Lussigny sank into a brown study. After a while, he spoke up. "When Professor Ashley gave me the first inkling of Operation Mars and asked me to comment on radio communication for the expedition across this wide, interstellar space, I'll have to admit that I thought the whole thing was just a crazy brainstorm. But since I've seen all this and heard the story, I'm getting awfully keen for it."
"Don't fool yourself, doctor, it's on its way" said Holt. After a glance at his watch, he touched Hansen's shoulder. "It's about time we got started towards the observatory."
"How do you get there?" asked Lussigny. "Is it in a space suit and with a reaction pistol?"
"No indeed," laughed the General. "That's a thing of the past for trips as long as this. Time has brought luxuries. They'll go in one of the busy bees and take off from the rim direct."
"You don't even have to go back to the Central Station?"
"Not a bit of it. The busy bee is a little space boat and it hangs in a bay on the rim, like a bomb. You get into it just as if you were entering any other compartment of Lunetta.
The bee is pressurized by the same system as the whole. You simply close an inner and outer bulkhead door; the pilot pushes a button; and out of the bay you drop by centrifugal force. Once you're away from Lunetta's rim, he starts a little rocket motor and that gives you a push in whatever direction you want to go."
"So far, it's perfectly clear," marveled Lussigny, "but I'd like to know how the bee gets back into its nest in the rim."
"It's not so complicated. Perhaps you noticed that there's a rail running circumferentially around the rim. The bee has a snap hook which is pushed gently against the rail, engaging it in the hook. Since the rim of Lunetta is in rotation, the bee slides along the rail until one of the bays approaches. Shortly before the bay reaches the bee, a wedging action slows up the snap hook in its movement along the rail. This, of course, accelerates the bee in such a manner that its movement is integral with that of the rim at the moment it registers with the opening of the bay. This automatically closes an electric circuit which, by a suitable mechanism, pulls the bee into the bay. At the top of the bay is an automatic hermetic sealing device which connects the interior of the bee with that of Lunetta again. So, only two doors need be opened to get back into the rim of Lunetta."
"What an amazing gadget!" mused Lussigny. "But, General, that sort of thing must eventually slow down Lunetta's rotation."
"Certainly it does. But just imagine how great the effect must be of such things as the landing of something as massive as the Siriusl That not only affects our RPM and our planes of rotation, but it even does things to our orbit around the Earth, to some extent."
"How do you compensate for that?" asked Lussigny.
"We have a couple of swiveling rocket motors on the periphery of Lunetta and a couple more at opposite ends of the Control Station. When our prescribed rate or plane of rotation varies beyond certain limits, or we get somewhat out of orbit, all we have to do is to start these motors for a short time and restore our rates."
"Tell me," said Lussigny, "does the gravitation of the Moon affect Lunetta's orbit deleteriously?"
"Yes indeed; it's a very considerable factor in the corrections we have to make. As you know, the Moon and the Sun produce marked phenomena even on Earth by their gravitational effects — flood and ebb tides for example. They affect our orbit quite unpleasantly, particularly because the Moon circles the Earth in the plane of the ecliptic whereas our orbit is at right angles to that plane."
"It seems to me that these corrections must cost quite a lot of propellants, and you have to freight them up gallon for gallon."
"That's right, Doctor. But it isn't so bad, practically. We just steal a bit of the propellants from the ferry ships. Ships like the Sirius always, or almost always, have a full eight tons more propellants in their tanks than they require for the return trip to Earth.
They all carry it, just in case… Well, we simply tap off the excess and keep up our supply in that way. It's not a complicated procedure. We have permanent hose connections at the mooring cone in the Control Station. The storage tanks are right under the walkways in the rim of Lunetta. All we have to do is to connect up, open a valve, and the propellants flow into the tanks by centrifugal force. The same stuff is used to drive the busy bees.
But I think, gentlemen, it's about time to get moving. How about my taking Dr. Lussigny to our radio station? Later you can have a quiet talk with our meteorologists.
They report weather back to Earth every two hours and can give you much data on interference by weather, night effects and magnetic storms on our radio communications.
Colonel Holt and Professor Hansen might as well go right to the busy bee and take off for the observatory."
The inside of the busy bee was fitted out almost like an automobile. The pilot sat in the left front seat behind a steering wheel, but steering pedals like those of an aircraft replaced the familiar accelerator and clutch.
The controls operated like those of an aircraft in that the bee could be controlled around its longitudinal axis by turning the wheel, while forward and backward movements of the wheel lowered or raised the nose. To the right or left it was directed by the pedals.
These controls were connected to a swiveling rocket motor in the tail, except for those affected by the turning of the steering wheel. That movement displaced a pair of vanes located in the jet exhaust of the motor.
The bee was also provided with another rocket motor in its nose, coupled to the same controls. Both motors were actuated by a single throttle from the center of the instrument panel. Pushing the handle of the throttle forward started the rear motor, while pulling it back from neutral gave thrust to the front one, after stopping the rear. Thus the bee could be accelerated ahead, or retarded at will. Neither motor operated with the throttle in neutral.
There were but two instruments on the panel. One showed acceleration and deceleration. The other was one of the so-called integrators that had for many years been part and parcel of rocketry. It indicated the relative velocity attained by the rocket drive as referred to some predetermined moment at which the integrator had been cut in.
The outside of the busy bee suggested a cylindrical drum, one side of which consisted of dark-tinted glass. Bees were exclusively for operation in space, outside the atmosphere, and hence needed neither streamlining nor stabilizing fins, such as are required by terrestrial rockets. The method of pressurizing the interior was similar to that used in submarines.
Holt and Hansen strapped themselves into the rear seats and the release allowed the bee to be flung out of its bay. The pilot pressed the throttle forward for a short period, after which the familiar weightlessness, which they had no longer felt while within the rim of Lunetta, reestablished itself. They remained in their seats only by reason of their safety belts. Over the pilot's shoulder they could see a tiny, shimmering disk which floated in space a few miles ahead.
"See the observatory?" asked Holt. "It's still about eight miles away according to my guess. We're making about 60 miles an hour with respect to Lunetta and we're approaching the observatory along an ellipsoidal path. If my guess is right, we ought to be there in about eight minutes."
"As an astronomer, I ought to understand that," said Hansen, "but there's a thing about these bee trips that puzzles me. Our additional speed of 60 mph above Lunetta's ought to increase our centrifugal force to keep the forces exactly balanced. On the other hand, the observatory precedes Lunetta exactly in her orbit. So it seems we might pass outside the observatory…"