Astrotwins — Project Blastoff (12 page)

Egg looked skeptical. “How major an upgrade over existing technology are we talking about?”

“I can't be sure,” said Mr. Drizzle, “because my results are based on lab experiments only. But if my calculations are correct, the specific impulse would be around 350 seconds.”

Mrs. O'Malley raised her hand. “Uh, excuse me. Not to sound stupid, but—
specific impulse
?”

“It's a measure of how much power a propellant delivers in a given time,” Mr. Drizzle said.

“You need a fuel capable of delivering a high specific impulse—a bunch of power in a short time—if it's going to put a spacecraft in orbit, Mom,” Egg said.

“So what does a specific impulse of 350 seconds mean?” Mrs. O'Malley asked.

Egg, Mark, and Scott were smiling. With Barry's help they had already done the calculations based on
the weight of their spacecraft and their astronaut. If the rocket and rocket engine were truly lightweight, they knew exactly the specific impulse they needed.

Egg answered for all of them. “It's enough to launch a 3,000-pound spacecraft into orbit, Mom—a spacecraft right about the size of
Friendship 7
.”

Or the size of
Crazy 8
.

That school year, Mark and Scott were assigned to the same sixth-grade class, with Mr. Hackess as their teacher.

Mr. Hackess had been teaching sixth grade for thirty years and using the same first-day-of-school assignment for twenty-five of them, an essay called “Three Things I Learned This Summer.”

“Three Things I Learned This Summer”

by Mark Kelly

One thing I learned this summer is how to be an astronaut. How you do this is you practice a lot. How you practice is you have a simulator. You can make one out of boxes if you don't have a big budget. You cut up the boxes into the right shapes, then put labels
on with markers and tape to show controls. Then you lie there and your brother tells you a thing that could go wrong for an astronaut, and you tell him what you would do if you were the astronaut. And you show him with the pretend controls how you would do it.

Another thing I learned is how to build a rocket. You need to learn how to fabricate with metal to do this. One of the tools you use is called a sheet roller, and another one is called a metal shear. My friend Lisa and her dad Mr. Perez helped teach me how to use them. It was hard but after a while I got the hang of it.

The third thing I learned is that NASA launched a probe to Mars in August. No rocket from Earth has ever gone there before that we know about. The mission's name is Viking. It will arrive at Mars next summer. I think it would be cool to go to Mars.

“Three Things I Learned This Summer”

by Scott Kelly

I learned there is no up or down if you are in space. So you have to have an IMU in your spacecraft. IMU stands for inertial measuring unit. It has gyroscopes. When your spacecraft moves, the gyroscopes swivel around in a bracket called a gimbal to show what your spacecraft is doing in comparison to them, like whether it is rolling over or facing right
or left or tilting up and down. This is called your spacecraft's
attitude
, and it is not the same as being grumpy or happy or can-do.

I learned an important thing that Albert Einstein figured out. What it is is time slows down for objects moving very fast through space. So an astronaut going very fast in space gets older a tiny bit less fast than someone going a normal speed. This is true, but from my own experience it does not make sense. Here is an example. I worked very fast for most of the summer, and time seemed to go very fast, too.

I learned my brother, Mark Kelly, is a little better at riding roller coasters than me.

When Mark and Scott got their papers back, they both had “Excellent!” written at the top in red ink. On Mark's it said “Very creative!” On Scott's it said “Nice use of vocabulary!” Mr. and Mrs. Kelly were so proud, they posted them side by side on the refrigerator.

The
Crazy 8
team tried their best to stay on schedule, but still they got behind. It wasn't till a Saturday in late September that they were ready to move operations to the launch site, and Lisa asked her dad if he could lend a hand—and a truck.

“The launch site?” Mr. Perez repeated. “But you don't have a launch site.”

“Actually,” Scott said, “we do.”

Egg jumped in to explain. “It's because we want everything to be as realistic as possible. So Scott and Mark found a launch site.”

“We've been working there, too,” said Mark, “building a blockhouse, uh . . . for optimum realism.”

Besides the truck, a forklift and a cherry picker were
required to raise the pieces onto the trailer and secure them under tarps. Seeing all the help they were getting, Mark began to worry. “How are we ever going to be able to repay these nice people?”

“Chocolate chip cookies,” said Egg. “After the launch—after the science fair—we will bake about a zillion.”

*  *  *

The weather that fall was great—Indian summer, everybody called it. If things had been normal, Mark and Scott would have raced through their homework every day and gone outside to ride bikes. But things hadn't been normal since Grandpa had had the bright idea that they should build something together so they'd stop fighting.

So instead, what they did with every spare moment was run simulations. In fact, the simulator made from boxes had been repaired so many times, it was more duct tape than cardboard and the labels describing what was where had fallen off.

Scott told Mark it was okay about the labels—by now Mark should know every switch, control, and display so well that he didn't need them—and Mark realized it was true. He did know them. All the practice had done its job. They were going to be ready.

Then came the Tuesday afternoon before launch, and everything changed.

Mark thought back over what happened that day
approximately one zillion times. He tried to blame somebody other than himself, but in the end he couldn't. He was too honest. Sure, he had had help from forces outside his control. But you couldn't really blame a little kid for being a little kid, or a dog for being a dog.

“Just one more,” Scott had said. He was sitting on his bed, which in the simulation was Mission Control.

“I can't,” Mark said.

“You can have a break after one more.”

Mark took a deep breath, squinched his eyes closed, let the breath out, and opened his eyes. “Okay, fine. What went wrong this time?”

“You're in a spin.”

“How fast?”

“One revolution per second. What happens?”

Mark tried to imagine spinning in zero gravity.
Crazy 8
had a single tiny window: depending on the attitude of the spacecraft, the stars, the moon, and Earth would appear in it and be gone at a dizzying rate.

“Uh . . . my vision blurs. I've got maybe half a minute till I black out.”

“Check. What do you do?”

“Check fuel level.”

“It's 30 percent—way less than what you expect.”

“Uh . . . maybe one of the reaction control system—RCS—thrusters
is stuck?”

“Maybe. What do you do?

“Curse Egg for doing a bad job building the thruster?”

“Not helpful.”

“It might be a short circuit.”

“It might, but you can't exactly rewire the system at this point.”

“So I ask Mission Control to look at the telemetry. Maybe they can identify the broken thruster.”

“You're out of radio range.”

“Are you kidding me?”

“You're out of range!”

“Okay, okay, you don't have to yell. Well . . . then maybe I close the valves one by one till the bad one stops firing, then I go back and reopen the good ones.”

“
Maybe
you do? You're about to black out!”

“Okay, definitely—that's definitely what I do.” Playing the part of the thruster controls were old light switches. As Mark flipped each one, Scott made whooshing noises to signify the sound of firing thrusters. Finally, Scott was silent—and Mark knew he'd hit the right one.

“I'm safe!” Mark announced.

“Wait—now you hear a crackle on your headset, and I say:
Crazy 8
, this is Greenwood Control, do you read me?”

“Roger. Go ahead, Greenwood Control.”

“The radar says you're out of attitude 15 degrees in
yaw, and your RCS fuel is low. What happened up there? Over.”

“I don't know. I went into a spin and had to shut down the RCS and we wasted a lot of fuel before I could figure out which one to turn off.”

“Uh-oh,
Crazy 8
. You know what that means, right? Over.”

“Uh . . . I'm not spinning anymore?”

“
Besides
that.”

“Uh—oh yeah. Without sufficient fuel for the RCS, I won't be able to control attitude during re-entry. I could be in a tough spot.”

“That's affirmative,
Crazy 8
. Howard is going to send new re-entry targets for you to type into the computer. You will have to come home sooner and not make the complete orbit. We don't want you to run out of fuel. Looks like you'll be landing either in California or Nevada. Look for a big hole in the ground—that's the Grand Canyon. Oh—and I'll tell Mom you're going to be late for dinner.”

“Roger that,” said Mark. “Can we take a break now?”

“You go ahead,” Scott said. “I'm just going to work on the checklist some more.”

Mark didn't argue. In fact, he was grateful for his brother's hard work. The checklist was the list of what to do at each point in the mission, from prelaunch to recovery. If the flight was going to go smoothly, if Mark
was going to be safe, nothing could be forgotten.

In the homemade simulator, Mark had to lie on his back with his bent legs draped over a footstool. It had been uncomfortable at first, but by now he was getting used to it. With one thing on his mind—getting out of the house—he pivoted free of the simulator seat, rocked back onto his shoulders, and kicked forward to a standing position. Then he trotted past Scott, through the bedroom doorway, down the hall and out the front door.

Mission accomplished: He was in the sunshine at last!

Mom and Dad were both at work. Major Nelson was probably napping on the sofa in the living room. He wasn't allowed to be up there, but he knew Scott and Mark didn't enforce the rules the way Mr. and Mrs. Kelly did.

Later Mark realized the dog must have woken up when he heard the door open.

Now that he was outside, Mark didn't have a clear idea of what he wanted to do. Grab his bike? Climb a tree? Chuck a ball against the garage door?

For a moment, it was good just to feel the sunshine, and he wished he were a normal kid with nothing better to do than go to school and come home and watch TV.

Out of the corner of his eye, Mark saw little Lori from next door riding her pink bicycle on the sidewalk. The training wheels were off, and she looked pretty
confident. He bet her mom was watching through the kitchen window and looked over. There she was, and she waved at him. He waved back and at the same time heard a thump behind him.

It took him half a second to identify the reason for the thump and half a second more to foresee what was going to happen next—and in that time the catastrophe had already begun to play out. Major Nelson, convinced that bicycles are a constant and dangerous threat, was galloping full speed toward Lori.

“Major Nelson!”
Mark yelled, and took off across the front yard.

Somewhere in the back of his mind, he saw himself as a body in motion accelerating on a vector, hoping to intersect a canine body in motion before it intersected a third body, this one on wheels and five years old.

This could all be plotted out on
x
and
y
coordinates, the velocities represented by
V
and acceleration by
A
. Howard could enter it into his computer, or Barry into his brain. Using trigonometry to solve it, you'd shortly have at least a theoretical answer to the question: Will Mark stop Major Nelson before Major Nelson knocks Lori down?

Of course, math could not answer every question—like how long Lori would cry and how mad her mother
would be.

It was those unknowns that propelled Mark into a last-second Hail Mary leap that described a neat arc ending at the point on the sidewalk at which Major Nelson was tackled.

Lori, meanwhile, was surprised but unhurt.

And Mark's left arm was broken.

“So I guess you're happy,” Mark said.

It was later that same night, the lights were out, and the boys were in bed at last. With all the excitement, it was the first time they had been alone together since the accident. Mark had a cast on his arm. The doctor had given him a pill to take for pain, but Mark told his parents he didn't want it.

“No, I'm not happy,” Scott said. “And that's a mean thing to say. I know you're disappointed and your arm hurts, but it's still mean, so take it back.”

“I won't,” said Mark.

“We can wait and launch when your arm heals,” Scott said.

“Ha!” said Mark. “By the time my arm's better, the weather will be too chancy, not to mention that we can't
leave the rocket sitting out that long. Somebody will see it and ask questions. Besides, Egg's Science Fair is in two weeks.”

“So Barry can fly. It doesn't have to be me,” Scott said.

“You're the only one who's done all the sims with me. You're flying, and I'm Mission Control, and that's the only thing that'll work. So, like I said, I guess you're happy.”

“You're right,” Scott said. “I am. In fact, you didn't see me, but I let Major Nelson out on purpose so he'd go after Lori and you'd have to chase him and get hurt.”