Rocket-minded visitors often expressed wonderment that there was no sign of propulsive power plants in evidence and there was an interesting and ingenious answer to their questions.
Long before, the designers had decided to use the well-tested Sinus cargo spaces.
The rocket motors themselves were welded on and the diameter of their nozzles filled out the whole after-section of the ferry vessels which they conventionally propelled.
It was at this point that old Spencer's flexible ingenuity had saved the day.
"When you're assembling in the orbit of departure, just rob the Siriuses of their rocket motors and install 'em in the Mars vessels," he had said.
Peyton had objected to leaving a lot of valuable ferry ships circling indefinitely and impotently around the Earth, whereupon Spencer went on:
"You won't have to do that at all. A Sirius doesn't need 200 tons of thrust to get back to Earth. She can do it with a couple of thousand kilos if they work a bit longer. So you just ship up a few propulsion plants from the old rocket fighters and install them in place of the cannibalized thrust units. They are so small that they will not fill out the openings in the sterns of the ships, but we can have some sheet metal cover plates made up in sections to be installed around their little nozzles to cover the open wounds. The plates will go into the cargo spaces without difficulty."
Not long after the World Congress handed down its historical decision, Professor Ashley the wise, graying head of the World Research Board lived up to his promise andassigned suitable research institutes, university facilities and specialized companies to a vast number of partial research and development problems related to Operation Mars. The difficult task of coordinating this worldwide program with the constantly changing design and construction work going on in Long Beach came under the cognizance of the Development Commission appointed by Braden. This commission drew the contracts in detail and supervised the distribution of work; Holt, Spencer and Peyton were members.
When Operation Mars began to take tangible shape, a veritable army of engineers and technicians went to work on a wide variety of problems of which instrumentation for Martian conditions was not the least difficult.
Pressure altimeters for the Martian atmosphere were developed in conjunction with other types and special gyro-compasses for the caterpillars replaced magnetic instruments in view of the lack of information on Mars's magnetism.
In order to set the control gyros on the ships and to adjust the ship's attitude in spacefor a power maneuver, a new and ingenious device had been developed. The problem was to adjust the gimbal system of the attitude gyros to a direction established in each individual case by the navigators for both the main power maneuvers proper, and the corrective maneuvers as obtained by the running navigational fixes. This being accomplished the ship had to be brought into the same attitude in space. The Sperry Company in Great Neck had developed a device for this purpose which worked as follows. Two small telescopes were mounted on a gimbal system in which the position gyros were suspended. These telescopes were to be centered on two fixed stars and kept on them by light-sensitive cells. This established a plane in space upon which an arbitrary system of reference with three coordinates could be built up, having the vessel itself as a center.
Three scales attached to the prime axes of the gimbal system could be set to the angularity of the desired three-dimensional heading as referred to this arbitrary system of reference.
After this had been done, the gyros were started, and this brought the entire gimbal system automatically into the prescribed special attitude. When, after several minutes of operation, this attitude was attained, the triple attitude flywheels of the ship were set in motion and continued to run until the ship itself coincided with the special attitude of the control-gyro system.
The purpose of this device was to eliminate lengthy adjusting to and fro, and to bring the Mars vessels more rapidly and more accurately to the desired headings for any power maneuvers.
There were a great number of mathematical labors to be performed aside from such technical developments as those described.
First there was the task of recomputing the voyaging ellipses to comply with the departure date and time selected. As a navigational essential, it called for the utmost precision, although not affecting the basic layout of the ships. Into these computations would enter accurate elliptical orbits for both Earth and Mars, the complicated interaction between solar and planetary gravities when the vessels approached either planet, not to mention aberrations in the flight paths produced by other heavenly bodies such as Jupiter and the terrestrial and Martian moons. This last mentioned factor called for the closest scrutiny.
Furthermore, it was necessary to run another set of computations for the four main power maneuvers as affected by these more accurately worked out data. The periods of power application would be long, particularly the earlier ones, and it would be necessary that the ships' attitudes coincide with their curved, powered flight paths. This could only be done by gradual alteration of the spatial attitudes, such alteration being impressed by the control gyros in accordance with a set time program. The initial power maneuver of departure from the terrestrial orbit would last 66 minutes — more than a full hour; and during that time a ship would more than half circumnavigate the Earth along the departure orbit. The velocity would change but slowly until the final hyperbolic escape velocity was reached, and this would give the track of departure a marked curvature, to be accurately complied with by the control gyros. All the other power maneuvers posed the same problem, although to a continually lessening degree.
Bitter experience had taught the Space Forces that captains and navigators must be freed as far as possible from involved computations while under the stresses of a voyage.
Burck's adventure with Hercules had redoubled the efforts to furnish ship commanders with flight data already prepared for all eventualities and unforeseen deviations from the prescribed track, from which they could determine proper procedures immediately and without lengthly calculations.
The high accuracy required for navigation in interplanetary space even made a further step necessary to prepare the Mars expedition. The vast program of the many thousands of flight path calculations required to cover the multitude of variations encountered by the most minute deviation from the predetermined track could only be handled with the help of huge electronic computers, which, since 1940, had begun to relieve mathematicians of the burden of tedious numerical calculations. These electronic super-brains supplied their results in the form of a magnetic tape, on which the solution was imprinted in a magnetic pattern. The hieroglyphs on the tape were usually decoded by a separate printing machine which retransformed them into ordinary figures.
What was more obvious, then, than to utilize the magnetic tape itself for the guidance and control of the ship, rather than to have the navigator first take figures from a table and adjust the control devices accordingly? It was comparable to running a punched tape printed with musical notes directly through an electric piano, which played the symphony, although without expression, yet with absolute assurance against discords.
Several thousand magnetic tapes were compiled from the many computations and each ship was to carry such a collection for its navigation. A handbook, crammed with diagrams and auxiliary tables, served the navigator as a key for picking the proper tape once a certain deviation from the prescribed track had been ascertained by running fixes.
Notwithstanding all these preparations, it had been thought necessary to develop a novel type of electronic computer, small and light enough to be taken along by each of the expedition's ships. These computers were to stand by for entirely unforeseen events and were capable of producing guidance tapes while enroute.