288:, is sometimes used as a lift gas when hydrogen and helium are not available. It has the advantage of not leaking through balloon walls as rapidly as the smaller molecules of hydrogen and helium. Many lighter-than-air balloons are made of aluminized plastic that limits such leakage; hydrogen and helium leak rapidly through latex balloons. However, methane is highly flammable and like hydrogen is not appropriate for use in passenger-carrying airships. It is also relatively dense and a potent
329:). It is non-flammable and much cheaper than helium. The concept of using steam for lifting is therefore already 200 years old. The biggest challenge has always been to make a material that can resist it. In 2003, a university team in Berlin, Germany, has successfully made a 150 °C steam lifted balloon. However, such a design is generally impractical due to high boiling point and condensation.
25:
159:, an amount of gas (and also a mixture of gases such as air) expands as it is heated. As a result, a certain volume of gas has a lower density as the temperature is higher. The temperature of the hot air in the envelope will vary depending upon the ambient temperature, but the maximum continuous operating temperature for most balloons is 250 °F (121 °C).
432:
590:
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aerogel material and the air contained within. In 2021, a group of researchers successfully levitated a series of carbon aerogels by heating them with a halogen lamp, which had the effect of lowering the density of the air trapped in the porous microstructure of the aerogel, allowing the aerogel to float.
624:
Because of the enormous density difference between water and gases (water is about 1,000 times denser than most gases), the lifting power of underwater gases is very strong. The type of gas used is largely inconsequential because the relative differences between gases is negligible in relation to the
457:
In a theoretically perfect situation with weightless spheres, a "vacuum balloon" would have 7% more net lifting force than a hydrogen-filled balloon, and 16% more net lifting force than a helium-filled one. However, because the walls of the balloon must be able to remain rigid without imploding, the
580:
This calculation is at sea level at 0 °C. For higher altitudes, or higher temperatures, the amount of lift will decrease proportionally to the air density, but the ratio of the lifting capability of hydrogen to that of helium will remain the same. This calculation does not include the mass of
194:
posed by hydrogen. The extremely high cost of helium (compared to hydrogen) has led researchers to re-investigate the safety issues of using hydrogen as a lift gas, especially for vehicles not carrying passengers and being deployed away from populated areas. With good engineering and good handling
470:
with a density less than air, the lightest recorded so far reaching a density approximately 1/6th that of air. Aerogels don't float in ambient conditions, however, because air fills the pores of an aerogel's microstructure, so the apparent density of the aerogel is the sum of the densities of the
601:
At higher altitudes, the air pressure is lower and therefore the pressure inside the balloon is also lower. This means that while the mass of lifting gas and mass of displaced air for a given lift are the same as at lower altitude, the volume of the balloon is much greater at higher altitudes.
129:
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 (gram per liter) at
340:
is lighter than air and could theoretically be used as a lifting gas. However, it is extremely corrosive, highly toxic, expensive, is heavier than other lifting gases, and has a low boiling point of 19.5 °C. Its use would therefore be impractical.
374:
is lighter than air (density 0.900 g/L at STP, average atomic mass 20.17 g/mol) and could lift a balloon. Like helium, it is non-flammable. However, it is rare on Earth and expensive, and is among the heavier lifting gases.
628:
A submerged balloon that rises will expand or even explode because of the strong pressure reduction, unless gas is able to escape continuously during the ascent or the balloon is strong enough to withstand the change in pressure.
272:
has been used as a lifting gas in balloons, but while inexpensive, it is relatively heavy (density 0.769 g/L at STP, average molecular mass 17.03 g/mol), poisonous, an irritant, and can damage some metals and plastics.
363:, which is 7% lighter than air, is technically capable of being used as a lifting gas at temperatures above its boiling point of 25.6 °C. Its extreme toxicity, low buoyancy, and low boiling point have precluded such a use.
182:
Hydrogen is extremely flammable. Some countries have banned the use of hydrogen as a lift gas for commercial vehicles but it is allowed for recreational free ballooning in the United States, United
Kingdom and Germany. The
701:
of earth atmospheric pressure – so a huge balloon would be needed even for a tiny lifting effect. Overcoming the weight of such a balloon would be difficult, but several proposals to explore Mars with balloons have been
260:
and other gases, was also used in balloons. It was widely available and cheap. Disadvantages include a higher density (reducing lift), its flammability and the high toxicity of the carbon monoxide content.
243:
that cannot be practically manufactured from other materials. When released into the atmosphere, e.g., when a helium-filled balloon leaks or bursts, helium eventually escapes into space and is lost.
170:, being the lightest existing gas (7% the density of air, 0.08988 g/L at STP), seems to be the most appropriate gas for lifting. It can be easily produced in large quantities, for example with the
540:= 9.8066 m/s = 9.8066 N/kg; V = volume (in m). Therefore, the amount of mass that can be lifted by hydrogen in air at sea level, equal to the density difference between hydrogen and air, is:
402:
is an unsaturated hydrocarbon that's 3% less dense than air. Unlike nitrogen however, ethylene is highly flammable and far more expensive, rendering use as a lifting gas highly impractical.
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235:
Although abundant in the universe, helium is very scarce on Earth. The only commercially viable reserves are a few natural gas wells, mostly in the US, that trapped it from the slow
609:), must be able to expand enormously in order to displace the required amount of air. That is why such balloons seem almost empty at launch, as can be seen in the photo.
206:
through many materials such as latex, so that the balloon will deflate quickly. This is one reason that many hydrogen or helium filled balloons are constructed out of
131:
391:
and abundantly available, because it is the major component of air. However, because nitrogen is only 3% lighter than air, it is not a good choice for a lifting gas.
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for a human habitat that would float in the atmosphere of Venus at an altitude where both the pressure and the temperature are Earth-like. In 1985, the Soviet
229:
The diffusion issue shared with hydrogen (though, as helium's molecular radius (138 pm) is smaller, it diffuses through more materials than hydrogen).
1403:
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are the most commonly used lift gases. Although helium is twice as heavy as (diatomic) hydrogen, they are both significantly lighter than air.
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352:
is 10% lighter than air and could be used as a lifting gas. Its extreme flammability and low lifting power make it an unattractive choice.
1005:
108:
812:
783:, can be filled with helium gas to create a solid which floats when placed in an open top container filled with a dense gas.
717:
1170:
Sun, Haiyan; Xu, Zhen; Gao, Chao (2013-02-18). "Multifunctional, Ultra-Flyweight, Synergistically
Assembled Carbon Aerogels".
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balloon is impractical to construct with any known material. Despite that, sometimes there is discussion on the topic.
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or partial vacuum. As early as 1670, over a century before the first manned hot-air balloon flight, the
Italian monk
763:
for the least dense (lightest) solid. Aerogel is mostly air because its structure is like that of a highly vacuous
508:) rather than upon their ratios. Thus the difference in buoyancies is about 8%, as seen from the buoyancy equation:
734:'s largest moon, has a dense, very cold atmosphere of mostly nitrogen that is appropriate for ballooning. A use of
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68:
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A balloon can only have buoyancy if there is a medium that has a higher average density than the balloon itself.
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is lighter than air (density 0.804 g/L at STP, average molecular mass 18.015 g/mol) due to water's low
616:. A superpressure balloon maintains a higher pressure inside the balloon than the external (ambient) pressure.
171:
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density of water. However, some gases can liquefy under high pressure, leading to an abrupt loss of buoyancy.
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is the second lightest gas (0.1786 g/L at STP). For that reason, it is an attractive gas for lifting as well.
75:
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A major advantage is that this gas is noncombustible. But the use of helium has some disadvantages, too:
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is about 50% denser than Earth air, ordinary Earth air could be a lifting gas on Venus. This has led to
639:(upside down bags) that they fill with air to lift heavy items like cannons and even whole ships during
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A different approach for high altitude ballooning, especially used for long duration flights is the
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879:(No. FAA-H-8083-11A). Washington, D.C.: Federal Aviation Administration. 2008. pp. 3-9–3-10.
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284:(density 0.716 g/L at STP, average molecular mass 16.04 g/mol), the main component of
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deployed two helium balloons in Venus's atmosphere at an altitude of 54 km (34 mi).
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Sean A. Barton (21 October 2009). "Stability
Analysis of an Inflatable Vacuum Chamber".
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It is also possible to combine some of the above solutions. A well-known example is the
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The lifting power in air of hydrogen and helium can be calculated using the theory of
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Thus helium is almost twice as dense as hydrogen. However, buoyancy depends upon the
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it is however a major safety hazard, on a scale even greater than that of hydrogen.
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Therefore, the amount of mass that can be lifted by helium in air at sea level is:
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is slightly lighter than molecular nitrogen with a molecular mass of 27.7. Being
1231:"Light-induced levitation of ultralight carbon aerogels via temperature control"
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is due primarily to the large proportion of air within the solid and not the
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are a type of deep-sea submersibles that use gasoline as the "lifting gas".
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of radioactive materials within Earth. By human standards, helium is a
1408:
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1229:
Yanagi, Reo; Takemoto, Ren; Ono, Kenta; Ueno, Tomonaga (2021-06-14).
892:"Long Permanence High Altitude Airships: The Opportunity of Hydrogen"
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and the buoyant force for one m of hydrogen in air at sea level is:
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when compared with typical atmospheric gases such as nitrogen gas (N
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and the buoyant force for one m of helium in air at sea level is:
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207:
1078:"HeiDAS UH – Ein Heissdampfaerostat mit ultra-heiss-performance"
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or pumped through a hose from the diver's ship on the surface.
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which combines a core of helium with an outer shell of hot air.
138:, and so lighter-than-air gases have a density lower than this.
890:
Bonnici, Maurizio; Tacchini, Alessandro; Vucinic, Dean (2014).
18:
988:
Speight, James G. (2000). "Fuels, Synthetic, Gaseous Fuels".
953:(Thesis). OPUS Augsburg, University at Augsburg. p. 30.
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use ballast tanks and trim tanks with air to regulate their
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While not a gas, it is possible to synthesize an ultralight
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Theoretically, an aerostatic vehicle could be made to use a
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Thus hydrogen's additional buoyancy compared to helium is:
950:
Permeation
Barrier for Lightweight Liquid Hydrogen Tanks
605:
A balloon that is designed to lift to extreme heights (
1241:(1). Springer Science and Business Media LLC: 12413.
746:
proposal included a balloon to circumnavigate Titan.
16:
Gas used to create buoyancy in a balloon or aerostat
49:. Unsourced material may be challenged and removed.
775:construction materials. Taking advantage of this,
691:has a very thin atmosphere – the pressure is only
597:that has been able to reach a height of 36 km
195:practices, the risks can be significantly reduced.
134:(STP) and an average molecular mass of 28.97
1376:SEAgel Aerogel lighter than air solid. Not a UFO
132:standard conditions for temperature and pressure
990:Kirk-Othmer Encyclopedia of Chemical Technology
202:hydrogen molecule is very small, it can easily
779:, in the same family as aerogel but made from
568:1 m × 1.114 kg/m × 9.8 N/kg= 10.9 N
552:1 m × 1.202 kg/m × 9.8 N/kg= 11.8 N
151:Heated atmospheric air is frequently used in
8:
1325:"NASA's 'frozen smoke' named lightest solid"
454:envisioned a ship with four vacuum spheres.
581:the envelope need to hold the lifting gas.
1348:Administrator, NASA Content (2015-04-15).
178:, but hydrogen has several disadvantages:
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1246:
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965:"Balloon flight - Historical development"
915:
576:11.8 / 10.9 ≈ 1.08, or approximately 8.0%
190:is frequently cited as an example of the
109:Learn how and when to remove this message
308:Gases theoretically suitable for lifting
1027:The Boston Medical and Surgical Journal
998:10.1002/0471238961.0701190519160509.a01
844:
544:(1.292 - 0.090) kg/m = 1.202 kg/m
1350:"Aerogels: Thinner, Lighter, Stronger"
1107:Tom D. Crouch (2009). Lighter Than Air
661:, essentially making them underwater "
560:(1.292 - 0.178) kg/m = 1.114 kg/m
1289:"Is There an Atmosphere on the Moon?"
7:
1057:Colorado Aviation Historical Society
685:because it has almost no atmosphere.
47:adding citations to reliable sources
1053:"Timothy S. Cole - Honored in 1995"
896:European Transport Research Review
673:Balloons on other celestial bodies
647:. The air is either supplied from
14:
1323:Stenger, Richard (May 9, 2002).
23:
1383:from the original on 2021-12-21
1021:Terry, Herbert (14 July 1881).
813:Buoyancy compensator (aviation)
34:needs additional citations for
1404:Lighter-than-air - An overview
1303:"Exploring Mars With Balloons"
818:Cloud Nine (tensegrity sphere)
1:
833:Vacuum airship/Vacuum balloon
387:has the advantage that it is
1119:Journal of Applied Mechanics
681:Balloons cannot work on the
1083:. Aeroix.de. Archived from
1039:10.1056/NEJM188107141050202
947:Schultheiß, Daniel (2007).
744:Titan Saturn System Mission
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1248:10.1038/s41598-021-91918-5
857:www.engineeringtoolbox.com
538:gravitational acceleration
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917:10.1007/s12544-013-0123-z
256:, a mixture of hydrogen,
1178:(18). Wiley: 2554–2560.
853:"Air - Molecular Weight"
767:. The lightness and low
585:High-altitude ballooning
172:water-gas shift reaction
969:Encyclopedia Britannica
877:Balloon Flying Handbook
452:Francesco Lana de Terzi
153:recreational ballooning
1192:10.1002/adma.201204576
712:atmosphere. Because CO
641:underwater archaeology
598:
475:Hydrogen versus helium
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319:gaseous state of water
241:non-renewable resource
142:Gases used for lifting
1429:Hydrogen technologies
1373:Grommo (2008-06-20),
761:Guinness World Record
614:superpressure balloon
592:
434:
1023:"Coal-Gas Poisoning"
532:= Buoyant force (in
232:Helium is expensive.
127:lighter-than-air gas
43:improve this article
1409:Airship Association
1184:2013AdM....25.2554S
1141:2008JAM....75d1010B
908:2014ETRR....6..253B
645:shipwreck salvaging
500:of the densities (ρ
155:. According to the
1434:Airship technology
1235:Scientific Reports
1172:Advanced Materials
803:Balloon (aircraft)
620:Submerged balloons
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1149:10.1115/1.2912742
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333:Hydrogen fluoride
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58:"Lifting gas"
55:
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48:
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37:
32:This article
30:
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1454:Mass density
1385:, retrieved
1375:
1368:
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1353:
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1085:the original
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722:Vega program
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637:lifting bags
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607:stratosphere
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313:Water vapour
299:
296:Combinations
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198:Because the
192:safety risks
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176:electrolysis
166:
150:
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99:October 2012
96:
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41:Please help
36:verification
33:
286:natural gas
237:alpha decay
208:Mylar/BoPET
123:lifting gas
1418:Categories
1387:2018-01-16
1359:2018-01-16
1334:2018-01-16
1309:2012-10-21
1094:2012-10-21
974:2021-08-17
862:2018-01-16
839:References
655:Submarines
498:difference
415:pyrophoric
323:molar mass
186:Hindenburg
69:newspapers
1424:Aerostats
1257:2045-2322
1216:205248394
1200:0935-9648
1157:118896629
1062:17 August
934:255617917
926:1866-8887
759:held the
755:In 2002,
718:proposals
593:MAXIS: a
524:) × g × V
350:Acetylene
345:Acetylene
1439:Buoyancy
1381:archived
1275:34127746
1208:23418099
808:Buoyancy
793:Aerostat
787:See also
740:proposed
736:aerobots
708:has a CO
663:airships
659:buoyancy
491:buoyancy
480:Hydrogen
411:Diborane
406:Diborane
400:Ethylene
395:Ethylene
385:nitrogen
379:Nitrogen
254:coal gas
248:Coal gas
200:diatomic
188:disaster
168:Hydrogen
163:Hydrogen
1266:8203743
1180:Bibcode
1137:Bibcode
904:Bibcode
798:Airship
773:silicon
769:density
757:aerogel
696:⁄
595:balloon
536:); g =
528:Where F
468:aerogel
462:Aerogel
282:Methane
277:Methane
270:Ammonia
265:Ammonia
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777:SEAgel
765:sponge
751:Solids
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732:Saturn
633:Divers
534:Newton
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484:helium
448:vacuum
442:(1670)
421:Vacuum
220:Helium
215:Helium
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1444:Gases
1212:S2CID
1153:S2CID
1127:arXiv
1088:(PDF)
1081:(PDF)
930:S2CID
728:Titan
706:Venus
702:made.
389:inert
383:Pure
136:g/mol
90:JSTOR
76:books
1354:NASA
1271:PMID
1253:ISSN
1204:PMID
1196:ISSN
1064:2021
1002:ISBN
922:ISSN
781:agar
689:Mars
683:Moon
643:and
635:use
516:= (ρ
482:and
435:The
372:Neon
367:Neon
317:The
62:news
1261:PMC
1243:doi
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