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1. Types of balloons 2. Visibility 3. Derelicts and cutdown 4. Balloon motion 5. Twilight effects 6. Lighted balloons 7. Frequency of flights 8. Balloon UFOs 9. Conclusions |
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Three kinds of balloons can give rise to UFO sightings: neoprene or rubber balloons which expand during ascent from six feet to 30 ft. in diameter; polyethylene balloons which are partially inflated on the ground and fill out at float altitude to a diameter of 100 ft. to 400 ft.; and small super-pressure balloons called "ghost" balloons.
The relative visibility of a balloon depends on its type, size, material, time-of-day, and altitude. The human eye can usually detect a balloon against a bright sky background when the intercepted arc is 0.5 mil or greater. The radiosonde balloon is visible in daylight to a distance of two to four miles. During ascent, the "ghost" balloon is visible against the bright sky background at a distance of about two miles. At altitude the intercepted arc of "ghost" balloon varies
The large polyethylene balloons absorb about 5% of sunlight; however, they scatter and reradiate as much as 20 - 30% of the inci- dent light. This scattering is very much a function of angle. Polyethylene balloons are always visible at altitude during daylight hours when the sky is clear. It is often difficult to focus the eyes on the balloon, but once seen it is easy to relocate the balloon. The "ghost" balloon is not visible above 20,000 ft. during daylight hours.
Polyethylene balloons are shaped more like a pear than a sphere, although they always appear spherical from the ground to the naked eye. Glass fiber tapes affixed to the gore seams are used to strengthen polyethylene balloons carrying heavy payloads. Observed from the ground through a telescope, a shell effect gives a taped balloon a saucer-like appearance. The tape itself, which is the basic reflecting element, is quite shiny and reflects well. On very lightly loaded systems the balloons are tapeless; heavier loads require the glass fiber tapes. As seen through the telescope, then, the taped balloons appear much shinier and are distinguished by their scalloped appearance.
Another phenomenon that might be witnessed by an observer during the day is what is known as the "cutting down" of a balloon. When the decision has been made to terminate a balloon's flight, the tracking aircraft will send a destruct signal to the balloon's control and command mechanism and a squib will fire. This will detach the payload and shatter the balloon. The payload is then tracked by the plane as it parachutes to the ground. Occasionally, however, the balloon will not shatter.
The shattering of a balloon during payload detachment is easily visible (especially in the late afternoon or early morning). However, the entire operation is not. The payload chute is only 60 ft. in diameter so that it is barely visible. The tracking plane which sends
With improved balloon materials, there were a number of cases in 1966 where the balloon did not shatter but continued its ascent. Normally, if the balloon does not shatter, it should rise so fast after the shock that the gas does not escape rapidly enough to prevent bursting. Occasionally the balloon will begin to stretch, and if there is no weakness in it, the balloon could remain aloft at that higher altitude for four or five days. It might fly at 130,000 or 140,000 ft. until sunset at which time the gas will cool, reducing the volume by 5%. This causes the balloon to descend a few thousand feet. In daytime, at high altitudes the balloon's skin tends to run colder than the atmospheric temperature. As the balloon cools in the evening, it starts to descend because it has lost its volume. When it gets to approximately 60,000 - 70,000 ft., where the atmospheric temperatures are colder, the balloon is warmer than ambient temperature. It then picks up the 5% lost solar heat and continues to float along at this altitude until the next morning when it warms up and returns to maximum altitude.
For example, a 1,000,000 cu. ft. balloon, launched in France came down in Montana in August 1966, after having remained aloft for 27 days. This balloon had been traveling at 60,000 to 100,000 ft.
Actual balloon movement during the day is no more discernible than the movement of hands on a clock. At many times a balloon will appear to move if there are clouds in the sky just as a flagpole might seem to fall over when one is looking at it while lying on his back. The moon
A small balloon observed in the first few thousand feet of ascent, of course, will be quite obviously moving. Our very large balloons climb at a rate of 700 - 1,000 ft/mm; radiosonde balloons ascend at 1,000 - 1,200 ft/min. As these balloons reach higher altitudes, they could encounter strong wind shears (changes in velocity associated with changes in altitude) of the order of 30 knots/l,000 ft. Hence, velocity could change by as much as 30 knots in a minute, but even this would not make a large change in position. The angular movement would always be small over any one-minute period.
With respect to daylight sightings, pilots invariably estimate that balloons they see are considerably lower than their true height. For example, a pilot flying at 30,000 or 40,000 ft. will always report that the balloon is between 10,000 and 40,000 ft. above him. He will never say it is 100,000 ft. above him. The difficulty arises because no one conceives of a balloon 300 ft. in diameter. There is no depth to the balloon and no background which permits an estimate of either size or distance.
A frequent occurrence in Boulder, Colo., when searching for a balloon which has been recently launched, is to focus on the fluffy balls from a cottonwood tree floating 50 - 100 ft. above the observer. The cottonwood ball has been tracked on several occasions for two to three minutes before its motion convinced the observer that it was a one-inch cottonwood ball at 100 ft. and not a 10-ft. balloon at 10,000 ft.
Just after sunset, a balloon may still be in sunlight. At this time the contrast becomes sharp and the balloon is clearly visible. A good bright balloon appears at least as bright as the brightest we ever see Venus when the planet is high in the sky: This "twilight effect" may continue from 20 min. to two hours.
The neoprene balloons are also visible at twilight. An Australian scientist made experiments at NCAR for about a year using a new technique for measuring ozone. He flew a neoprene balloon with a little stopper attached which permitted the gas to escape and enabled the balloon to remain aloft for one or two hours at altitude instead of ascending and bursting. To make measurements of the reflectance of the sun on the balloon and determine the ozone concentration, he launched the balloons so that they would reach 100,000 ft. above the observing site just after sunset. These balloons were plainly visible about sunset, continued to become brighter and brighter, and then receded to a faint glow before disappearing.
Small rubber pilot balloons are still being used in many countries. For night soundings these two-foot diameter rubber balloons are tracked by small candles placed under the balloon. A single candle in a little holder has been used. The holder creates an even glow and keeps the candle from going out. The candle has been replaced in most countries by small battery-powered bulbs of approximately two candle power. Although the pilot balloon tracked by theodolite is no longer in common use in the U. S., a light is still used on radiosonde balloons at night to assist the observer to acquire the balloon, particularly if the night is dark and the trackers have had difficulty locking the radar set on the target. The blinking, bobbing light swaying under a pilot balloon or radiosonde balloon produces an exciting and attractive UFO. The FAA requires that large polyethylene scientific balloons carry lights when below 60,000 ft. at night. They can provide an awesome sight as they slowly ascend.
About 100 polyethylene balloons are flown each year from Palestine, Tex. San Angelo, Tex. has been an active launch area with as many as 100 - 200 per year. Chico, Calif., during the winter months has about ten flights, and Holloman AFB, N. M. (White Sands), has approximately 50 - 100 per year. Minneapolis remains still a center of balloon activities with 20 - 50 flights per year -- usually of small polyethylene balloons.
In addition, there are other field programs during the year that are undertaken by universities and manufacturers. Ten to 20 flights are made from Cardington, England each summer. A continuing flight program is conducted from Aire sur L'Adior, France. Australia, Russia, India, and Brazil have active flight programs using large polyethylene balloons.
About 100,000 of the small neoprene balloons are flown each year in the United States for routine observation. Radiosonde balloon flights constitute a vast undocumented area. They are generally sent up four times a day. Flight schedules are all based on Greenwich time. At some times of the year at some places in the country, the balloons will be going into altitude at twilight. There are approximately 100 sites in the United States that send up radiosondes four times a day. Records of launch time and location for these balloons are kept in Asheville, N. C.
A radiosonde balloon ascending to 100,000 ft. at twilight and then shattering can be the source of reports of a fiery object in the skies which disappears in a burst of flame.
Two situations are illustrated that have produced UFO reports. In January 1964, a large balloon was flown from the Glen Canyon Dam area near Pago, Ariz. It was a 6,000,000 cu. ft. balloon with a light payload. The balloon, which was flying at 135,000 ft., had encountered extremely strong winds. About three hours after it reached altitude
At altitudes of 5,000 - 10,000 ft. we fly a different kind of "ghost" balloon. This cylinder-shaped balloon is approximately 20 ft. long and about two feet in diameter. We flew one of these from Boulder on 23 June 1965 at an altitude of 6,500 ft. We lost the balloon after a few hours. It went through some rather heavy showers, and seventeen days later over the Azores a silvery object like a long spear was sighted in the sky. At the same time as the silvery object was seen -- all of the clocks on the Azores stopped. Later investigation determined that an electrician short-circuited the island's clock power supply while he was working on a fuse box.
The public at large and even many scientists are unaware of the great number of balloon launchings that occur every year in all parts of the world. The majority of such launchings are for meteorological studies, but some relate to other atmospheric or astronomical research.
By far most of the balloons launched for whatever purpose go unobserved except by those directly interested in their performance. They perform their missions and are cutdown or burst unnoticed by the public. This is due to the fact that most launchings take place at times and under conditions which make observation -- and misidentification -- of them unlikely or impossible. As a result, when a balloon is observed