An artist's rendering depicts the Next Generation Interceptor, designed by Lockheed Martin as the newest addition to the Ground-based Midcourse Defense system. (Lockheed Martin)

Defense giant Lockheed Martin has won a contract to continue development of a new interceptor to protect the United States from an intercontinental ballistic missile attack.

The U.S. Missile Defense Agency announced Monday that it selected the company as the sole developer of its Next Generation Interceptor program.

The interceptor is slated to be the most technically advanced in the U.S. Ground-Based Midcourse Defense system, a network of radars, interceptors and other equipment used to defend the U.S. from threats posed by countries like North Korea.

The system was designed to protect the entire country. It targets ballistic missiles during the longest part of their flight, after their boosters burn out and while they coast in space toward a target.

Lockheed Martin beat rival defense company Northrop Grumman for the main contract. Both companies were awarded separate contracts to develop initial designs in 2021.

The Missile Defense Agency had expected to select a winning contractor next year, after both companies completed a critical design review. But agency officials told congressional lawmakers last week that they accelerated their decision partly because of budget restraints.

The interceptor program will be worth nearly $18 billion over its lifetime, according to government estimates. The new interceptors will be able to handle more complex threats than current missiles, according to agency officials.

The midcourse defense system is comprised of staging bases at Fort Greely, Alaska, and Vandenberg Space Force Base, Calif., with 22 ground-based interceptors at each location.

The first Next Generation Interceptor is expected to be operational by late 2028, the agency said.