As the hunt for the missing Malaysia Airlines jet expanded into the daunting vastness of the Indian Ocean, a satellite communications company confirmed on Friday that it had recorded electronic “keep alive” ping signals from the plane after it disappeared, and said those signals could be analyzed to help estimate its location.

The information from the company, Inmarsat, could prove to be the first big break in helping narrow the frustrating search for the plane with 239 people aboard that mysteriously disappeared from radar screens a week ago, now hunted by a multinational array of ships and planes that have fanned out for thousands of square miles.

Inmarsat, a Britain-based satellite communications provider of systems to ships and airplanes, had equipment aboard the Malaysia Airlines Boeing 777 jetliner, said David Coiley, the vice president of the company in charge of the aviation business. The equipment automatically communicates with satellites, much as a mobile phone would automatically connect to a network after passing through a mountain tunnel, he said.