Created Scientific Devices For NASA

Mario Humberto Acuña, 68, a NASA astrophysicist whose scientific instruments have flown on more than 30 NASA missions to every planet in the solar system, including the sun, died March 5 of multiple myeloma at his home in Bowie.

Dr. 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.

"Rather than wait for chance events to happen, we decided to go out there and simulate natural conditions," Dr. Acuña told Time magazine that year. There is a need "to better understand what would happen if the magnetosphere disappeared."

Ten years later, he told the New York Times: "Suppose that we had a large geomagnetic storm during the Super Bowl and all of your equatorial spacecraft get knocked out of alignment. The man on the street would immediately notice. He doesn't know what caused it, but he will certainly care."

Dr. 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."

Discussing Mars, he said, between narrator interruptions: "Nature had big surprises for us, beyond our wildest expectations. We found these huge magnetic fields in the crust, and all of a sudden a completely unexpected and unknown planet, in a sense, emerged . . . and not only that, at an intensity which is 20 to 30 times that of the Earth.

"The puzzle was, where did the water go? . . . We found two very large impact basins in the southern hemisphere of Mars, which are Hellas and Argyre. There was absolutely no magnetization over them. Which immediately meant that they were formed after the magnetic field of Mars had ceased to exist, and the estimate is that these impacts took place more than 4 billion years ago."

Born in Cordoba, Argentina, on March 21, 1940, Mario Humberto 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.

Dr. 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, Dr. 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 of Bowie; four children, James Acuña of Tallinn, Estonia, Andrew Acuña of Ellicott City, Daniel Acuña of Owings Mills and Marta Aebischer of Exton, Pa.; three sisters; a brother; and five grandchildren.