Talk:Space elevator

The figure in the section Cable section covers half of the equation; I, unfortunately, can't fix it. 46.135.41.66 (talk) 08:53, 1 July 2025 (UTC)

I moved it out of the way. —Tamfang (talk) 19:17, 1 July 2025 (UTC)

Worth mentioning somewhere that the term beanstalk alludes to Jack and the Beanstalk – but where? —Tamfang (talk) 04:21, 29 August 2025 (UTC)

The article says Jerome Pearson was "inspired by Arthur C. Clarke's 1969 speech before Congress" but what speech is this? No such speech is mentioned in the Arthur C. Clarke article, in NASA's Astronautics and Aeronautics chronology for 1969, or in any other source Google can find.

There are a few possibilities. 1) Clarke appeared on July 24, 1975 as a witness before the House of Representatives Subcommittee on Space Science, but this was after Pearson submitted his Acta Astronautica article in September, 1974. 2) He also contributed to the 1959 "The Next Ten Years in Space 1959-1969 -- Staff Report of the Select Committee on Astronautics and Space Exploration," but that wasn't a speech. Finally, 3) An article Clarke wrote for the St. Louis Dispatch on July 18, 1969 was read into the Congressional Record on September 18, 1969 by Rep. Olin E. Teague of Texas.

Alas, Jerome is no longer with us, or I would ask him. In his absence, maybe someone else knows how this claim got into the article and can clear it up for us. ~2025-31794-41 (talk) 04:58, 7 November 2025 (UTC)

The steel example shows tensile strength of 2GPa in the table. The quoted source provides 5GPa value. The 5GPa value is unrealistic, from what I could find online, 2GPa tends to be on the upper limit of steels. The calculated taper ratio appears to be incorrect no matter if you use 2GPa or 5GPa. Based on equations in paragraph above, the correct values should be:

• 2GPa: 7.70237×10^78 (which is orders of magnitude higher)
• 5GPa: 3.58633×10^31 (which is at least the same order of magnitude, maybe they are using slightly different values of some constants or there is another issue)

Based on equations in the same paragraph as the example table, the values should be:

• 2GPa: 1.58477×10^83
• 5GPa: 1.90540×10^33

There appears to be some error in the equations or in the calculated examples. At best the table was incorrectly copied from the paper. I don't know how it should be corrected as I'm no expert in physics. Peto1994 (talk) 12:05, 1 March 2026 (UTC)

Copied from the paper, page 128. It appears they mis-copied the "max tensile strength" from the paper, the paper specifies 5,000 GPa for steel. The results are absurd in any case, they are designed to showcase carbon nanotubes as a viable material, by using a vastly over-optimistic strength. There was considerable debate about this table when added, but was left in after partisans simply outlasted skeptics. Tarl N. (discuss) 05:30, 2 March 2026 (UTC)