Nippon Iridium Corp., a satellite cell phone service operator using the Iridium LLC system, set in motion moves to close its service by applying to the Ministry of Posts and Telecommunication for permission to stop accepting new subscribers.

Company officials said services could end as soon as March 18. When approved, the company will begin buying back cell phones from its 4,200 subscribers.

The halting of service has started because of the restructuring difficulties Iridium has faced, coupled with last week’s announcement by Eagle River Investments LLC not to bail out the bankrupt mobile satellite service provider.