IN AUGUST a Chinese “Long March” rocket streaked into space. That is hardly unusual; there were nearly three dozen such launches last year. But having begun to orbit the Earth, the rocket’s payload then swung back down, glided through the upper atmosphere and crashed into the ground, missing a target by about 40km. According to the Financial Times, which first reported the news, this was a test of a new, nuclear-capable hypersonic glide vehicle. China has insisted that it merely conducted a “routine test of a space vehicle to verify technology of spacecraft's reusability”. Yet the demonstration reportedly stunned American officials. “We have no idea how they did this,” one of them told the newspaper. What are hypersonic gliders and why do they matter?
Conventional intercontinental ballistic missiles (ICBMs) follow a parabolic trajectory, like a ball thrown into the air which falls back down under the action of gravity. That makes them visible and predictable. A missile fired at America from either Russia or China must arc high over the North Pole, where it can be spotted by American and Canadian radar systems in the Arctic. And although some warheads can manoeuvre a little once they re-enter the atmosphere, it is easy to work out roughly where they are headed.
China’s latest test appears to involve two different technologies: orbital weapons and glide vehicles. Orbital weapons, rather than going up and down in a parabolic arc, briefly enter orbit around the Earth. The Soviet Union operated such a weapon, the Fractional Orbital Bombardment System (FOBS), from 1969 to 1983—fractional because it did not complete a full revolution of the Earth, in the manner of a satellite.
The advantage of this is that a warhead can travel to America over the South Pole, thus bypassing existing radar shields. In recent years Russia has said it is building a FOBS-capable ICBM, and some think that the huge size of new North Korean missiles suggest a similar interest. China has long worried that American missile defence might undermine its relatively small, though apparently expanding, nuclear arsenal.The military drawback of orbital systems is that the rocket engines required to bring the warhead back into the atmosphere take up room, leaving less for nukes, and, when fired, tend to be visible from the infra-red sensors aboard American satellites.
Glide vehicles work differently. They are also lofted on a rocket but either get released in the upper atmosphere, before they ever get into space, or re-enter very quickly. Their design, with a high lift-to-drag ratio, means that they can then glide, unpowered, much farther than the re-entry vehicle of a normal ICBM warhead. They stay lower than either ICBM or orbital systems—thus hiding better from radar—and can take long and convoluted routes that avoid ground-based missile defences.
If the Financial Times’s description of China’s test is accurate, its significance would lie in the combination of these two technologies in a single weapon system. “China appears first in the world to combine an old concept of FOBS with modern glider technology,” says Tong Zhao, a Beijing-based expert at the Carnegie Endowment, a think-tank. America has explored orbiting and glider technologies in its X-37B spacecraft, operated by the air force, says Mr Zhao, but “China appears the first to turn this combination...into a prototype strategic strike weapon.”
Some experts are puzzled by why China would mesh these two things together, not least because putting a glider into orbit would seem to dilute its ability to hide from radar. Joshua Pollack, editor of the Non-Proliferation Review, a journal, speculates that the weapon might, like Russia’s enormous Sarmat missile, be “multi-functional”, with “the flexibility to evade defences in an unpredictable manner”. America, he notes, has begun testing its Aegis missile-defence system, installed aboard dozens of warships, against ICBM targets in space. Orbital weapons and glide vehicles could dodge different interceptors in different ways, hedging China’s bets. Other possibilities are that the glider is present to improve accuracy, or that Chinese gliders presently lack the range to take southerly polar routes without piggybacking on a FOBS-like weapon.
Missile defence may be the motivation for much of this effort. In 2002 America tore up the Anti-Ballistic Missile treaty with Russia and poured huge sums into anti-missile systems. Although American officials insist that these systems were designed to intercept North Korean and Iranian missiles, rather than Russian or Chinese ones, that was little consolation in Beijing.
Chinese efforts may therefore be intended, in part, to ensure that the country’s arsenal remains effective. But more recent—and growing—geopolitical tensions, including those around flashpoints like Taiwan, may play a role too, suggests Mr Zhao. China believes that nuclear strength “helps force the US to accept peaceful co-existence”, he says. The view in Washington, by contrast, is that China is now embarked on a dramatic and threatening nuclear expansion, reinforced by the revelation, earlier this year, of two large fields of suspected ICBM silos in northern China. The Biden administration is currently writing a major review of nuclear policy, due next year. Its drafters will have plenty to ponder.
More from The Economist explains:
Does America have troops in Taiwan?
What to look out for at COP26
Is India running out of coal?
"What" - Google News
October 18, 2021 at 11:42PM
https://ift.tt/3vlABVM
What is China’s new hypersonic glide vehicle? - The Economist
"What" - Google News
https://ift.tt/3aVokM1
https://ift.tt/2Wij67R
Bagikan Berita Ini
0 Response to "What is China’s new hypersonic glide vehicle? - The Economist"
Post a Comment