Space For Sale
Page 37
“Griffin, first stage, everything looks to be within the tolerances from here,” First Stage Control radios back.
“I know it's within the tolerances, but I wanna know why it's doing that. If chamber pressure is low we might have a leak between the pumps and Engine 4,” K replies quickly.
“We don't see a problem outside of the chamber pressure from down here,” First Stage Control replies. At that instant, a loud bang resonates through the whole rocket right up to the spacecraft and an alarm goes off in the cabin.
“The computer shut down Engine 4,” Kingsley says before Tim can ask what that was.
“What was the noise then? Shutting down an engine shouldn't sound like an explosion,” Tim barks back. However Kingsley is preoccupied by readings in engines 1 and 7, which are two of the three engines adjacent to engine 4.
“I've got warning lights on Engine 1 and Engine 7,” Kingsley reads off.
“We lose two more and we're at an automatic abort,” Tim says.
“I know,” K barks back.
“Switch the computer engine controls to abort-passive,” Tim orders. That's a switch that prevents the computer from preemptively shutting down any more engines. The computer might sense a problem and shut down too many engines for them too handle. With it switched to abort-passive the odds of a catastrophic explosion go up, as it now relies on human inputs to shut down a troubled engine. Engine abort-passive doesn't prevent the computer from shutting down an engine that reaches certain higher tolerances, so it can still shut down an engine that's too far gone, but it won't shut one down preemptively. This switch has no effect on the Griffin's abort computer, which can still trigger an automatic abort in which the Griffin capsule activates its engines and rockets off the top of the Eagle 9 in an instant if it senses a catastrophe.
“I already did,” Kingsley replies quickly. “Control, what's the story on engines 1 and 7?”
“They were running a little hot after the shutdown of 4, but look normal now, do you read different?” The call comes from Mission Control.
“I've got high chamber pressures on 1 and 7,” Kingsley replies.
(T+1:00) Guidance: Vehicle is 6 kilometers in altitude, velocity of 239 meters per second, downrange distance 1 kilometer.
“We're watching it closely too,” First Stage Control replies.
“What's the story K?” Tim asks.
“I'll watch them close, but I'm not shutting anything down preemptively. We can't lose another engine until at least two minutes.”
“What happened to Engine 4?” Tim asks.
(T+1:14) Rocket Control: Vehicle is supersonic
“I don't know,” K replies. “Low chamber pressure, then the computer shut it down. That's all I know.”
“What about first-stage return?” Tim asks. Tim doesn't have to say anything more, K knows exactly what he's saying.
“First Stage Return,” K calls on the radio, that's Josh Yerino's call sign.
“FSR,” Josh calls back.
“Let's call off the attempt at powered FSR. We absolutely have to recover the first stage to diagnose the problem with Engine 4. I don't want to risk it losing control and crashing into the ocean.”
“But K, powered descent only runs on the center engine, it shouldn't be any less stable because of the lost engine, and I can override the computer and deploy parachutes early if it doesn't look right.”
(T+1:26) Guidance: Max-Q. Vehicle has reached maximum aerodynamic pressure.
K debates allowing the attempt to recover the first stage with a powered descent. If it fails and the stage hits the ocean at high speed, it will probably sink and all the data will be lost. Then again, the data of even a brief attempt at powered descent will be invaluable to the development of the Hummingbird II.
“Call it off,” K decides. “Negative powered descent.”
“Roger,” Yerino responds.
(T+1:38) Second Stage Control: Second stage has started engine chill.
“How are 1 and 7 doing?” Tim asks.
“The chamber pressures are high because they're compensating to make up for the thrust imbalance. I don't know why I didn't think of that sooner,” K replies.
“Just keep an eye on them,” Tim replies.
(T+2:00) Guidance: Vehicle remains on nominal trajectory, vehicle is 29 kilometers in altitude, velocity of 1 kilometer per second, and downrange distance of 23 kilometers.
(T+2:15) Flight Engineer, Kingsley Pretorius: Griffin power systems nominal.
(T+2:30) Guidance: Vehicle remains on nominal trajectory, vehicle is 49 kilometers in altitude, velocity of 1.8 kilometers per second, and downrange distance of 58 kilometers.
(T+2:42) Rocket Control: Approaching MECO-1.
“Did you switch MECO-1 to engines 4 and 6?” K calls quickly. AT MECO-1, two of the 9 engines are scheduled to be shut down and for the remaining first stage burn-time, the Eagle 9 becomes an Eagle 7. However the engines normally powered down are Engines 1 and 9. If they shut down both 1 and 9 with 4 already out, they will be in trouble.
“Roger, Griffin, MECO-1 was automatically changed to shut down Engine 6 to counter Engine 4. Expect MECO-1 to come seven seconds late, that's at T-plus-two-five-seven.”
“Roger,” K replies.
(T+2:57) Stage One Control: MECO-1.
(T+2:58) Rocket Control: Approaching MECO-2.
“Here comes stage separation,” K shouts to his passengers. “Get ready for a jolt.”
(T+3:05) Stage One Control: MECO-2.
(T+3:05) Guidance: Flight computer in second stage.
The remaining seven engines are shut down and the first stage's job is done. For a brief moment in time, at a point 80 kilometers high, they experience a brief zero-g respite from the three solid minutes of acceleration as their stomachs float up into their throats.
(T+3:06) Payload Control: Griffin has sensed MECO-2.
(T+3:07) Rocket Control: Stage one separation confirmed.
(T+3:08) Second Stage Control: Second stage online.
(T+3:10) Range Officer: Range confirm clean separation.
(T+3:14) Second Stage Control: Second stage at full power.
And just like that, the over 200-foot-tall rocket is now just a 70-foot-tall rocket. The first stage falls away as the second stage and its single Arthur engine fires up. With the second stage working fine, and no more alarms or cautions, Kingsley breathes a sigh of relief.
“Ladies and Gentlemen, this is your Flight Engineer speaking,” K announces to his passengers. “If you'll direct your gaze to the nearest window you will see the blackness of space replacing the blue sky. We are now coming up on the Karman Line, that is 100 kilometers in altitude, making you all astronauts...again. Take notice that the fasten seat belt sign is still on and we ask that you wait until we reach orbit before you attempt to join the 100-mile high club, if you know what I mean. Now if you'll direct your gaze up to the docking windows, a part of the spacecraft is about to be explosively discarded.”
(T+3:55) Payload Control: Nose-cone separation.
The white rounded nose cone blasts up and away. The Griffin will quickly pass it as it falls away to an uncontrolled re-entry and splashdown in the North Atlantic. The passengers strain to look up through the docking window to see the blackness of space. The second stage doesn't quite push the astronauts into their seats as forcefully as the first stage. Four minutes into flight, they're experiencing about 1.3 Gs.
(T+4:10) Second Stage Control: Second stage propulsion systems nominal.
(T+4:25) Guidance: Vehicle remains on nominal trajectory, vehicle is 146 kilometers in altitude, velocity of 3.2 kilometers per second, and downrange distance of 344 kilometers.
(T+4:45) Second Stage Control: Second stage propellant utilization is active.
(T+5:23) Guidance: Vehicle remains on nominal trajectory, vehicle is 180 kilometers in altitude, velocity of 4 kilometers per second, and downrange distance of 539 kilometers.
(T+6:00) Rocket Control: Secon
d stage propulsion nominal
(T+6:01) Payload Control: Power systems nominal, good telemetry lock on stage 2.
(T+6:27) Guidance: Vehicle remains on nominal trajectory, vehicle is 200 kilometers in altitude, velocity of 4.6 kilometers per second, and downrange distance of 768 kilometers.
(T+7:31) Guidance: Vehicle remains on nominal trajectory, vehicle is 209 km in altitude, velocity of 5.6 km per second, and downrange distance of 1077 km.
(T+8:34) Guidance: Vehicle is now on terminal guidance
(T+9:12) Payload Control: LOS (Loss of Signal) Cape.
(T+9:19) Second Stag Control: Approaching MECO-3.
“MECO-3,” Second Stage Control says over the headset just as the five passengers of Griffin 2 hear the rocket quit and they float up into their restraints.
“Shutdown confirmed,” Commander Bowe says. In an instant, second stage separation occurs. Inside the Griffin they hear a pop as explosive bolts separate the Griffin Trunk from the top of stage two. Several calls come over the crackling radio, called up by people who were a couple miles away from the Griffin only ten minutes ago when it was sitting on the pad. In just ten minutes the Griffin is over 1200 miles away.
“Flight computer is in separation state.”
“Griffin has sensed separation.”
“Vehicle is orbital. Apogee 346 kilometers, perigee 220 kilometers.”
“Mission Control, this is Launch Control, Griffin is all yours.” While Mission Control assumed responsibility, Commander Bowe was already activating the thruster pods and giving Griffin 7 a slight nudge away from the second stage. There would be no repeat of the thruster pod problem.
“Copy Launch Control, thanks for the ride,” Mission Control says. “Griffin 7, this is Mission Control.”
“Copy mission, this is Griffin 7,” Commander Bowe calls back.
“You are go for solar panel deployment.”
“Copy, go for solar panel- what the hell is that?” Bowe asks. Kingsley's pre-launch vomit has floated up into the cabin. “Alright, we've got some loose debris in here, give us a moment to clean it up.”
Kingsley laughs as he reaches for a small white towel and corrals the little balls of vomit and directs them into a sick bag. Luckily for the passengers, with their helmets on and connected directly to life-support they are immune from the smell inside the cabin. Arnold laughs as a glob of vomit floats up in front of him. He taps at the floating ball with his finger tips, watching it ripple as it floats away.
“Shoot that this way,” Richard Branson says as he holds out a sick bag. Arnold gives the ball of puke a little push and lets it float several feet towards Richard's open bag.
“He shoots, he scores!” Arnold announces.
“Once a little boy, always a little boy,” Caroline says.
“Alright Hawthorne, we're ready to continue,” Bowe says as Arnold and Kingsley direct free-floating gobs of Cuban food into plastic sick bags. The commander presses the touch screen, commanding the solar panel covers to be jettisoned, which is accompanied quickly by a quiet pop. “Standby Hawthorne,” Bowe says. “K, look at that.”
Kingsley looks to the panel and discovers that the computer doesn't show a clean separation of the left solar panel cover. “Try the command again,” K says. Bowe hits the manual override to force the left panel cover jettison, but nothing happens.
“Alright Hawthorne, we don't have a light for left solar panel cover jettison.”
“Standby Griffin,” Mission control calls back.
“What does that mean?” Caroline asks nervously.
“It's not a big deal,” K replies quickly. Kingsley manipulates one of his consoles, pulling up the views from several on-board cameras. There are three cameras inside the Griffin Capsule, two cameras on the nose for docking, and a sixth camera mounted on the side of the capsule inside a small service bay, trained on the grappling arm attachment point. The Griffin is designed to rendezvous within 10 meters of the space station where one of the ISS's grappling arms will attach to this spot, then manually position the capsule into the docking node. This attachment point is part of the service bay which is hidden by a protective cover during launch. Kingsley skips ahead several steps in the checklist and opens the protective cover. The panel opens and reveals quite a view from the service bay camera. The service bay is on the “bottom” of the capsule, that is if you call the nose the front and the trunk/heat shield the rear. The camera shows a cloudy North Atlantic beneath and behind them.
“Roll right ninety degrees,” Kingsley instructs Commander Bowe. If the solar panel covers did jettison correctly, they should be floating slowly away from the Griffin. As the Griffin rolls, the astronauts are very slightly pushed out of their seats. “Oh god,” Kingsley says, holding back more vomit.
“What?” Bowe asks.
“Space hangovers are a bad idea,” K replies. The service bay camera's view moves northward toward the pole then above the thin blue line. There they find the stark white solar panel cover approximately thirty meters out and floating away in a slow tumble.
“There she is,” Bowe says.
“Hawthorne, Griffin, we have a visual on the cover, looks like it's just a faulty indicator light, going ahead with panel deployment,” Kingsley radios down. K presses the deploy button and the two solar panels unfold silently from their mounting point on the Griffin Trunk. A graphical display shows the panels deploying, as well as their power output.
“Rolling back level,” Bowe says as he rotates the Griffin capsule so the panels face the sun. Local time beneath the Griffin is approximately 4 p.m., so the sun is not directly overhead. However the solar panels can rotate from their trunk mounting point so they will face the sun as evenly as possible.
“And we've got green lights for power output from all panels,” K says. With the panels deployed, the next step is the first of a series of burns to enable a rendezvous with the International Space Station which is more than 6,000 miles ahead of them, and in a higher orbit.
The ISS lives at around 400-420 kilometers in altitude above the Earth, and at an orbital inclination of 51 degrees (orbital inclination is how offset the orbit is from the equator, an orbit directly over the equator would have an inclination of 0 degrees, while a polar orbit, orbiting from north to south, would have an inclination of 90 degrees). The Griffin just after orbital insertion is at less than 250 kilometers in altitude. A mere ten minutes after orbital insertion, the first burn is performed, raising the apogee, or high point in an orbit around the Earth, to 380 kilometers, an altitude they will reach forty five minutes later over the south Pacific.
To reach the ISS, they will need to raise up to a circular orbit at 410 kilometers and get to that circular orbit in sync with the ISS. If you were to get to the same orbit as the ISS, but be some distance behind it, then you would forever chase it around the globe, never catching up. If you then burn towards the ISS, you would actually raise into a higher orbit, and fall behind. This is the counter-intuitive art of orbital rendezvous. A lower orbit is a shorter distance. Think of a track with separate lanes. The runner on the inside lane would have a shorter distance to travel. However, in space, your speed determines your orbital height, and your orbital height determines the distance and the period of your orbit. In order to catch up with another object in orbit, you must be in a lower orbit. To be in a lower orbit, you must slow down. But, if you look at the velocities, a lower orbit is actually faster than a higher orbit. Confused yet?
The Moon orbits the Earth at an altitude that varies between 362,570 km and 405,410 km. The Moon travels in its orbit at an average of 1.022 km/s or about 2,286 mph. By comparison, the ISS orbits at an altitude, that varies due to atmospheric drag, of about 415 km and at a speed of about 7.7 km/s or 17,200 mph. The ISS orbits the Earth about 15 times a day, while the Moon orbits the Earth once a month. Between the low orbit of the ISS and the high orbit of the Moon, there is a point where the orbital period is one day. A satellite in this sweet-spot is a geosynchronous sate
llite. Geosync orbit is at an altitude of about 42,160 km and a velocity of 3.075 km/s, or 26,200 miles and a speed of 6880 mph. So you see, at a higher orbit you have a longer distance to cover since you're farther out on the orbital “track” and you're going slower.
Griffin 7 will attempt to go from liftoff to docking in about six hours. It used to take about two days for the Soyuz to take three astronauts from liftoff to docking, however they tried out a more expedited approach with several Progress supply missions before using it in manned Soyuz missions in 2013. Griffin 7 will follow the same approach. At liftoff, the ISS was about a third of the Earth ahead of the Cape. Since the Griffin launches into a lower orbit, it's continually picking up ground...in space. It takes six very precise burns at exact times to raise the orbit in incremental steps toward rendezvous in under six hours. Since it's such a short time there's not enough time for the crew to doff their flight suits, since it's a time consuming procedure and they are required to be suited when they dock. Once in orbit for thirty minutes, there's a forty minute window in which they won't make any burns and thus the crew can unstrap from their seats and stretch their legs for the first time.
“The Captain has turned off the fasten seat belt sign and you are now free to move about the cabin,” Kingsley announces in his best attempt at mimicking a mustachioed, grizzled co-pilot. Arnold, Caroline, and Richard take off their gloves and then start on their helmets. Kingsley looks to Tim and gives him a smirk.