With tensions rising in Ukraine following the invasion by Russia and the subsequent sanctions by the European Union and other Western alliance countries such as the United States, Japan and South Korea, the possibility of a nuclear war arises not only in the conversations of experts, but among ordinary people. And one of the questions many people are asking is whether it is possible to stop anuclear bomb in mid-flight.

According to the Federation of American Scientists, Russia has a total of 5977 nuclear warheads in its inventory - the most in the world. By comparison, the United States has 5427, France has 290, and the United Kingdom has 225. On Sunday, Russian President Vladimir Putin placed its nuclear forces on "special combat readiness," warning the West about the risks involved inescalation of the East European conflict.

The Bulletin of the Atomic Scientists says Russia's arsenal includes 4447 warheads, of which 1588 are arranged on ballistic missiles and heavy bomber bases. It adds that there are "approximately 977 additional strategic warheads, with 1912 non-strategic warheads" in reserve custody.

However, experts have already stated that the exact number of warheads and weapons is not known due to secrecy involving strategy and security issues.

The defense against a nuclear bomb

Over the years, one of the options suggested for defense against a nuclear bomb has been the creation of a shield or defense system that could protect people. Various attempts have been made since the 1950s in the United States, but so far the country has only a flawed system that most experts believe is not capable of effectively protecting Americans against a bombnuclear, according to Philip E. Coyle III, a senior scientist adviser at the Center for Arms Control and Nonproliferation.

"This is the most difficult thing the Pentagon has ever tried to do, as our nearly 70-year attempts show," Coyle recounted.

There are several challenges in building a defense. According to Laura Grego, an astrophysicist and expert on missile defense and space security at the Union of Concerned Scientists, intercepting an intercontinental ballistic missile (ICBM) is really difficult.

After launch, the ICBM spends 15 minutes travelling through the space vacuum before re-entering the atmosphere before reaching its target. This allows three interception points in its journey: at launch, when it is in space and after it returns to the atmosphere, already approaching its final target.

But each of these possibilities has limitations.

Intercepting a nuclear bomb

Defense on posting

Greek said that "the launch phase takes from one to a few minutes in duration," which leaves little time for a rocket to intercept and "kill" the missile. Moreover, considering that rival countries like Russia and the United States have large territories, their missiles would likely be deployed well inland. This means that ocean-based interceptors would not reach themissile in its launch phase.

United States ground base. The test was conducted on June 22, 2014. The interceptor was launched from Vandenberg Air Force Base in California and successfully destroyed the simulated enemy missile over the Pacific Ocean. Image: Missile Defense Agency/U.S. Department of Defense

Another problem with this type of interception is that it must be precise, hitting an exact point on the missile. If this is not done, the missile "may not reach exactly the intended target. It will land at another point, such as Canada, something Canada will not like," Grego added.

Unmanned aerial vehicles were once an option, but they don't have the war power to destroy a missile, the astrophysicist added.

Mid-course defense

The most viable option is to intercept the missile during its longest phase, in space. But that alternative also has its problems.

"The missile flies at 24,000 to 27,000 mph. Going at that high speed, if you miss by an inch, you end up missing by a mile. "And there is another obstacle: there is no air resistance in space.On the occasion that there is a balloon in the shape of a warhead, it is difficult for the missile to distinguish between the two.And because balloons are light, a sophisticated warhead could easily release 20 or 30 decoy balloons tomake it difficult to locate the warhead, Greek said.

The last alternative is an intercept after the missile returns to the atmosphere.But the speed at which it approaches makes the strategy a bit tricky.The U.S. military has tested that option in recent decades.Under George W. Bush, a ground-based medium-range missile defense system was put into operation.Since then, it has erred in 9 of 17times, according to the military.

"The failure of the in-flight intercept tests is all the more surprising because they are highly planned tests for success. If these tests were done to circumvent U.S. defenses, as an enemy would indeed do, the failure rate would be even worse," Coyle said.

And even if the designs were redesigned with good planning and technologies, some challenges regarding nuclear defense seem insurmountable, Grego said. For example, so far, no one has been able to solve the problem of decoy warheads in space.

Conclusion

Several tests have been conducted by scientists and the military, but it is still difficult to design an accurate defense against a nuclear bomb. Furthermore, we do not know if the technology to stop a nuclear bomb in mid-flight already exists, as much information related to nuclear weapons and defense is kept secret by the nations that possess this category of power. We will only know of its existence in the event of a nuclear war - something we prefer not to have for the time being.