CHAPTER 5

  The great educational exhibits had long been closed and only a fewsections of the amusement park of the big exposition remained open. Thegiant solar beacon, its brilliant colors changing every second,maintained a solemn solitary watch over the exhibition buildings, whilehere and there groups of fair visitors wandered wearily back to theirhotels.

  There was a sudden flurry of activity at the space-ride concession. GusWallace and Luther Simms tumbled out of the shack and raced into theirship. Once inside the ancient craft, they secured the hatch and turnedtoward each other smiling broadly. Wallace stuck out his hand.

  "Put 'er there, Simms. We did it!"

  The two men shook hands heartily.

  "By the craters of Luna," said Simms, "I thought we'd never make it! Andif we did, that it wouldn't be there!"

  "But it was, Simms! It was! And now we've got it!"

  "Yeah," agreed the other. "I never worked so hard in all my life. Butit's worth it. Are we going to set the Solar Guard back on its ear!"

  Wallace laughed. "Not only that, but think of what the boss will saywhen we show up with it!"

  "You know, Wallace," said Simms, a sly look on his face, "we could takeit and use it ourselves--"

  "Don't even think a thing like that!" snapped Wallace.

  "Oh, of course not," said Simms hurriedly. "It doesn't pay to cross theboss. There's enough here for all of us."

  "You know," mused Wallace, "there's only one thing I regret."

  "What's that?" asked his partner.

  "That I didn't get a chance to kick the space dust out of that punk,Cadet Manning!"

  "Forget him," said Simms, waving his hand. "You'll meet him againsomeday. Besides, why think about him, when you've got the wholeuniverse at your finger tips?"

  "You're right. But someday I'm going to catch him and tear him apart!"snarled Wallace. "Come on. We've got to change over to atomic drive onthis baby. I don't want to hang around here any longer than I have to."

  "Yeah," said Simms. "Be pretty stupid if we're caught now!"

  The two men climbed down into the power deck and began the job ofrefitting the freighter from chemical to atomic drive. Having alreadyoutfitted the vessel with atomic engines, it was a simple matter tochange the exhaust, reset the feed lines, and emplace the protectivelead baffles. In an hour the two spacemen were ready to blast off.

  "There she is," said Simms, standing back to survey their work. "As fastas anything in space, except the Solar Guard cruisers on hyperdrive."

  "O.K.," said Wallace. "Let's get out of here!"

  Minutes later, in a jet car speeding along the main highway toward theexposition grounds, Captain Strong, Mike Hawks, and the three cadets ofthe _Polaris_ saw a rocket ship blast off. They watched it disappearinto the dark space above.

  "That might be they," said Strong to Hawks. "I'd better alert the patrolship near the space station and tell them to pick them up."

  "That couldn't be Wallace and Simms, sir," said Astro.

  "How do you know, Astro?" asked Strong.

  "That was an atomic-powered ship. The wagon Wallace and Simms have is achemical job. I know the sound of her jets almost as well as I do the_Polaris_."

  Hawks looked at Strong.

  "You can depend on Astro's opinion, Mike," said Strong. "He was bornwith a rocket wrench in his hand and cut his teeth on a reactor valve."

  They soon reached the outskirts of the exposition grounds and wereforced to slow down as they wound their way through the darkenedstreets. In the amusement section, the last of the whirlaway rides andgames of chance had closed down and only the occasional roar of a cagedanimal in the interplanetary zoo disturbed the night.

  Hawks drove the low, sleek jet car around the fair, taking a short cutthrough the outdoor mercuryball field and pulled up in front of the_Polaris_.

  The five spacemen turned toward the concession site across the promenadeand stopped, aghast.

  "Gone!" exclaimed Strong. "Astro, you made a mistake! It was their shipwe saw blasting off. It's too late to warn the space-station patrol.Wallace and Simms could be anywhere in space now!"

  "But, sir," protested Astro, "I'm certain that an atomic-powered shipblasted off. And their old freighter was a chemical burner!"

  "Well," said Hawks resignedly, "they're not here."

  "Come on," said Strong, getting out of the jet car. "Let's take a lookaround."

  Strong and Hawks hurried across the street to the empty lot and thethree cadets followed.

  "Take it easy, Astro," said Tom, when he saw the big Venusian grippinghis fists in frustration. "Anyone could make a mistake."

  "That's just it," said Astro. "I'm not mistaken! Those jokers must havechanged over from chemical fuel to reactant drive!"

  "But why?" asked Roger. "That would cost more than they could make inten years of hauling passengers on joy rides!"

  Astro whirled around and faced the two cadets. "I'm telling you the shipthat blasted off from here was an atomic drive. I don't know any morethan that, but I _do_ know that!"

  There was a sudden shout from Strong and the three boys hurried to theshack. The Solar Guard captain and the exposition commissioner werestanding inside and playing the beam of an electric torch around thewalls.

  "Looks as though you were right about the atomic drive, Astro," saidStrong. He flashed the light into one corner where a tangled jumble oflines lay on the floor. "That's feed-line gear for a chemical burner,and over there"--he played the light on some empty cartons--"is what'sleft of the crate's lead baffling it shipped in. They must have changedover to atomic drive recently."

  Astro accepted the statement with a nod. It wasn't in the nature of thebig cadet to boast. Now that the secret of the ship had been resolved,he turned, like the others, to the question of why?

  "I think the best thing we can do," said Strong, "is to spread out andsearch the whole area. Might find something to indicate where theywent." Commissioner Hawks nodded his head in agreement.

  While Tom, Roger, and Astro searched outside, Strong and Hawks wentthrough the drawers of the dusty desk standing in one corner.

  "Nothing here but a record of the flights they made, bills for chemicalfuel delivered, and the like," said Hawks at last. "They were losingmoney on the operation, too. Think they might have just gotten fed upand pulled out?"

  Strong was rummaging around in one corner of the shack. "I'd go alongwith that, but for one thing, Mike," he said. "Take a look at this." Heheld up a small cloth bag. "There's dirt in the bottom of this bag. Andthere are about fifty more bags in that corner."

  "Dirt!" exclaimed the commissioner.

  "Yep," said Strong grimly. "So we found out who was dumping the dirt.But we still haven't found out why."

  "Or where it came from," said Hawks.

  Strong tossed the bag into the corner. "Well, I guess I'd better make areport to Commander Walters."

  Hawks moved to the corner where the pile of chemical feed-line equipmentlay on the floor. "Want to take a look at this stuff? Might be somethingimportant in it."

  Strong thought a moment. "We can have the cadets do that. I want to getthis report off to Walters right away, and issue an order to pick upWallace and Simms."

  "On what charges, Steve?" asked the commissioner. "I mean, what's wrongwith what they've done?" The commissioner's question was based on one ofthe cardinal rules among all Solar Guard officers of authority. "Has theman committed any crime?"

  Steve realized this and answered slowly. "They've changed over toreactor drive without a license or permission. That's a violation of thespace code, section twenty-one, paragraph A. That is punishable by asuspension of space papers, and if the intention proved to be willfulneglect of the code, a year on a penal asteroid. I think we can get themon that."

  The captain stepped to the door and called the cadets.

  "Find anything?" he asked, when they entered the shack.

  "Nothing, sir," replied Tom. "Except more evidence that they changedover
to atomic drive."

  "That's enough" said Strong. "I'm going to send a report to CommanderWalters. Is the teleceiver on the _Polaris_ hooked up, Roger?"

  "Yes, sir," replied Roger. "But Astro will have to start up theauxiliary generators to give you power."

  "Very well, then," said Strong. "Corbett, you give Astro a hand on thepower deck. And while we're gone, Manning, you go through that feed-linejunk there in the corner and see if there's anything important in it!"

  "Aye, aye, sir," replied Roger.

  Strong and Hawks, followed by Tom and Astro, left the shack and hurriedto the _Polaris_.

  On the power deck, Tom and Astro made the necessary connections on thegenerator, and in a few minutes, as power surged through the ship,Strong flipped on the teleceiver.

  "Attention! Attention! This is Captain Strong on the _Polaris_ callingCommander Walters at Space Academy! Earth emergency circuit, priorityB--"

  In a few moments the Solar Guard officer's call had been picked up by amonitor station on Earth and relayed directly to Space Academy.Commander Walters was roused out of bed, and when he appeared on theteleceiver screen, Strong saw he was still in sleeping dress.

  "Sorry to disturb you, sir," said Strong, "but something has come uphere at the exposition that needs your immediate attention."

  "That's quite all right, Steve," said the commander with a smile. "Whatis it? Manning get into more trouble?"

  "No, sir," answered Strong grimly. "I wish it were as simple as that."He quickly related the details of the strange dirt cloud and hissuspicions of Wallace and Simms. Walters' expression grew serious.

  "I'll get out an emergency bulletin on them at once, Steve. Meantime,you have full authority to head an investigation. Use any service youneed. I'll confirm my verbal order with official orders at once. Get onthis thing, Steve. It sounds serious."

  "I will, sir, and thanks!" said Strong.

  "End transmission!"

  "End transmission," returned Strong, flipping off the teleceiver andturning to the ship's intercom. "Attention, power deck! Corbett, you andAstro go back to the shack and give Roger a hand. I'm going to work withthe commissioner here setting up search operations."

  "Aye, aye, sir," replied Tom from the power deck.

  The two cadets hurriedly closed the power units and left the ship.

  "Did you hear what Captain Strong said, Astro?" asked Tom. "Searchoperations."

  "I wonder what's up," the big Venusian remarked. "They don't set upsearch operations unless it's awfully serious!"

  "Come on," urged Tom. "Maybe Roger's found something."

  They entered the shack together and Tom called out, "Say, Roger, CaptainStrong just spoke to Commander Walters at the Academy and--"

  The curly-haired cadet stopped short. "Astro, look!"

  "By the rings of Saturn!" exclaimed the big cadet.

  The two cadets stood gaping at a huge hole in the middle of the room.The wooden floor was splintered around the edges of the opening andseveral pieces of the chemical feed-line equipment lay close to theedge, with trailing lines leading down into the hole. They heard a lowmoan and rushed up to the hole, flashing their lights down into it.

  "Great galaxy!" yelled Tom. "Astro, look! It's a shaft! It must be athousand feet deep!"

  "And look!" bellowed Astro. "There's Roger! See him? He's hanging there!His foot's caught in that feed-line cable!"

  The big cadet leaned over the hole and shouted, "Roger! Roger! Are youall right?"

  There was no answer from the shaft. Nothing but the echo of Astro'svoice.