While the Antelope Valley is often described as the “Aerospace Valley,” SpaceX in Hawthorne is eyeing an 18-acre site at the Port of Los Angeles for a future facility to build commercial transportation vessels so massive they must be moved by water.

Last week, the Los Angeles Board of Harbor Commissioners approved an environmental review for the project proposed for Terminal Island, clearing the way for a potential 10-year lease, with up to two 10-year extensions, the Daily Breeze reported.

The South Bay-based rocket maker already leases 8.1 acres in San Pedro’s Outer Harbor, where rocket boosters and other spacecraft returning from orbital missions can be docked.

But the new facility on the former Southwest Marine Shipyard would be used “to design, develop, and manufacture prototypes and first-generation models of specialized commercial transportation vessels,” according to a project description cited by the Breeze.

Billionaire entrepreneur Elon Musk plans to design a deep-space rocket, called the BFR, for missions to Mars and to transport passengers around the world in record time.

Neither SpaceX nor port officials would elaborate on plans for the site, but they confirmed that talks have begun, according to the Breeze.

“At the direction of Mayor (Eric) Garcetti, the port has entered into preliminary negotiations with SpaceX for this site,” port spokesman Phillip Sanfield told the Breeze.

SpaceX spokeswoman Eva Behrend added that the company “is in preliminary discussions with the Port of L.A. about the potential of leasing additional land for operations.”

According to a project description in a California Environmental Quality Act review, “the vessels, once complete, would be too large for delivery by road and thus must be taken via supply barge, necessitating the facility be located adjacent to the water.”