Metadata: DateAn electronic databack was added to the camera to automatically record the date and time on the film when the photograph was taken beginning with STS41D (August 1984). Databacks sometimes malfunction. You can distinguish cases with estimated dates by whether or not the TIME field also has an entry. This field can only be entered from databack records.
For short-duration missions (<30 days), if no other date is available, we enter the month and year of the median day of the mission. If there are an even number of days in a mission, and the median straddles a change in month, then the first month and year are used. For short- and long-duration missions, the scientists who worked with the mission on a daily basis help to provide estimated date information when the databack malfunctions.
Nadir point data (the NLAT, NLON, PDATE, PTIME, ORB, AZI, ALT, ELEV database fields) are calculated using the times recorded by the camera equipment. If post-mission analysis determines that there are errors in the time recorded, then a time adjustment is estimated and nadir data cannot be calculated. If the time is off by less than a minute, the seconds field is blanked out. If the time is off by a minute or more but less than an hour, then the minutes and seconds fields are blanked out. If the time is off by an hour or more then the whole time field (hour, minute and second) is blanked out.
If post-mission analysis determines that there are errors in the date recorded, then the correct date is estimated if possible. If the correct date cannot be estimated, then as much date as can be verified (such as month or year) is entered in the field.