"Jack Vance - Sail 25" - читать интересную книгу автора (Vance Jack)

Weske rose to his feet. "A wonder somebody hasn't killed him."
"I wouldn't want to try it," said Culpepper. "He looks tough." He made a gesture, stood up, brow furrowed in
thought. Then he went to look along the passageway into which Henry Belt had made his departure. There, pressed to
the wall, stood Henry Belt. "Yes, sir," said Culpepper suavely. "I forgot to inquire when you wanted us to convene
again."
Henry Belt returned to the rostrum. "Now is as good a time as any." He took his seat, opened his red book. "You,
Mr. von Gluck, made the remark 'My gracious' in an offen-sive tone of voice. One demerit. You, Mr. Weske, employed
the terms 'tyrannical lunatic' and 'megalomania,' in reference to myself. Three demerits. Mr. McGrath, you observed
that freedom of speech is the official doctrine of this country. It is a theory which presently we have no time to
explore, but I believe that the statement in its present context carries an overtone of insubordination. One demerit. Mr.
Culpepper, your imperturbable complacence irritates me. I prefer that you display more uncertainty, or even
uneasiness."
"Sorry, sir."
"However, you took occasion to remind your colleagues of my rule, and so I will not mark you down."
"Thank you, sir."
Henry Belt leaned back in the chair, stared at the ceiling. "Listen closely, as I do not care to repeat myself. Take
notes if you wish. Topic: Solar Sails, Theory and Practice Thereof. Material with which you should already be familiar,
but which I will repeat in order to avoid ambiguity.
"First, why bother with the sail when nuclear jet-ships are faster, more dependable, more direct, safer and easier to
navigate? The answer is threefold. First, a sail is not a bad way to move heavy cargo slowly but cheaply through
space. Secondly, the range of the sail is unlimited, since we employ the mechanical pressure of light for thrust, and
therefore need carry neither propulsive machinery, material to be ejected, nor energy source. The solar sail is much
lighter than its nuclear-powered counterpart, and may carry a larger complement of men in a larger hull. Thirdly, to
train a man for space there is no better instrument than the handling of a sail. The computer naturally calculates sail
cant and plots the course; in fact, without the computer we'd be dead ducks. Nevertheless the control of a sail
provides working familiarity with the cosmic elementals: light, gravity, mass, space.
 "There are two types of sail: pure and composite. The first relies on solar energy exclusively, the second carries a
sec-ondary power source. We have been assigned Number Twenty-Five, which is the first sort. It consists of a hull, a
large parabolic reflector which serves as radar and radio antenna, as well as reflector for the power generator; and the
sail itself. The pressure of radiation, of course, is extremely slightтАФon the order of an ounce per acre at this distance
from the sun. Necessarily the sail must be extremely large and extremely light. We use a fluoro-siliconic film a tenth of a
mil in gauge, fogged with lithium to the state of opacity. I believe the layer of lithium is about a thousand two hundred
molecules thick. Such a foil weighs about four tons to the square mile. It is fitted to a hoop of thin-walled tubing, from
which mono-crystalline iron cords lead to the hull.
"We try to achieve a weight factor of six tons to the square mile, which produces an acceleration of between g/one
hun-dred and g/one thousand, depending on proximity to the sun, angle of cant, circum-solar orbital speed, reflectivity
of surface. These accelerations seem minute, but calculation shows them to be cumulatively enormous. G/one hundred
yields a velocity increment of eight hundred miles per hour every hour, eighteen thousand miles per hour each day, or
five miles per second each day. At this rate interplanetary distances are readily negotiableтАФwith proper manipulation
of the sail, I need hardly say.
"The virtues of the sail I've mentioned. It is cheap to build and cheap to operate. It requires neither fuel, nor
ejectant. As it travels through space, the great area captures various ions, which may be expelled in the plasma jet
powered by the parabolic reflector, which adds another increment to the acceleration.
"The disadvantages of the sail are those of the glider or sailing ship, in that we must use natural forces with great
precision and delicacy.
"There is no particular limit to the size of the sail. On Twenty-Five we use about four square miles of sail. For the
present voyage we will install a new sail, as the old is well worn and eroded.
"That will be all for today."
Once more Henry Belt limped down from the dais and out the passage. On this occasion there were no comments.