“Faster than a speeding bullet! More powerful than a locomotive! Able to leap tall buildings in a single bound!” What are we talking about? Superman, of course! When they debuted in the early 1940s, the first nine Superman cartoons were the pinnacle of retro-futurism in animation, filling viewers’ screens with visions of autonomous robots, machines that made the earth tremble, and telescopes with the capacity to shoot comets out of the heavens. They also introduced America to one of the most enduring and beloved of larger-than-life heroes, Superman, and taught generations of fans to look to the sky and exclaim “It’s a bird! It’s a plane! It’s Superman!”
But how fast is a speeding bullet exactly? According to the popular science series MythBusters, the average bullet travels at around 2500 feet per second, or 1700 miles per hour.(1) But in flight Superman was faster than that – faster than supersonic, he had to be hypersonic. Hypersonic? Put simply, it’s just a matter of scaling the numbers up – let us explain…
In aeronautical terms, flight speeds are referred to not in terms of miles per hour as for land travel speeds but as ‘Mach’ numbers. Mach 1 is approximately 760 miles per hour at sea level, but decreases to around 660 miles per hour at altitude. Mach 2 is double that number, and Mach 3 is triple that number. Any speeds up to Mach 5 are known as supersonic, and speeds faster than Mach 5 – 3600 miles per hour land speed equivalents or 5 times the speed of sound – are hypersonic.
And under certain circumstances humans can travel comfortably at Mach speeds. The current record for the fastest moving humans is held by a trio of astronauts – famously Eugene Cernan, John Young, and Thomas Stafford who crewed NASA’s Apollo 10 mission in 1969. On their way back from the Moon, the astronauts achieved what many would see as a superhero peak speed of 24,790 miles per hour relative to planet Earth. And even now – more than four decades later – theirs is a record we have yet to beat.
Within the confines of our own planet’s atmosphere, however, we are somewhat slower. Formerly the fastest commercial airliner, the supersonic Concorde sped passengers on transatlantic flights at around 1350 miles per hour, twice the speed of a conventional aircraft. And Airbus, with its plans to offer commercial trips on its ‘Son of Concorde’, an AS2 craft, will begin test flights in 2021 at 1217 miles per hour between London and New York. So, within the commercial sector, we are making progress. But arguably it is in the military and defense arenas that the largest leaps forward are being made with the growing interest in creating craft that can travel at hypersonic speeds – that is, upwards of Mach 5.
Born of the early ballistic missiles, a new generation of Tactical Boost Glide (TBG) vehicles are being developed by Lockheed Martin, the American aerospace, defense, security, and advanced technologies company, headquartered in Bethesda, MD. For Lockheed Martin, the $147 million contract offers the opportunity to create ‘a high-speed delivery system that could bomb targets thousands of miles away in an hour or less [similarly to what] other countries, including Russia and China, are working on.’(2) The device itself is basically a rocket with an arrow-shaped nose cone. In deployment, it will be carried to a cruising altitude by a B52 bomber before being launched. Once airborne, its internal rockets will boost it to a higher altitude allowing it to achieve up to Mach 20 speed. To give some sense of what this means, Mach 20 is around 13,200 miles per hour at altitude. This would allow the TBG vehicle to travel from London, England to Sydney, Australia – a journey of some 11,000 miles – in approximately 49 minutes. Less time than it takes to order up a pizza for delivery and grab your first slice.
But what’s the need for this kind of speed? The answer is both tactical and political. Until recent times, we have relied on surface to air missiles (SAMs) to combat potentially incoming threats. And the US is not the only country to have them in reserve:
“Today’s air defense systems now boast “double digit” SAMs such as the SA-10 and the more advanced SA-21, a series of Russian long range SAMs which are proliferating around the world to countries such as China, Iran, North Korea, Syria, and Venezuela. These missiles feature modern electronics and sensors, with some variants able to hold targets at risk from up to 250 miles away.”(3)
But in terms of strategic national defense, hypersonic devices represent the next generation of tactical airborne weaponry.
As revolutionary as stealth technology was just one short generation ago (and turbojet technology was before that), hypersonics are thought by many in the defense industry to represent the most precise and clinical way of foiling increasingly sophisticated defenses to neutralize targets. Given their ultimate speed, hypersonic vehicles offer unparalleled first strike opportunities, compressing the ‘shooter-to-target window.’ Known also as the ‘fourth dimension effect’ – in essence, time warfare – a hypersonic weapon offers an opportunity to get ahead of the enemy’s management of the conflict, gaining the ultimate tactical upper hand.
But in less theoretical terms what does this all mean? According to one report, it suggests strongly that the face of modern warfare is evolving. Take, for instance, the case of the United Kingdom’s new aircraft carriers, the HMS Queen Elizabeth and the HMS Prince of Wales. Commissioned at a total cost of almost $7.75 billion, the state-of-the-art vessels would become sitting ducks in the event of a hypersonic missile strike. Russia’s testing of Zircon missiles – which have the capacity to travel at 4,600 miles per hour – could theoretically sink either ship in a single strike. And, according to naval expert, Pete Sandman, “Even if the missile is broken up or detonated by close-in weapons, the debris has so much kinetic energy that the ship may still be badly damaged.”(4)
Back on this side of ‘The Pond,’ the benefit to our national security is encapsulated in a 2016 study published by the Mitchell Institute for Aerospace Studies, ‘Hypersonic Weapons and US National Security: A 21st Century Breakthrough.’
“Instead of working to establish air superiority, establish tanker support, position personnel recovery assets, establish airborne command and control networks, prosecute electronic warfare, and infiltrate attack platforms through myriad defenses, a hypersonic strike would unfold far more rapidly, with far fewer support requirements. Unable to intercept these high speed weapons, a first strike wave could simultaneously eliminate the most heavily defended enemy nuclear facilities and key targets in a fraction of the time, at a much lower threshold of risk to attackers.”(5)
And this applies not only to long-established targets but also to ‘pop-up’ threats, transforming airpower and revolutionizing military operations by using increasingly more effective, comparatively less expensive, and lower-risk approaches to battlefield encounters.
And we are not alone in our R&D interest. In 2014, Russia re-emphasized its commitment to testing a new hypersonic weapon by 2020, and between 2014 and 2015 China conducted no fewer than five acknowledged test flights. Similarly in India, a partnership between that country’s Defence Research and Development Organization (DRDO) and Russia’s NPO Mashinostroeyenia has seen the completion of the second version in the series of Brah-Mos hypersonic cruise missiles, capable of travelling at speeds up to Mach 7. And with this level of foreign interest in mind, the then acting assistant Secretary of Defense for Research and Engineering, Alan Shaffer, commented: “We, the United States, do not want to be the second country to understand how to control hypersonics.” (6)
Indeed, there is a significant amount to understand. For instance, in what ways does hypersonic travel affect a weapon’s potential payload? Depending on the specifications of the individual weapon itself, perhaps it doesn’t and here’s why.
Hypersonic devices are coming to represent the next generation of weaponry precisely because of two factors: velocity and altitude.
At hypersonic speeds, the device itself becomes a weapon when ‘the kinetic energy of [the object] traveling at Mach 20 is transferred to a target.’(7) In other words, the sheer destructive power of a collision between a stationary object – say, an enemy missile on a launch pad or a terrorist safe house – and the incoming hypersonic device obviates the need for a payload of explosives.
Moreover, even the practical considerations of the physics and engineering involved in hypersonic flight are different from that of supersonic speed. Take, for example, the issue of surface temperature. At hypersonic speeds, airflows across the surface of a craft can reach into the thousands of degrees Fahrenheit meaning that, without adequate protection, vehicles will potentially face structural melting or burning due to thermal expansion and the resulting distortion. In fact, as little as ‘a few seconds’ exposure to a hot hypersonic airflow can destroy a conventional aluminum or composite-structure airplane or missile. Hypersonic vehicles require high-temperature materials—nickel alloys, graphite-based composites, and ceramics—coupled with shaping that minimizes the destructive effects of sustained blowtorch-like heating.’(8)
So to ensure that the parts can withstand these types of in-flight conditions, quality control of both components and processes is crucial – from the guidance and radar electronics to the superstructure, the aerodynamics to the strike potential. And this is where the use of a high-security, state-of-the-art cleanroom in the manufacture and quality control of all components, and the regulation of tools and processes is crucial. Just like its bio-medical, pharmaceutical, and electronics counterparts, the aerospace industry as a whole has a requirement for the use of controlled and sterile environments – specifically cleanrooms – for the manufacture of precision components for all stages of the project – from initial research, to development, and to final delivery.
Given the degree of pinpoint accuracy that is required in the manufacture of the high-level systems for hypersonic devices, absolute contamination- and pollution-control are critical. Aerospace industry cleanrooms typically feature HEPA or ULPA filters which are able to capture contaminants at the sub 0.3 micron level for microbiological filtering of spores and bacteria in the air. They also offer chilled water plants, steam plants, process utilities such as compressed air, hydrogen, de-ionized water, high purity piping for gases, solvents and liquids, and chemical waste systems. From monitoring systems for particulate count and size, to air-flow regulation and vapor control, protection against molecular contaminants such as hydrocarbons and silicone, pressurization, and temperature and humidity control, the cleanroom – with its HVAC, fire suppression, air showers, and pass-through chambers – must become the de facto center of operations when even the tiniest of defects can result in enormous fiscal losses. Or worse.
As the Mitchell Institute report concludes: “Though hypersonics, in particular hypersonic strike weapon technology, is ripe for exploitation as a theater and global strike game changer, it is not yet clear whether America will own that advantage first. Though the US is investing in hypersonics and their maturation, it is not on a guaranteed path to near term success. Clear and consistent commitment to a disciplined plan to address remaining technology challenges has yet to emerge from America’s recent efforts in this field.”(9)
With that said, the nation’s cleanrooms and the resources of our own contamination control industry stand ready to support that ‘clear and consistent commitment’ as and when it is made.
Do you have thoughts on the role of the cleanroom within the aerospace industry? Do you work within a cleanroom environment within the defense services? What’s your opinion on the newest generation of long-range tactical weapons? We’d love to know your thoughts!