Tom glanced at the astral chronometer over the control board of the _Polaris_ and sighed with relief. It was nine P.M. He turned to the intercom.
"Attention, please! Attention, please! The exhibit is now closing for the night. All visitors will kindly leave the ship immediately." He repeated the announcement again and turned to smile at the last lingering youngster ogling him before being yanked toward an exit by a tired and impatient mother.
The hatch to the radar bridge opened and Roger climbed down the ladder to flop wearily in the pilot"s seat in front of the control panel.
"If one more scatterbrained female asks me how the astrogation prism works," groaned the blond cadet, "I"ll give it to her and let her figure it out for herself!"
Astro joined them long enough to announce that he had made sandwiches and brewed hot chocolate. Tom and Roger followed him back to the galley.
Sipping the hot liquid, the three cadets looked at each other without speaking, each understanding what the other had been through. Even Astro, who normally would rather talk about his atomic engine than eat, confessed he was tired of explaining the functions of the reaction fuel force feed and the main valve of the cooling pumps.
"The worst of it is," sighed Astro, "they all pick on the same valve.
What"s so fascinating about one valve?"
Tom"s job on the control deck was less tiring, since his was more of a command post, which demanded decisions, as conditions arose, rather than a fixed routine that could be explained. But even so, to be asked over and over what the astral chronometer was, how he could read time on Earth, Mars, Venus, t.i.tan, Ganymede, and all the satellites at the same time was wearing on the toughest of young spirits.
Eager to forget the grueling day of questions and answers, the cadets turned their thoughts to the mysterious midnight activity that had been taking place around the s.p.a.ceship concession during the last ten days.
"I just can"t figure out what those guys are up to," said Roger, blowing on his hot chocolate. "We"ve watched those guys for over a week now and no one has even come near them with anything that could be smuggled."
"Could be a small package," suggested Astro, his mouth full of ham sandwich. "Somebody could take a ride and slip it to them."
"Hardly," said Tom. "Remember, that ship blasts off like she"s loaded to the nose with cargo. And then she comes back like a feather. You can tell by the sound of her jets. So it wouldn"t be anything small enough for someone to carry."
"Yeah, I guess you"re right," agreed Astro.
"Well," said Tom finally, "I"m stumped. I think the only thing left to do is to decide if it"s anything important enough to tell Captain Strong about. Working on the _Polaris_ twelve hours a day and staying up all night to watch those two jokers has me all in."
Roger and Astro looked at each other and then silently nodded their agreement.
"O.K.," said Tom, "we"ll go to the skipper"s hotel in Venusport and tell him the whole thing. Let"s see what he makes of it."
At that moment Captain Strong was in the office of Exposition Commissioner Mike Hawks trying to make sense out of a series of reports that had landed on the commissioner"s desk. Hawks watched him carefully as he studied the papers.
"You say this is the ninth report you"ve received since the fair opened, Mike?" asked Strong finally.
Hawks nodded. He hadn"t known whether to laugh off or seriously consider the nine s.p.a.ce skippers" reports that the sky over the exposition site was dirty.
"Yes, Steve," he said. "That one came from the skipper of an express freighter. He blasted off this morning and ran through this so-called dirt. He thought it was just a freak of nature but reported it to be on the safe side."
"I don"t suppose he took a sample of the stuff?"
"No. But I"m taking care of that," replied Hawks. "There"s a rocket scout standing by right now. Want to come along?"
"Let me finish these reports first."
"Sure thing."
As Strong carefully checked each report, Commissioner Hawks rose and began to stride restlessly back and forth across the s.p.a.cious office. He stopped in front of the window and stared out over the exposition grounds, watching the thousands of holiday visitors streaming in and out of the buildings, all unaware of the strange mystery in the sky above them. Hawks" attention was drawn to the giant solar beacon, a huge light that flashed straight out into s.p.a.ce, changing color every second and sending out the message: "Quis separabit h.o.m.o"--Who shall separate mankind?
This beacon that at the beginning of the exposition had reached into the black void of s.p.a.ce like a clean bright ray was now cloudy and murky--the result of the puzzling "dirty sky."
"All right, Mike," Strong announced suddenly. "Let"s go."
"Get anything more out of those reports?" asked Hawks, turning back to his desk.
"No," replied the Solar Guard officer. "They all tell the same story.
Right after blast-off, the ships ran into a dirty sky."
"Sounds kind of crazy, doesn"t it?"
"Crazy enough to check."
Hawks pressed a b.u.t.ton on the desk intercom.
"Yes, sir?" replied a metallic voice.
"Have the rocket scout ready for flight in five minutes," Hawks ordered.
He snapped off the intercom without waiting for a reply and turned to Strong. "Let"s go, Steve."
The two veteran s.p.a.cemen left the office without further comment and rode down in the vacuum elevator to the highway level. Soon they were speeding out to the s.p.a.ceport in Hawks" special jet car.
At the blast-pitted field they were met by a young Solar Guard officer and an elderly man carrying a leather case, who were introduced as Lieutenant Claude and Professor Newton.
While Claude prepared the rocket scout for blast-off, Strong, Hawks, and Newton discussed the possibility of lava dust having risen to great heights from another side of the planet.
"While I"m reasonably sure," stated Newton, "that no volcano has erupted recently here on Venus, I can"t be sure until I"ve examined samples of this so-called dirt."
"I"ll have Lieutenant Claude contact the University of Venus," said Hawks. "Their seismographs would pick up surface activity."
Claude stuck his head out of the hatch and reported the ship ready for blast-off. Strong followed the professor and Hawks aboard and strapped himself into an acceleration chair. In a moment they were blasting through the misty atmosphere of Venus into the depths of s.p.a.ce.
Fifteen minutes later, Hawks and Strong were standing on the hull of the ship in s.p.a.ce suits, watching the professor take a sample of a dirty black cloud, so thick it was impossible to see more than three feet.
Strong called to the professor through the s.p.a.cephone.
"What do you make of it, sir?" he asked.
"I wouldn"t want to give you a positive opinion without chemical tests,"
answered the professor, his voice echoing in Strong"s fish-bowl helmet.
"But I believe it"s one of three things. One, the remains of a large asteroid that has broken up. Two, volcanic ash, either from Venus or from Jupiter. But if it came from Jupiter, I don"t see how it could have drifted this far without being detected on radar."
Now, holding a flask full of the black cloud, the professor started back to the air lock.
"You said three possibilities, professor," said Strong.