The Global horizontal sounding technique (GHOST) program was an atmospheric field research project in the late 1960s for investigating the technical ability to gather weather data using hundreds of simultaneous long-duration
balloon
A balloon is a flexible bag that can be inflated with a gas, such as helium, hydrogen, nitrous oxide, oxygen, and air. For special tasks, balloons can be filled with smoke, liquid water, granular media (e.g. sand, flour or rice), or light so ...
s for very long-range global scale
numerical weather prediction
Numerical weather prediction (NWP) uses mathematical models of the atmosphere and oceans to predict the weather based on current weather conditions. Though first attempted in the 1920s, it was not until the advent of computer simulation in th ...
[ in preparation for the ]Global Atmospheric Research Program The Global Atmospheric Research Program was a fifteen-year international research programme led by the World Meteorological Organization and the International Council of Scientific Unions. It began in 1967 and organised several important field exper ...
(GARP).
Technology
The GHOST program was to demonstrate technology for a program that would, ultimately, gather data from thousands of balloons simultaneously.[ Unlike ]radiosonde
A radiosonde is a battery-powered telemetry instrument carried into the atmosphere usually by a weather balloon that measures various atmospheric parameters and transmits them by radio to a ground receiver. Modern radiosondes measure or calcula ...
balloons which collect vertical atmospheric sounding Atmospheric sounding or atmospheric profiling is a measurement of vertical distribution of physical properties of the atmospheric column such as pressure, temperature, wind speed and wind direction (thus deriving wind shear), liquid water content, ...
data over the release point during a relatively short ascent lasting a few hours, horizontal sounding balloons stay aloft for much longer periods lasting several weeks or months, floating at a constant-density altitude.
The GHOST design explored the performance a superpressure balloon
A superpressure balloon (SPB) is a style of aerostatic balloon where the volume of the balloon is kept relatively constant in the face of changes in ambient pressure outside the balloon, and the temperature of the contained lifting gas. This all ...
with a spherical two-layer PET film envelope holding the gas inside at a higher pressure than the surrounding atmosphere, allowing it to maintain a nearly constant altitude. These gas balloon
A gas balloon is a balloon that rises and floats in the air because it is filled with a gas lighter than air (such as helium or hydrogen). When not in flight, it is tethered to prevent it from flying away and is sealed at the bottom to prevent t ...
s float at a constant density altitude
The density altitude is the altitude relative to standard atmospheric conditions at which the air density would be equal to the indicated air density at the place of observation. In other words, the density altitude is the air density given as ...
,lifting gas
A lifting gas or lighter-than-air gas is a gas that has a density lower than normal atmospheric gases and rises above them as a result. It is required for aerostats to create buoyancy, particularly in lighter-than-air aircraft, which include free ...
due to solar heating[ is avoided in a superpressure balloon, since the inextensible PET film allows the pressure to rise as the gas is heated, rather than allow the volume to expand. This allows them to drift with, and track, horizontal atmospheric air currents at a constant air pressure level (a constant altitude) above the Earth's surface.
The electronics payload was suspended below the balloon on a tether that also acted as a ]high frequency
High frequency (HF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten ...
band radio antenna
In radio engineering, an antenna or aerial is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver. In transmission, a radio transmitter supplies an ...
. The GHOST payload included a sun angle sensor that varied the repetition rate of its Morse code
Morse code is a method used in telecommunication to encode text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code is named after Samuel Morse, one of ...
radio signal to allow technicians on the ground to locate it using an HF receiver and a set of sun angle tables.[
The balloons could not be flown in the Northern Hemisphere because the ]Soviet Union
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...
would not permit overflights at the time.
Results
231 GHOST balloons were launched in a four-year period between March 1966 and December 1969.Christchurch
Christchurch ( ; mi, Ōtautahi) is the largest city in the South Island of New Zealand and the seat of the Canterbury Region. Christchurch lies on the South Island's east coast, just north of Banks Peninsula on Pegasus Bay. The Avon River / ...
, New Zealand by the U.S. National Center for Atmospheric Research
The US National Center for Atmospheric Research (NCAR ) is a US federally funded research and development center (FFRDC) managed by the nonprofit University Corporation for Atmospheric Research (UCAR) and funded by the National Science Foundatio ...
(NCAR), continued to fly for an additional 76 days, completing 35 circumnavigation
Circumnavigation is the complete navigation around an entire island, continent, or astronomical object, astronomical body (e.g. a planet or natural satellite, moon). This article focuses on the circumnavigation of Earth.
The first recorded circ ...
s of the Earth. The longest flight of the program was 744 days, or just over two years.
Legacy
For the measurements of the GARP program, the demonstrated flight lifetime at low altitudes (below 12 km) proved to be too short, despite many redesigns of the balloon system to improve the performance. Without both upper level and lower level long-duration balloons, the GHOST system idea was deemed infeasible for the GARP requirements. The GHOST program was superseded by research on the 'Carrier Balloon' system, also known as 'Mother GHOST'.Vincent E. Lally
Vincent E. Lally (October 13, 1922 – September 20, 2005) received a B.S. in Meteorology from the University of Chicago in 1944. After service in the Pacific as a meteorologist and radar officer in the United States Army Air Corps, Army Air Corps ...
of NCAR received the Otto C. Winzen Lifetime Achievement Award from the American Institute of Aeronautics and Astronautics
The American Institute of Aeronautics and Astronautics (AIAA) is a professional society for the field of aerospace engineering. The AIAA is the U.S. representative on the International Astronautical Federation and the International Council of ...
in 2003 for his pioneering work in the application and development of superpressure balloons for worldwide atmospheric measurements, including the GHOST program.
References
Further reading
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*{{cite journal
, doi = 10.1175/1520-0469(1973)030<0003:TMUAFI>2.0.CO;2
, author = Solot, S.B.
, author2=Angell, J.K.
, year = 1972
, title = The Mean Upper-Air Flow in Southern Hemisphere Temperate Latitudes Determined from Several Years of GHOST Balloon Flights at 200 and 100 mb
, journal = Journal of the Atmospheric Sciences
, volume = 30
, issue = 1
, pages = 3–12
, issn = 1520-0469
, bibcode = 1973JAtS...30....3S , doi-access = free
External links
MSN Encarta: Ballooning
2009-10-31)
Balloons (aeronautics)
Uncrewed vehicles
Meteorological instrumentation and equipment
Scientific observation