Pima County has started the construction of SpacePort Tucson and a building it will lease to World View, a local space technology company.

Construction is on track for completion in December on county-owned land south of Tucson International Airport, county officials said in a news release Tuesday.

Site clearing and preparation were completed in May and construction of the outer shell began this month. Swaim and Associates is the architect and Barker Morrissey is the contractor.

The Board of Supervisors approved an agreement with the high-altitude-balloon company in January, agreeing to spend $15 million to build facilities for use by the company in exchange for 20 years of lease payments.

World View will lease the county-owned building for use as a headquarters and manufacturing facility. The county also will own SpacePort Tucson and will contract with World View to manage the launch-pad facility.

The Goldwater Institute filed suit against the county in April, alleging county residents will bear the tax burden of the agreement’s “unlawful expenditures.” The lawsuit claims the county violated the state’s gift clause by extending its credit to a private company without a public purpose.

Pima County Administrator Chuck Huckelberry has countered that the agreement is not a gift, and that World View will pay $4.2 million more than the county is spending on the building, among other costs. The company is expected to create 400 to 500 high-paying jobs here, the county says.