Metadata: ROLL field

NASA has used the single letter E to identify images that were originally captured in digital form including electronic still camera (ESC) and High Definition Television (HDTV) images. The NASA number is of the form sXXeYYYY where XX is the 2-digit Shuttle Mission, and YYYY is an arbitrarily assigned sequential number. This database organizes photograph identifiers (IDs) into three components, a mission component, a roll component and a frame component. In order to accommodate ESC and HDTV imagery, since it has no film "roll", it was originally decided to use "ESC" and "HDTV" as the roll. This provided more clarity to the casual user and helped avoid possible future conflicts with other non-ESC/HDTV roll IDs being assigned E (some roll IDs in the past have been single letters).

EarthKAM (also known as KidSat), a NASA-funded educational project where middle school students control a camera mounted on the Space Shuttle or International Space Station, has cross-indexed its images with our database so that searches of our database will also find relevant EarthKAM images. During its time on the Space Shuttle, the EarthKAM-assigned number is of the form STS0XX-ESC -YYYYYYYY, where XX is the 2-digit Shuttle mission number, and YYYYYYYY represents the MET (mission elapsed time) of the image. These images were also numbered separately by NASA, and a cross-reference table is available. From the International Space Station, EarthKAM numbers will be of the form

ISSxxx.ESCy.dddhhmmss

where

xxx is the station increment - the crew number, so flights in October and December 2001 will have the mission designation ISS003

y is the EarthKAM mission designation - for the first EarthKAM data taking opportunity within a station increment y will be 1, for the second 2 and so on. So for the flight in October 2001 the first two fields in the Image ID will be ISS003.ESC1 and in December they will be ISS003.ESC2

dddhhmmss is the time (GMT) the image was taken - ddd is the julian day of year (001-365), hh is the hour (00-23), mm is the minute (00-59) and ss is the second (00-59). GMT is Greenwich Mean Time, (aka UTC) and reflects the mean solar time along the Earth's prime meridian.

so for an image capture at 11:30 PM GMT on October 1 on our first official EarthKAM "flight" on ISS the Image ID will be...

ISS003.ESC1.274233000


In an effort to distinguish NASA's ESC from EarthKAM's ESC, it was decided that this database would adopt NASA's convention of using only the single letter E as the roll component of the photograph ID for non-EarthKAM images taken with the ESC, and would follow EarthKAM's numbering conventions for the images they acquired using the ESC. So in April of 2002, all NASA ESC image IDs were changed over to using the single letter E for the roll component. Using HDTV as the roll identifier for HDTV images does not conflict with EarthKam's convention, so this database retains the HDTV roll identifier.

The search tools have been set to consider ESC, E and HDTV as roll synonyms so that images will be returned for searches using either convention.