Space Cover 501: Orbit Covers BindersThe majority of space cover collectors are familiar with Orbit covers – manned, unmanned, FDC, etc. – that were produced from John Glenn's flight (which had only printed words) through the first shuttle missions. Many collectors are also aware of the "plugged 9" suspect covers that were produced by Orbit covers.
What may be new to collectors is that for both Project Gemini and Project Apollo specific pages were produced that the Orbit covers could be mounted on and placed into specially produced binders. Collectors were able to purchase binders and the "blank" pages to mount there covers. Here are examples of the page.
The pages and binders are hard to find and usually the binder covers are not in very good shape. Here is a copy of the Project Gemini binder.
The pages also included room for the full presentation sheets produced by Orbit covers.
Finally, here is an image of the binder for Project Apollo. Similar pages were produced
The prices for these vary greatly as many have only blank pages, others have some covers, some have plugged 9 covers included, and some completely full. So check the dealer tables for binders... you might just find a set!