"That's quite so," replied Spencer. "But there's plenty of time enroute for meticulous navigation. Throughout the 260 days of the voyage there will be constant checks on the position of the ships and any aberrations from the predetermined track will be computed and corrected. As I informed you, there is available a certain propellant reserve, and this can be used for any corrective maneuver found necessary."
From the serried ranks of the committee an elderly gentleman wearing nose glasses rose and inquired how positions could be plotted in space.
"That's relatively simple," answered Spencer waving his cheroot. "The navigating officer will simply take the stadimetric angle between any planet in the plane of the ecliptic and some star in the same plane. Since the voyage takes place in that plane and since the Ephemeris gives the positions of both planets and stars, this angle will immediately fix the position of the ship. Our experienced spacemen call this procedure the 'determination of planetary parallax.' The same measurement may be taken perpendicular to the plane of the ecliptic by finding the angle between some fixed star and a planet when a line drawn between them cuts the plane of the ecliptic at right angles.
This will also give a check on whether the vessel has strayed from the plane of the ecliptic, and the data for the appropriate corrective maneuver."
Spencer looked around for further questioners, whereupon a spare, gray man looking somewhat like a retired cowman spoke up. "You mentioned that food, water and oxygen for the crews is an important factor in the cargo requirement of your space ships. That is quite plausible in the face of the long duration of the voyage. Can you tell us something about the rations on which your weight calculations are based?"
"With pleasure," said Spencer. "I hope you will excuse me if I don't have all these figures in my head, so let me just look into my papers."
He sank his ham-like paws into his briefcase and, after some digging, produced a folder.
"Now let's see," he said, leafing through the pages. "First of all, we're allowing to each of the 70 men 120 kilograms for personal baggage. This baggage included, we reckon that all in all, crew weight will be 14 metric tons. This makes two tons apiece for each of the seven returning passenger ships.
Each man will require 1.235 kg of breathing oxygen per day on the average, as has been confirmed by practical experience in Lunetta. Since both on the outbound leg of the voyage and during the waiting time oxygen can be drawn from the cargo vessels, the oxygen supply of the passenger ships can be limited to the needs of the return trip, 260 days. Each of the passenger ships will therefore need for its crew of ten an absolute minimum of 10 times 1.235 times 260, equals 3,220 kg of oxygen. Each ship will actually be provided with 5 tons.
"Water will be needed to the extent of 2 kg per person per day. For the passenger ships, that's twice 10 times 260, equals 5,200 kg. We're providing 5.5 tons. We're also supplying an extra 2 tons of non-potable water. It will be stored in a special system and used for cleaning purposes and the like. Oddly enough, this utility water will increase daily as the result of water recuperated from the air-drying plant. This recuperation will amount to about 1.62 kg per person per day. It comes from perspiration and moisture in the breath of the personnel, and there's no reason at all why it cannot be employed for utility purposes, after thorough treatment, of course. Thus the utility water will increase during the return trip to 6.2 tons from the original 2 tons. Of course, the drinking supply will be correspondingly diminished.
"Where food's concerned, we reckon with a daily consumption per person of 1.2 kg — that's about Army standard — and each passenger vessel will require about 3.12 tons of food as a minimum. We shall provide 3.5 tons. Food containers will weigh around one ton, making 4.5 tons in all.
"When all this is added up, each of the seven passengers ships will haul 2 tons of pay load composed of the crew and their personal belongings, 5 tons of oxygen, 5.5 tons of potable water, 2 tons of utility water and 4.5 tons of food, or 19 tons altogether.
"In this connection let me give you the remaining figures affecting the terminal weight of the passenger ships. Personnel spaces of each ship will be spherical and have an empty weight of 3 tons, more or less. Furnishing and fittings will raise this to around 4 tons. Air and water recuperation equipment calls for another 3 tons; navigational and course-keeping gear, 2 tons; while the electrical generating plant weighs another 2 tons.
That's 30 tons altogether.
"Now, the rocket power plant, as presently used in the top stage of the Sirius-class, weighs almost exactly 10 tons, and we expect to use it without alteration. This includes rocket motor, gas turbine-driven propellant pumps, and gas generator for the turbine, as well as valves, tubing and all the various components. The tanks for the final thrust maneuver weigh a scant half-ton and the required structure, after jettisoning the other tanks, weighs not quite one ton. And so we reach a total empty weight for each passenger vessel of 41.5 tons, including the entire useful load. You will recall that this gives us a leeway of 9 tons per ship, since we actually based all performance calculations on a terminal weight of 50.5 tons."
Spencer seated himself once more and looked expectantly at the cowman. "Seems all right to me," said the latter. "I get the idea that you've gone far enough into this thing to start right in building your strange gadgets the moment the appropriation's through. And I guess it wouldn't be long before the whole outfit would go busting off into space…"
Spencer hurriedly got to his feet.
"Hold on a moment, sir" he protested solemnly. "It's not as simple as that. When you get down to the details of a job of this kind, it is so involved and varied that it will call for years of work on the part of a veritable army of scientists and engineers, not to mention production men in every imaginable field. That will have to be gone through before we can even dream of launching the convoy into space.
"Let us not deceive ourselves, gentlemen. There are enormous problems ahead of us. It will be much like an attempt to climb some very high and rugged mountain. Often we shall see what we believe to be its summit clearly before us, not far away. But when we reach it, we shall find that it is not the true summit and that a strenuous climb still lies ahead.
"All I had hoped to accomplish today was to convince you that it is even now technically possible to fly to Mars using means, materials and methods which are presently available to us. In no way do I desire to minimize the difficulties facing the project. But I am absolutely certain that if our work is begun with adequate facilities, Mars will soon conceal no more mysteries than Moscow."
Chapter 7 — What of Life on Other Planets
When Spencer had finished, not a man in the Mars Committee doubted that a voyage to Mars was technically possible, and the effect of his presentation was a lasting one. But in the public press, and even among the members of the committee, there were those who vociferously questioned the value of the objectives of the undertaking, and furiously opposed the expenditure of the vast s'ums which the enterprise could not fail to demand.