“Hyperventilating a little, I think.” A few moments later, with the G-forces steadily rising, he noticed his companion’s breathing became more normal. “He’s looking better,” he reported.
“That’s because home base reports he’s unconscious,” Boomer said. “Don’t worry—they’re monitoring him closely. We’ll have to watch him when he wakes up, but if he got the anti-motion-sickness shot as he was directed, he should be fine. I’d hate to have him blow chunks in his oxygen helmet.”
“I could’ve done without that last bit of detail, Boomer,” the conscious passenger said wryly.
“Sorry, sir, but that’s what we have to be ready for,” Boomer said. He was astonished that the passenger didn’t seem to be having one bit of difficulty breathing against the G-forces, which were now exceeding two Gs and steadily increasing as they accelerated—his voice sounded as normal as back on Earth. “Battle Mountain may adjust his oxygen levels to keep him asleep until the medics are standing by.”
“My home base won’t like that,” the passenger pointed out.
“It’s for his own good, believe me, sir,” Boomer said. “Okay, everybody, we’re approaching Mach three and fifty thousand feet, and the ‘leopards’ are beginning to transform from turbofan engines to supersonic combustion ramjets, or scramjets. We call this ‘spiking,’ because a spike in each engine will move forward and divert the supersonic air around the turbine fans and into ducts where the air is compressed and mixed with jet fuel and then ignited. Because there are no spinning parts in a scramjet as there are in a turbofan engine, the maximum speed we can attain goes to around fifteen times the speed of sound, or about ten thousand miles an hour. The scramjets will kick in shortly. We’ll inert the fuel in the fuel tanks with helium to avoid having unspent gas in the fuel tanks. Stay ahead of the Gs.”
This time, Boomer did hear some grunts and deep breaths over the intercom as moments later the engines went completely into scramjet mode and the Midnight spaceplane accelerated rapidly. “Passing Mach five . . . Mach six,” Boomer announced. “Everything looks good. How are you doing back there, sir?”
“Fine . . . fine, Boomer,” the passenger replied, but now it was obvious that he was fighting the G-forces, clenching his stomach and leg muscles and pressurizing a lungful of air in his chest, which was supposed to slow blood flowing to the lower parts of his body and help keep it in his chest and brain to help him stay conscious. The passenger looked over at his companion. His seat had automatically reclined to about forty-five degrees, which helped his blood stay in his head since he couldn’t perform the G-crunches while unconscious. “How . . . how much . . . longer?”
“I hate to break it to you, sir, but we haven’t even gotten to the fun part yet,” Boomer said. “The scramjets will give us the maximum velocity and altitude while still using atmospheric oxygen for fuel combustion. We want to conserve our BOHM oxidizer as long as possible. But around sixty miles’ altitude—three hundred and sixty thousand feet—the air will get too thin to run the scramjets, and we’ll switch to pure rocket mode. You’ll feel . . . a little push then. It won’t last long, but it’ll be . . . noticeable. Stand by, sir. Another ninety seconds.” A few moments later, Boomer reported: “?‘Leopards’ spiking . . . spiking complete, scramjets report full shutdown and secure. Stand by for rocket transition, crew . . . back me up on the temp and turbopump pressure gauges, Gonzo . . . standing up the power, now . . . good ignition, rockets throttling up to sixty-five percent, fuel flows in the green, throttles coming up . . .” The passenger thought he was ready for it, but the breath left his lungs with a sharp BAARK! at that moment . . . “Good primary ignition, nominal turbopump pressures, all temps in the green, stand by for one hundred percent power, here we go . . . ready . . . ready . . . now.”
It hit like a car crash. The passenger felt his body crushed backward into his seat—thankfully the computer-controlled seat was anticipating it, simultaneously reclining, cushioning, and bracing his body weight against the sudden force. The nose of the Midnight felt as if it was aimed straight up, but that feeling lasted only a few moments, and soon he had no idea of up or down, left or right, forward or backward. For a moment he wished he was unconscious like his companion, unaware of all these strange, alien forces battering his body.
“One-six . . . one-seven . . . one-eight,” Boomer announced. The passenger was not quite sure what any of that meant. “Passing four-zero . . . five-zero . . . six-zero . . .”