2. BOOM BOX
Automotive Safety for People Who Drive On Bombs
AS SOMETIMES HAPPENS IN rural America, someone has shot up a road sign. The sign—a right-turn arrow on a yellow background—stands on a paved lane along the edge of Chesapeake Bay. Given the gape of the hole and the fact that the road traverses Aberdeen Proving Ground, there’s a good chance it wasn’t made by a bullet. A proving ground is a spread of high-security acreage set aside for testing weapons and the vehicles meant to withstand them. In the words of the next sign up the road: Extreme Noise Area.
I’m headed for Aberdeen’s Building 336, where combat vehicles come to be up-armored—as the military likes to up-say it—against the latest threats. Mark Roman, my host this morning, oversees the Stryker “family” of armored combat vehicles. He’ll be using them for an impromptu tutorial in personnel vulnerability: the art and science of keeping people safe in a vehicle that other people are trying to blow up.
My extremely uneducated guess is that some sort of shaped charge hit that sign. A shaped charge is an explosive double whammy used for breaching the hulls of vehicles and harming the people inside them. The first blast propels the murderous package to its target. On arrival, the impact detonates a wad of explosives packed inside. The blast slams a metal disc positioned in front of the explosives. Combined with the weapon’s contour, the energy of the blast shapes the metal into an extremely fast, close-range projectile that can punch through the hull of an armored vehicle with little trouble. RPGs (rocket-propelled grenades) are the ones most people have heard of, though there are ever bigger, deadlier iterations. Defense Industries of Iran is said to have one that can push through 14 inches of steel. Shooting a traffic sign with a shaped charge is like using a leather punch on a Kleenex.
By and large, an army shows up to a war with the gear it has on hand from the last one. The Marines arrived in Iraq with Humvees. “Some of the older ones had canvas doors,” says Mark, who was one of those Marines. His hair has since gone silver, but he’s retained the ready, let’s-do-this physicality that the Marine Corps seems to impart. When I asked a question about a new blast-deflecting chassis, he grabbed some wheeled mechanics’ boards and we rolled beneath a Stryker and finished the conversation on our backs.
Early on in Iraq, the Army tried plating vehicles with MEXAS armor panels, which work well against heavy machine-gun fire. “We were like, crap,” Mark recalls. “This does not stop an RPG.” You might as well have armored your vehicle with right-turn signs. Another thought was to add tiles of reactive armor, a sort of exploding Pop-Tart affair. When an RPG hits it, the filling explodes. This outward-directed blast serves to negate the blast of the RPG—and any passing pedestrian. Given that much of the fighting during the first Iraq conflict took place in urban areas—and was ostensibly an effort to “win hearts and minds” among the populace—reactive armor would have been a poor choice.
Besides, something cheaper and simpler had been found to work. Mark rolls out from under and leads the way to another Stryker, this one in a hoopskirt of heavy-duty steel grating called slat armor. The nose of an incoming RPG gets pinched between two slats, which duds it. It’s like squeezing your nose to stop a sneeze: It either prevents the explosion from happening or blocks the expulsion of nasty stuff. Either way, it proved effective. Strykers would lumber back to base like up-armored hedgehogs, bristling with RPGs. Slat armor worked so well that Iraqi insurgents largely gave up on RPGs.
And switched to making bombs. Early on in the Iraq war, improvised explosive devices were hidden on the sides of roads. Since these IED blasts hit vehicles broadside, the Army responded by flanking them with armor plates and replacing windows with “Pope glass”—two-inch thick transparent armor of the type that keeps His Holiness whole on his own tours of duty. Better, but it left the machine-gun turret exposed. Platoons tried piling sandbags up there, but they’d burst apart and literally sandblast the gunner. More ballistic shielding was added.
And thus more weight. All the added armor had Humvee engines screaming and straining on the uphills, and brakes burning out on the downs. Safety modifications on the Strykers added 10,000-plus pounds—far more than the vehicle was built to handle. You can beef up the suspension and tires, replace the engine—all of which was done—but you’ve still got problems. Past a certain tonnage, an armored vehicle begins to Godzilla the landscape. It breaks up asphalt, collapses levees. Exceeds the cargo capacity of the planes that deliver it. For every piece of armor and reinforcement, people like Mark would be called on to ditch something of similar weight. And the Stryker was never a lushly appointed vehicle. There is no onboard toilet. (There are empty Gatorade bottles.) The early ones didn’t even have air-conditioning. I tell Mark I’m glad to see some cup holders were left in place. I recognize the brief, polite silence that follows. It’s Mark Roman rendered mute by the fullness of my ignorance. They’re rifle holders.
Fast-forward to Afghanistan: land of the hundred-pound IED. To get around the up-armoring, insurgents came at vehicles from below, burying the explosives in the middle of the road rather than on the sides of it. As on most trucks, the chassis on US combat vehicles at that time were flat. Where newer generations of vehicles have V-shaped or double-V-shaped chassis to deflect the energy unleashed in a blast, the flat ones took it head-on. And because the seats were bolted to the passenger compartment floor, the energy would transmit directly to passengers’ feet, spines, and pelvises. Smacked them bad.
Newer vehicles have higher clearance. The force of a blast diminishes rapidly as it radiates outward. The energy at one or two feet is still so condensed that it can act like a solid projectile and break through vehicle floors. Once the integrity of the hull is breached, any loose piece of vehicle or gear becomes a projectile. Soldiers and Marines would pile sandbags on the floors of Humvees for the same reason aviators used to sit on their body armor instead of wearing it. Because death came up from below.
The underbody blast scenario was dire enough that US Central Command rolled out the procedural big guns: They issued a JUON (say, joo-on): a Joint Urgent Operational Need Statement. The statement surely ran longer than fifteen words, but the gist was this: Get us some combat vehicles that can drive over bombs and keep everyone inside alive. Nine vendors submitted prototypes for what would come to be known as MRAPs (say, em-wraps): mine-resistant, ambush-protected. But without fielding them first, how do you know which one is safest—and precisely how safe it is? You hire a “personnel vulnerability analyst.”
The Army Research Laboratory snapped up Nicole Brockhoff, premed at Johns Hopkins, with a graduate degree in biodefense. The youngest person to win the Secretary of Defense Meritorious Civilian Service Award. Bench presses 190. She’s come down from her office in the Pentagon to attend to some things, and agreed to make me one of them. Whenever Mark takes over the explaining, Brockhoff drops back and takes out her phone. She does not seem rude, just grindingly busy and determined to stay on top of her day. I see her come and go in my peripheral vision, pacing, answering email. She gives the impression of someone for whom idleness is almost physically unbearable. She is gorgeous, articulate, fast-moving, powerful. Lesser humans left blinking in her wake.
Brockhoff offers to show me another anti-IED modification: the energy attenuating seat. We climb inside the passenger compartment of a Stryker infantry carrier, which does not have a door but rather a drop-down ramp, like a circus boxcar. The first good thing about these new seats is that they are no longer bolted to the floor. Second, they ride on special shock-absorbing pistons. What’s special are the collapsible, replaceable metal inserts that slow the seat’s downstroke and keep it from bottoming out. The catch is that in order for passengers to protect their feet and lower legs, they need to keep them off the floor. The footrests on the base of each seat are for the person sitting directly across. Meaning that one soldier has to straddle the other’s knees for hours at a time. Mark, who has joined us, adds that having the knees up like that tends to make the butt go numb. “Like when you’re reading on the toilet too long. And you get toilet palsy.”