On the net he first pulled up a schematic of the Hawk and the school rocket. They looked different, but the systems were the same. Next he brought up a simple outline of a DC-3 and launched a search program to match its fuel systems against the Hawk. It only took a second to spot the difference.
“Guys, we got a problem.”
Terry whirled. “What do you mean? It worked perfectly.”
Dave’s anger shot out like a jack in the box. “Like hell it did. We had fuel starvation to the engines four times in the flight.”
“But I’m using the school’s pumps,” Joe defended himself.
“We’re doing a lot more with those pumps than the school ever intended. We need pressurized fuel tanks. We can’t just pump fuel. We’ve got to push it out at the same time.” Dave passed what was showing on his glasses through to theirs.
Terry fumed for a second, but, as his eyes flitted over what showed on his glasses, his face went to a puzzled frown. In a minute he focused on Dave. “You’re right.”
Dave put his anger back in the box. The guys weren’t stupid. Dumb sometimes, but not stupid. “That’s what they do on a DC-3.”
“Shit,”Joe shook his head. “My Dad does helium welding, so getting it isn’t a problem, but a bottle of that stuff and tubing will weigh at least a pound.” An extra pound of structure meant twenty-three more pounds of fuel and three more cubic feet of missile.
“I’ve been saving a half-pound reserve. You can have it.” Dave offered.
“This’ll use up what we’ve saved too,” Terry said sheepishly. “We’re out of luck if we have to add another ounce.”
Two weeks later, the rocket was ready for the science fair, but systems integration was going on even as the judges circulated. Mr. Montgomery showed up just before the judges with Ms. Harrison, the principal. “Here’s one of this year’s most exciting projects, for the whole city,” he told her.
“And what are you boys doing?”
That was Dave’s question. “We will determine if the microwave radiation left over from the Big Bang was equal in all directions. We have designed instrumentation to measure the background microwave radiation from that event.” Mom’s last words to him this morning had been to speak slowly and say his words properly; Dave was just glad his voice didn’t squeak.
Ms. Harrison seemed impressed. “I remember when those results were first published. It was earth shaking. To think, students at my school can repeat them. How do you propose to do that?”
The boys took turns explaining their “official” project. The principal nodded as she followed them. Dave concluded. “We’ll be launching near Blue Lake early Sunday morning. There won’t be much activity on the water and it will give us an extra 4,000 feet.”
Ms. Harrison turned to Mr. Montgomery. “You’re following all the safety precautions.”
“Yes, I ordered the primer cord this morning. I’ll be range safety officer.”
“Good, I haven’t been up to the lake in a while. I just might come,” she said without looking back as she headed for the three girls who had grown a modified strain of bacteria to increase the recoverable rate of methane from closed landfills.
“We’d be glad to have you witness this project.” Mr. Montgomery called after her.
“Primer cord?” Dave’s voice did break this time.
“Yeah. You boys didn’t think we’d let an experiment as dangerous as this one go without special safety precautions. The chute handles problems if something goes wrong on the way down. The explosives take care of things on the way up.”
“How much does it weigh?” Joe choked on the words.
“Oh, about a pound, including the detonator receiver. Why?”
“We’ll need to make allowances for the weight.” Terry said, glancing at the other two.
“You boys do that.” Mr. Montgomery left.
“Don’t say a word. We’ll talk tonight,” Terry ordered.
“Where are we going to get a whole pound?” Joe tossed his plans on the desk in Dave’s room.
“I can scratch some of my receivers, but damn, all of them together don’t weigh more than two pounds. We’ll lose half our data.”
“What about the parachute?” Terry asked.
“What about it? They’ll check it before launch,” Dave growled.
“Yeah, but will they measure how far the ropes stretch?”
Joe nodded, “I can trim them a bit, the chute too, and we’ve got a little extra room for fuel.”
“Look at everything,” Terry ordered.
It took them an hour. Here an access plate with four screws was replaced with a three screw version. There a support truss was pared down another .005 mm. A tiny fuel cell took the place of the solar panels.
“All we need is a couple of hours of data,” Terry insisted.
Dave gritted his teeth and made the compromise.
It was almost midnight when Dave calculated the final weight scheme, then fed it through a ballistic simulation. “If the wind and weather are right, we make orbit,” Dave concluded, pushing back from his desk. Before the others could start celebrating, Dave whirled his chair around. “But we don’t have anything to spare. We’ll have to make every burn count. I’ll write the launch code.” Dave fixed Terry with unblinking eyes. “The computer flies the Hawk.”
“Right. Whatever it takes. You do it.”
It felt good for someone else to compromise for a change.
The two left to make the changes needed to the Hawk. The first thing Dave did was erase the code for ground control of the Hawk’s flight. Touch a star.
The launch pad was an empty concrete parking lot beside the lake. The high pressure front Dave was counting on had moved in during the night. The air was crisp and cool—and as thin as they needed. The chill had also cleared the lake of boats. Now if they could just catch a moment when the wind was nothing, they’d have it made.
The boys fueled the Hawk by first light. Mr. Montgomery and Ms. Harrison watched. Terry pumped hydrogen peroxide from a fifty-five gallon drum that said 50 percent concentration. No one asked what it really was. Joe emptied three red, five gallon cans into the fuel tank, then poured some from a fourth. Joe’s dad didn’t say anything about it being JF-D, and again, nobody asked. Joe screwed the access plates on as Mr. Montgomery wound the primer cord and attached the detonator to one of the last screws.
They had trudged half way to their picnic table command center when Joe felt his pockets. “I shouldn’t have any screws left.” He pulled three out. Waving a screw driver, he took off for the rocket like a track star. “Get ready. I’ll only take a second.”
Ms. Harrison frowned. “I hope this won’t be as bad as an old NASA launch. I have things to do today, but I guess you can’t expect kids to stay on schedule like TWA.”
For a moment it looked like Mr. Montgomery might follow Joe, but he patted his belly. “If I go, we won’t launch before sunset.”
Ms. Harrison laughed with him and they continued on.
“What do you think he’s up to?” Dave whispered to Terry.
“I don’t know, but we better be ready for anything.”
The boys trotted for their gear. Dave quickly pulled on two gloves and a full helmet. He could clear it if he had to, but when he opaqued it, nothing would interfere with what he saw today.
Joe was frantically dancing around the rocket, hands waving, body obscuring what he was doing. Dave checked the automated launch sequencer. Everything was running smoothly. Whatever Joe was doing, he hadn’t messed with anything important.
Dave did another traffic check. There was nothing on the Portland scope to worry about. Mr. Montgomery had actually got them listed in a Notice to Aviators. Blue Lake was closed to air traffic for the next two hours. Nice to be able to count on adults for something, even if it was only to look after themselves.