[ExI] Vacuum Balloons Tech

[BillK]

So I discussed vacuum balloons with an AI (of course).  :)

The first response was that vacuum balloons are not possible at present.
(But I didn't let that deter me).

Answer -
No, vacuum balloons are not practically possible with current materials and
technology. Here are the key reasons why:

Buckling is the main issue that prevents vacuum balloons from being
feasible. The external atmospheric pressure would cause the vacuum balloon
shell to buckle and collapse inward, even for extremely strong materials
like diamond. [3] The required material strength-to-density ratio to resist
buckling exceeds what is achievable, even with theoretical materials like a
diamond shell or honeycomb structures. [3][4]

The compressive strength calculation alone is insufficient - it disregards
the buckling failure mode. Using the formula for critical buckling pressure
of a sphere shows that no known material can practically withstand the
immense external pressure. [3]

While some have proposed using a double-walled design with pressurized air
between the walls, this would negate any buoyancy benefits as the overall
density could not be less than air. [3]

Despite over 350 years of proposals and attempts, no one has successfully
demonstrated a working vacuum balloon prototype due to these fundamental
material limitations. [3][4] Vacuum balloons remain an unrealized
theoretical concept with current technology.

Citations:
[1]
https://engineering.stackexchange.com/questions/2307/can-vacuum-balloon-become-possible-with-this-idea
[2]
https://www.reddit.com/r/theydidthemath/comments/2e6m04/self_could_a_vacuum_balloon_be_possible/
[3] https://en.wikipedia.org/wiki/Vacuum_airship
[4] https://www.mdpi.com/2673-4117/2/4/30
[5]
https://science.howstuffworks.com/science-vs-myth/everyday-myths/question194.htm
--------------------

I didn't give up. As I had inside information, I asked - Is a Los Alamos
engineer working on this?

Answer -
Yes, according to the search results, Miles Beaux, a materials scientist at
the Los Alamos National Laboratory, is leading a team working on developing
a vacuum balloon or "air-buoyant craft" using ultra-lightweight aerogel
materials. [1][2]

The key points about Beaux's work on vacuum balloons at Los Alamos are:

- Beaux's goal is to develop an aircraft that floats without heat or helium
by creating a hollow sphere containing a vacuum, making it lighter than the
surrounding air to stay aloft. [2]

- They are using polyimide aerogels, which are extremely lightweight yet
strong enough to withstand atmospheric pressure and maintain the internal
vacuum. [2]

- They have produced small prototypes ranging from lemon to soccer ball
size that can hold a vacuum for up to 12 hours without active pumping. [3]

- However, these small prototypes are not yet buoyant in air. Beaux
estimates they need to build a 1.4-meter diameter sphere for it to generate
sufficient lift to float. [2]

- Beaux and his team have made rapid progress over the past five years,
progressing from aerogels 34 times denser than air to within 10 times the
density of air, which is close to achieving air buoyancy. [1]

So in summary, yes, the Los Alamos scientist Miles Beaux is actively
working on developing a practical vacuum balloon design using aerogel
materials as part of a team at the national laboratory. [1][2][3]

Citations:
[1]
https://www.thomasnet.com/insights/scientists-create-vacuum-balloon-for-air-travel/
[2]
https://discover.lanl.gov/publications/national-security-science/2021-winter/building-a-better-balloon/
[3]
https://www.salon.com/2020/09/27/helium-shortage-vacuum-balloons-science-medicine-party-industry-inventors-engineering/
[4]
https://discover.lanl.gov/publications/1663/2021-august/lighter-than-air/
[5] https://www.osti.gov/servlets/purl/1881814
----------------------

To clarify the problem, I then asked - What are the main challenges faced
by the Los Alamos team in developing the vacuum balloon?

Answer -
The main challenges faced by the Los Alamos team in developing the vacuum
balloon or "air-buoyant craft" are:

1. Scaling up the prototypes to a large enough size (around 1.4 meters
diameter) to generate sufficient buoyancy to float. So far, they have only
produced small prototypes ranging from lemon to soccer ball size that
cannot yet hover. [1][5]

2. Developing aerogel materials with the required combination of ultra-low
density (within 10 times the density of air), high strength to withstand
atmospheric pressure, and ability to maintain vacuum over long periods.
[1][5]

3. Engineering a vessel design and fabrication process that can create a
large, lightweight, vacuum-sealed sphere strong enough to avoid buckling
under external air pressure. [5]

4. Achieving a vacuum level inside the sphere that reduces its overall
density below that of air to enable buoyancy. [5]

5. Integrating a lightweight vacuum pump system to actively maintain the
vacuum over extended periods for sustained flight. [5]

6. Overcoming skepticism and the prevailing view that a practical vacuum
balloon is impossible to realize with current materials and technology. [5]

The Los Alamos team, led by Miles Beaux, has made significant progress by
using polyimide aerogels and advancing from prototypes 34 times denser than
air to within 10 times air density. However, scaling up to a buoyant
full-scale prototype remains a key challenge they are actively working to
overcome. [1][5]

Citations:
[1]
https://www.thomasnet.com/insights/scientists-create-vacuum-balloon-for-air-travel/
[2]
https://discover.lanl.gov/publications/1663/2021-august/lighter-than-air/
[3]
https://engineering.stackexchange.com/questions/2307/can-vacuum-balloon-become-possible-with-this-idea
[4] https://www.osti.gov/servlets/purl/1881814
[5]
https://discover.lanl.gov/publications/national-security-science/2021-winter/building-a-better-balloon/
-----------------------------

I note that the  AI mentions the vacuum pump requirement. An airship needs
a method of adjusting the buoyancy so that it can ascend and descend as
necessary. As well as drive engines.
Research continues.......

BillK
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