Each PDS data product has a “Product Identifier (Product Id)”. The product id is a permanent, unique identifier assigned to a data product by its producer. The product id is unique within a data set. The product id is a character string up to 40 characters in length. Many producers embed information about the product in the product id. For example, the product ids of HiRISE data products include both the mission phase and the orbit number in which the data product was generated.