Talk:Space elevator safety

This is the talk page for discussing improvements to the Space elevator safety article.
This is not a forum for general discussion of the article's subject.

Put new text under old text. Click here to start a new topic.
New to Wikipedia? Welcome! Learn to edit; get help.

Article policies

Find sources: Google (books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL

Spaceflight Low‑importance

	Spaceflight portal This article is within the scope of WikiProject Spaceflight, a collaborative effort to improve the coverage of spaceflight on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.SpaceflightWikipedia:WikiProject SpaceflightTemplate:WikiProject Spaceflightspaceflight articles
Low	This article has been rated as Low-importance on the project's importance scale.

Architecture

	Architecture portal This article is within the scope of WikiProject Architecture, a collaborative effort to improve the coverage of Architecture on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.ArchitectureWikipedia:WikiProject ArchitectureTemplate:WikiProject ArchitectureArchitecture articles
???	This article has not yet received a rating on the project's importance scale.

Engineering

	Engineering portal This article is within the scope of WikiProject Engineering, a collaborative effort to improve the coverage of engineering on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.EngineeringWikipedia:WikiProject EngineeringTemplate:WikiProject EngineeringEngineering articles
???	This article has not yet received a rating on the project's importance scale.

Citataions Needed[edit]

Each section is clearly marked "Citations needed", why all the extra ones in the text itself? --D3matt (talk) 00:06, 23 August 2009 (UTC)[reply]

Effects of Thermal Fluctuations[edit]

The article might include some information about the problems induced by fluctuations in the thermal environment of the cable. The linear coefficient of thermal expansion for graphite is relatively small. A nominal value is 1.4x10^-6 °F^-1. But a cable up to geosynchronous orbit is 35,786 km long and for a uniform temperature change of 10 °C the thermal expansion would be 0.9 km. The difference between day and night temperatures at the ground level can be 15 °C or so and one would expect higher fluctuation at higher altitudes. The cable would be exposed to thermal cycling and one would have to take into consideration the thermal stresses that would be induced and compensate for the changes in length. --Jbergquist (talk) 00:24, 29 September 2009 (UTC)[reply]

The worst case scenerio for thermal fluctuations is when the cable passes through the Earth's shadow at the time of the equinoxes. The difference between lunar day and night temperatures is 260 °C. Most of the cable will pass in and out of the shadow at the same time. Normally most of the cable will be sunlit but the portion below low Earth orbit will experience more regular thermal cycling. --Jbergquist (talk) 01:49, 29 September 2009 (UTC)[reply]

For a space elevator rotating in a plane passing through both the Sun and the Earth (conditions at equinox) one can estimate the thermal fluctuations by assuming that the elevator behaves thermally like a black body. One can see the effects of thermal inertia in the following table,

Diameter (m)	Mean Temp (°C)	P-P ΔT (°C)
0.2	-10.16	31.14
2.0	-8.67	3.29
20.0	-8.66	0.33

The are two cycles per day. --Jbergquist (talk) 05:55, 29 September 2009 (UTC)[reply]

Highly biased framing... propose changing title...[edit]

The framing of this article is highly biased and negative. Did Chicken Little write this? In any engineering project, engineering challenges must be addressed. This is no different. Space elevators tend to attract smart people who are good at thinking up things that could be a problem. By framing those things as important "show stoppers", it strokes the ego of the guy who thought it up! I've seen this over and over again. Smart guys immediately start thinking about ways it can't work. Good for them. We need to think ahead and address real problems.

But, not all of them are real problems. Indeed, some are not problems at all and need have no impact on design. Most have simple low risk solutions straightforwardly addressable by simple low-impact design features. Some are more difficult to address and pose greater challenges, however "SHOW STOPPER" should never be used (or implied). In addition to the phrase being flippant and unencyclopedic, "SHOW STOPPER" implies that there is no solution around the problem. "SHOW STOPPER" is extremely biased toward a negative perspective and not neutral.

"Safety" as in "Space Elevator Safety" is an inappropriate title as most of the items listed are not "safety" issues, but merely normal engineering design challenges. Some are "safety" with regard to possible hazards to the system, but few are actual human safety-of-life issues.

I propose the article be retitled "Space Elevator Design Challenges" or something like that.

108.7.5.106 (talk) 17:33, 9 August 2010 (UTC)[reply]

"Show Stopper" can be used as part of a quote, of course. But, the tone of the quote should be properly interpreted. The editor/writer needs to 1) apply his/her expertise, and 2) take the quote in context. "Show stopper" in the quote didn't really mean "well, that's it, space elevator is impossible". The guy was just being colorful. The editor's expertise (and neutrality) must desaturate the color and not be pushed around by it! :-)

108.7.5.106 (talk) 17:42, 9 August 2010 (UTC)[reply]

Regarding the last paragraph on the Van Allen belts and shielding, I noticed that in the Wikipedia entry on boron nitrade (under nanotubes) states "BN materials are of particular theoretical value as composite structural materials in future manned interplanetary spacecraft, where absorption-shielding from cosmic ray spallation neutrons is expected to be a particular asset in light construction materials." Is this relevant to the Van Allen belts discussion? Star A Star (talk) 07:47, 24 October 2011 (UTC)[reply]

Human Caused Problems[edit]

The main page fails to mention the most obvious causes for problems and failure of a space elevator- people. War and terrorism come immediately to mind, but threats might also come from the odd disgruntled citizen or employee and rebellious teenagers. It might be impossible to protect every inch of the cable from attacks, either from the surface of the planet or from space. Without such protection, however, what would be the point of creating the structure in the first place. Your trillions of dollars gone, poof! The space elevator might be highly desirable, and technologically feasible in the near future, but unless its made of sterner stuff, it will be a waste of money in a trice. 67.81.236.32 (talk) 00:47, 23 November 2011 (UTC)[reply]

True, they would require defense, but that is no different than any other piece of high-value infrastructure. The possible need for national military-strength defense (or other national-level intelligence for prevention) might be the thing that causes these things to be "national assets" as opposed to private enterprises that many (like myself) imagine and prefer.

But then, they could also be designed creatively to require less defense, so that the efficiency of defense brings the defense costs down to levels feasible for private investment to take the full risk. I have some ideas about how to do that, but I'm not talking about them here! :-)

108.7.10.211 (talk) 23:43, 15 June 2012 (UTC)[reply]

Direction of fall[edit]

"If the break occurred at higher altitude, up to about 25,000 km, the lower portion of the elevator would descend to Earth and drape itself along the equator east of the anchor point"

The citation doesn't mention direction (east or west). However, the Earth rotates east, so I would assume the cable falls to the west. 98.127.119.21 (talk) 23:55, 6 April 2014 (UTC)[reply]

My assumption is that it's not this simple. E.g. the cable could break apart while falling - just how would depend on the material and it's construction. E.g. each sliver of the cable is moving at a different sub-orbital speed, which might cause the falling cable to curve in unobvious ways as it falls. E.g. some of the cable might melt as the atmosphere slows it down and heats it up. So you have to choose a material & structure, and then do the mathematical modeling to see what would happen in each case. Lentower (talk) 04:49, 7 April 2014 (UTC)[reply]

Electrostatic fields[edit]

There's ANYTHING about Electrostatic risks!

Electrostatic fields could create different types of problems (tape jam, lightnings, etc.)

Even a very little electrostatic difference could make tapes collide frequently, due to their length and reciprocal narrowness.

Electrostatic fields can be originated by radiations, climber's friction, atmospherical phenomena. — Preceding unsigned comment added by 95.232.15.59 (talk) 04:50, 26 April 2014 (UTC) 95.232.15.59 (talk) 04:53, 26 April 2014 (UTC)[reply]

External links modified[edit]

Hello fellow Wikipedians,

I have just modified one external link on Space elevator safety. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:

Added archive https://web.archive.org/web/20080919070924/https://science.nasa.gov/headlines/y2000/ast07sep_1.htm to https://science.nasa.gov/headlines/y2000/ast07sep_1.htm

When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.

This message was posted before February 2018. After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than regular verification using the archive tool instructions below. Editors have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the RfC before doing mass systematic removals. This message is updated dynamically through the template {{source check}} (last update: 18 January 2022).

If you have discovered URLs which were erroneously considered dead by the bot, you can report them with this tool.
If you found an error with any archives or the URLs themselves, you can fix them with this tool.

Cheers.—InternetArchiveBot (Report bug) 08:44, 11 November 2017 (UTC)[reply]