Only weeks after a Colorado-built spacecraft entered into orbit around Mars, the solar system put on a show that is now teaching us more about the red planet.

On Oct. 19, 2014, the comet Siding Spring flew past Mars, coming within about 87,000 miles of the planet. That’s extremely close — a little more than one-third of the distance from the Earth to the moon.

NASA’s Mars Atmosphere and Volatile Evolution spacecraft, or MAVEN, had arrived at the planet only the month before to try to discover what happened to Mars’ early atmosphere.

Researchers shut down many of MAVEN’s instruments to protect them as the comet passed, but a few remained operational to observe its effect.

When Siding Spring’s magnetosphere came in contact with Mars’ atmosphere, the planet’s magnetic field was thrown into chaos.

“We saw a significant impact at Mars,” said Bruce Jakosky, MAVEN’s principal investigator from the University of Colorado’s Laboratory for Atmospheric and Space Physics. “It completely disrupted the Mars magnetosphere.”

The comet’s effect was comparable to a large solar storm, according to a study published in Geophysical Research Letters

.

MAVEN also has observed solar wind, generated by bursts of gas and magnetic energy from the sun, stripping away Mars’ atmospheric gases and sending them out into space. So the comet’s flyby might have given researchers another clue in solving the mystery of how Mars’ atmosphere disappeared.

The effects from the comet lasted about a day before Mars’ magnetic field returned to normal, Jakosky said.

Was this what the researchers were expecting?

“We had no clue,” Jakosky said. “This was something that had never happened before. This isn’t something we set out to study, but we took advantage of this natural experiment.”

If a similar event happened near Earth, the results would be very different, Jakosky said.

Mars doesn’t have a magnetic field generated from its core, like Earth does, he said. That field disappeared about 4.2 billion years ago. Instead, Mars’ weak magnetic field is created in its upper atmosphere.

Earth’s magnetic field gives it more protection from solar winds, so it’s not entirely clear what would happen if a comet passed close by, Jakosky said.

But we would get “the most spectacular meteor shower the Earth has ever seen,” he said.

The $671 million MAVEN, which launched from Cape Canaveral, Fla., in November 2013, was built at Lockheed Martin in Jefferson County and carried into space aboard an Atlas V rocket made by Centennial-based United Launch Alliance.

The craft entered into Mars orbit in September 2014.

Jakosky says MAVEN’s instruments are healthy and its mission continues.

LASP, based at CU-Boulder, leads the mission’s science operations. About $300 million from the 2015 project budget stayed in Colorado, and the MAVEN team includes about 40 LASP workers.

Jennifer Campbell-Hicks: 303- 954-1903, jhicks@denverpost.com or @JenniferCHicks