ISO 21460:2015 defines the Proximity-1 Space Link Protocol Physical Layer. The specification for the channel connection process, provision for frequency bands and assignments, hailing channel, polarization, modulation, data rates, and performance requirements are defined in this document.

Currently, the Physical Layer only defines operations at UHF frequencies for the Mars environment.

The Data Link Layer is defined in the two separate CCSDS Recommended Standards entitled, Proximity-1 Space Link Protocol-Coding and Synchronization Sublayer (reference [2]), and Proximity-1 Space Link Protocol-Data Link Layer (reference [3]).

ISO 21460:2015 does not specify

a) individual implementations or products;

b) implementation of service interfaces within real systems;

c) the methods or technologies required to perform the procedures; or

d) the management activities required to configure and control the protocol.