The US Army is developing a truck-mounted laser weapon to destroy rockets, artillery shells and mortars.
Aerospace giant Boeing has been awarded a contract to start on the first phase of the project - designing a control system for the laser beam.
The solid state laser weapon would eventually be mounted on a 10-tonne, eight-wheel-drive tactical truck.
The American military has several programmes underway to develop battlefield lasers.
Under the Phase I contract, worth $7m (£3m), Boeing will develop a preliminary design for a "rugged beam control system" to be used on a Heavy Expanded Mobility Tactical Truck (HEMTT).
The control system is needed to accurately point and focus a laser beam on an enemy target.
The objective of the High Energy Laser Technology Demonstrator (HEL TD) programme is to demonstrate that a mobile, solid state laser can effectively counter rockets, shells and mortars.
Pat Shanahan, vice president and general manager of Boeing Missile Defense Systems, said the contract was important because "it supports a cornerstone of the Army's high-energy laser programme".
He added: "We believe this is the next step for developing a weapon system that can change the face of the battlefield."
Solid state, electrically powered lasers are one of several "directed energy" technologies being investigated by the US Army.
Chemically powered lasers have been able to achieve megawatts (one megawatt equals one million watts) of power; but they are large and heavy, and require a constant supply of chemical fuels.
Solid state lasers may lack this power potential, but they tend to be compact and lightweight, holding promise for the development of vehicle-mounted weapons.
A beam control system accurately points and focuses the laser
Massachusetts-based Textron Systems and Northrop Grumman are the only companies currently working on solid state lasers for the US military. In 2005, they were selected to separately develop a 100 kilowatt (kW) solid state laser by 2010.
A group at the Lawrence Livermore National Laboratory has hit 67 kilowatts (kW) of average power in the laboratory with a pulsed solid state laser.
Pulsed laser beams switch on and off very rapidly. The US military is said to favour a continuous wave (CW), or "always-on" laser.
The lethality of a laser comes from more than just the power level. Achieving good beam quality - a measure of how well-focused the laser beam is - is paramount, as is the duration of the beam, or its "run time".
The Airborne Laser will shoot down missiles in their "boost" phase
The Boeing contract contains options that, if exercised, will call for the company to build and test part of the beam control system integrated on its vehicle platform.
The options would increase the contract cost for the total programme to approximately $50m (£24m).
Boeing is also one of several companies, including Northrop Grumman and Lockheed Martin, building the Airborne Laser (ABL) for the US military.
The ABL consists of a high-energy, chemical oxygen iodine laser (COIL) mounted on a modified 747 freighter aircraft. It is designed to shoot down enemy ballistic missiles in their early boost phase, when they are most vulnerable.