September 25, 2023

Military experts refer to hypersonic warheads as the next big thing in intercontinental warfare. You will see emerging weapons, which can deliver nuclear or conventional ammunition, zigzagging through the atmosphere at speeds of up to five miles per second to outsmart early warning satellites and some interceptors. The super-fast weapons, say experts, are suitable for surprise attacks.

President Trump has boasted of his “super dupers” and even called the planned weapon “Hydrosonic”, a brand for electric toothbrushes. Last year, its budget asked the Pentagon to spend $ 3.2 billion on hypersonic weapons research, up $ 600 million from the previous year. And as President-elect Joseph R. Biden Jr. takes command of the nation’s military, he must consider keeping up the defense work done in the Trump years.

Now independent experts have examined the technical performance of the planned weapon and have come to the conclusion that the advertised features are more illusory than real. Your analysis will be published this week in Science & Global Security.

In an interview, David Wright, a physicist at the Massachusetts Institute of Technology and author of the new analysis, described the superweapon as a mirage.

“There are many claims and not many numbers,” he said. “When you put in the numbers, you realize that the claims are nonsense.”

Military officials called the paper immaterial and said it was based on outdated data. However, they refused to publish new findings.

“Because of the classified nature of hypersonic technologies, we are not at liberty to publicly discuss the current capabilities,” said Jared Adams, chief spokesperson for the Agency for Advanced Defense Research Projects (Darpa), in an email.

Richard L. Garwin, physicist and longstanding advisor to the federal government, described the paper as “very good and important”. He added that he had given defense officials his own similar criticisms of hypersonic warheads.

James M. Acton, a nuclear analyst with Carnegie Endowment for International Peace, described the paper as “serious, credible, and important work.”

Dr. Wright is a member of MIT’s Nuclear Safety and Policy Laboratory and conducted the analysis with Cameron L. Tracy, a materials scientist with the Union of Concerned Scientists, a private group based in Cambridge, Massachusetts that often supports arms control.

By definition, hypersonic vehicles fly at more than five times the speed of sound – or up to a dozen times faster than jetliners. The warheads soar into space on a traditional long-range missile, but then quickly descend into the atmosphere to move, care for, and otherwise maneuver. They are basically blunt gliders. The curved top surfaces of their wedge-shaped bodies give them the lift force of an airplane wing.

Dr. Wright and Dr. Tracy based their analysis on the Hypersonic Technology Vehicle 2 – an experimental warhead developed by the Air Force and Darpa. Their findings also apply to other American prototypes, as well as to devices being developed by China, Russia and other countries.

The computer simulations relied on the physics of moving bodies and public revelations about the Hypersonic Technology Vehicle 2 to model its most plausible flight paths. The team focused on the characteristic phases of hypersonic flight – when the vehicle zooms through the atmosphere and then reaches a destination.

The two experts say their computer modeling fills public gaps in terms of the overall performance of the weapon, as well as its possible interactions with existing military systems for detecting and defeating weapons launched from remote locations.

In their work they see that the weapon essentially does not outsmart early warning satellites and interceptors. For example, current generations of space-based sensors can track the fiery twists and turns of the weapon during most of its flight through the atmosphere.

And, surprisingly, given the gun’s fast reputation, they say their analysis shows that it will fly intercontinental distances slower than ballistic missiles and warheads fired on low flight paths known as depressive trajectories. In war, such tactics are seen as a good way for attackers to evade interceptors and reduce warning time.

Dr. Wright and Dr. Tracy conclude that the proposed new weapon is “evolutionary – not revolutionary” at best.

In their work, the authors contrast their results with military claims. For example, they cite the 2019 Senate testimony of General John E. Hyten, the Air Force officer who was then responsible for the US Strategic Command, which controls the country’s nuclear missiles. The time it takes for a hypersonic warhead to complete an attack, General Hyten said, “could be half as long” as a standard missile. “It could be even less,” he added.

The conflicts between public views on hypersonic warheads and their actual capabilities arise, according to the two experts, from overrated official claims intended to “justify the expenditure necessary for their development and use”.

The American military is currently researching half a dozen hypersonic weapons. Dr. Wright said the limited amount of public information about how they worked and flight data made the better known Hypersonic Technology Vehicle the best available window of the current status and future potential of the prototype arms.

The team’s analysis focuses on an underlying physics problem that they believe casts doubt on the new class of weapons in general.

This is what aeronautical engineers call the ratio of lift to drag. The esoteric term is a measure of the lifting force versus air resistance. The lifting pushes a fast moving aerodynamic body upwards and the air resistance tries to counteract the forward movement, which in the worst case leads to a standstill.

Dr. Wright said the team’s analysis of the hypersonic vehicle used a lift to drag ratio of 2.6. In contrast, jetliners and some birds have an approximately eight times higher ratio. In other words, the warheads are nondescript fliers at best.

The limited power of the curved, glowing hot surfaces to produce significant lift force without also creating much drag undermines claims that the weapon can fly long distances on complex flight paths, he said.

“Unless they found a magical way to keep these systems going,” said Dr. Wright, “they’re going to have problems.”

Policy experts expect the Biden administration to focus on promoting arms control and it is likely that the Trump administration’s plans for hypersonic warheads will be scrutinized. Hypersonic weapons are one of the issues defense experts address in early talks with Russia and China, including the possibility of finding ways to impose restrictions.

Ned Price, a spokesman for the Biden transition team, declined to comment on the hypersonic warheads issue.

“President-elect Joe Biden will have an experienced team to solve these complex problems,” wrote Hans Binnendijk, a former National Security Council official, last month, suggesting ways to revive arms control. “But it takes time and creativity to be successful.”