DHAHRAN, SAUDI ARABIA, FEB. 2 -- On the opening day of Operation Desert Storm, Air Force Capt. Jay Johnson flew his first-ever combat mission as pilot of an F-16A fighter-bomber on a raid over Baghdad. Flying above and through the sound-and-light-show barrages of Iraqi antiaircraft fire, Johnson dropped his bombs and returned safely to his air base in central Saudi Arabia.

His plane was not touched. Neither were those of his colleagues in the 157th Air National Guard Tactical Fighter Squadron. Johnson was amazed: "Hopefully, all the electronic stuff we have and the tactics that we're using are working, and probably God was looking out for us, too, because it was really heavy up there."

God's intentions remain a mystery, and pilot skills and tactics are intangibles. But the "electronic stuff" in the sky over Iraq -- aircraft equipped with radar that confuses enemy air defenses, or missiles that destroy them before they can target U.S. planes -- is a documented fact. As a result, allied warplanes have been able to fly almost unmolested through Iraqi airspace on the overwhelming majority of combat missions flown since the Persian Gulf War began Jan. 17.

Clearing the skies is the work of the Air Force's EF-111 Raven electronic countermeasures plane and the Navy's EA-6B Prowler, airborne bundles of technology whose jammers can make the radar screen of an Iraqi surface-to-air-missile (SAM) operator look like a New England snowstorm.

Electronic countermeasures aircraft are one of several space-age weapons that have proven reliable -- and in many cases, indispensable -- in combat during Operation Desert Storm, the first full-scale war the United States has fought since Vietnam. For military planners and defense contractors, Desert Storm is a nail-biter, the acid test for trillions of dollars in defense spending over the last 15 years.

And for more than 500,000 U.S. soldiers deployed in the Arabian Desert, the war tests the promises made on behalf of new equipment that has seldom, if ever, been used in actual battle. If it doesn't do what it says it's supposed to do, you're dead.

The EA-6B has thus become "so important that you would not run a strike without us. And if you do, you're insane," said a Navy electronic-warfare specialist, Lt. Steve Schwing, 29, of Austin, Tex.

Other weapons have also given evidence of their effectiveness in early fighting. The AGM-88 High-Speed Anti-Radiation, or HARM, missile has become the radar killer of preference, working in concert with the Ravens and Prowlers. The planes find the radar, and the HARMs destroy it.

The Army's Patriot anti-missile missile has also won high marks, both from U.S. officials and Israeli leaders who are relying on Patriots to thwart strikes by Iraq's Soviet-designed Scud missiles.

The ungainly, cumbersome-looking Patriot batteries, up to now, have not missed, according to military officials, but Scuds that went unchallenged or were only partially destroyed have killed two people in Tel Aviv and caused some damage in several other places in Israel and the Saudi Arabian capital, Riyadh.

A third success is the Tomahawk cruise missile, fired from the decks of the battleships USS Wisconsin and USS Missouri and an assortment of destroyers and cruisers at targets deep inside Iraq.

Finally, Desert Storm has resurrected the reputations of two warplanes at opposite ends of the aesthetic spectrum. The surreal, black F-117 "stealth" fighter, designed to slip through air-defense radar, bombed high-priority targets in downtown Baghdad in the first days of the war.

And the ugly, hulking A-10 Thunderbolt II -- popularly known as the Warthog -- has proven itself repeatedly against troops, tanks, Scud launchers and other targets along the Saudi-Kuwaiti border and in southern Iraq. In more than two weeks of war, only one A-10 has been shot down -- a testament, pilots and maintenance personnel say, to the titanium-reinforced cockpit and the basic resilience of a plane that can lose a big piece of wing and still fly home.

Many other weapons still remain to be battle-tested and will get the opportunity if and when Desert Storm becomes a ground war. These include the M1A1 Abrams tank, the Bradley Armored Fighting Vehicle and new multiple-rocket launch systems, among others.

The Army, however, is rushing to inspect hundreds of Bradleys, its premier armored infantry transports, for a transmission defect that could render them sitting ducks in combat, the Associated Press reported today. The problem could limit their speed to approximately 10 to 12 mph, according to an Army memo sent to commanders in Saudi Arabia last week.

But so far, the Persian Gulf War has been fought primarily in the air. Light losses have been the rule among U.S. aircraft -- 15 U.S. planes have been shot down in more than 37,000 allied combat and support sorties -- and it is clear that electronic jamming and countermeasures have played a major role in protecting allied air power.

The electronic warfare planes use technology developed over many years. Its basic aim is simple: Identify enemy radar -- broad-beam search radar, narrow-beam, fire-control "lock-on" radar and everything in between -- and override its signal by sending out one of your own.

"The best jamming is subtle," said Navy Lt. Cmdr. Rick Morgan. "I have seen operators who were being jammed tap their radar consoles, flip some switches and dials, then turn the thing off and call for a {technician}: 'This thing is broken.' The best jamming is when they don't even know they're being jammed."

Just as effective has been a combination of high-powered, unsubtle jamming and HARM rockets, which can be delivered by jamming planes or by other aircraft, like the Air Force's F-4G Wild Weasel, designed to seek out enemy radar and kill it.

In the opening sorties of Desert Storm, this combination offered Iraqi SAM operators two bad choices: Keep their radar on and risk swallowing a HARM before launching their own missiles, or shut their down equipment to stay out of the HARMs' way and fire the SAMs blind, or "stupid" -- unguided and therefore relatively unthreatening. No U.S. aircraft has been reported destroyed by a SAM.

"About all the SAMs they have fired that we have seen so far are unguided," said Cmdr. Mark Lawrence, intelligence officer aboard the aircraft carrier USS Theodore Roosevelt. "Because they are afraid of our HARM missiles, they blink them {radar sets} on and off, or just leave them off."

The HARMs, which weigh 800 pounds and have a range of 10 nautical miles, can "remember" their target's last fix. Even if the enemy turns off his radar, the HARM will fly to the source of the last signal.

Desert Storm has served as a proving ground for several other guided missiles, and none has gained more fame than the Patriot, first built in 1979 but untested in warfare until Jan. 18. The Patriot system identifies the number and types of targets, tracks them, distributes them among various Patriot launchers, fires the missiles and decides whether it needs to fire additional missiles to ensure a kill. It reacts to targets so rapidly and collects such massive amounts of information in so little time that the operators of the batteries do little but monitor the progress of intercepts, ready to override if anything goes wrong.

Like the Patriot and HARM, Tomahawk cruise missiles had never been fired in combat before Operation Desert Storm. During the first day of the war, the USS Wisconsin coordinated 45 cruise missile launches from a half-dozen ships in the Red Sea and Persian Gulf. The targets were unspecified "strategic sites" in the Baghdad area. Tomahawks can carry a 1,000-pound high-explosive warhead more than 800 miles, traveling as low as 500 feet.

The missiles are supposed to be accurate enough to land within 10 yards of their targets, but at least one has fallen in a residential area of Baghdad. Analysts suggested it had been brought down by ground fire before it reached its target. Still, Navy analysts praised what one called the cruise missiles' "tremendous job" in taking out "hard" strategic targets in the first days of the war.

Other furtive visitors to Baghdad in the earliest raids were the F-117A "stealth" fighters of the Air Force's 37th Tactical Fighter Wing. It was an F-117 that put a laser-guided, 2,000-pound bomb through the tower of a building on the banks of the Tigris River to open Desert Storm. A second bomb disappeared through the skylight of a "presidential facility" in Baghdad and exploded.

The A-10 -- a small, slow, low-tech aircraft designed to provide close air-support for infantry and armored units -- was already out of production and deemed obsolete when Desert Storm began. With a seven-barrel 30mm Gatling gun firing depleted-uranium bullets and eight tons of ordnance under its stubby wings and fuselage, the A-10 fights methodically but can have a devastating effect.

In the absence of an allied ground offensive, the A-10 has not yet played its traditional role, but it has proved effective going after tactical "soft" targets -- armor, artillery positions, bunkers and the like -- as long as the weather is clear. The A-10 has no radar, and pilots must see their targets to hit them.

This article includes material from military pool reports.

Tomahawk: Rocket-launched cruise missile is fired from U.S. ships or submarines and guided to target by on-board computer. Tomahawks were the first weapons used in pre-dawn raids on Iraq and Kuwait.

A-10 Thunderbolt II: The slow and low-flying Thunderbolt is the air force's primary tank-killing aircraft -- virtually a slow-flying 30mm gun. The plane flies over enemy armored columns and tries to knock out tanks and personnel carriers.

SLAM: The Standoff Land Attack Missile has an on-board video camera and sophisticated three-way guidance system for targeting. The satellite-guided missile, fitted to carrier-based aircraft, can strike targets on land or sea.

F117A: Designed to penetrate heavily defended sites such as Iraqi communications centers, this advanced fighter's "stealth" characteristics make it hard to detect until after it has released its weapons.

Patriot: The tactical air defense system, designed to destroy missiles or aircraft, has been used with great success against Iraqi Scuds. A Patriot missile is fired, guided to the target by ground and onboard radar, and detonated -- ideally within feet of the enemy's weapon.

EA-6B: The sophisticated and costly Prowler is an electronic countermeasures aircraft, packed with high-tech equipment capable of deceiving and disrupting enemy communication systems.

HARM: The High-Speed Anti-Radiation Missile contains a high-explosive warhead fragmented into thousands of small steel cubes. When a HARM missile hits its target, the cubes fly out to damage enemy radar antenna.

Compiled by James Schwartz -- The Washington Post