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took aboard the 200-ton landing boat. By the time they got itsecured, the radio already was sounding warnings for blastoff.

  Zero hour arrived. Again Jonner pulled levers and again the faint glowappeared around the tail of their distant tug. Across space the exhaustof the _Marsward XVIII_ flared into blinding flame. In a moment, itbegan to pull ahead visibly and soon was receding like a meteor.

  Near the _Radiant Hope_, the space station seemed not to have changedposition at all.

  "The race is not always to the swift," remarked Jonner philosophically.

  "And we're the tortoise," said T'an. "How about filling us in on thisjaunt, Jonner?"

  "Is should, Jonner," agreed Qoqol. "T'an know all about crazy newengine, I know all about crazy new orbit. Both not know all. You tell."

  "I planned to, anyway," said Jonner. "I had figured on having Serj in onit, but he wouldn't understand much of it anyhow. There's no use inwaking him up."

  Serj was the ship's doctor-psychologist and fourth member of the crew.He was asleep below on the centerdeck.

  "For your information, Qoqol," said Jonner, "the atomic engine produceselectrical energy, which accelerates reaction mass. Actually, it's acrude ion engine. T'an can explain the details to you later, but theimportant thing is that the fuel is cheap, the fuel-to-cargo ratio islow and constant acceleration is practical.

  "As for you, Tan, I was surprised at your not understanding why we'lluse low acceleration. To boost the engine power and give us more Gs,we'd either have to carry more fuel or coast part of the way onmomentum, like an ordinary rocket. This way's more efficient, and our63-day margin over the _Marsward_ each way is more than enough forunloading and loading more cargo and fuel."

  "With those figures, I can't see how Marscorp expects to win thiscompetition," said T'an.

  "We've got them, flat, on the basis of performance," agreed Jonner. "Sowe'll have to watch for tricks. I know Marscorp. That's why I arrangedto take aboard that G-boat at the last minute. Marscorp controls all theG-boats at Marsport, and they're smart enough to keep us from usingthem, in spite of the Space Control Commission. As for refueling for thereturn trip, we can knock a chunk off of Phobos for reaction mass."

  The meteor alarm bells clanged suddenly, and the screen lit up once witha fast-moving red line that traced the path of the approaching object.

  "Miss us about half a mile," said Jonner after a glance at the screen."Must be pretty big ... and it's coming _up_!"

  He and T'an floated to one of the ports, and in a few moments saw theobject speed by.

  "That's no meteor!" exclaimed Jonner with a puzzled frown. "That'sman-made. But it's too small for a G-boat."

  The radio blared: "All craft in orbit near Space Station 2! Warning! Allcraft near Space Station 2! Experimental missile misfired from WhiteSands! Repeat: experimental missile misfired from White Sands!Coordinates...."

  "Fine time to tell us," remarked T'an drily.

  "Experimental missile, hell!" snorted Jonner, comprehension dawning."Qoqol, what would have happened if we hadn't shifted orbit to takeaboard that G-boat?"

  Qoqol calculated a moment.

  "Hit our engines," he announced. "Dead center."

  Jonner's blue eyes clouded ominously. "Looks like they're playing forkeeps this time, boys."

  * * * * *

  The brotherhood of spacemen is an exclusive club. Any captain,astrogator or engineer is likely to be well known to his colleagues,either personally or by reputation.

  The ship's doctor-psychologist is in a different category. Most of themsign on for a few runs for the adventure of it, as a means of gettingback and forth between planets without paying the high cost of passageor to pick up even more money than they can get from lucrativeplanetbound practice.

  Jonner did not know Serj, the _Radiant Hope_'s doctor. Neither T'an norQoqol ever had heard of him. But Serj appeared to know his business wellenough, and was friendly enough.

  It was Serj's first trip and he was very interested in the way the shipoperated. He nosed into every corner of it and asked a hundred questionsa day.

  "You're as inquisitive as a cadet spaceman, Serj," Jonner told him onthe twenty-fifth day out. Everybody knew everyone else well by then,which meant that Jonner and Qoqol, who had served together before, hadbecome acquainted with T'an and Serj.

  "There's a lot to see and learn about space, Captain," said Serj. He wasa young fellow, with fair hair and an easy grin. "Think I could gooutside?"

  "If you keep a lifeline hooked on. The suits have magnetic shoes to holdyou to the hull of the ship, but you can lose your footing."

  "Thanks," said Serj. He touched his hand to his forehead and left thecontrol deck.

  Jonner, near the end of his eight-hour duty shift, watched the dials.

  The red light showing the inner airlock door was open blinked on. Itblinked off, then the outer airlock indicator went on, and off.

  A shadow fell across Jonner briefly. He glanced at the port and reachedfor the microphone.

  "Careful and don't step on any of the ports," he warned Serj. "Themagnetic soles won't hold on them."

  "I'll be careful, sir," answered Serj.

  No one but a veteran spaceman would have noticed the faint quiver thatran through the ship, but Jonner felt it. Automatically, he swung hiscontrol chair and his eyes swept the bank of dials.

  At first he saw nothing. The outer lock light blinked on and off, thenthe inner lock indicator. That was Serj coming back inside.

  Then Jonner noted that the hand on one dial rested on zero. Above thedial was the word: "ACCELERATION."

  His eyes snapped to the radio controls. The atomic pile levers werestill at their proper calibration. The dials above them said the engineswere working properly.

  The atomic tug was still accelerating, but passengers and cargo were infree fall.

  Swearing Jonner jerked at the levers to pull out the piles aboard thetug.

  A blue flash flared across the control board, momentarily blinding him.Jonner recoiled, only his webbed safety belt preventing him fromplummeting from the control chair.

  He swung back anxiously to the dials, brushing futilely at the spotsthat swam before his eyes. He breathed a sigh of relief. The radiocontrols had operated. The atomic engines had ceased firing.

  Tentatively, cautiously, he reversed the lever. There was no blue flashthis time, but neither did the dials quiver. He swore. Something hadburned out in the radio controls. He couldn't reverse the tug.

  He punched the general alarm button viciously, and the raucous clangorof the bell sounded through the confines of the ship. One by one, theother crew members popped up to the control deck from below.

  He turned the controls over to Qoqol.

  "Take readings on that damn tug," Jonner ordered. "I think our cablebroke. T'an, let's go take a look."

  When they got outside, they found about a foot of the one-inch cablestill attached to the ship. The rest of it, drawn away by the tug beforeJonner could cut acceleration, was out of sight.

  "Can it be welded, T'an?"

  "It can, but it'll take a while," replied the engineer slowly. "First,we'll have to reverse that tug and get the other end of that break."

  "Damn, and the radio control's burned out. I tried to reverse it beforeI sounded the alarm. T'an, how fast can you get those controlsrepaired?"

  "Great space!" exclaimed T'an softly. "Without seeing it, I'd say atleast two days, Jonner. Those controls are complicated as hell."

  They re-entered the ship. Qoqol was working at his diagrams, and Serjwas looking over his shoulder. Jonner took a heat-gun quietly from therack and pointed it at Serj.

  "You'll get below, mister," he commanded grimly. "You'll be handcuffedto your bunk from here on out."

  "Sir?... I don't understand," stammered Serj.

  "Like hell you don't. You cut that cable," Jonner accused.

  Serj started to shrug, but he dropped his eyes.

  "They paid me," he said in a
low tone. "They paid me a thousand solars."

  "What good would a thousand solars do you when you're dead, Serj ...dead of suffocation and drifting forever in space?"

  Serj looked up in astonishment.

  "Why, you can still reach Earth by radio, easy," he said. "It wouldn'ttake long for a rescue ship to reach us."

  "Chemical rockets have their limitations," said Jonner coldly.

  "And you don't realize what speed we've built up with steadyacceleration. We'd head straight out of the system, and nothing