Space Platform Part 20

Talley, the co-pilot, looked sick. Then he said: "Correction. It's been five pushpots exploded and five pilots killed this week. It's getting a little bit serious." He looked sharply at Joe. "Better drink your coffee before you go look. You won't want to, afterward."

He was right.

Joe saw the crashed pushpot half an hour later. He found that his ostensible a.s.signment to the airfield for the investigation of sabotage was quaintly taken at face value there. A young lieutenant solemnly escorted him to the spot where the pushpot had landed, only ten feet from a hangar wall. The impact had carried parts of the pushpot five feet into the soil, and the splash effect had caved in the hangar wall-footing. There'd been a fire, which had been put out.

The ungainly flying thing was twisted and torn. Entrails of steel tubing were revealed. The plastic c.o.c.kpit cover was shattered. There were only grisly stains where the pilot had been.

The motor had exploded. The jet motor. And jet motors do not explode.

But this one had. It had burst from within, and the turbine vanes of the compressor section were revealed, twisted intolerably where the barrel of the motor was ripped away. The jagged edges of the tear testified to the violence of the internal explosion.

Joe looked wise and felt ill. The young lieutenant very politely looked away as Joe's face showed how he felt. But of course there were the orders that said he was a sabotage expert. And Joe felt angrily that he was sailing under false colors. He didn't know anything about sabotage.

He believed that he was probably the least qualified of anybody that security had ever empowered to look into methods of destruction.

Yet, in a sense, that very fact was an advantage. A man may be set to work to contrive methods of sabotage. Another man may be trained to counter him. The training of the second man is essentially a study of how the first man's mind works. Then it can be guessed what this saboteur will think and do. But such a trained security man will often be badly handicapped if he comes upon the sabotage methods of a second man--an entirely different saboteur who thinks in a new fashion. The security man may be hampered in dealing with the second man's sabotage just because he knows too much about the thinking of the first.

Joe went off and scowled at a wall, while the young lieutenant waited hopefully nearby.

He was in a false position. But he could see that there was something odd here. There was a sort of pattern in the way the other sabotage incidents had been planned. It was hard to pick out, but it was there.

Joe thought of the trick of b.o.o.by-trapping a plane during its major overhaul, and then arming the traps at a later date.... A private plane had been fitted to deliver proximity rockets in mid-air when the transport ship flew past. There was the explosion of the cargo parcel which was supposed to contain requisition forms and stationery. And the attempt to smash the entire Platform by getting an atomic bomb into a plane and having a saboteur shoot the crew and then deliver the bomb at the Shed in an officially harmless aircraft....

The common element in all those sabotage tricks was actually clear enough, but Joe wasn't used to thinking in such terms. He did know, though, that there was a pattern in those devices which did not exist in the blowing up of jet motors from inside.

He scowled and scowled, racking his brains, while the young lieutenant watched respectfully, waiting for Joe to have an inspiration. Had Joe known it, the lieutenant was deeply impressed by his attempt at concentration on the problem it had not been Major Holt's intention for Joe to consider. When Joe temporarily gave up, the young lieutenant eagerly showed him over the whole field and all its workings.

In mid-morning another pushpot fell screaming from the skies. That made six pushpots and six pilots for this week--two today. The things had no wings. They had no gliding angle. Pointed up, they could climb unbelievably. While their engines functioned, they could be controlled after a fashion. But they were not aircraft in any ordinary meaning of the word. They were engines with fuel tanks and controls in their exhaust blast. When their engines failed, they were so much junk falling out of the sky.

Joe happened to see the second crash, and he didn't go to noon mess at all. He hadn't any appet.i.te. Instead, he gloomily let himself be packed full of irrelevant information by the young lieutenant who considered that since Joe had been sent by security to look into sabotage, he must be given every possible opportunity to evaluate--that would be the word the young lieutenant would use--the situation.

But all the time that Joe followed him about, his mind fumbled with a hunch. The idea was that there was a pattern of thinking in sabotage, and if you could solve it, you could outguess the saboteur. But the trouble was to figure out the similarity he felt existed in--say--a private plane shooting rockets and overhaul mechanics planting b.o.o.by traps and faked shippers getting bombs on planes--and come to think of it, there was Braun....

Braun was the key! Braun had been an honest man, with an honest loyalty to the United States which had given him refuge. But he had been blackmailed into accepting a container of atomic death to be released in the Shed. Radioactive cobalt did not belong in the Shed. That was the key to the pattern of sabotage. Braun was not to use any natural thing that belonged in the Shed. He was to be only the means by which something extraneous and deadly was to have been introduced.

That was it! Somebody was devising ingenious ways to get well-known destructive devices into places where they did not belong, but where they would be effective. Rockets. Bombs. Even radioactive cobalt dust.

All were perfectly well-known means of destruction. The minds that planned those tricks said, in effect: "These things will destroy. How can we get them to where they will destroy something?" It was a strict pattern.

But the pushpot sabotage--and Joe was sure it was nothing else--was not that sort of thing. Making motors explode.... Motors don't explode. One couldn't put bombs in them. There wasn't room. The explosions Joe had seen looked as if they'd centered in the fire basket--technically the combustion area--behind the compressor and before the drive vanes. A jet motor whirled. Its front vanes compressed air, and a flame burned furiously in the compressed air, which swelled enormously and poured out past other vanes that took power from it to drive the compressor. The excess of blast poured out astern in a blue-white flame, driving the ship.

But one couldn't put a bomb in a fire basket. The temperature would melt anything but the refractory alloys of which a jet motor has to be built.

A bomb placed there would explode the instant a motor was started. It couldn't resist until the pushpot took off. It couldn't....

This was a different kind of sabotage. There was a different mind at work.

In the afternoon Joe watched the landings, while the young lieutenant followed him patiently about. A pushpot landing was quite unlike the landing of any other air-borne thing. It came flying down with incredible clumsiness, making an uproar out of all proportion to its landing speed. Pushpots came in with their tail ends low, crudely and cruelly clumsy in their handling. They had no wings or fins. They had to be balanced by their jet blasts. They had to be steered the same way.

When a jet motor conked out there was no control. The pushpot fell.

He carefully watched one landing now. It came down low, and swung in toward the field, and seemed to reach its stern down tentatively to slide on the earth, and the flame of its exhaust scorched the field, and it hesitated, pointing up at an ever steeper angle--and it touched and its nose tilted forward--and leaped up as the jet roared more loudly, and then touched again....

The goal was for pushpots to touch ground finally with the whole weight of the flying monstrosity supported by the vertical thrust of the jet, and while it was moving forward at the lowest possible rate of speed.

When that goal was achieved, they flopped solidly flat, slid a few feet on their metal bellies, and lay still. Some hit hard and tried to dig into the earth with their blunt noses. Joe finally saw one touch with no forward speed at all. It seemed to try to settle down vertically, as a rocket takes off. That one fell over backward and wallowed with its belly plates in the air before it rolled over on its side and rocked there.

The last of a flight touched down and flopped, and the memory of the wreckage had been overlaid by these other sights and Joe could think of his next meal without aversion. When it was evening-mess time he went doggedly back to the mess hall. There was a sort of itchy feeling in his mind. He knew something he didn't know he knew. There was something in his memory that he couldn't recall.

Talley and Walton were again at mess. Joe went to their table. Talley looked at him inquiringly.

"Yes, I saw both crashes," said Joe gloomily, "and I didn't want any lunch. It was sabotage, though. Only it was different in kind--it was different in principle--from the other tricks. But I can't figure out what it is!"

"Mmmmmm," said Talley, amiably. "You'd learn something if you could talk to the Resistance fighters and saboteurs in Europe. The Poles were wonderful at it! They had one chap who could get at the tank cars that took aviation gasoline from the refinery to the various n.a.z.i airfields.

He used to dump some chemical compound--just a tiny bit--into each carload of gas. It looked all right, smelled all right, and worked all right. But at odd moments. .h.i.tler's planes would crash. The valves would stick and the engine'd conk out."

Joe stared at him. And it was just as simple as that. He saw.

"The n.a.z.is lost a lot of planes that way," said Talley. "Those that didn't crash from stuck valves in flight--they had to have their valves reground. Lost flying time. Wonderful! And when the n.a.z.is did uncover the trick, they had to re-refine every drop of aviation gas they had!"

Joe said: "That's it!"

"That's it? And _it_ is what?"

Then Joe said disgustedly: "Surely! It's the trick of loading CO_2 bottles with explosive gas, too! Excuse me!"

He got up from the table and hurried out. He found a phone booth and got the Shed, and then the security office, and at long last Major Holt. The Major's tone was curt.

"Yes?... Joe?... The three men from the affair of the lake were tracked this morning. When they were cornered they tried to fight. I am afraid we'll get no information from them, if that's what you wanted to know."

The Major's manner seemed to disapprove of Joe as expressing curiosity.

His words meant, of course, that the three would-be murderers had been fatally shot.

Joe said carefully: "That wasn't what I called about, sir. I think I've found out something about the pushpots. How they're made to crash. But my hunch needs to be checked."

The Major said briefly: "Tell me."

Joe said: "All the tricks but one, that were used on the plane I came on, were the same kind of trick. They were all arrangements for getting regular destructive items--bombs or rockets or whatever--where they could explode and smash things. The saboteurs were adding destructive items to various states of things. But there was one trick that was different."

"Yes?" said the Major, on the telephone.

"Putting explosive gas in the CO_2 bottles," said Joe painstakingly, "wasn't adding a new gadget to a situation. It was changing something that was already there. The saboteurs took something that belonged in a plane and changed it. They did not put something new into a plane--or a situation--that didn't belong there. It was a special kind of thinking.

You see, sir?"

The Major, to do him justice, had the gift of listening. He waited.

"The pushpots," said Joe, very carefully, "naturally have their fuel stored in different tanks in different places, as airplanes do. The pilots switch on one tank or another just like plane pilots. In the underground storage and fueling pits, where all the fuel for the pushpots is kept in bulk, there are different tanks too. Naturally! At the fuel pump, the attendant can draw on any of those underground tanks he chooses."

The Major said curtly: "Obviously! What of it?"

"The pushpot motors explode," said Joe. "And they shouldn't. No bomb could be gotten into them without going off the instant they started, and they don't blow that way. I make a guess, sir, that one of the underground storage tanks--just one--contains doctored fuel. I'm guessing that as separate tanks in a pushpot are filled up, one by one, _one_ is filled from a particular underground storage tank that contains doctored fuel. The rest will have normal fuel. And the pushpot is going to crash when that tank, and only that tank, is used!"

Major Holt was very silent.

"You see, sir?" said Joe uneasily. "The pushpots could be fueled a hundred times over with perfectly good fuel, and then one tank in one of them would explode when drawn on. There'd be no pattern in the explosions...."