DARPA is getting ready to move to the next phase of its High Energy Liquid Laser Area Defense System (HELLADS) program to demonstrate a laser weapon system compact enough to be carried on board a tactical aircraft - say a B-1B bomber or an AC-130 gunship - without affecting their ability to perform traditional missions.
The research agency has signalled its intent to award a 24-month contract to either or both of the HELLADS developers - General Atomics and Textron Defense Systems - to build and ground-test a 150kW laser compatible with the requirement for a weapon-system weight of 750kg.
Graphic: DARPA
That is substantially smaller than any previous high-energy laser - small enough to fit in one weapons bay on a B-1, leaving the other free for conventional bombs. And much smaller than the chemical Advanced Tactical Laser flown in - and fired from - a C-130 testbed.
DARPA's notices of intent say both General Atomics and Textron should have demonstrated their full-scale "unit cell" laser modules and completed preliminary design of the 150kW electric laser by the end of the current phases of their HELLADS contracts.
The two companies have different approaches to producing a 150kW laser. In General Atomics' design a laser beam passes through a series of thin-disk laser amplifiers and the coolant in which they are immersed (hence "liquid laser"). The system comprises two 75kW modules that plug together to make a single laser resonator.
Graphic: Textron Defense Systems
Textron's design is built up of three 50kW unit cells using the company's ThinZag technology - so called because the beam zig-zags through each slab-laser amplifier module. Textron developed ThinZag for the Pentagon's Joint High Power Solid-State Laser program, which has the goal of demonstrating 100kW in the lab (a feat Northrop Grumman accomplished, but Textron so far has not).
HELLADS goes beyond JHPSSL as the plan is to take the lasers out of the lab, integrate them into a demonstration weapon system (being developed by Lockheed Martin), and fire at representative targets - from the ground initially, but DARPA hopes the Air Force will fund a follow-on flight demonstration.
