Scientific Use of Balloons in the Second Half of the Twentieth Century

During the second part of the twentieth century and into the current century, balloons have gathered data used by researchers in many discipline areas. Instruments on high-altitude balloons have carried out magnetosphere research and studied the magnetic field around the Earth and how it interacts with cosmic winds, as well as studies on micrometeorites and cosmic dust. Simultaneous flights of balloons launched from widely separated locations have mapped plasma flow and the interaction of plasma wave particles. Instruments carried by balloons have performed planetary observations, visible light particle sampling, and pressure-temperature sensing.

Balloon instruments have answered questions about the concentration of ozone, carbon dioxide, carbon-14, nitrous oxide, and ratios of oxygen and nitrogen in the atmosphere above 100,000 feet (30,480 meters). They have measured trace constituents in the stratosphere that reveal ozone depletion from manmade propellants in aerosol sprays and the emission of nitrogen oxides from jet aircraft. Geophysicists and earth scientists have used balloons to monitor earth resources, take pictures from the air, and study light from the aurora and constellations. Biologists and aerospace medical specialists have sent plants and animals into the upper atmosphere via balloons.

During the Cold War, balloons were used to collect data on atmospheric radiation levels. The Atomic Energy Commission's Project Ash Can, with some co-sponsorship by the Advanced Research Projects Agency (ARPA), monitored radioactivity in the environment. Launched in 1956, Ash Can used polyethylene balloons designed by Otto Winzen to collect particle samples in the stratosphere. These samples were tested for the presence of radioactive dust raised by nuclear blasts and nuclear bomb tests.

As part of the Stratoscope program, a series of three 10-million-cubic-foot (283,169-cubic-meter) Winzen balloons were launched from the deck of the Valley Forge aircraft carrier in the Caribbean starting on January 26, 1960. These huge thin-film polyethylene plastic balloons lifted cosmic ray research equipment weighing two tons (1,814 kilograms) for the National Science Foundation (NSF) above 100,000 feet (30,480 meters).

On March 10, 1960, the Office of Naval Research (ONR) and National Center for Atmospheric Research (NCAR) sent Coronascope I, another solar instrument package, to 80,000 feet (24,384 meters) and a second coronascope aloft on May 3, 1964, under a 32-million-cubic-foot (906,139-cubic-meter) balloon.

Stratoscope II was an even more ambitious project. The balloon carried a 3.5-ton (3,175-kilogram) astronomical observatory that took high-resolution celestial photos. Launched on January 13, 1963, the balloon's 36-inch (91-centimeter) telescope transmitted infrared spectral data on the Moon, Mars, Venus, six giant red stars, and other space phenomena. The information gleaned from the Stratoscope and other balloon explorations changed existing astronomical theories on the evolution and structure of the stars and the characteristics of the planets.

In January 1959, Project Stargazer began to study high-altitude astronomical phenomena from above 95 percent of the Earth's atmosphere, which allowed undistorted visual and photographic observations of the stars and planets. On December 13-14, 1962, Captain Joseph Kittinger and astronomer William White rose to an altitude of 82,200 feet (25,055 meters) over New Mexico in the Stargazer gondola. In addition to obtaining valuable telescopic observations, the flight provided useful information relating to the development of pressure and associated life support systems during an extended period on the edge of space.

During the second part of the twentieth century, giant plastic balloons built of better materials were able to carry heavier cargoes higher and higher. These giant balloons were so tough that they carried instruments through 155 mile per hour (249 kilometers per hour) jet stream winds and temperatures as low as minus 86 degrees Centigrade (minus 123 degrees Fahrenheit). They were exposed to the full force of cosmic and solar radiation and proved remarkably reliable. By 1972, the largest balloons had a 53-million-cubic-foot (1.5-million-cubic-meter) capacity, measured 750 feet (229 meters) tall, had 24.8 miles (40 kilometers) of heat-welded seams, and could carry seven tons (6,350 kilograms) of instruments to low altitudes or lighter packages to 31 miles (50 kilometers).

In 1970, the United States launched more than 500 high- and constant-altitude balloons. In addition to x-ray, gamma ray, infrared, and ultraviolet instruments, balloons have also carried instruments performing neutron spectroscopy and those that have counted micrometeorites. On October 16, 1970, an x-ray telescope from the Massachusetts Institute of Technology (MIT) lofted by a 34-million-cubic-foot (962,663-cubic-meter) balloon remained above 148,000 feet (45,110 meters) for more than 10 hours.

One of the most unusual flights of the 1970s, combined science and art. Vera Simons and Rudolf J. Englemann, a National Oceanic and Atmospheric Administration scientist, planned a series of four Da Vinci flights to study atmospheric structure, turbulence, and pollution; the suspension of fine particles in clean air; gather landscape and cloud images for art; and demonstrate the balloon as kinetic visual art. Their second flight, Da Vinci II, launched on June 8, 1976, and traveled the length of the St. Louis plume, an air pollution band, for 24 hours.

In 1960, two years after the National Aeronautics and Space Administration (NASA) was established, the NCAR was organized in Boulder, Colorado, under the sponsorship of the National Science Foundation, to coordinate the activities of more than 40 universities engaged in atmospheric and cosmic research. Among its activities, the organization has coordinated work in balloon construction, instrumentation, telemetry, and tracking and has launched some of the largest plastic balloons to date.

NASA also maintains a significant scientific balloon program. NASA's Scientific Ballooning Program plays an important role in the agency's scientific investigations into the upper atmosphere, high-energy astrophysics, stratospheric composition, meteorology, aeronomy (the science of the physics and chemistry of the upper atmosphere), and astronomy.

NASA uses large unmanned helium balloons to explore the atmosphere on the edge of space and to place scientific instruments and equipment into space. Balloons make an inexpensive platform for developing new technologies and payloads and are quick to construct. They also have more flight opportunities than rockets, satellites, or human missions and provide more accurate vertical flight profiles, although satellites provide broader area coverage. Balloons have been important for the development of spacecraft and spaceflight instrumentation. For example, the coronagraph used on Skylab (launched on May 4, 1973) was the final improved design stemming from earlier balloon-borne models.

In 2000, two balloon experiments sponsored by NASA, MAXIMA and BOOMERANG, determined that the Universe is geometrically flat; will expand forever; and comprises about five percent ordinary visible matter, thirty percent dark matter of an unknown nature, and 65 percent dark energy, a mysterious force that is accelerating the expansion rate of the Universe.

Cutting-edge cosmic radiation balloon research continues to the present day. On January 4, 2001, NASA launched TopHat successfully from McMurdo Station, Antarctica. TopHat is a hat-shaped experiment that sits on top of a main balloon and carries the Advanced Thin Ionization Calorimeter for Louisiana State University. The balloon circled above Antarctica at 120,000 feet (36,576 meters) for two weeks collecting light from the cosmic microwave background radiation. Observing the microwave background, which was formed 300,000 years after the big bang, enables scientists to understand the nature of the Universe when it was an infant. TopHat is just one of many balloon cosmic radiation experiments. The Advanced Thin Ionization Calorimeter, another balloon experiment that Louisiana State University has flown over Antarctica, gathered data on galactic cosmic rays.

Other research includes NASA's Ultra-Long Duration Balloon (ULDB) program, which has had two test launches from Alice Springs, Australia, in early 2001. ULDB is the largest single-cell, super-pressure (sealed) balloon ever flown. Made of a newer lightweight polyethylene, the balloon is partially inflated with helium at launch and expands as it rises. It uses enhanced computer technologies, high-tech materials, and advanced design for long-range (around the world), long-duration (100 days) flight. The ULDB floats at 115,000 feet (35 kilometers), three to four times higher than passenger planes and above 99 percent of the Earth's atmosphere. The project has been testing the balloon material on these launches and has determined that modifications to its composition may be needed. When the project becomes operational, ULDB experiments will study the source of cosmic rays generated from supernovae shock waves and survey X-ray-emitting objects in the universe.

--Linda Voss

Sources:

Memo From ULDB Project Manager Steve Smith, March 13, 2001.

"Ultra-Long Duration Balloon Status Report." NASA Release 01-40, March 12, 2001.

On-Line References:

"MSAM/TopHat." http://topweb.gsfc.nasa.gov/balloon/index.html

"All About Ballooning." http://topweb.gsfc.nasa.gov/balloon/index.html

NASA's Scientific Ballooning Program. http://lheawww.gsfc.nasa.gov/docs/balloon/balloon_top.html

Ultra-Long Duration Balloon Program. http://www.wff.nasa.gov/~uldb/index.html