This is the orbit number the space craft was on when the photograph was taken. Note that this is only meaningful on short duration flights which orbited the Earth. Specifies the angle in degrees from north to the location of the sun clockwise measured at the nadir location. Specifies the sun elevation angle. This is the angle from the horizon to the sun measured in degrees at nadir.
Negative values indicate that the sun is below the horizon.
Specifies the altitude above the Earth's surface of the space craft in nautical miles. This is the name of the mission using an approved standard for Earth Observations purposes. At least one mission has odd roll IDs which start a letter. For these missions simply left justify. The roll identifies the roll of film the photograph is on.