New 21,000-square-foot “tactical” data center is being built adjacent to the company’s massive 500,000-square-foot data center.

Apple is building a high-security “tactical” data center on the site of its massive data center in Maiden, N.C., according to records reviewed by the Hickory Daily Record.

According to design plans filed with Catawba County, the new 21,030-square-foot data center will store clusters of servers in 11 rooms and be guarded by “mantraps” at either end. To enter the building, people will have to pass one door that closes behind them before being cleared to enter the building through a second security door. The building will also be surrounded by an 8-foot-high chain-link security fence.

The current project will cost Apple about $1.8 million, far less than the reported $1 billion it spent to build the 500,000-square-foot behemoth of a data center on the same property. To help power the massive data center, Apple is building two solar array installations in the area, which when combined will bring in 84 million kilowatt-hours of power annually.

The newspaper said the plans show the smaller data center T-boning the larger data center, as well as showing “the footprint for a larger data center that would run nearly parallel to the existing one” and T-bone the smaller one under construction, suggesting that Apple has more plans for expanding the site.

Other permits issued for the site describe a new building with a reinforced concrete pad that would house a hydrogen fuel cell facility. The permit describes the cost of construction at $4.1 million.