WASHINGTON: The hypersonic Air-Launched Rapid Response Weapon (ARRW) will conduct its first booster test this week, a landmark for the Air Force — but the Pentagon’s hypersonics R&D director sounded two notes of caution.
First, Michael White warned, future tests must not be marred by sloppy mistakes: “If [for example], we forgot how to do a checklist and tighten a pin on a fin, and we lose a flight vehicle because our fin falls off, that’s not acceptable failure. …. Quite frankly, we’ve got a ways to go. I’m not going to be satisfied with the health of the industrial base until we are routinely, successfully flying hypersonic weapons in our prototype development program. And so far we haven’t been able to do that routinely.”
Second, White said, while “boost-glide” hypersonics weapons like ARRW will become operational first, smaller and cheaper “air-breathing” hypersonic cruise missiles are “probably the most significant” contribution the Air Force will make. “The hypersonic cruise missile is, in my mind, a game changer,” he told the Air Force Association’s online Aerospace Warfare Symposium.
Maj. Gen. Andrew Gebara, director of plans at Air Force Global Strike Command, agreed. “ARRW … it’s available, it’s good capability, it’s quick,” Gebara said, speaking at AFA alongside White. “We’ll [be] buying capability by the end of ’22….that will actually be provided to the combatant commanders, if necessary.
“[But] we also want to get to that cruise missile capability,” he said, referring to the more compact Hypersonic Attack Cruise Missile (HACM). “I can put four ARRWs on a bomber….I could put 20 HACMs on a bomber if done right – and maybe more.”
Boost-Glide vs Air-Breathing
What’s the big difference among types of hypersonic weapons? In short, it’s size. For a given size of warhead, boost-glide weapons are bigger and more expensive – and also faster.
A boost-glide hypersonic weapon, as the name implies, launches on a rocket booster, very much like an ICBM, which gets it up to near Mach 20. Then the “glide vehicle” containing the warhead detaches and coasts, like a glider, through the upper atmosphere. While the glide vehicle has no engine to generate more thrust, it can maneuver far more nimbly than a conventional ballistic missile, potentially allowing it to bypass missile defenses.
An air-breathing hypersonic cruise missile, by contrast, is a much smaller weapon that flies through the atmosphere like a jet – specifically, it’s a high-speed variant called a scramjet – under continuous power, making it…
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