SpaceX aims to secure a minimum of 80,000 cell sites across the US, and it’s in talks with at least one major cellular infrastructure company to reach that goal, according to people familiar with the matter.

The agreements would solidify the rocket and satellite giant’s path toward building a fourth nationwide wireless carrier, said the people, who asked to not be identified because the discussions are private. One of the companies they’re in talks with is Crown Castle Inc., which, along with American Tower Corp. and Vertical Bridge Holdings, are among the largest owners of cellular towers. When asked on a Wednesday earnings conference call whether Crown Castle is discussing leases with SpaceX, Amazon.com Inc. or other satellite-based telecom providers, Chief Executive Officer Chris Hillabrant said, “You can assume that we’re talking to all parties.”

He declined to discuss specific customer details.

American Tower declined to comment. SpaceX and Vertical Bridge didn’t immediately respond to requests for comment.

Mobile networks rely on antennas placed on towers across the country to transmit wireless signals. Carriers such as AT&T Inc., Verizon Communications Inc. and T-Mobile US Inc. typically lease room for their equipment at the tower sites because it’s more cost effective than owning and maintaining them, in part because the facilities can be shared. The value of the deals with SpaceX could reach into the billions.

SpaceX Chief Executive Officer Elon Musk has made no secret of his intentions to create a standalone wireless carrier from scratch, threatening the existing dominant providers with increased competition from a well-funded and politically potent new rival. While the prospect requires significant investment, Musk is plowing ahead.

SpaceX recently acquired low-band spectrum that will help it parlay its Starlink satellites and other elements into what Musk described as a “major mobile carrier.”The company won Federal Communications Commission approval to launch 15,000 satellites designed to provide mobile service directly to phones. Wireless tower sites are another key component that SpaceX must assemble to establish reliable links with users on the ground.

“We will be building out our terrestrial networks so there’s broad-based connectivity anywhere that SpaceX and Starlink are allowed to operate,” Musk said during SpaceX’s earnings call this week. Satellite launches plus spectrum acquisition “will pave the way for Starlink Mobile to become a major mobile carrier in the US,” he said.

Crown Castle’s Hillabrant said SpaceX’s acquisition of the low-band spectrum is a “huge milestone” in being able to provide broad mobile coverage.

Tower companies’ share prices rose on the news of SpaceX’s latest spectrum purchase earlier this month, suggesting that the market anticipates major business coming their way as SpaceX seeks to build larger-scale infrastructure to implement the new airwaves.

SpaceX has already said it plans to use its home Internet equipment to emit mobile signals in the areas surrounding customers’ installations. Those sites are located where subscribers are, however, and not necessarily where they are needed to provide consistent coverage for a network, according to the research firm MoffettNathanson LLC.