Sometime in the coming weeks, a B-52H bomber will load a missile high into the air and launch it at an unprecedented speed toward its target, according to the United States Air Force. If everything goes according to plan, this missile will accelerate by more than five times the speed of sound before deploying a fictitious second stage that will readily “disintegrate” somewhere in the atmosphere.
The missile, known as the AGM-183A, is said to be the first hypersonic weapon – or Airborne Rapid Response Weapon (ARRW) – in the United States arsenal. It must move so quickly through the atmosphere – about 20 times the speed of sound – at altitudes so low that it is impossible for enemy missile defense systems to fire from the air. And its speed means it can be useful in destroying “high-value, time-sensitive targets”, the Air Force said in a statement.
Hypersonic missile designs, including this one, usually involve two stages.
First, a rocket accelerates the weapon at many times the speed of sound, while remaining at a much lower altitude than intercontinental ballistic missiles (ICBMs) that are high above the atmosphere before launching its nuclear charges.
Second, he releases a glider that carries the gun for the final leg of its journey to the target, riding through the atmosphere like a surfer rocking and rippling over the waves – adding another wrinkle to any attempt to bring it down.
This lower altitude, in theory, makes a hypersonic weapon more difficult to detect and more difficult to destroy: it is more difficult to detect for the same reason that it is more difficult to see an airplane when you are standing on the ground at an airport 5 miles away. distance than a plane 10 miles in the air approaching that airport to land; the closer an object is to the ground, the more things – from trees to buildings and another plane – get in the way. And a hypersonic missile is theoretically more difficult to shoot down, more or less for the same reason; most missile defense technology is designed to intercept an ICBM near the peak of its arc in space. Up there, an anti-missile defense system has a clearer line of sight to the target and the ICBM itself moves in a more predictable way.
A hypersonic Mach 20 glider would actually move at almost the same speed as a decades-old ICBM, which can accelerate to similar speeds during its space travel, but must cover a much greater distance to reach the same target. (It’s the difference between driving straight from New York to San Francisco and driving between the two cities with a stopover in the Arctic Circle.)
Related: 7 technologies that transformed war
The USA is not the only country that works with hypersonic weapon technology. How Live Science previously reportedRussian President Vladimir Putin first announced his country’s hypersonic weapons program in 2018, promising that the country’s hypersonic weapon would reach Mach 20.
Pavel Podvig, a military analyst, told Live Science at the time that these weapons are unlikely to be useful.
“It has been described as a weapon in search of a mission,” he said. “My opinion is that you really don’t need that kind of ability. In fact, it doesn’t change much in terms of your ability to hit targets.”
That’s because ICBMs are already perfectly capable of escaping from missile defense systems. The United States has the most advanced missile defense technology in the world; and according to Laura Grego physicist of the Union of Concerned Scientists and many other analysts just don’t work. Therefore, it is not clear why a hypersonic missile would be needed to reach any other country. The Air Force emphasizes the idea that an ARRW can be useful against “time-sensitive” targets, because of its high speed (at least in comparison with non-ICBM missiles normally used to launch non-nuclear weapons).
The danger with hypersonic weapons, said Podvig, is that they are not covered by existing treaties designed to prevent arms races.
And there is still a lot of uncertainty surrounding the technology. “These systems create greater risk of [strategic] miscalculation, “said Podvig,” and it is not clear whether we can effectively deal with these risks. “
In the meantime, there are doubts about whether hypersonic technology will work.
The next test will demonstrate only the missile itself, not the glider, which is the latest technology. (Rockets that go very fast have been around for a long time. Gliders that fly much faster than an F-16 don’t.) And, as The Drive pointed out, this test has also been postponed. The missile arrived at Edwards Air Force Base in California on March 1, and the Force had originally said that the test would take place on March 6. Then, the March 5 statement extended that deadline to “the next 30 days” without explanation.
Meanwhile, an independent analysis published in 2020 in the journal Science and Global Security argued that “fundamental physics” imposes strict limits on the usefulness of these weapons. They showed that the physics of atmospheric flight prevents these weapons from being fast enough to substantially exceed ICBMs, and that it would be relatively easy to detect the launch of a hypersonic missile with the right satellite. The idea that hypersonic missiles would offer a revolutionary upgrade over ICBMs, the researchers argued, is a “social” phenomenon, not a scientific one.
Originally published on Live Science.