The Sentinel - Arthur C. Clarke [82]
The World Space Foundation hopes to launch a small solar-sailer, either from the U.S. Shuttle or the European Space Association “Ariane” rocket, in connection with Vancouver’s EXPO ’86. Anyone wishing to support this project can contact the WSF at P.O. Box Y, South Pasadena, Calif. 91030.
There is also an enthusiastic French group (U3P—Union pour la Promotion de la Promotion Photonique, 6 rue des Ramparts Coligny, Venerque 31120, Portet-sur-Garonne) planning a solar race around the Moon, hopefully by 1985–6. (Unmanned, of course—again the ESA Ariane would be used as a launcher.)
And a few months ago I received a fascinating letter from Dr. V. Beletsky, of the Keldysh Institute of Applied Mathematics, Moscow, enclosing his book Essays on the Motions of Space Bodies. One whole chapter is devoted to an analysis of “The Wind From the Sun,” with a detailed integration of the trajectories of “Diana” and “Sunbeam.” To my pleased surprise, Dr. Beletsky wrote: “The data mentioned in your story has proved to be quite sufficient to integrate the differential equations of yacht motions. Integration results almost completely agree with situation in your story!! Have you also integrated the equations of yachts’ motions? If not, why such close agreement of such unobvious details. If yes, why is such important characteristic as the total flight time not in agreement?—2 days in your story and 5 in mine. . . .”
I had to confess that any agreement must have been more luck than integration. Though I had done some back-of-the-envelope calculations to make sure that the velocities and accelerations were not ridiculous, I had certainly not computed the orbit in any detail.
Incidentally, the story’s original title, under which it first appeared in Boy’s Life (March 1964) was the rather obvious “Sunjammer.” However, Poul Anderson had the same idea almost simultaneously, so I had to make a quick change of name. . . .
THE ENORMOUS DISC OF SAIL strained at its rigging, already filled with the wind that blew between the worlds. In three minutes the race would begin, yet now John Merton felt more relaxed, more at peace, than at any time for the past year. Whatever happened when the Commodore gave the starting signal, whether Diana carried him to victory or defeat, he had achieved his ambition. After a lifetime spent designing ships for others, now he would sail his own.
“T minus two minutes,” said the cabin radio. “Please confirm your readiness.”
One by one, the other skippers answered. Merton recognized all the voices—some tense, some calm—for they were the voices of his friends and rivals. On the four inhabited worlds, there were scarcely twenty men who could sail a sun yacht; and they were all there, on the starting line or aboard the escort vessels, orbiting twenty-two thousand miles above the equator.
“Number One—Gossamer—ready to go.”
“Number Two—Santa Maria—all O.K.”
“Number Three—Sunbeam—O.K.”
“Number Four—Woomera—all systems GO.”
Merton smiled at that last echo from the early, primitive days of astronautics. But it had become part of the tradition of space; and there were times when a man needed to evoke the shades of those who had gone before him to the stars.
“Number Five—Lebedev—we’re ready.”
“Number Six—Arachne—O.K.”
Now it was his turn, at the end of the line; strange to think that the words he was speaking in this tiny cabin were being heard by at least five billion people.
“Number Seven—Diana—ready to start.”
“One through Seven acknowledged,” answered that impersonal voice from the judge’s launch. “Now T minus one minute.”
Merton scarcely heard it. For the last time, he was checking the tension in the rigging. The needles of all the dynamometers were steady; the immense sail was taut, its mirror surface sparkling and glittering gloriously in the sun.
To Merton, floating weightless at the periscope, it seemed to fill the sky. As well it might—for out there were fifty million square feet of sail, linked