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(aerospace engineering)
Any aircraft that derives its buoyancy or lift from a lighter-than-air gas contained within its envelope or one of its compartments; for example, ships and balloons.



an aircraft that is lighter than air. The lifting force of an aerostat is produced by a gas that is less dense than air—hydrogen or helium—contained in a casing, in conformity with Archimedes’ principle. A distinction is made between controlled (dirigible), noncontrolled or free-flight (with a spherical casing—spherical aerostats or balloons and stratostats), and captive (kite) aerostats. Variation in the flight altitude of a free aerostat is realized in the following manner: lift is achieved by reducing the mass of the aerostat by discarding part of the ballast (usually bags of sand); descent is accomplished by decreasing the lifting force through the release of part of the gas through a valve. The lift and descent of a captive aerostat are accomplished with a winch.

Free aerostats are used chiefly for sporting and research purposes. Radiosondes, rescue aerostats, pilot balloons, jumper halloons, stratostats, and automatic aerostats with telemetric, meteorological, and other equipment are examples of free aerostats. Automatic aerostats are used to investigate jet streams and the formation of cyclones, for photographing the earth’s surface, in the determination of the effect of cosmic radiation in the lower layers of the stratosphere on living organisms, and also as starting platforms for the launching of meteorological rockets and as a means of elevating telescopes. Captive aerostats are used for meteorological purposes (probing of the atmosphere), in the hauling of timber in mountainous regions that are otherwise inaccessible, and so on.

Barrage aerostats are used in military work for antiaircraft defense of military, industrial, and other objectives. When air attack threatens, the aerostats ascend into the air in specific combat arrangements (“winches in a line,” “winches in two lines,” “winches over an area”). Their action is calculated for the destruction or damage of enemy airplanes by collision with cables, aerostat casings, or explosive charges suspended on the cables. During the Great Patriotic War, barrage aerostats of 100–400 cu m in volume were successfully used in the antiaircraft defense systems of Moscow, Leningrad, and other cities. Single barrage aerostats ascended to an altitude of up to 2,500 m, double ones (two aerostats on one cable) up to 4,500 m. Observation aerostats are employed to observe the field of battle and to correct the firing of artillery. They have a suspended gondola for the crew and are equipped with a telephone connection to the ground. The volume of observation aerostats is 400–1,000 cu m and higher.


Polozov, N. P., and M. A. Sorokin. Vozdukhoplavanie. Moscow, 1940.
Stobrovskii, N. G. Nasha strana—rodina vozdukhoplavaniia. Moscow, 1954.


aerostatclick for a larger image
A lighter-than-air craft that can be either a balloon or an airship. It normally refers to the former. It is buoyant in atmosphere up to a height at which it displaces air equal to its mass. It is normally tethered and carries a payload consisting of radar, communications, or other observation devices.
References in periodicals archive ?
Similar in size to the TV antenna, each aerostat radar is a work of art.
Throughout the route brief, the section lead failed to brief the location of, or a plan for transiting areas where aerostats were operating.
It will be on the lines of an aerostat blimp, except that it will not be tethered but move freely because it will be propulsionbased.
Commenting on the deal, CEO Ali Al Yafei said: "The existing co-operation between ADASI, as developers of aerostat systems, and Icarus, as accomplished manufacturers of aerostat envelopes, has made it clear to both parties that there is great potential in establishing an even closer level of co-operation in the future.
Caption: The unusual combination of Military Sealift Command high-speed vessel Swift (HSV-2) and a tethered Raven Aerostar TIF-25K aerostat demonstrated their potential counter illicit trafficking and other transnational organised crime at sea during Operation Martillo in the Caribbean in spring 2013.
com/research/n7mv7p/global_aerostat) has announced the addition of the "Global Aerostat Systems Market 2015-2019" report to their offering.
NORAD officials are working closely with the FAA (Federal Aviation Administration) to ensure air traffic safety, as well as with our other interagency partners to address the safe recovery of the aerostat," said the statement.
Limited Tenders are invited for Procurement Of Aerostat Spares
Just east of busy Interstate 95 at Aberdeen Proving Grounds in Maryland, a powerful radar attached to an aerostat scans the air and sea for threats.
The efficiency of the aerostat provides army personnel the advantage of earlier enemy detection, giving them an ample time to strategise their defence.
John Christopher, editor of the professional balloonists' magazine Aerostat, said: "He is a very likeable guy who is not a great egotist.