ASI W9700496r1.0
#99 October 1996
Section 6.9.3.2.099.of the Artemis Data Book
Peter Kokh
"MOUNTAINS MADE FOR LAUNCHTRACKS"When the idea of using an Earth-captive virtual first stage e.g. a spaceship-carrying rocketpowered dolly accelerating along a track up the western slope of some convenient mountain, first was published, I'm not sure. I first saw the idea drama-tically illustrated in the early 50s film "When Worlds Collide".
We are all familiar with the advantages of launching Eastward from low latitudes, as close to the equator as possible, to get a piggyback boost from the Earth's own angular momentum as it rotates on its axis. The maximum boost, at the equator, is 1,037.9 mph (1670.25 kph) = circumference of the Earth divided by 24 hours in the day. This boost diminishes as you move away from the equator to the north or south. The percentage of available boost at any latitude is given by the cosine of the latitude degree. For example, Cape Canaveral, Florida lies at at 28x N. The cosine of 28x is 0.88295 which gives the percentage [88.29%] of the boost available at the equator, or 916 mph.
We are also, most of us, aware of the penalty, in the form of drag, incurred by launching through a thick atmosphere. If we could launch not only from on or near the equator, but from high altitude as well, launch efficiency would be maximized (translatable into higher altitude, larger payload, or both).
Early '50s science fiction writers almost universally imagined that White Sands, New Mexico would be the major gateway to space. Eventually NASA decided for political, military, and, Oh Yes, range safety reasons that this country's major spaceport would be along Florida's Atlantic coast. But Wernher Von Braun, the make-it-happen guru of modern spaceflight, actually had had a better idea when he proposed that the World spaceport be located on a high mountain plateau in central New Guinea, 5x N. Von Braun, of course, was a multi-stage rocket man, and the idea of using an Earth-captive virtual first stage in the form of a mountain-slope climbing rocket sled dolly would have meant turning over an important part of launch operations to a separate team of scientists and contractors.
While the rocket sled idea remains "a path not chosen", prime fodder for the writer of "what if" alternate histories, the idea is essentially sound. Without discussing the technical and engineering features and merits of such a spaceship launch track, let's take a look at just what actual terrestrial mountains might make the final cut. Here is our short list of the top four, with some comments. We have them listed in order of their summit heights, even though a launch track might not reach it.
Range Safety and clearance: best clearance is to the north for polar launches, for which Cayambe offers no advantage. 2,000 miles East to the Atlantic over the sparsely populated north Amazon basin.
Range Safety and clearance: 300 miles west of the Indian Ocean coast (in southern Somalia) over sparsely populated terrain.
Range Safety and clearance: 70 miles to open water to the East for eastward launches.
Range Safety and clearance: Open water 25 miles to the south for southward launches only, a major drawback. Some 2,000 miles from the East African coast (in Somalia).
Excluded from this list are active volcanoes, and mountains that lack good seaport access. Arthur C. Clarke fictionalized ("Fountains of Paradise") a space elevator from a mountain in Ceylon (Sri Lanka) at 6xN. In truth, Mt. Pidurutalagala, the highest peak, is only 8,281 ft. and nearby Adam's Peak a thousand feet less. Both, however, have good eastward clearance over the southern Bay of Bengal.
Any effort to pick a site and build a mountainslope launch track would also have to factor in local political stability or the lack of it. If we were to pick just one such facility, serving all the world, my vote would have to be for Mount Kenya. It is tall, smack on the equator, central to the world's popula-tion, has fair weather, good access to a major port, and arguably acceptable range clearance. MMM
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