October 28, 2011:
Version 1A-2 of the U.S. Excalibur 155mm GPS guided shell has been cleared for use in combat. This is the extended range version, which can hit targets with precision up to 40 kilometers away (with the M777 howitzer, or up 60 with longer barreled howitzers). This is particularly useful in Afghanistan, where the current (23 kilometer) shell is restricted by its short range. Even so, some veteran American artillerymen are firing their 155mm guns for the first time in four or five years, now that they are operating in Afghanistan instead of Iraq.
In 2004, when the counter-terrorism campaign began in Iraq, it was quickly realized that artillery units were not needed. Smart bombs were far more accurate and effective. Excalibur did not show up until 2007. So in the meantime, most artillery units were converted to light infantry, and performed security and counter-terrorism tasks. Eventually, many Cold War era artillery units were disbanded, made obsolete with the arrival of GPS guided shells and MLRS rockets.
While the Excalibur proved useful in Iraq, it didn't increase the workload of the few 155mm howitzers that were being used there. But Afghanistan was a different story, with the troops spread over a much larger area. This was the kind of situation that the new M777 towed 155mm howitzer was made for. So the artillery battalions attached to combat brigades once more had something to do in Afghanistan.
The 155mm Excalibur "smart shell," got into service a year late because testing kept revealing more bugs in the system. For example, there were problems with some shells not getting the GPS signal. If the Excalibur shell does not get the GPS signal, you have to make sure it's unguided trajectory will take it where there are no friendly troops or civilians. Having to do this every time you use Excalibur can be complicated, time consuming, and often not possible. These problems were solved, but then some temperature related problems were encountered. They were fixed, and eventually, four years ago, Excalibur was ready for combat. The first version had a range of 23 kilometers. The extended (40 kilometer) version was expected to follow quickly. But there were more problems with that than anticipated.
Problems with getting "smart shells" to work effectively is nothing new. Back in the 1980s, the 155mm Copperhead round was developed, at great expense, to take out tanks with one shot. The Copperhead was laser guided. That is, it homed in on laser light that a forward observer was creating by pointing a laser at the target. It was the same technique used with laser guided bombs. But this was expensive technology for an artillery shell. Each of the 3,000 Copperhead shells eventually built, cost several hundred thousand dollars (the price varied, up to half a million bucks, depending on who was doing the calculating). While a "dumb" artillery shell will land within 75 meters of the aiming point, the Copperhead would land within a meter or two. But so what? It turned out there were many easier, and cheaper, ways to destroy enemy tanks. This was demonstrated during the 1991 Gulf War, when a few Copperhead shells were used, successfully, but to reactions of, "whatever."
Russia developed its own version of Copperhead, Krasnopol, and sold some to India. During a 1999 war with Pakistan, high in the Himalayan Mountains, Krasnopol proved very useful in taking out enemy bunkers, without causing avalanches or destroying the few pathways up the steep hills. However, Krasnopol had not been tested at such high altitudes (over 4,000 meters) and in such cold weather. There were problems that had to be fixed.
The Indians paid about $40,000 for each Krasnopol shell (two thirds what the Copperhead was supposed to cost originally), and eventually found it a good investment. This encouraged the American developers of the next generation smart shell, Excalibur. But GPS guided shells proved to be a tough technology to perfect, and when Excalibur arrived, it found itself with some stiff competition. In Iraq, the troops had been using the 227mm MLRS GPS guided rocket for two years. With a range of 70 kilometers, a few GMLRS (G for "Guided") vehicles (each carrying eight rockets), can cover a huge area with very accurate fire. The GMLRS has been a great success, and the army had to hustle to get enough rockets built to meet demand. The shorter range Excalibur was more popular because of its smaller explosive load. Each 45.5 kg (100 pounds) shell has about 9.1 kg (20 pounds) of explosives. The 227mm MLRS GPS rocket carried over 68 kg (150 pounds) of explosives. In too many cases, range was the key factor. The GMLRS could reach the target, Excalibur could not. Now, Excalibur has longer reach, and will be called on more often.