Mario Humberto Acuña ’60, a NASA astrophysicist whose scientific instruments have flown on more than 30 NASA missions to every planet in the solar system as well as the sun, died March 5 of multiple myeloma at his home in Bowie, Md. Acuña, a specialist in the interactions of magnetic fields and plasmas and the instruments used to measure them, was a key player in the 1997 discovery that Mars has a magnetic field and that the planet in an early era churned with internal heat and other powerful forces, remarkably like the geology of Earth today. He was credited with the discovery of a magnetic disturbance around Jupiter, which led to the discovery of its ring. He was also a member of a multinational team in 1984 that created the first manmade comet as part of a study of the magnetosphere, the powerful magnetic bubble that surrounds the earth. Acuña was elected to the National Academy of Sciences in 2007. He also received NASA’s highest honor in 1996, the Distinguished Service Medal. His facility at explaining advanced scientific concepts won him an appearance in the 2003 PBS Nova episode “Magnetic Storm.” Born in Cordoba, Argentina, on March 21, 1940, Acuña graduated from the University of Cordoba in 1962. He received a master’s degree in electrical engineering from the University of Tucuman in Argentina in 1967. While in school, he worked for the Argentine National Space Research Commission. After graduation, he moved to the Washington area and joined Fairchild-Hiller Corp. to provide engineering and scientific support to NASA. He later became the head of its electronics division. In 1969, he began working with NASA’s Goddard Space Flight Center, where he remained for the next 40 years. He received a doctorate in space physics from Catholic University in 1974. Acuña was principal investigator for NASA’s Mars Observer Magnetic Field Investigation and also participated in the Defense Meteorological Satellite Program, which collected weather data for the military. His laboratory was recognized worldwide for its development of instruments that measure geophysical magnetic fields, plasmas, electromagnetic waves, gamma rays, and X-rays. In addition, Acuña was project scientist and science manager for the International Solar Terrestrial Physics Program, a $2.4 billion research effort with Japan, Europe, and Russia involving more than 1,000 investigators and the launch of several spacecraft in the 1990s. He was a fellow of the American Geophysical Union and a founding member of the Latin American Association of Space Geophysics. Survivors include his wife of 42 years, Barbara Acuña, 3902 Claxton Pl., Bowie, MD 20715-1340; four children, James Acuña, Andrew Acuña, Daniel Acuña, and Marta Aebischer; three sisters; a brother; and five grandchildren.