Authors: Dale Brown
“I'm perfectly happy to stay here, Boomer.”
“I want you to get the full effect of what you're about to experience, and the cockpit is the best place for that, sir,” Boomer said. “But the G-forces are pretty strong as we go hypersonic, and the jump seat isn't stressed for hypersonic flight. But when you unbuckle to come back up to the cockpit, sir,
that
will be a moment you'll never forget.”
“We've been hooked up to oxygen for an awfully long time, Boomer,” the passenger asked. “A few hours at least. Will we have to stay on oxygen on the station?”
“No, sir,” Boomer replied. “Station's atmospheric pressure is a little lower than sea-level pressure on Earth or the cabin pressure on the spaceplaneâyou'll feel as if you're at about eight thousand feet, similar to cabin pressure on an airliner. Breathing pure oxygen will help purge inert gases out of your system so gas bubbles won't lodge in your blood vessels, muscles, your brain, or joints.”
“The âbends'? Like scuba and deep-sea divers can get?”
“Exactly, sir,” Boomer said. “Once we're on station you can take it off. For those of us who do space walks, we go back to prebreathing for a few hours because the suits have an even lower pressure. Sometimes we even sleep in an airlock sealed up with pure oxygen to make sure we get a good nitrogen flush.”
Takeoff was indeed thirty minutes later, and soon they were flying north over western Idaho. “Mach one, sir,” Boomer radioed back on intercom. “First time going supersonic?”
“Yes,” the passenger said. “I didn't feel anything abnormal.”
“How about Mach two?”
“We just went
twice
the speed of sound? That quickly?”
“Yes, sir,” Boomer said, the excitement obvious in his voice. “I like to loosen up the âleopards' at the beginning of every missionâI don't want to find out at Mach ten or Mach fifteen that there might be a problem.”
“â
âLeopards'?”
“My nickname for the hybrid turbofan-scramjet-rocket Laser Pulse Detonation Rocket System engines, sir,” Boomer explained.
“Your invention, I believe?”
“I was the lead engineer for a very large team of Air Force engineers and scientists,” Boomer said. “We were like little kids in a candy store, I swear to God, even when the shit hit the fanâwe treated a huge âleopards' explosion as if we tossed a firecracker into the girls' lav in high school. But yes, my team developed the âleopards.' One engine, three different jobs. You'll see.”
Boomer slowed the Midnight spaceplane down to midsubsonic speed and turned south over Nevada a short time later, and Jessica Faulkner came back to help the passenger into the mission commander's seat on the right side of the cockpit, get strapped in, and plug her suit's umbilical cord into a receptacle, and then she unfolded a small seat between the two cockpit seats and secured herself. “How do you hear me, sir?” Faulkner asked.
“Loud and clear, Jessica,” the passenger replied.
“So that was the âfirst stage' of our three-stage push into orbit, sir,” Boomer explained over the intercom. “We're at thirty-five thousand feet, in the troposphere. Eighty percent of Earth's atmosphere is below us, which makes it easier to accelerate when it's time to go into orbit. But our tanker has regular air-breathing turbofan engines, and he's pretty heavy with all our fuel and oxidizer, so we have to stay fairly low. We'll rendezvous in about fifteen minutes.”
As promised, the modified Boeing 767 airliner emblazoned with the words SKY MASTERS AEROSPACE INC on the sides came into view, and Boomer maneuvered the Midnight spaceplane in position behind the tail and flipped a switch to open the slipway doors overhead. “Masters Seven-Six, Midnight Zero-One, precontact position, ready, âbomb' first, please,” Boomer announced on the tactical frequency.
“Roger, Midnight, Seven-Six has you stabilized precontact, we're ready with âbomb,' cleared into contact position, Seven-Six ready,”
a computerized female voice replied.
“Remarkableâtwo airplanes traveling over three hundred miles an hour, flying just a few feet away from one another,” the passenger in the mission commander's seat remarked.
“Wanna know what's even more remarkable, sir?” Boomer asked. “That tanker is unmanned.”
“What?”
“Sky Masters provides various contract services for the armed forces all over the world, and the vast majority of their aircraft, vehicles, and vessels are unmanned or optionally manned,” Boomer explained. “There's a human pilot and boom operator in a room back at Battle Mountain, watching us via satellite video and audio feeds, but even they don't do anything unless they have toâcomputers do all the work, and the humans just monitor. The tanker itself isn't flown by anybody but a computerâthey load a flight plan into the computer, and it flies it from start-taxi to final parking without any human pilots, like a Global Hawk reconnaissance plane. The flight plan can be changed if necessary, and it has lots of fail-safe systems in case of multiple malfunctions, but the computer flies the thing all the way from start-taxi to engine shutdown back at home base.”
“Amazing,” the passenger said. “Afraid your job will be given to a computer someday, Dr. Noble?”
“Hey, I'd
help
them design the thing, sir,” Boomer said. “Actually, the Russians have been sending Soyuz and unmanned Progress cargo vessels up to the International Space Station for years, and they even had a copy of the space shuttle called Buran that did an entire space mission unmanned. I think I'd rather have a flight crew if I was flying into orbit on a Russian spacecraft, but in a few years the technology will be so refined that passengers would probably never notice.”
As the passenger watched in absolute fascination, the spaceplane glided up under the tanker's tail, and a long boom steered by small wings lowered from under the tail down toward the spaceplane. Guided by green flashing director lights and a yellow line painted under the tanker's belly, Boomer moved forward under the tail until the green director lights went out and two red lights illuminated.
“How do you tell when you're in the right position, Boomer?” the passenger asked.
“There's a certain âpicture' between the tanker's belly and the windscreen frame that you learn to recognize,” Boomer replied. “Not very scientific, but it works every time. You get a feel for it and recognize if you're too close or too far away, even at night.”
“You do this
at night
?”
“Of course,” Boomer said matter-of-factly. “Some missions require night ops, and of course it's always night where we're going.” As he was speaking, Boomer pulled off a tiny bit of power, and all forward motion stopped. “Midnight Zero One, stabilized in contact position, ready for contact,” he radioed.
“Roger, Zero One,”
the female-voiced computer replied. A nozzle extended from the end of the boom, and moments later they heard and felt a gentle
CL-CLUNK!
as the tanker's nozzle slid into the slipway and seated itself in the refueling receptacle.
“Showing contact,”
the computer voice reported.
“Contact confirmed,” Boomer said. On intercom he said, “All I do now is follow those director lights and stay on the tanker's center line.”
“If the tanker is fully computerized, shouldn't the receiver aircraft be able to do a rendezvous by computer as well?” the passenger asked.
“It canâI just prefer to fly the thing in myself,” Boomer said.
“Impressing the VIP on board, right?”
“After what you'll see today, sir,” Boomer said, “I and my meager flying skills will be the
least
impressive things you'll see on this flight.”
“You said âbomb,' not âfuel,'â
” the passenger said. “We're not taking on fuel?”
“First we're taking on a special liquid oxidizer called
B-O-H-M
, or borohydrogen metaoxide, âbomb'âbasically, refined hydrogen peroxide,” Boomer said. “Our engines use BOHM instead of liquid oxygen when we switch to pure rocket enginesâit's impossible, at least with today's technology, to transfer supercooled liquid oxygen from a tanker aircraft. âBomb' is not as good as cryogenic oxygen, but it's much easier to handle and far less costly. We don't take on any âbomb' before takeoff to save weight; we'll take on jet fuel last so we have the maximum for the mission.”
It took over fifteen minutes to download the thick oxidizer, and another several minutes to purge the transfer system of all traces of BOHM oxidizer before switching over to begin transferring JP-8 jet fuel. Once the jet fuel began transferring to the Midnight spaceplane, Boomer was visibly relieved. “Believe it or not, sir, that was probably the most dangerous part of the flight,” he said.
“What was? Transferring the BOHM?” the passenger asked.
“Noâmaking the switch from BOHM to jet fuel in the tanker's transfer system,” Boomer admitted. “They rinse the boom and plumbing with helium to flush all the âbomb' out before the jet fuel moves through. The boron additives in the oxidizer help create a much more powerful specific impulse than regular military jet fuel, but mixing BOHM and jet fuel, even in tiny amounts, is always dangerous. Normally, the two mixed together needs a laser for ignition, but any source of heat, a spark, or even vibration of a certain frequency can set it off. The experiments we did at Sky Masters and at the Air Force test centers made for some spectacular explosions, but we learned a lot.”
“Is that how you got your nickname, âBoomer'?”
“Yes, sir. Perfection requires mistakes. I made a ton of them.”
“So how do you control it in the engines?”
“The laser igniters are pulsed, anywhere from a few microseconds to several nanoseconds, to control the detonations,” Boomer explained. “The stuff goes off, believe me, and it's massive, but the specific impulse lasts just an instant, so we can control the power . . .” He paused, long enough for the passenger to turn his helmeted head toward him, then added, “. . . most of the time.”
They could virtually feel the second passenger in the back stiffen nervously, but the passenger in the front seat just chuckled. “I trust,” he said, “that I won't feel a thing if something goes wrong, Dr. Noble?”
“Sir, an uncontrolled âleopards' explosion is so big,” Boomer said, “that you won't feel a thing . . . even in your
next
life.” The passenger said nothing, but just did a big nervous “GULP.”
The JP-8 transfer went much faster, and soon Colonel Faulkner was helping the front-seat passenger to get strapped into his seat in the back beside the plainly still-nervous second passenger. Soon everyone was seated and the crew was ready for the next evolution. “Our tanker is away,” Boomer said, “and as planned he's dropped us off over southwestern Arizona. We'll make a turn to the east and start our acceleration. Some of the sonic boom we'll create might reach the ground and be heard below, but we try to do it over as much uninhabited area as we can to avoid irritating the neighbors. We're monitoring the flight computers as they finish all the checklists, and we'll be on our way.”
“How long will it take?” the first passenger asked.
“Not long at all, sir,” Boomer replied. “As we briefed on the ground, you'll have to deal with the positive G-forces for about nine minutes, but they're just a bit more than what you'd feel taking off aboard a fast bizjet, strapped into a dragster, or on a really cool roller coasterâexcept you'll feel them for a longer period of time. Your suit and the design of your seat will help you stay consciousâin fact, you may âred out' a little because the seat is designed to help keep blood in your brain instead of the G-forces pulling it out, and the more pressure you get, the more blood will stay.”
“How long will we have to stay in orbit before we can chase down the space station?” the passenger asked. “I've heard it sometimes takes days to link up.”
“Not today, sir,” Boomer said. “The beauty of the spaceplane is that we're not tied to a launch pad set on one particular location on Earth. We can make our own launch window by adjusting not only our launch time but changing our insertion angle and position relative to our target spacecraft. If we needed to, we could fly across the continent in just a couple hours, refuel again, and line up on a direct rendezvous orbit. But since we planned this flight so long ago, we could minimize the flying, gas up and go, and save fuel just by planning when to take off, when and where to refuel, and being in the right spot and right heading for orbit. By the time we finish our orbital burn and coast into our orbit, we should be right beside Armstrong Space Station, so there's no need to chase it down or use a separate Hohmann transfer orbit. Stand by, everyone, we're starting our turn.”
The passengers could barely feel it, but the S-19 Midnight made a sharp turn to the east, and soon they could feel a steady pressure on their chests. As directed, they sat with arms and legs set against the seats, with no fingers or feet crossed. The first passenger looked over at his companion and saw his chest within his partial-pressure space suit rising and falling with alarming speed. “Try to relax, Charlie,” he said. “Control your breathing. Try to enjoy the ride.”
“How is he, sir?” Gonzo asked on intercom.
“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 worryâthey'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.”