What Are Patriot Missiles, and Why Does Ukraine Want Them?

WASHINGTON — After months of debate, the Biden administration said on Wednesday that it was sending its most advanced ground-based air defense system, the Patriot, to Ukraine, responding to Kyiv’s urgent request to help defend against an onslaught of Russian missile and drone attacks.

The Patriot system is part of a $1.8 billion aid package for Ukraine that was announced as President Volodymyr Zelensky of Ukraine arrived in Washington to meet with President Biden and other officials.

Americans of a certain age may draw their introduction to Patriot missiles back to the Persian Gulf war in 1991, when a series of them brought down one Iraqi Scud missile after another, in defense of Israel.

The Patriot is now one of the most sought-after air defense systems on the American weapons market, used by Saudi and Emirati forces in Yemen and throughout the NATO alliance in Europe. Israel still uses it. Now, add Ukraine to the list.

Here’s a look at the air defense system.

What are Patriot missiles?

The Patriot is a mobile surface-to-air missile and antiballistic missile system that can shoot down incoming missiles before they hit their intended targets. Patriot batteries can also shoot down aircraft. Mounted on trucks, to be moved around at will, each system is capable of holding four missile interceptors. In military circles, they are viewed as a security blanket, protecting a population, troops or even buildings from incoming fire.

The U.S. military has deployed Patriot batteries in numerous conflicts over the past 30 years. Most recently, U.S. troops at Al Dhafra Air Base in the United Arab Emirates fired Patriot interceptors at missiles headed toward the base in January, U.S. Central Command said.

Why did Ukraine request them?

Kyiv hopes to use that security blanket to help block incoming missiles. Since President Vladimir V. Putin of Russia ordered the invasion of Ukraine in February, Moscow has unleashed a torrent of missile and airstrikes on both civilian and military targets in Ukraine.

But in recent weeks, after a humiliating withdrawal of Russian troops from Kherson — the southern city that Mr. Putin had only a month before claimed as part of his country’s territory — Moscow has been relentless. Russia has pounded Ukrainian power plants, heating systems and other energy infrastructure, leaving millions of people to fend off freezing winter temperatures without electricity or heat.

This month, Russian drone strikes on the southern Ukrainian port city of Odesa plunged more than 1.5 million people into darkness. The government in Kyiv sees the Patriot system as a way to help shore up Ukraine’s air defenses.

Beyond the practical, Kyiv sees symbolic advantages in the Patriot system: proof that the United States, rather than tiring of support for Ukraine, is intensifying efforts to help it resist the Russian onslaught.

What can they do?

Patriot batteries can project defenses out some 600 miles. While they are far from foolproof, they can target and shoot down long-range ballistic missiles and aircraft from hundreds of miles away. They also have powerful radar systems — better than comparable air defense systems — that make it easier for Patriots to differentiate who is friend and who is foe.

How much do they cost?

A lot. One single interceptor missile costs about $4 million, according to the Center for Strategic and International Studies. Each launcher costs around $10 million. That may limit their use to situations in which incoming airstrikes are going to cause a lot of damage or cost lives.

Are the missiles foolproof?

Not by a long shot. Patriot missiles have plenty of critics — a headline in Foreign Policy in 2018 claimed that “Patriot Missiles Are Made in America and Fail Everywhere,” which U.S. military officials said was hyperbole. But the public has been misled about Patriot performance before. During the gulf war, military officials said the system intercepted all but two Iraqi Scud missiles. Later, the Pentagon had to revise that to a 50 percent shoot-down rate.

Today, the efficacy rate is believed to be higher, but it is hard to find accurate figures. Military experts say it is important to know how — and in what circumstances — to use one.

How many people does it take to use one?

A Patriot battery needs close to 100 people to use it, officials say. Ukrainian troops would have to be trained to operate the system. But the learning curve should not be that steep, as Ukrainian service members have shown themselves to be quick studies on military systems.