 years of operation and exploration last August and September. Despite their vast distance, they continue to communicate with NASA daily, still probing the final frontier.  Voyager 1, now almost 13 billion miles from Earth, travels through interstellar space northward out of the plane of the planets. The probe has informed researchers that cosmic rays, atomic nuclei accelerated to nearly the speed of light, are as much as four times more abundant in interstellar space than in the vicinity of Earth. This means the heliosphere, the bubble-like volume containing our solar system's planets and solar wind, effectively acts as a radiation shield for the planets. Voyager 1 also hinted that the magnetic field of the local interstellar medium is wrapped around the heliosphere. Voyager 2, now almost 11 billion miles from Earth, travels south and is expected to enter interstellar space in the next few years. The different locations of the two Voyagers allow scientists to compare right now two regions of space where the heliosphere interacts with the surrounding interstellar medium using instruments that measure charged particles, magnetic fields, low-frequency radio waves and solar wind plasma. Once Voyager 2 crosses into the interstellar medium, they will also be able to sample the medium from two different locations simultaneously.
ICSO has the honour to host a Special Guest Plenary Talk with Stamatios Krimitzis, a PI in the Voyager program who has been following the missions since the start. 



Stamatios Krimigis is Emeritus Head of the Space Exploration Sector of the Johns Hopkins Applied Physics Laboratory (APL), occupies the Chair of Science of Space at the Academy of Athens, and is Principal Investigator on NASA’s Voyagers 1, 2, and the Cassini-Huygens missions, among others. He received his Ph.D in Physics from the University of Iowa (1965), served on the faculty, moved to APL in 1968, became Chief Scientist (1980), Space Department Head (1991) and Emeritus in 2004. He has built instruments that have flown to all nine classical planets beginning with Mariner 4 to Mars in 1965. He has published nearly 600 papers in peer-reviewed journals and books with over 18,000 citations. He is a three-time recipient of NASA’s Exceptional Scientific Achievement Medal Recent awards include the Council of European Aerospace Societies the CEAS Gold Medal in 2011, the European Geophysical Union Jean Dominique  Cassini Medal (2014), the American Institute of Aeronautics and Astronautics Van Allen Space Environments Award (2014), the National Air and Space Museum (NASM) Trophy for Lifetime Achievement (2015), the International Academy of Astronautics (IAA) Laurels Award for MESSENGER (2015), the American Astronautical Society Space Flight Award, the NASM Trophy for Current Achievement (New Horizons Team), and the NASA Distinguished Public Service Medal, all in 2016, the IAA Theodore von Karman Award (2017), and was elected member of the Academia Europaea (2017).