Helium

Helium is created as a byproduct of radioactive decay within the solid Earth. Continental crust, which is enriched in uranium and other radioactive elements, is a constant source for helium. Because it is inert, helium does not combine with minerals in the crust, but it does readily dissolve into fluids such as ground water and natural gas, which typically contains 0.2 to 1.5% He by volume. Eventually the helium reaches the surface, for example in hot spring water (Persoz et al. 1972), and is released into the atmosphere. Earth's gravity is too weak to retain the helium molecule (single He atom), so it ultimately escapes into space.

Helium was little known prior to the 20th century. This changed with discovery that helium is a significant component of natural gas in some situations. An exploration well drilled in 1903 near Dexter, Kansas produced a nonflammable gas. Analysis demonstrated that helium comprised ~1% of the natural gas by volume (Nat. Acad. Sciences 2000). Military applications for a lifting gas stimulated a need for helium during World War I. When the United States entered the war, helium production was tasked to the Bureau of Mines (BOM), and three experimental helium extraction plants were built in Texas.

Following the war, the U.S. Navy pursued lighter-than-air flight, and BOM constructed additional helium productions plants in Texas. Helium in the ground was owned by the federal government, but some commercial production also took place during the 1920-30s in Kansas and Colorado. World War II led to a huge increase in helium production, primarily for lifting Naval reconnaissance aircraft, as well as for development of nuclear energy. Existing helium extraction plants were expanded, and new plants were built in Kansas, New Mexico and Texas in connection with natural gas fields.

During the Cold War of the 1950-60s, helium was viewed as a strategic resource, and a helium production and storage program was enacted by Congress in 1960 to create a Federal Helium Reserve (Nat. Acad. Sciences 2000). This act also allowed private (commercial) production of helium, which the federal government would guarantee purchase for storage. However, following the successful Apollo Mission to the Moon, demand for helium declined substantially during the 1970s. The federal government canceled its purchase contracts, and many helium production plants closed. The Exell Plant, near Amarillo, Texas, became the primary BOM helium extraction plant.

In 1997, Congress eliminated the Bureau of Mines and transferred the Federal Helium Reserve to the Bureau of Land Management (BLM). At roughly the same time, the Helium Privatization Act of 1996 required closing of federal helium production facilities, which were mothballed in 1998. Thus all helium production in the United States today is done by private companies, although the Federal Helium Reserve still exists in Bush Dome reservoir in the Cliffside gas field near Amarillo, Texas. Main producing states are Texas and Kansas, primarily from the vast Hugoton-Panhandle gas field, with additional helium from Oklahoma, Colorado, Utah and Wyoming. Much of the crude helium from Texas and Oklahoma is shipped via a federal helium pipeline to Kansas for further purification and liquefaction at Otis and Bushton.

Taken from National Academy of Sciences (2000).

Sign outside helium plant at Otis, Kansas.

The SFAP blimp is constructed of a single layer of urethane, a plastic material that retains helium well and is durable under field condtions. It holds approximately 240-250 cubic feet (~7 m³) of helium (one large tank), which provides a payload lift of about 3 kg (7 lbs). Four rigid tail fins stablize the blimp while in flight, and multiple attachment points along the keel allow for fastening the tether line and camera rig. Camera rigs are the same as used for kite aerial photography, and the blimp easily lifts camera systems weighing up to 1½ kg (~3 lbs).

The following pictures were taken during the maiden flight of the helium blimp at Cheyenne Bottoms, in central Kansas (June 2003).

	Laying out the blimp envelope on ground tarp. Body of the blimp is gold and tail fins are black to provide high visibility in the sky.
	Inflating the blimp from large helium tank in the trailer. Zac Andereck operates the tank valve, and Tamara Korenman holds the inflation hose in the tail of the blimp.
	Blimp is fully inflated with ~250 cubic feet of helium. Kelby Harrell prepares to remove the inflation hose and tie off the tail.
	J.S. Aber attachs a camera rig and tests the balance of the blimp. Position of the tether line and camera rig were adjusted to trim the blimp position.
	Blimp in stable flight position with camera rig ready for action. Sara Acosta (sitting) and Margaret Landis operate the tether line and reel.
	Blimp in flight with camera rig for aerial photography. The blimp measures 13 feet (4 m) long and easily lifted all our single-camera rigs in light wind (<10 mph).

As in all forms of aerial photography, clear sunny sky is essential. Large tethered blimps are subject to the same flying restrictions as are large kites or other tethered platforms--500 feet (150 m) maximum height is permitted without submitting a flight plan with the nearest airport. This height limit is well within the typical range employed for small-format aerial photography. A laser rangefinder is utilized to determine flying height of the blimp. Blimp aerial photography is normally conducted at two heights, ~100 m and ~150 m above the ground.

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