• 04/11/1970 Launch date
• 04/13/1970 Explosion aboard the Service Module
• 04/14/1970 Crucial loop around the Moon
• 04/17/1970 Splashdown date

The covers on this list may or may not be addressed, (if addressed it can be either by rubber stamp, label or typed, anything other than as noted here will be specified). However many of these covers are unaddressed.

Tracking station covers may have a dated postmark on any day of the flight, sometimes the date may be after the splashdown date due to various conditions, such as postoffice being closed or there was a delay in getting the covers to the postoffice, usually because the servicer was tracking the spacecraft!

The majority of these tracking station covers have some sort of cachet provided by the tracking station (which can be a rubber stamp or label cachet) or just a station return address. Private cachet(s) may have been applied to further describe the flight.

The first part of the description is the postmark city and state or country as shown on the cover.

The rest of the description tells something about that particular tracking station, such as:

1. What kind of tracking station it is.
2. What kind of a cachet it has.
3. If it has an autograph of importance (however many covers also may be autographed and not noted).
4. If it is cancelled on a significant date during the Apollo flight, otherwise the date on the cover could be any date during the flight or a few days later (as explained above).
5. If it has a special postage stamp affixed.
6. And other notes that tell about the cover.

Some cover may be listed two or more times, depending on the difference between them, such as if autographed or not, or if it has a special postage stamp affixed or cancelled on a different date of significance, etc.