One of the longest-running mysteries in the data center world appears to have been sold after it was revealed that Facebook is secretly funding a new, $1.5 billion facility in Altoona, Iowa. The facility, which has been referred to by officials as “Project Catapult” is touted as “the most technologically advanced in the world”, and covers some 1.4 million sq. ft., and will ultimately house three separate 466,000 sq. ft. data centers, to be built in two separate phases.

Facebook is yet to make any public comments about its new data center project, but the Des Moines Register cites legislative sources as having informed them of the social media sites involvement. So far, there’s no word on when the new facility might open, nor how many jobs it may create.

What we do know however, is that the project has been given a definite go-ahead by state officials, although details such as tax credits and other incentives are still to be hashed out. Apparently, the social media firm is seeking wind energy production tax credits, while a new rate for water payments is also being negotiated.

The Data Center Knowledge blog adds more information, saying that although the power behind the facility has been a mystery, it had long suspected Facebook was the company behind it as the site plans resemble those of its facilities in North Carolina and Oregon. However, it was also thought that Apple might be involved somehow, due to the possible use of fuel cells and solar arrays at the facility. Iowa had apparently competed with Nebraska to build the facility, which that state had codenamed “Project Edge”.

Presuming that everything goes to plan, the facility will be the fourth major data center owned and operated by Facebook, adding to its existing facilities in North Carolina, Oregon and Sweden. It would also become Iowa’s third major data center, alongside complexes owned by Microsoft and Google.