E-Systems, a Dallas-based electronics firm, has opened a major second plant in Northern Virginia that is expected to expand its employment by 800 persons.

The new building to support its Melpar Division in Falls Church is a three-story, three-unit structure in the High Ridge Corporate Office Park at the intersection of Interstate Rte. 66 and U.S. Highway 50. The Melpar Division, the firm's scientific and engineering arm, employes 1,200 people, according to a company representative.

The new building is one-third finished and now houses 250 employes. Within a year that number should grow to 800, the representative said.

E-Systems is the 57th largest federal defense contractor with $275 million in prime contracts last year.

E-Systems Chairman John W. Dixon said the Melpar Division has contributed substantially to the company's growth, "and the acquisition of the new space is essential to the support of their growth."

"The new facility gives us access to a larger labor market," said Talbot Huff, vice president and general manager of Melpar. "We need the space to support additional engineering development. The proximity of the new facility, which is less than eight miles from our existing facility, is an important asset."