China showcased its DF-17 hypersonic missile in service at its 2019 military parade marking the 70th anniversary of the founding of PRC. Russia has also showcased its hypersonic weapons. The US, however, plans to deploy its first hypersonic weapon by 2028.
Hypersonic weapons are the weapons of future, but the US began research of such weapons much later and allocated much less funds than China and Russia in the research and development of such weapons while wasting lots of resources in developing useless Zumwalt destroyers and LCSs and troublesome F-35s. It began to attach importance to the development of hypersonic weapons only after China and Russia have deployed such weapons. That proves that the US is no longer world leader in weapon development.
Note: the Global Strike described in Popular Mechanics’ article will be HGV (hypersonic glide vehicle) the same as DF-17. As HGV is fast enough to strike anywhere within a couple of hours why shall it be deployed in a submarine to make development more complicated.
A DF-17 is deployed on a mobile truck that can be hidden in China’s 5,000-km tunnels more secure than in a submarine.
China is now developing hypersonic aircraft powered by jet, scramjet and rocket that can take off and land on conventional airfield. It, however, will take years for the US to obtain HGV missiles.
Comment by Chan Kai Yee on Popular Mechanics’ article “One of the Pentagon’s First Hypersonic Weapons Will Ride on Submarines”, full text of which can be viewed at https://www.popularmechanics.com/military/weapons/a31004425/global-strike-hypersonic-submarine/?source=nl&utm_source=nl_pop&utm_medium=email&date=022020&utm_campaign=nl19490819&src=nl.
By: Valerie Insinna February 11
WASHINGTON — The Air Force has cancelled the Hypersonic Conventional Strike Weapon program, one of the two major hypersonic weapons being spearheaded by the service.
While the development is a blow to Lockheed Martin, which was developing HCSW, it’s other hypersonic weapons program with the Air Force — the Air-Launched Rapid Response Weapon — will proceed, Air Force spokeswoman Ann Stefanek confirmed on Feb. 10.
Because of budget pressures, the Air Force was forced to choose between funding HCSW and ARRW in FY21, and opted to keep ARRW due to it being a more “unique glide body design” compared with HCSW, which was similar to hypersonic weapons under development by other services, Stefanek said. ARRW is on track for a early operational capability in FY22.
“We will continue to work collaboratively with our sister services to see how we can most effectively leverage each other’s capabilities, ensuring the most prudent use of taxpayer dollars,” she said in an emailed statement.
Lockheed was notified on Monday that its work on HCSW will conclude after a critical design review this spring. The program’s cancellation was not due to poor performance, Stefanek added.
“The HCSW team pioneered significant advancements in hypersonic technology development and integration of existing, mature technologies for use in various hypersonic efforts across the Department of Defense, including Army, Navy, and Missile Defense Agency programs,” she said. “The HCSW team successfully met all developmental milestones. These advancements will serve to expedite the generation and demonstration of various hypersonic weapon capabilities in the near future.”
In total, the Air Force hopes to invest $382 million on hypersonic prototyping in FY21, down from $576 in FY20.
The Air Force initially envisioned HCSW as a long-range stand-off missile capable of being launched from an aircraft and traveling faster than speeds of Mach 5.
Lockheed in 2018 won the HCSW contract, which had a value of up to $918 million and covered “design, development, engineering, systems integration, test, logistics planning, and aircraft integration support.” Then the company selected Aerojet Rocketdyne in 2019 to provide the solid-fuel rocket motor.
Source: Defense News “The Air Force just killed one of its hypersonic weapons programs”
Note: This is Defense News’ article I post here for readers’ information. It does not mean that I agree or disagree with the article’s views.
Can the U.S. military match it? How capable is it?
by David Axe October 1, 2019
Follow @daxe on Twitter
The People’s Liberation Army on Oct. 1, 2019 revealed a new hypersonic missile that could pose a major threat to U.S. forces in the Pacific region.
The DF-17 hypersonic glide vehicle, or HGV, made its public debut as part of the PLA’s sprawling, 15,000-person military parade in Beijing commemorating the 70th anniversary of the founding of the People’s Republic of China.
While other countries also are working on hypersonic weapons — meaning powered or gliding precision-guided munitions that can travel faster than five times the speed of sound — the DF-17 apparently is the first or second hypersonic glide vehicle in the regular inventory of any military. Russia claimed it also would deploy an HGV in 2019.
The 16 DF-17s that featured in the parade all were atop what appeared to be DF-16 medium-range ballistic missiles. In actual use, the DF-16 would boost the DF-17 to Mach five or faster, at which point the DF-17 would separate from the booster and angle toward its target, maneuvering to correct its course or evade enemy defenses.
It’s unclear whether the DF-17 carries a warhead. “It is likely that the DF-17 is configured as a conventional munition with its destructive effect derived from the kinetic energy of the HGV,” commented Andrew Tate, an expert with Jane’s.
With a range of potentially a thousand miles or more, the DF-17 could threaten U.S. forces and their allies across the Western Pacific.
Nozomu Yoshitomi, a retired Japanese army general who now is a professor at Nihon University, told Reuters the DF-17 could render obsolete existing defenses. “There is a possibility that if we do not acquire a more sophisticated ballistic missile defense system, it will become impossible for both the United States and Japan to respond,” Yoshitomi said.
“We don’t have any defense that could deny the employment of such a weapon against us,” Gen. John Hyten, then the commander of U.S. Strategic Command, told the Senate Armed Services Committee in March 2018.
Hypersonic weapons are proliferating. In late December 2018, Russian President Vladimir Putin announced that the Russian military had tested its Avangard hypersonic glide vehicle in order to “successfully verify all of its technical parameters,” state-owned TASS news agency reported.
“On my instructions, the industrial enterprises and the defense ministry have prepared for and carried out the final test of this system,” Putin said, according to TASS. “The test was completely successful: all technical parameters were verified.”
Meanwhile, the United States is just beginning to acquire its first battery of HGVs. The Pentagon in late 2018 awarded Dynetics and Lockheed Martin contracts worth a combined $700 million to build 20 “common” hypersonic vehicles, fit eight with guidance systems and install them on four launchers. The U.S. Army could form its first HGV-launching unit as early as 2023.
The U.S. Navy and U.S. Air Force also plan to deploy versions of the same common HGV. The Navy’s would launch vertically from submarines in the same way that subsonic Tomahawk cruise missiles do today.
The Air Force could equip its heavy bombers with the weapons. The flying branch recently proposed its B-1 bombers as launch platforms for hypersonic missiles — this despite the B-1 fleet’s lingering reliability problems.
In rushing to be first, Russia and China could end up fielding an unreliable weapon, one U.S. official has claimed. In July 2018, Michael Griffin, the U.S. Defense Department’s undersecretary of defense for research and engineering, asserted that despite rivals’ progress the United States remained the world leader in hypersonic-weapons research.
The Pentagon determined there was no need to hurry up and equip troops with an unrefined weapon, Griffin told the U.S. Congress. “We didn’t see a need for it.”
America’s hypersonic weapons would mature “through the 2020s,” Griffin said. “You’re going to see our testing pace stepping up, and you’re going to see capability delivery from the early ’20s right through the decade.”
David Axe serves as Defense Editor of the National Interest. He is the author of the graphic novels War Fix, War Is Boring and Machete Squad.
Source: National Interest “Check Out China’s New DF-17 Hypersonic Glide Vehicle: A Real Killer?”
Note: This is National Interest’s article I post here for readers’ information. It does not mean that I agree or disagree with the article’s views.
The double-wing plane just aced wind tunnel tests at speeds of nearly 5,600 miles per hour.
By Jeffrey Lin and P.W. Singer February 26, 2018
A team of researchers at the Chinese Academy of Sciences have tested a hypersonic plane in a wind tunnel to speeds of Mach 7, or 5,600 miles per hour, according a paper published (PDF) in the Chinese journal Physics, Mechanics and Astronomy.
The project is led by Cui Kai, who’s part of the Key Laboratory of High Temperature Gas Dynamics at the Chinese Academy of Sciences, though the plane is likely a biproduct of research from other Chinese hypersonic programs, too, including those with military ties.
This reported breakthrough comes hot on the heels of other Chinese hypersonic successes, including China’s DF-17 HGV as well as various scramjet test flights and rocket-powered spaceplanes.
The test adds teeth to U.S. Admiral Harry Harris’s warning to Congress that China is looking to lead the global hypersonic arms race. Hypersonic vehicles are considered potential strategic game-changers. The speed would allow for greater global reach, but also could nullify current air defenses. For his part, Cui touted the project’s peaceful uses, remarking in his article that it could fly from Beijing to New York in two hours.
The I Plane (named for its frontal resemblance to the capital letter “I”) has one pair of forward swept wings on its fuselage center line as well as a pair of joined, swept delta wings mounted on top of the rear fuselage (like a giant T tail). This provides increased lift compared to more spartan, single-wing hypersonic plane designs like the Lockheed Martin SR-72 and CASIC Tengyun. That extra lift increases the I Plane’s payload-to-takeoff-weight ratio, though the increased weight of the bonus wings would likely require more powerful low-speed engines. The I Plane’s wings are positioned so that the shockwaves from sonic booms (which can cause turbulence and drag) are redirected to improve flight performance and stability.
As further proof of China’s high-speed ambitions, the Key Laboratory of High Temperature Gas Dynamics has another hypersonic breakthrough in the works: a record-breaking wind tunnel that will reportedly begin operations in 2020. It’s designed to produce speeds of up to Mach 36, making it the world’s most powerful wind tunnel, overtaking the Mach 30 LENX-X facility in Buffalo, New York. For reference, a Mach 36 aircraft would fly from China to California in just 14 minutes.
The wind tunnel will also be large enough to hold aircraft models with a wingspan of 3 meters (the world’s largest current hypersonic wind tunnel, China’s JF-12, has a 2.5-meter diameter). What’s more, the ability of Chinese wind tunnel objects to withstand the high temperatures generated by Mach 36 winds would imply significant Chinese advances in temperature-resistant materials for hypersonic aircraft.
China’s hypersonic programs indicate the nation’s getting serious about extending its economic and military reach. In addition to conventional instruments of global military power like aircraft carriers, it has invested in revolutionary technology like quantum communications, exascale supercomputers, and hypersonic aircraft that could reach any point on Earth in a couple hours.
Peter Warren Singer is a strategist and senior fellow at the New America Foundation. He has been named by Defense News as one of the 100 most influential people in defense issues. He was also dubbed an official “Mad Scientist” for the U.S. Army’s Training and Doctrine Command. Jeffrey is a national security professional in the greater D.C. area.
Source: Popular Science “China’s hypersonic aircraft would fly from Beijing to New York in two hours”
Note: This is Popular Science’s report I post here for readers’ information. It does not mean that I agree or disagree with the report’ views.
Researchers pushed a scaled-down version of their I-plane to seven times the speed of sound and say its double layer of wings held up surprisingly well
PUBLISHED : Wednesday, 21 February, 2018, 9:46pm
UPDATED : Thursday, 22 February, 2018, 11:49am
A Chinese research team has come up with a novel design for an ultra-fast plane they say will be able to take dozens of people and tonnes of cargo from Beijing to New York in about two hours.
The plane would travel at hypersonic speed – meaning at more than 6,000km/h (3,700mph), faster than five times the speed of sound – according to the team, which is also involved in China’s top secret hypersonic weapons programme.
The speed of sound is about 343 metres per second, or 1,235km/h.
“It will take only a couple of hours to travel from Beijing to New York at hypersonic speed,” the researchers led by Cui Kai wrote in a paper this month in Physics, Mechanics and Astronomy, published by Science China Press.
At present, it takes a normal passenger jet about 14 hours to fly between the two cities – a distance of about 11,000km.
Why hypersonic flights may not take off in Asia, and the plane makers who hope to change that
Cui and his team at the Chinese Academy of Sciences in Beijing tested a scaled-down model of the plane in a wind tunnel which was also used to carry out aerodynamics evaluations for China’s newest hypersonic weapon prototypes.
They pushed the model plane to seven times the speed of sound – which works out to more than 8,600km/h – and found it performed surprisingly well, with low drag and high lift.
The team at the academy’s Key Laboratory of High Temperature Gas Dynamics, under the Institute of Mechanics, have called the new hypersonic vehicle the “I-plane”.
That name comes from the shadow cast by the aircraft on the ground – in the shape of a capital “I” – when it is bearing down like a dive-bomber.
With two layers of wings, the I-plane design resembles that of biplanes used during the first world war. The earliest type of aircraft, most biplanes disappeared after the 1930s as plane designers pursued higher speeds and fuel efficiency.
Fast-forward to 2018, and China’s latest hypersonic vehicle features lower wings that reach out from the middle of the fuselage like a pair of embracing arms. A third flat, bat-shaped wing meanwhile extends over the back of the aircraft.
The researchers said this biplane design means the aircraft will be able to handle significantly heavier payload than existing hypersonic vehicles that have a streamlined shape and delta wings.
At extremely high speeds, they said the double layer of wings works together to reduce turbulence and drag while increasing the aircraft’s overall lift capacity.
The amount of lift generated by the new hypersonic vehicle was about 25 per cent that of a commercial jet of the same size, according to the study. That means an I-plane as big as a Boeing 737 could carry up to five tonnes of cargo, or 50 passengers. A typical Boeing 737 can carry up to 20 tonnes of cargo or around 200 passengers.
Cui and his team were not immediately available for comment.
While Cui’s design has provided an answer to the aerodynamic configuration problem encountered by previous hypersonic plane models, many issues still need to be tackled for this to move beyond the conceptual stage.
All known hypersonic vehicles being developed worldwide are still in the experimental stage because of the many technological challenges that exist, and none of them can take passengers yet.
Major countries including China and the United States are meanwhile racing to develop hypersonic weapons, and a hypersonic vehicle would enable them to effortlessly penetrate another country’s missile defence system.
But at this stage, existing hypersonic vehicles – such as the US Air Force’s X-51 Waverider and China’s WU-14 hypersonic glide vehicle – have capacity for just a small, lightweight payload such as a compact nuclear warhead. This has severely limited the application of the technology.
Travelling at hypersonic speed will also generate a huge amount of heat, possibly exceeding 1,000 degrees Celsius (1,800 Fahrenheit), and if that heat cannot be insulated or dispersed effectively, it could prove fatal. Although researchers have found potential solutions to this problem – such as using heat-resistant materials and a liquid-cooling system to push the heat out – this aspect again is still experimental.
The I-plane, however, could be a game changer, according to a Chinese aircraft designer working on military research projects who declined to be named because of the sensitivity of the subject.
The researcher, who is not directly involved in the I-plane but has been informed about the project, said Cui’s team also worked on the development of China’s most advanced hypersonic weapons, so the tests would likely move from wind tunnel to open field.
He added that the hypersonic vehicle could potentially be used to transport anything from flowers to bombs, and likewise, passengers could be tourists or military special forces.
“We’re talking about something like a hypersonic heavy bomber,” he said.
The paper has sent ripples through the hypersonic research community, he added. “It’s a crazy design, but somehow they’ve managed to make it work,” the researcher said.
But the I-plane is not strictly a biplane, he said, because it has been designed to deal with different physics. At hypersonic speed, aerodynamics become counter-intuitive – the biggest force of resistance does not come from the air ahead but the waves generated by the plane itself.
The project reflected China’s ambition to overtake the US on developing new strategic weapons, according to the researcher.
“This will require original rather than knock-off designs,” he said, adding that the I-plane was part of a new family of aircraft in development that had not been reported until now. “It could lead to a huge step forward in hypersonic technology,” he said.
The US has also been experimenting with hypersonic aircraft. Lockheed Martin is developing the SR-72, a hypersonic reconnaissance and strike aircraft, and announced early progress on its programme in June.
In September, Aviation Week reported that a small subscale demonstrator aircraft had been spotted landing at a US Air Force facility in California, indicating early tests of the unmanned SR-72. Lockheed declined to comment directly on the sighting.
Beyond the design board, Lockheed is also working on a supersonic passenger plane. Supersonic refers to a rate of travel beyond the speed of sound; supersonic aircraft are considered the forerunners of hypersonic vehicles.
Lockheed’s Quiet Supersonic Technology X-plane (QueSST) is designed to fly at Mach 1.4 (over 1,700km/h) and at over 55,000 feet (almost 17,000m). If its development goes according to plan, the passenger jet could halve travel time from Beijing to New York to less than seven hours.
The X-plane, dubbed the “the son of Concorde”, is expected to carry out a test flight in 2020 after Lockheed recently secured funding to build the jet, according to US media reports this month.
The Concorde turbojet-powered supersonic passenger plane was in operation from 1976 until 2003. It could travel at up to more than twice the speed of sound (over 2,000km/h), with seating for more than 120 passengers. It was eventually grounded because of high costs amid a downturn in the commercial aviation industry.
China has tested various types of hypersonic vehicles over the Gobi Desert in recent years, some capable of reaching 10 times the speed of sound.
It is also building the world’s fastest wind tunnel to simulate hypersonic flight at speeds of up to 12 kilometres per second (or 43,200km/h). At such velocity, a Chinese hypersonic vehicle could reach the west coast of the United States in less than 14 minutes.
This article appeared in the South China Morning Post print edition as: ‘i-plane’ team aims for China to U.S. in 2 hours
Source: SCMP “Beijing to New York in 2 hours? Chinese team reveal hypersonic plane ambition”
Note: This is SCMP’s report I post here for readers’ information. It does not mean that I agree or disagree with the report’ views.
by Eric Baculinao Feb 17 2018, 4:55 am ET
BEIJING — The Chinese New Year began with the traditional lighting of firecrackers on Friday, but the country’s military has been working on incendiaries on an entirely different scale.
Over the past year, the nation that invented gunpowder has been rolling out an array of high-tech weapons that some experts say could threaten the global superiority of the United States.
“The U.S. no longer possesses clear military-technical dominance, and China is rapidly emerging as a would-be superpower in science and technology,” said Elsa B. Kania, an adjunct fellow at the Center for a New American Security, a Washington think tank.
The Chinese People’s Liberation Army “might even cut ahead of the U.S. in new frontiers of military power,” she added.
Despite the recent sharp rhetoric from President Donald Trump, analysts say an open conflict between Beijing and Washing is unlikely. Others dismiss the idea that China might soon outpace the U.S. in military power.
“There is serious self-congratulation and boastfulness about China’s real military ability,” according to Wu Ge, a military analyst and columnist for China’s liberal-leaning Southern Weekly newspaper.
Still, it is clear that significant milestones have been reached by a country that, alongside Russia, is categorized in Trump’s national security strategy as a “revisionist power” — a nation seeking to redefine the world along values contrary to America’s.
Here are five of China’s most eye-grabbing innovations:
1. An electromagnetic railgun
Earlier this month, pictures emerged showing what some experts believed was an electromagnetic railgun mounted on a ship. A Chinese military analyst, Cheng Shuoren, was quoted by the state media as saying it was an engineering feat of “epoch-making significance.”
Instead of explosives, railguns use powerful electromagnets to fire projectiles as far as 100 nautical miles (115 miles) at seven times the speed of sound. This dwarfs the range and speed of conventional guns, whose ammunition can travel only 10 to 20 nautical miles.
That allows a railgun to attack ships, aircraft and land targets with the range and accuracy normally expected from missiles.
The U.S. has tested similar technology but never at sea. If confirmed, the Chinese variant would be the first time such a weapon had been deployed on water.
2. High-tech warships
A potential flashpoint between China and the U.S. lies in the South China Sea. A web of overlapping territorial claims in the energy-rich region has not stopped Beijing from building military facilities on small islands and reefs.
This has coincided with China making serious upgrades to its naval ability. Last summer, it launched its most modern military vessel, the Type 055.
The 12,000-ton stealth guided-missile destroyer, given the code name “Renhai” by NATO, is expected to go into full service this year. It has been built for anti-aircraft, anti-missile, anti-ship and anti-submarine warfare and is expected to play an instrumental role in China’s future aircraft-carrier battle formations.
China launches first domestically built aircraft carrier
China’s first domestically-built aircraft carrier, the Type 001A, takes water at Dalian Port in northeast China’s Liaoning province in April 2017. Bei piao / AP
It follows the launch last year of China’s second aircraft carrier, Type 001A. This 65,000-ton vessel is a domestically produced variant of its first carrier, the Liaoning, a retrofitted Soviet model built in 1985. The Type 001A can host 35 aircraft compared to only 24 on the Liaoning, and could enter service by the end of the year according to some analysts.
China is now working on a third carrier, an 80,000-ton vessel dubbed Type 002, that will be able to host more than 40 aircraft and is expected to feature an advanced catapult that can launch heavier jets more quickly.
Some local experts predict China’s strategy of regional strength means it will eventually need four to five carrier battle groups, smaller than the U.S. global strategy that requires 10 to 11 groups.
“China’s naval modernization covers all areas of the fleet, and the speed and scale of it is impressive,” the International Institute for Strategic Studies, a London-based think tank, noted in July.
3. Familiar fighter jets
China last week announced that the Chengdu J-20, its first homemade stealth jet dubbed Black Eagle, had entered combat service, breaking the stealth fighter monopoly of the U.S. and its allies in the Asia-Pacific region.
An answer to America’s F-22 and F-35, the J-20 is a fifth-generation fighter that can engage targets 120 miles away and deliver precision strikes.
But the similarities between the Chinese aircraft and its American counterparts may not be coincidental. U.S. officials have accused the Chinese military of hacking into their computer systems and stealing information relating to their cutting-edge equipment.
Some experts say that the striking similarities are clear evidence that this stolen know-how has allowed Beijing to play catch-up.
Undeterred, China is now developing its second stealth fighter, the Shenyang J-31 Falcon, which experts say could eventually be deployed on China’s aircraft carriers and compete in the global export market.
Boosting the Chinese Air Force further was the recent successful flight of the world’s largest amphibious aircraft, the AG600 Kunlong, which was designed for maritime rescue but, with a range of 2,800 miles, can play a potentially important role in the South China Sea.
China is also improving its Y-20, the world’s largest military transporter currently in production, by replacing its Russian engines with ones produced at home. With a cargo capacity of 70 tons, it could serve as a carrier of China’s air-launched rocket system.
4. A hypersonic glide vehicle
China carried out the first tests in November of a “hypersonic glide vehicle” named the DF-17, according to The Diplomat, an online magazine covering the Asia-Pacific region.
This medium-range weapon differs from a regular ballistic missile by gliding back to Earth on a slower, flatter trajectory that evades the gaze of radar-enabled U.S. missile defenses.
Neither the U.S. nor Russia are believed to have test-flown this type of technology but both are developing it.
Once deployed, the DF-17 could supplement the DF-21D, a medium-range ballistic missile known as China’s “carrier killer.”
Last year, China also brought into service its latest generation of intercontinental ballistic missile, the DF-41, which can carry 10 maneuverable warheads and has a range of 7,500 to 9,300 miles. That capability puts the entire U.S. within range.
5. Artificial Intelligence
Chinese researchers have revealed plans to upgrade the country’s nuclear submarines with artificial intelligence, signaling efforts to tap into military uses for AI.
China unveiled an ambitious plan in July to “lead the world” in this field, with a goal of creating a $150-billion AI industry by 2030.
In the same month, swarm intelligence — the coordinated deployment of autonomous machines — was demonstrated when a state-owned company successfully launched 119 drones that performed formations in the sky.
For the Chinese People’s Liberation Army, said Kania of the Center for a New American Security, effective military applications of artificial intelligence will include cyber and electronic warfare as well as “swarms of drones that might be used to target high-value U.S. weapons platforms, such as aircraft carriers.”
She added that China’s armed forces could also use AI to help them make better decisions on the battlefield.
Source: NBC “These Chinese military innovations threaten U.S. superiority, experts say”
Note: This is NBC’S report I post here for readers’ information. It does not mean that I agree or disagree with the report’ views.
SCMP says in its report “China fires up advanced hypersonic missile challenge to US defences” yesterday that China tested its DF-17 hypersonic missile twice on November 1 and two weeks after the first. As both tests were successful, DF-17 may be operational by around 2020, US intelligence sources were quoted as saying.
The HGV technology can also be used on China’s DF-41 multi-warhead ICBM with a range of 12,000 km to hit anywhere in the US.
Previously China conducted at least 7 tests of DF-ZF hypersonic glide vehicle (HGV) with only one failure. Experts say that DF-17 is a weaponized model of DF-ZF prototype. So far missile defense has less than 50% success rate in intercepting ICBM, but ICBM with HGV technology is even more complex and difficult to defend.
The US depends on THAAD to intercept China’s ICBMs but short-range HGV ballistic missile can destroy THAAD’s radar to make the US unable to detect the launch of ICBMs in time, according to experts.
The US, Russia and China are all developing HGV but the US lags behind China due to its focus on hypersonic aircraft.
Comment by Chan Kai Yee on SCMP’s report, full text of which can be found at http://www.scmp.com/news/china/diplomacy-defence/article/2126420/china-fires-advanced-hypersonic-missile-challenge-us.