Now the crane fetched four large rectangular cover plates. These would close the annular gap between the two stages. Just before the baby booster's motor fired, these cover plates would be released by explosive bolts so that the jet might freely emerge around the lower stage's conical top. The ignition cable leading to the explosive bolts was plugged in, and thus the first part of the assembly was complete.
When the top stages had completed their trip to the orbit of departure and returned, after discharging their freight they landed on a runway not far from the assembly shed. The runway stood on piles within the protected waters of the atoll, and the date of completion had been a masterpiece of coordination between the Space Forces and the contractors.
Like the others, the top stages also were thoroughly checked after each landing. A hangar was available for this purpose, nor were they approved for other flights until the inspection had been completed.
When their retractable wings were spread, they looked rather more like conventional all-wing aircraft than rockets. Their wings were highly raked, and had two conspicuous steps where the thinner retractable outer wings protruded from the thicker mid-sections.
The span was 52 meters. Approximately where the first step of the telescoping retraction took place, were two vertical stabilizers with rudders behind them.
In comparison with the Martian landing craft, with their much greater span, their hulls appeared rather fat and stubby. This was largely due to the huge flat bases, 9.8 meters across. Without this great area, the top stages could not have expanded their gases of combustion down to almost one hundredth of an atmosphere. Thus with their length of but 15 meters the hulls appeared rather like short artillery projectiles.
The top stages, when belonging to cargo vessels, received their loads of non-fluid cargo immediately after their inspections, and were towed to the assembly sheds on their own landing gear. Their wings were hydraulically retracted as the tractor drew them into the shed. Here two thick, round steel tubes were inserted transversely fore and aft, so that each protruded from both ends. The four ends were picked up by slings from the crane, the ship was hoisted horizontally and the landing gear was retracted. When the ship had been hoisted halfway, the stern was lowered and finally swung into position above the double booster and lowered into its seat. Thus the third stage, once in place, comprised the forward point of the whole enormous rocket.
When the three stages had been joined, two men entered the pilot's cabin in the top stage and thoroughly checked the various flight mechanisms. If everything worked well, the ship was declared in flight condition.
There were four separate launching sites on Christmas Island, two of them being operated in conjunction with each assembly shed. When a ship was to be launched, one of the great sliding doors in the building opened to permit its 60 meters of height to pass out. The powered launching platform, complete with jet deflector and running upon widegauge tracks, bore the vertical rocket ship to the takeoff site, located a scant mile from the building. The site itself was no more than a wide concrete platform permitting various auxiliary vehicles to approach the waiting rocket ship and eliminating, as far as possible, any damage from the pelting of the surroundings with rocks and pebbles that would take place if the mighty blast of the jet were to impinge upon unprepared ground.
When the site was reached, the launching car was immovably anchored by tong-like brake shoes to the rails and a web-like series of propellant hoses was attached. Each of the three stages was filled with two propellants independently through separate hose lines.
A system of pipelines connected the filling stations at the launching sites with the storage tanks near the harbor. There was a fuel meter on each outlet, permitting maximum accuracy during the tanking procedure.
When the filling was over, the elevator gantry on its trailer was brought alongside the ship and the crew went aboard. All was ready for another takeoff for the orbit of departure.
Braden's schedule called for the departure of two ships every twelve hours. They would be launched almost simultaneously and proceed in formation to the orbit of departure. This cycle of 12 hours was determined by the positions of the growing Mars vessels in their orbit, for there were only certain moments at which a Sinus ship could take off from Christmas and reach them. The orbit of departure lay in the plane of the ecliptic, namely at an angle of 23.5 degrees to the plane of the Equator; it is in the plane of the ecliptic that both Earth and Mars circle around the Sun. The group of vessels on which the assembly work was being done circled the Earth once every two hours and this made them cross the equator once every hour. In the meantime, the Earth was slowly rotating under the orbit of departure, making a complete revolution every 24 hours. Hence, after every half revolution, or 180 degrees, the same point on the equator which was now just under the vessels, would again be exactly under them, they having meanwhile made six full circles around the Earth.
Therefore it was always possible to launch a second flight just twelve hours after one launching had been made from Christmas Island. But if one flight had reached the orbit of departure in a northeasterly direction, the succeeding flight 12 hours later would be obliged to depart southeast, for only after a further 12 hours could the orbit of departure be attained via the northerly track.
Chapter 13 — Incidents and Adventures
No great achievement of a technical nature has ever taken place without exacting a tribute of sacrifice, and Braden's magnificent spacelift was not long in following suit.
It was noon on a March day in 1983 when the two ferry vessels, Andromeda and Max Valier, took off at the regulation interval of 3 seconds. Valier was the leader, with Andromeda close astern. Hardly had the ships begun to respond in velocity to the earsplitting roar of their great boosters than the ground crews noticed that Andromeda's comet-like propulsive jet suddenly collapsed to nothing. A few seconds later the enormous ship came to a standstill directly over their heads…
Contrary to orders, they had become so accustomed to uneventful launchings that they had left the protection of their bunkers as soon as the danger of fire and pounding rocks was over. Now they rushed madly back into cover, there to spend a few seconds of tortured waiting until what seemed a minor earthquake shook the solid bunker, flinging them from side to side. It was followed by a violent explosion, which died away in a series of smaller ones. Then all was silence.
They opened their steel doors to hear the wail of a siren which somehow injected a note of belated absurdity into the tragedy, as though anyone might have missed the earthquake; for some thousand feet distant from the launching platform a great mushroom of brown smoke ascended out of what seemed a volcano of roaring white flame. Above it all could be heard the diminishing thunder of the Valier on her path to Heaven. So intense was the heat from the pyre that not until some fifteen minutes had elapsed could the firefighters and their equipment approach close enough to spread their blankets of foam over what had once been the proud Andromeda.
She lay at the center of a shallow crater some 200 feet in diameter, where hydrazine was still burning with its acrid odor of ammonia. Pieces of the huge rocket combustion chamber could still be recognized, strewn over the bottom of the crater. The ruins of the second and top stages lay in a line along the walls of the bowl, indicating that at the moment of impact the great ship had already begin to turn her nose downwards. All around the crater were bits of shattered steel and sheet metal, interspersed with carbonized pieces of electrical equipment. It was quite plain that none of the crew of four had succeeded in leaving the vessel before the catastrophe, although the intense heat had destroyed all traces of their bodies.