History provides equally vivid demonstrations. Medical historian Philip Mackowiak compared eyewitness and officers’ accounts of Stonewall Jackson’s performance during a series of Civil War battles with the general’s opportunities for sleep, if any, in the days leading up to those battles. In 100 percent of the battles for which Jackson had had no chance to sleep in the three days prior, his leadership was rated “poor.” In the Battle of Gaines’ Mill, his chief of staff described him as “thoroughly confused from first to last.” His brigades were not merely “out of order”; “he did not know where they were.” The Battle of Glendale found Jackson “benumbed, incapable… of deep thought or strenuous movement… uninterested and lethargic.” At times during the Battle of Malvern Hill, Jackson “appeared to be almost a bystander.” In the midst of the Battle of McDowell, he was discovered napping.
For every twenty-four hours awake, Belenky told me, people lose 25 percent of their capacity for useful mental work. Jackson was leading the charge (or not) on 25 percent of his waking best. I’m trying not to think about a man named Patterson in one of the Tennessee’s machinery rooms. He’d been up for 22 hours trying to fix the electrolytic oxygen generator, a large, pulsing metal-hulled molecule splitter. “Basically it’s a hydrogen bomb,” he’d said cheerfully.
The longest Belenky has kept subjects awake is 85 hours—three-plus days—which is about the limit, he says. “They’re not,” he adds, “very useful to anybody.” There are people who claim to have stayed awake for 100 and even 200 hours, but because their brain waves weren’t continuously monitored, as Belenky’s subjects’ are, it’s impossible to be sure they weren’t microsleeping. The very tired can slip into Stage 1 sleep for a few moments, eyes open, carrying out some quasi-coherent version of whatever it is they’re up to. As anyone who has slept on an airplane knows, it’s possible to maintain muscle tone while sleeping—that is, until you slip into REM sleep, during which muscles relax. (When people fall sleep at odd times in their circadian cycle, they may enter REM early. Blame “early-onset REM” for the slack-jawed head-lolling that happens when you nap sitting up.)
Soldiers, including Stonewall Jackson’s, have on occasion reported sleeping during night marches. If you’re tired enough, Belenky says, your brain appears to briefly dissociate—one part sleeping, another awake. There are birds and marine mammals that manage this regularly. Dolphins and seals are able to sleep unihemispherically—with one half of their brain. This is because the other half needs to attend to breathing, which in their case requires swimming to the surface for air. When geese and ducks sleep in groups on the ground, the birds on the outer edge will keep one eye open and the corresponding brain hemisphere awake, scanning for predators.
From a military perspective, a soldier who could march or swim or look out for enemies while simultaneously catching up on sleep would be a desirable item. It fits right in with one of the goals of the military’s futuristically minded Defense Advanced Research Projects Agency (DARPA): “to enable soldiers to stay awake, alert, and effective for up to seven consecutive days without suffering any deleterious mental or physical effects and without using any of the current generation of stimulants.” This is why you’ll find the Defense Department on the sponsor lists of some of the basic research on unihemispheric sleep. If science could just figure out how the ducks do it, perhaps troops could be enabled—chemically or surgically, God only knows—to do it, too. Belenky scoffed. “We’re not even sure what triggers whole brain sleep.”
That hasn’t stopped military organizations from fantasizing about it. I came across a NATO symposium on Human Performance Optimization that included a roundup of medical technologies that might be repurposed to optimize warfighters. In among the prosthetic limbs “to provide superhuman strength” and the infrared and ultraviolet vision–bestowing eye implants was this: corpus callosotomy to “allow unihemispheric sleep and continuous alertness.” Surgeons have on occasion severed this connector between the brain’s halves as a way of reducing the number of seizures in patients with severe epilepsy. Does this in fact change how these patients sleep? No, says Selim Benbadis, director of the University of South Florida Comprehensive Epilepsy Program and the author of a paper on the procedure. He added that there are infants with incompletely developed corpora callosa and they sleep normally and with both hemispheres at the same time.
“They think a lot of harebrained things are good ideas,” Belenky said of DARPA. Yes, they do. The wish list also included “surgically provided gills.”
“RELEASE OF nuclear weapons has been authorized.” It’s the intercom man again. Even in a simulation, it’s a sickening thing to hear. I look around at the sailors standing near. One untangles an extension cord. His face betrays nothing. A sailor seated at a control console blows his nose. “Is this what it would be like?” I ask Murray. “If it were the real deal? Would people just be calmly carrying out their tasks, blowing their nose…” The whole business is straight off my fathometer.
Murray’s not playing this game. “If your nose is running, you blow it.”
Two sailors hustle past, each holding a corner of what looks at a glance like some kind of Lotto ticket. It’s the code for the key box, the box with the keys to launch the missiles. Two people must have a hand on it at all times once it’s out of safekeeping, for the same reason some airlines, in the wake of the 2015 Germanwings suicide flight, require a second person in the cockpit.
Were this an actual missile launch, I’d wager that adrenaline would keep the crew alert regardless of how long they’d been up. But the normal day-to-day routines of a ballistic missile sub are a good deal less invigorating. Most watches are just that: hour upon hour of watching. Watching displays, readouts, dials, sonar feed. It’s a worrisome mix: sleep deprivation, tedium, and large, potentially destructive items. “The Navy doesn’t want us to publish anything saying that these guys monitoring these nuclear reactors are falling asleep on watch,” Dyche told me. “But we know that’s happening.” Even awake, the tired are poorly suited for standing watch. When psychologists give sleep-deprived people a standard battery of cognitive tasks, their score on measures of “psychomotor vigilance”—paying attention and noticing shit—drops dramatically.
I never visited the Tennessee’s reactor and its tenders, because I didn’t have security clearance for that part of the sub, but I did visit the torpedo room. There are four of them, massive as medieval battering rams. Sweetly (I guess), they are named for the torpedomen’s wives. I asked the torpedoman on watch when last a US submarine had had cause to fire a torpedo at another vessel. He thought for a moment. “World War II.” He’s the Maytag Repairman, ready for action in the extremely unlikely event it’s called for. The torpedoman’s watch is a checklist of inspections, walk-arounds, paperwork. Always with the paperwork.[57] Outside of the sonar shack and the Missile Control Center, much of the Tennessee remains charmingly analog. I looked around the missile compartment at one point and thought, tuba parts. The torpedo launch console has big square plastic buttons—Flood Tube, Open Shuttle, Ready to Fire—that flash red or green, like something Q would have built into James Bond’s Aston Martin. The missile compartment has similarly retro-looking panels of buttons. They provided the setup for one of the more quotable things Murray said to me—a line that, were fewer precautions in place, could have joined “Houston, we’ve had a problem” or “Watch this” in the pantheon of understated taglines for calamity: “I wouldn’t lean on that.”
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By weight, a submarine carries more paperwork than it does people—despite the best efforts of Vice Admiral Joseph Metcalf III. Metcalf, who led the invasion of Grenada, waged an equally headstrong campaign for shipboard computerization—“a paperless ship by 1990,” he told the