The earliest instrumentation sites were simply open-air pads on the ground with a canvas sail cover. A wood fence kept out wandering cattle, but there was nothing to protect the instrument or the operators from the elements while it was in operation. The primary issue was the phenomenon of “atmospheric boil,” where heat waves would interfere with the image and distort the data. Blowing sand also presented a problem by scouring and scratching lenses and film. High heat impacted the operators, increasing the chance of user error.
An early Askania cinetheodolite field station in the late 1940s, before the instrument was elevated. Note the construction materials nearby for a future permanent shelter.
An early cinetheodolite station at Bern Site, on Holloman AFB. Note the Askania cinetheodolite covered by a canvas tarp and mounted on a concrete pad
Atmospheric boil (also called "atmospheric turbulence") is similar to heat ripples on a highway. It is caused by light bending in air that is slightly unstable (of slightly differing density), which warps what you see. This is made much worse in high-heat conditions combined with high optical magnification as is seen here. Note the lost detail and generally poorer image quality during the hot part of the day (right) compared to an earlier period, when the atmosphere was more stable (left). This loss of detail is problematic when studying missile flight behavior.
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To counter-act the problem of atmospheric boil, efforts were made to track flights early in the morning when the temperatures were more stable. In the absence of that, the military elevated cinetheodolites above the desert floor. The Navy pioneered this approach at their test ranges in California, and both the Army and Air Force quickly followed at WSPG. Dr. Ernst Steinhoff - a Paperclip scientist working at Holloman AFB - recommended raising the cinetheodolites at least 20 feet to limit the impact of atmospheric boil. The Army's first solution was small concrete and masonry buildings with the instrument affixed to a pedestal on the roof. This did little, however, to counteract the sun and wind and further refinements proved necessary.
A simple elevated cinetheodolite station. The instrument would have been covered with a canvas tarp when not in use.
An Army style elevated cinetheodolite station in use, circa 1949.
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The Army improved their cinetheodolite buildings with pedestals that could be raised and lowered, storing the instrument inside the building between missions.
The Air Force took a different approach and commissioned Santa Fe architect Kenneth Clark to design a two story building with triangular steel panels forming a pyramid at the top. These panels operated independently and allowed the operators to customize the protection for the instrument while in use to account for sun angle and wind direction. When all four panels were closed, they offered excellent protection for the instrument when not in use but limited the size of the instrument underneath.
US Air Force Cinetheodolite Shelter at Cowan Site.
The cinetheodolite shelter at Nan Site, showing the lift that would raise the cinetheodolite up through the roof for operation.
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Elevated shelters worked fine for cinetheodolites, but larger tracking telescopes required more substantial buildings. To solve the problem of protecting bigger instruments while allowing them to be exposed to the sky and retain a wide viewing angle, the Army developed retractable roof buildings. These varied from simple movable metal sheds on rails that rolled back to expose the telescope, to large buildings where the whole upper half could roll back and away from the instrument.
None of the existing solutions were ideal. The Air Force shelters were limited in the size of instrument they could protect, and the Army buildings still fully exposed the instrument during the mission. The final answer was the astrodome, a versatile fiberglass hemisphere or cylinder introduced to the Range in the late 1950s. Astrodomes had a panel that slid open to allow an instrument access to the sky, and the whole dome rotated with the instrument as it tracked its target, allowing researchers to limit exposure of the instrument to the elements even during operation. In addition, astrodomes were also inexpensive when compared to the cost of constructing an entire building, came in a variety of sizes, and could be mounted on steel towers and platforms, concrete buildings and pads, and even trailers to make them mobile.
One drawback, however, was that they were generally lower to the ground, resulting in problems with atmospheric boil that were avoided in elevated shelters.
This is a fixed-position, motorized astrodome. Inside is mounted an Askania KTH 53 cinetheodolite.
Fixed-position, motorized astrodome shelter housing a Contraves one-man cinetheodolite system.
This is a mobile cinetheodolite astrodome that was brought to a specific spot to track a launch and then brought back for analysis.
This is a Ballistic Camera Mounted in an Astrodome. Note the air conditioner at the base.
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Working out in the New Mexico desert comes with many advantages: frequently good weather with cloudless skies and excellent visibility, low population, and wide open, flat spaces. The desert also brings many unique challenges as well. How did the WSMR team overcome the oppressive heat's effects on the instruments and even the rippling effects of the air? How did they keep sand and debris out of the lenses and the gearing systems used to track flights? The answer was in the construction of buildings. Learn how the military experimented with different buildings to counter adverse environmental conditions here.
