Tucson-based Raytheon Missile Systems and predecessor Hughes Aircraft have been making TOW guided anti-tank missiles for 50 years, right here in Tucson.

And the company expects to keep making the aging but upgraded TOW (Tube-launched, Optically-tracked, Wireless guided) missile well into the next decade.

Raytheon - Southern Arizona's largest private employer with about 10,500 local workers - recently marked the 50th year since the U.S. Army picked Hughes to develop the original TOW, with a private ceremony at the company's plant at Tucson International Airport.

Since the first TOW missiles were delivered in 1969, more than 650,000 copies have been produced for the U.S. and its allies, and they've been used in every major conflict since the Vietnam War.

But today's TOW isn't your granddad's TOW.

Contracts for continual upgrades have produced several upgraded variants, including the longer-range and more capable TOW 2A, TOW 2B, TOW 2B Aero and TOW Bunker Buster (with deep-penetrating warhead).

And perhaps most notably, the TOW has lost its "tail."

The original TOW (which originally stood for Tube-Launched, Optically-tracked, Wire-guided) missile featured thin wires that spooled out for thousands of yards to carry guidance signals to the weapon.

The latest ground-launched TOW receives commands from the gunner through a wireless guidance link, eliminating the wire connection.

In 2006, Raytheon won its first contract to produce wireless TOWs. (Hughes had proposed a wireless TOW in the late 1980s, but it was not adopted.)

The next-generation TOW works with existing launch systems, and it remains the Army and Marine Corps' main heavy anti-tank and precision-assault weapon, Raytheon says. The TOW is in service in more than 40 international armed forces and is used on more than 15,000 ground, vehicle and helicopter launch platforms worldwide, the company says.

It's also a mainstay of the company's product line.

In October, Raytheon won a five-year, $349 million contract to provide 6,676 of the new wireless TOWs for the Army and Marines. The company booked $152 million in TOW contracts in 2011, when Missile Systems posted overall sales of $5.6 billion.

While a major Army missile development program, the Joint Air-to-Ground Missile, or JAGM, aims to replace the air-launched version of the TOW (along with the Hellfire and Maverick missiles), there's no replacement in the works for the ground-launched TOW.

Raytheon said recently it expects the TOW to remain in service with the U.S. military beyond 2025, though it previously has said it could last beyond 2050.

"We continue to look to the future and how we can make this weapon as relevant for the next 50 years as it has been for the past 50," Michelle Lohmeier, vice president of Raytheon's land-combat product line, said in remarks prepared for the the TOW 50th anniversary event.

Lohmeier noted that Raytheon has tested a new TOW propulsion system to provide increased range and reduced time of flight, reducing the risk to soldiers.

Meanwhile, a replacement for the air-launched TOW isn't expected anytime soon.

After nearly falling to the budget ax completely, the JAGM program has been put on hold. Raytheon and Lockheed Martin, which are competing for the program, have each been awarded contracts of about $65 million to continue technology development over the next couple of years.

Contact Assistant Business Editor David Wichner at dwichner@azstarnet.com or 573-4181.