The Maven spacecraft, which entered orbit around Mars in September last year, carries a suite of instruments to analyze the solar wind and its effects on the atmosphere.

The air disappears in mainly two ways. Sometimes an electron is knocked off an atom in the upper atmosphere, and then the charged atom is accelerated away by the electric and magnetic fields of the solar wind. Particles of air can also be knocked into space through collisions with incoming solar wind particles, like billiard balls.

Dr. Jakosky said the two phenomena are roughly equal in importance. The current papers focus on the effect on the charged atoms, usually escaping at a rate of about 100 grams, or almost a quarter of a pound, per second. During a solar storm on March 8, the rate of charged atoms flying into space was 10 to 20 times as high, as much as five pounds a second. That gave the team the first good measurements of what happens when a solar storm hits Mars. “This is hopefully going to help us fill in many pieces of that puzzle,” Dr. Jakosky said.

Jasper Halekas, a professor of physics and astronomy at the University of Iowa and a member of the Maven team, said the energy hitting the Martian atmosphere during the storm was equivalent to a million tons of TNT an hour. “That’s one large nuclear weapon per hour, if you like,” he said.