Before the visitors loomed two gigantic rocket ships about a quarter of a mile apart. Each was painted silver gray with a red nose and at the base were three red fins on which the rockets seemed to be poisedÖ

When Sandy said that she would like to see what the rocket motors looked like, Bud lowered the elevator car down to the launching platform underneath the ship. Both girls gulped at the maze of fuel pumps, pipes, tanks, numberless propulsion motors and platformsÖ

"But you don't have any windows in here!" Phyl exclaimed. "Aren't you going to be able to see anything?"

Bud smiled at her evident disappointment and said, "We do have tow portholes, but it can be pretty dangerous to take a peek."

He walked over to the wall and opened a circular steel shutter, exposing a good-sized porthole in which was set an extremely thick pane of orange-colored glass.

"Tom tells me that the glass in there will absorb most of the ultraviolet light, but even so we won't dare look toward the sun."

"You see," he continued, "the blanket of air around the earth protects us from most of the harmful radiation, but out in space the sun's rays are so strong they're deadly. That's why we have these shutters for the viewing ports. But since we have another one on the other wall, we'll be able to look our most of the time from one of them. No, we won't miss a thing," Bud concluded.

"I thought it was dark as night up in space," Sandy remarked.

"True, when you're out of the planet' atmospheres. But we might pick up the lights of spaceships from Mars, for instance," Bud replied. He grinned. "So it will be easy to avoid a crash."

"This rocket is in four stages and each stage is complete in itself," Bud explained. "The bottom section, or first stage, directly above us drops off first, then the next and the next. Finally, Tom and I will be in our own flying stage. Now let's go back up to the pilot canopy in the nose. I want to show you Tom's latest safety device."

They huddled in the narrow elevator. Bud pressed a button and the conveyor shot to the top stage. In some ways it resembled a plane, but the girls knew that during the early part of the flight, Tom and Bud would be strapped to a board tilted at a 45-degree angle from the upright rocket. Therefore the controls had been built to be within easy reach of this position.

"See this panel?" Bud asked. "It's Tom's foolproof control. If the first three stages don't drop off by themselves, this electronic attachment will cause an explosion and off they go!"

Sandy and Phyl looked around, awe-struck. This passenger section seemed lick such a tiny ship in which to make a trip through space. Commenting on this, they learned that it weighted seventeen tons, or only two percent of the rocket ship's total weight.

"But that's all we need," Bud declared. "The two bottom stages get the rocket up into space. The third is to get it in orbital motion. Our payload-stage motors are only used for braking on the return trip."

Fuel trucks piped the last gallons of liquid oxygen and alcohol into the dummy rocket ship. Mechanics and engineers bustled about, disconnecting fuel lines.

Ö

Öthey hurried to the launching area, where great tanks of nitric acid and liquid oxygen were being brought alongside the towering rocket.

Tom Swift was in the nose section, with Bud Barclay watching the young inventor give his flight plan a last-minute inspection. This was an automatic pilot in the form of an unwinding, perforated tape which ran through an electric brain. Metal pins would drop into the punched-out holes and make contact with various controls.

"So you expect this piece of plastic to act as guide during the trip and bring the last stage of this rocket right back to the island?" Bud asked dubiously.

"I sure do," Tom replied. "And when it lands, not even the robot jets will have to guide the rocket in."

ÖTom and Bud now tried on the spacesuits which would be carried in case of emergency. They had been constructed from a tightly woven wire fabric of extremely high bursting strength. The suits were covered on each side with an impermeable layer of a new synthetic rubber, joined together to permit movement, and were absolutely airtight.

Encased in these effective but clumsy garments, the boys would be able to survive exposure to the space void for a period of several hours, should a chance collision with one of the hundred thousand meteorites which fall to the earth daily damage the Star Spear.

Each of the pilotless jets carried an amazing mechanism called the landing forcer, an invention of Tom's. This instrument, directed from a beeper box in the control tower, could capture and steer intruding planes to Fearing's airstrip.

Öthe enemy pilot was trying to come from the right side. As he completed his turn for the new approach angle, the powerful landing forcer caught the plane in its electronic grip and rolled it violently away.

The group drove toward the launching area. Tom's mother and the girls were amazed to see how built-up the island was.

"I had no idea it was so complete," Mrs. Swift commented, as they passed the dock area with its numerous boats and the playfields for tennis, baseball, and other sports.

Then came the long barracks, the construction building, and finally the very modern-looking laboratory building.

The kicker was a rocket-fuel energizer. It consisted of a yard-long section of ten-inch pipe, tapering at each end into the smaller piping of the fuel lines. The bulge was loosely packed with a metallic oxide catalyst and covered at both ends with platinum gauze filters.

Tom's invention, using an alcohol-liquid-oxygen fuel combination, was designed to absorb the hyper-powerful radiation of the sun and shoot this solar energy into the liquid-oxygen supply, converting it into highly explosive, poisonous, blue liquid ozone.

With the help of the kicker, Tom's fuel would be much more efficient than any other combination yet know. In addition to the enormous combustion heat of alcohol and liquid oxygen, he would get additional thrust from the decomposition of the ozone and would decrease mass ratio.

Ö

He hooked the pump that was designed to carry the liquid oxygen through the kicker. Next, he attached a flowmeter to the pump to register the speed of the liquid.

In rocket flight, oxygen would have to flow through the kicker at a rate of several thousand gallons per minute to satisfy the hungry motors. Should anything interfere with this flow, the rocket would cease to operate and founder in space.

After filling the unit with red-dyed water, Tom squatted in front of the glass window in the pump model to view the flow through the kicker. He flicked on the power and listened to the even whirring of the pump.

"It's perfect" he murmured elatedly, as he watched the scarlet liquid bubbling through the unit.

Tom had installed his invention on top of the great plane and also a highly sensitive thermopile to record any effect of solar radiation on the liquid oxygen. A wire led from the instrument to a thermograph in the laboratory. This would show Tom what was taking place up above.

At eighteen miles above the earth Tom asked Bud to hold the plane stationary.

"Why here?" the copilot asked.

"Well, the short-wave-length radiation we are looking for doesn't reach the ground. It's filtered out by the atmosphere between twelve and twenty miles above the earth. We wont' get all of it here at this altitude, but enough to predict how well the kicker will work."

"Tom, when will that there kicker cut in?" he began.

"It's set to go into action at an altitude of forty-one miles," Tom replied.

"Forty-one!" Chow exclaimed. "Brand my nightmares, why do you wait so long?"

"Well, below forty-one miles there just isn't enough sunshine, Chow."

"Tell me, Tom, have you given it a name yet?"

Tom smiled ruefully. "No. I have a harder job naming some of these things than I do figuring them out. Have you any ideas?"

"How about calling it the Spacelane Brain?" Arvid Hanson suggested.

"This navigational equipment is designed only for the rather short distances that we expect to travel at first. When we really get out into space we'll depend more on the radius indicator."

"How does this invention differ from the ordinary aneroid altimeter that we use now?" Hank Sterling asked.

"An altimeter which depends on measuring atmospheric pressure won't work at very low air pressures," Tom replied. "This instrument picks up the noisy cosmic rays from the sun. The nearer the sun, the noisier the waves."

"How accurate is it?" Hanson asked.

"Within a few feet," Tom replied. "Frankly, this part of the instrument is not my own brain child. The idea has been kicking around for some time."

"You dreamed up the navigation part of it?" bud asked.

"Yes," Tom answered. "I took the principle of solar radiation and applied it to the stars. This instrument in the black case picks up the waves from three stars and the rocket's position is recorded on the dial--instantly."

"Let's see it work," Hank Sterling urged.

Tom flicked the toggle switch. A whirring sound began and the needle on the dial moved instantly to seventy-eight thousand feet. Another switch was snapped and five dots appeared on the upper dial.

"The black one at the bottom is the earth," Tom explained. "The three red ones are stars."

"The small one must be the fix--the position," Hanson said.

"That's it," Tom replied. "The point of intersection of the lines from the three stars."

"How do you know which stars are showing on your screen?"

"Each first-magnitude star sends its own distinct sound," Tom explained. "Listen."

Three slightly different beeps were coming from the instrument. From a chart Tom identified them as Deneb, Vega, and Altair.

"The greatest feature of this whole thing," Tom continued, "is that the instrument can be built into the automatic pilot."

"You mean," Hanson exclaimed enthusiastically, "that it makes navigation and steering a single operation?"

"That's right," Tom replied.

"Amazing," Hank Sterling commented. "And it certainly appears to be in perfect working order."

"I'm going up now in the Sky Queen to test the new dual-duty cosmic-ray altimeter and stellar sextant," Tom told his friends. "I'll have a distorter rigged up on top of the Flying Lab before it takes off."