Missile-maker MBDA has been contracted by Britain's Ministry of Defense to develop a new air-to-ground missile for the country's future F-35 fleet.

The four-year award for design and development work on the Spear 3, to be carried in the aircraft's internal weapons bay, is worth more than $595.9 million.

"This contract will give UK pilots a state-of-the-art British-designed weapon to be used on board our next-generation F-35B jets, with the precision and punch that we need to give decisive operational advantage over our adversaries and keep Britain safe," said Minister for Defense Procurement Philip Dunne.

The Spear 3, from the same family of missiles as MBDA's Brimstone, uses a turbojet engine rather than a rocket motor, giving it a range of more than 60 miles. It was successfully test-fired from an MOD Typhoon in March at a range in West Wales.

The new contract follows an initial $217.5 million assessment phase award.

"Delivering the solution for the UK's SPEAR 3 requirement is an important program for MBDA, and for the future operators of the F-35 in both the RAF and the Fleet Air Arm," said MBDA's Executive Group technical director and U.K. managing director Dave Armstrong. "The contract confirms SPEAR as the only weapon to meet the UK's operational requirements.

"It delivers a UK sovereign capability on the F-35 that will bring the kind of precision against moving targets previously seen with Brimstone, but at stand-off ranges that give the aircrew numerous advantages in terms of operational flexibility and survivability."

The missile is expected to be deployed by Britain in the mid-2020s.

MBDA is a joint venture of the Airbus Group, BAE Systems and Leonardo-Finmeccanica.