Bud gave a whoop of excitement and everyone crowded around the radarscope. Tom's steel-blue eyes checked the blip. Then he threw a switch which started an automatic plotting machine that had been prepared with the landing plan, and noted that the missile was slightly off the correct path. A new flow of information now began pulsing in as other ships' tracking radars recorded its course. The data was being fed automatically to the "capture" computer. This would analyze the correct flight path for the recovery missile, which would magnetically seize the returning traveler from Jupiter and bring it safely home. Tom quickly read off the results from the computer's dials, then busied himself again with the retarding-rocket controls. "Everything going okay, skipper?" Bud asked. Tom nodded. "I've readjusted the retarding rockets. They'll fire at the proper intervals to slow down the missile still further and bring it back on beam." The excited buzz of voices in the compartment gradually quieted as the clock ticked steadily toward the next step in the recovery operation. "Stand by for missile firing!" Tom snapped. A seaman relayed the order over the ship's intercom. Tense silence fell as Tom's eyes followed the sweep of the second hand. "All clear for blast-off!" came the talker's report. Tom pressed the firing button. A split second later the listeners' eardrums throbbed to a muffled roar from topside as the slender recovery missile shot skyward. The ship rocked convulsively from the shock of blast-off. Then it steadied again as the gyros damped out the vibrations. "Wow!" Bud heaved a sigh of relieved tension. Then he dashed from the compartment and up the nearest ladder for a quick look at the rocket as it disappeared into the blue. Tom watched the recovery missile intently on the radarscope. "Nice going, son," said Mr. Swift quietly. In response to his father's reassuring grip on his arm, Tom flashed him a hasty smile. For the first time, the young inventor realized he was beaded with perspiration and that his pulse was hammering. "It's a case of wait and hope," Tom murmured. [Illustration] On every ship and plane in the task force, eyes were glued to the radar screens. Two small blips were visible--one the Jupiter probe missile, the other the recovery missile--moving on courses that would soon intersect. Just as Bud returned to the compartment, several of the watchers gave startled gasps. "Another blip--coming in from nine o'clock!" Admiral Walter exclaimed. "What's that?" Tom stared at the new blip. It was moving steadily toward the meeting point of the first two missiles! "It's a thief missile!" Tom cried out. "Some enemy's trying to steal our probe data!" "Good night!" Bud gulped. "Who'd dare try that?" "I don't know," Tom muttered tensely. "But if those three missiles meet, our whole project will be wrecked!" "Better tape all readings!" Mr. Swift advised. "Right, Dad!"