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A zero-pressure balloon (ZP) is a style of aerostatic balloon that is unsealed at its base, creating a mechanism by which lifting gas can vent out the bottom of the balloon when the balloon becomes full, allowing the balloon to float at stable altitudes. During the day the gas heats up in the sun, and at night the gas cools causing them to descend. This limits the flight time of this type of balloon. [1] [2]
The Columbia Scientific Balloon Facility has flown more than 1,700 scientific balloons over 40 years and currently launches between 10 and 15 flights of this type of balloon per year. [1]
Zero-pressure balloons are filled with a lighter-than-air lift gas at a launch site where they are held to the ground during the launch process. Because lift gas expands as a balloon ascends, they are always smaller at launch then they are at higher altitudes. [3]
When ready to launch, the balloon is released and, if filled properly, will start to rise. As the balloon rises, the lift gas within it will expand causing the envelope to get larger. Zero pressure balloons are equipped with ducts to help release excess gas and manage internal pressure as the balloon ascends. The ducts allow excess gas to escape when the balloon gets full during ascent. As the balloon approaches the altitude at which it will float, it will continue to vent the lift gas that is causing it to rise. The more lift gas the balloon expels the less free lifting force exists and the slower the balloon will ascend until eventually it will stop ascending and start to "float", or remain at an altitude in the sky neither going up nor down. [3]
Zero Pressure Balloons can be designed with a natural balloon shape or near natural shape, meaning there is no circumferential stress on the balloon envelope. This design form allows the balloon shape to be both maximally efficient (meaning the least amount of balloon film possible is used for a given volume) while still being unpressurized. The natural balloon shape typically roughly resembles an elipsoid atop a cone. [4]
A hot air balloon is a lighter-than-air aircraft consisting of a bag, called an envelope, which contains heated air. Suspended beneath is a gondola or wicker basket, which carries passengers and a source of heat, in most cases an open flame caused by burning liquid propane. The heated air inside the envelope makes it buoyant, since it has a lower density than the colder air outside the envelope. As with all aircraft, hot air balloons cannot fly beyond the atmosphere. The envelope does not have to be sealed at the bottom, since the air inside the envelope is at about the same pressure as the surrounding air. In modern sport balloons the envelope is generally made from nylon fabric, and the inlet of the balloon is made from a fire-resistant material such as Nomex. Modern balloons have been made in many shapes, such as rocket ships and the shapes of various commercial products, though the traditional shape is used for most non-commercial and many commercial applications.
An aerobot is an aerial robot, usually used in the context of an uncrewed space probe or unmanned aerial vehicle.
An airship, dirigible balloon or dirigible is a type of aerostat (lighter-than-air) aircraft that can navigate through the air flying under its own power. Aerostats use buoyancy from a lifting gas that is less dense than the surrounding air to achieve the lift needed to stay airborne.
Jacques Alexandre César Charles was a French inventor, scientist, mathematician, and balloonist. Charles wrote almost nothing about mathematics, and most of what has been credited to him was due to mistaking him with another Jacques Charles, also a member of the Paris Academy of Sciences, entering on 12 May 1785.
An aerostat is a lighter-than-air aircraft that gains its lift through the use of a buoyant gas. Aerostats include unpowered balloons and powered airships. A balloon may be free-flying or tethered. The average density of the craft is lower than the density of atmospheric air, because its main component is one or more gasbags, a lightweight skin containing a lifting gas to provide buoyancy, to which other components such as a gondola containing equipment or people are attached. Especially with airships, the gasbags are often protected by an outer envelope.
In aeronautics, a balloon is an unpowered aerostat, which remains aloft or floats due to its buoyancy. A balloon may be free, moving with the wind, or tethered to a fixed point. It is distinct from an airship, which is a powered aerostat that can propel itself through the air in a controlled manner.
This is a list of aviation-related events during the 18th century :
A gas balloon is a balloon that rises and floats in the air because it is filled with a gas lighter than air. When not in flight, it is tethered to prevent it from flying away and is sealed at the bottom to prevent the escape of gas. A gas balloon may also be called a Charlière for its inventor, the Frenchman Jacques Charles. Today, familiar gas balloons include large blimps and small latex party balloons. For nearly 200 years, well into the 20th century, manned balloon flight utilized gas balloons before hot-air balloons became dominant. Without power, heat or fuel, untethered flights of gas balloons depended on the skill of the pilot. Gas balloons have greater lift for a given volume, so they do not need to be so large, and they can stay up for much longer than hot air balloons.
The Columbia Scientific Balloon Facility (CSBF), established in 1961 and formerly known as the National Scientific Balloon Facility (NSBF), is a NASA facility responsible for providing launch, tracking and control, airspace coordination, telemetry and command systems, and recovery services for unmanned high-altitude balloons. Customers of the CSBF include NASA centers, universities, and scientific groups from all over the world.
JP Aerospace is an American company that aims to achieve affordable access to space. Their main activities include high-atmospheric lighter-than-air flights carrying cameras or miniature experiments called PongSats and minicubes. They are also engaged in an Airship to Orbit project.
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 allows the balloon to keep a stable altitude for long periods. This is in contrast with much more common variable-volume balloons, which are either only partially filled with lifting gas, or made with more elastic materials. Also referred to as pumpkin or ultra long distance balloons (ULDB) balloons, the sealed balloon envelopes have a pumpkin shape at flight altitude.
Cluster ballooning is an extreme sport and a form of ballooning where a harness attaches a balloonist to a cluster of helium-inflated rubber balloons.
A thermal airship is an airship that generates buoyancy by heating air in a large chamber or envelope. The lower density of interior hot air compared to cool ambient air causes an upward force on the envelope. This is very similar to a hot air balloon, with the notable exception that an airship has a powered means of propulsion, whilst a hot air balloon relies on winds for navigation. An airship that uses steam would also qualify as a thermal airship.
A sky anchor is a system of two balloons in tandem, with a "zero-pressure" lifting gas balloon tethered to a superpressure balloon "anchor". The gas balloon is filled with a lifting gas and provides the buoyancy, while the superpressure balloon is filled with air, and pressurized to provide the desired ballast weight. In a passive sky anchor, the superpressure balloon is sealed, while in an active system, its pressure can be varied. Both versions have been tested in flight, but have had frequent failures with only occasional successful outcomes. The tandem arrangement makes launching difficult, and this complexity can lead to mission failure.
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, making it useful in lifting lighter-than-air aircraft. Only certain lighter than air gases are suitable as lifting gases. Dry air has a density of about 1.29 g/L at standard conditions for temperature and pressure (STP) and an average molecular mass of 28.97 g/mol, and so lighter-than-air gases have a density lower than this.
Osoaviakhim-1 was a record-setting, hydrogen-filled Soviet high-altitude balloon designed to seat a crew of three and perform scientific studies of the Earth's stratosphere. On January 30, 1934, on its maiden flight, which lasted over 7 hours, the balloon reached an altitude of 22,000 metres (72,000 ft). During the descent the balloon lost its buoyancy and plunged into an uncontrolled fall, disintegrating in the lower atmosphere. The three crew members, probably incapacitated by high g-forces in a rapidly rotating gondola, failed to bail out and were killed by the high-speed ground impact.
USSR-1 was a record-setting, hydrogen-filled Soviet Air Forces high-altitude balloon designed to seat a crew of three and perform scientific studies of the Earth's stratosphere. On September 30, 1933, USSR-1 under Georgy Prokofiev's command set an unofficial world altitude record of 18,501 m (60,699 ft).
Les Frères Robert were two French brothers. Anne-Jean Robert (1758–1820) and Nicolas-Louis Robert (1760–1820) were the engineers who built the world's first hydrogen balloon for professor Jacques Charles, which flew from central Paris on 27 August 1783. They went on to build the world's first manned hydrogen balloon, and on 1 December 1783 Nicolas-Louis accompanied Jacques Charles on a 2-hour, 5-minute flight. Their barometer and thermometer made it the first balloon flight to provide meteorological measurements of the atmosphere above the Earth's surface.
For environmental monitoring, Project Grab Bag was an air sampling program conducted in the United States in the stratosphere of above-ground nuclear weapons testing in the Soviet Union.
A balloon is a flexible membrane bag that can be inflated with a gas, such as helium, hydrogen, nitrous oxide, oxygen, or air. For special purposes, balloons can be filled with smoke, liquid water, granular media, or light sources. Modern day balloons are made from materials such as rubber, latex, polychloroprene, or a nylon fabric, and can come in many different colors. Some early balloons were made of dried animal bladders, such as the pig bladder. Some balloons are used for decorative purposes or entertaining purposes, while others are used for practical purposes such as meteorology, medical treatment, military defense, or transportation. A balloon's properties, including its low density and low cost, have led to a wide range of applications.
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