I removed the following statement as it seems a bit oddly written and unsure in itself, and I'm insufficiently familiar with the topic to correct it myself: "Makes possibly Trek's most blatant reference to the work done by C20 and C21 space station pioneer Gerard K. O'Neill. Other novels also mention him, but less obviously." --8of5 22:36, 2 June 2009 (UTC)

The original author of the comment may have been referring to an O'Neill_cylinder; don't know where the C20 or C21 designations come from. There must be a space station in the novel somewhere that sounds similar in shape to the proposed O'Neill cylinder... since there's no mention of "C20", "C21", "Gerard", or "O'Neill" anywhere in the book. --Captain Savar 23:00, 2 June 2009 (UTC)

I've seen C20, C21, etc used to refer to the 20th century, 21st century, etc. If your hypothesis is accurate then I would suggest a background note about "O'Neill cylinders" would be appropriate on the page for the space station, not sure it needs to be on this page though. --8of5 23:11, 2 June 2009 (UTC)