LOS ANGELES — Spirit, the scrappy robot geologist that captivated the world with its antics on Mars before getting stuck in a sand trap, is about to meet its end after six productive years.

Spirit has been incommunicado for more than a year despite daily calls by NASA. The cause of Spirit’s silence may never be known, but it’s likely the bitter Martian winter damaged its electronics, preventing the six-wheel rover from waking up.

The space agency tried every trick to listen for Spirit to no avail. Project manager John Callas of NASA’s Jet Propulsion Laboratory said the last commands will be sent up today. Though orbiting spacecraft will continue to listen through the end of May, chances are slim that Spirit will respond.

“Spirit went into a deep sleep,” said Callas, who said the plucky rover will be remembered for demystifying Mars to the masses.

When the rover team gets together this summer, David Lavery of NASA headquarters said the mood would likely be that of an Irish wake rather than a funeral.

“We drove it until its wheels came off,” he said.