Luminati Aerospace LLC, a Calverton startup seeking to nail down a $40 million property deal with the Town of Riverhead, is lining up new financing sources after ties with its earlier backer, Facebook Inc., were severed, the town supervisor said.

The company, which plans to develop solar-powered aircraft, will host an open house Friday to show off its composites manufacturing equipment.

Riverhead Town Supervisor Sean Walter, in a telephone interview last week, identified the social media giant as Luminati’s previously undisclosed financial backer. In fact, Walter said, Facebook representatives opened contact with him via email before he met Daniel Preston, the founder and chief executive of Luminati.

A Luminati spokesman, citing a nondisclosure agreement, said it could not identify its “previous investor,” but said it is “exploring a number of funding sources and a number of investors for the land deal.” Facebook, based in Menlo Park, California, did not respond to an email seeking comment.

In October 2015, Luminati paid $3.4 million to acquire the 16.3 acre property of Skydive Long Island at the Enterprise Park at Calverton (EPCAL). The company is now seeking to purchase almost 1,600 acres at EPCAL from the town for $40 million.

In 2015, Preston introduced a “dream team” of engineers and researchers to town officials at a public hearing and announced plans to develop solar-powered aircraft that could stay aloft indefinitely and beam internet service to unwired regions around the globe.

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Luminati staged a 13-minute public demonstration flight of a solar-powered aircraft in June 2016. The company claimed provenance of the aircraft, but later acknowledged that the fuselage and some other parts were made in Germany.

Walter said Luminati’s business model “is not necessarily to wholesale manufacture a plane start to finish.” Instead, he said, Luminati would build the “major structural components” and seek to have other aerospace manufacturers take space on its property and create a manufacturing ecosystem.

“Their hope is that once they start landing these contracts, other manufacturers will come in,” he said.

Luminati’s Friday open house will include a ribbon cutting at EPCAL’s Plant 6, where Grumman Corp. once manufactured F-14 Tomcats. Walter estimated that Luminati has invested about $20 million in the property over the past 18 months.

He said the town expects to hold a hearing this summer on the 1,600-acre sale at which Luminati would be required to disclose its financial backers. Complicating negotiations is oversight at parts of EPCAL by the state Department of Environmental Conservation, which is seeking to safeguard the habitats of some owls and other endangered species.

It’s unclear how Facebook’s discontinued role would affect Luminati’s business model.

Robert Botticelli, chairman and executive director of ADDAPT, an advocacy group for LI aerospace manufacturers, said Luminati’s aircraft could find demand from the military, a hot market that could help the company secure investors.

“If [Preston] is successful with even 50 percent of what he wants to do, he will have brought aircraft manufacturing back to Long Island,” Walter said.