Mars is a planet of dust and darkness.
It is even further away from the Sun than Earth.
It has dust storms so severe that the entire planet can be shrouded for months.
Its atmosphere requires the use of standardised spacesuits anywhere on the surface.
The UN sent colonists to Mars in three waves. The first wave was relatively minute in number and was largely composed of miners and asteroid capture and drilling teams originally operating out of Luna. They were put to task preparing the infrastructure necessary to allow for the arrival of the UN’s second and third waves who were to arrive in significant larger numbers.
It was the first wave that created Mars’ Visual Identification System (VIS) and this is largely due to Mars’ weather patterns. The United Nations ID system on Earth was simply an electronic code that tracks a citizen’s details and biometrics. However, little thought was given as to what that would mean on a planet where every individual would often be behind the helmet of a standard-issue spacesuit.
In optimal conditions, a colonist can identify others relatively easily. The UN’s spacesuit telemetry provides names immediately to the wearer once a digital handshake has been made. These rely on the use of short-range radio and confirmation from the UN’s satellites in orbit. Most of the satellites in orbit during the first wave were tasked with survey and mapping programs and did not provide assistance with suit telemetry. Moreover, Mars’ dust storms could jam and interfere with radio telemetry and communications making identification extremely difficult and needlessly time consuming.
The first wave solution was the use of helmet and suit stickers. It began as a method for allowing team members to more easily identify each other's particular role in the colony at a distance. These solutions were adhoc in nature and could vary wildly between colonies with stickers becoming a miniature coded language that could display a colonist’s job for the day or their long-term role at the colony base. As time went on, the first wave eventually adopted these to work in the form of individual identification allowing them to more easily work together without needing to enter the original spacesuit’s digital handshake range.
This is not to say that the VIS system was flawless from the start. Arguments were had over who got to wear what alongside confusion as to whether a design should refer to a particular role or whether it should refer to an individual. However, it still aided efforts on Mars as a whole. The main advantage was an increase in relative distance between groups of miners spread out across the Martian landscape. A first wave team could operate further apart and still know their rough position on a map due to the placement of their teammates around them.
The United Nations supported this initiative by providing databases to register helmet markers and allowed the spacesuits to store that information separately. This provided colonists a tool to identify each other at any given time, even during communications blackouts due to storms, satellite coverage failure or radiation hazards.
It has long been held that one can trust only those we meet face to face and to an extent this belief has persisted on Mars thanks to the VIS-à-VIS system established by the first wave.