  Collisionless shock waves are one of the main forms of energy conversion in
space plasmas. They can directly or indirectly drive other universal plasma
processes such as magnetic reconnection, turbulence, particle acceleration and
wave phenomena. Collisionless shocks employ a myriad of kinetic plasma
mechanisms to convert the kinetic energy of supersonic flows in space to other
forms of energy (e.g., thermal plasma, energetic particles, or Poynting flux)
in order for the flow to pass an immovable obstacle. The partitioning of energy
downstream of collisionless shocks is not well understood, nor are the
processes which perform energy conversion. While we, as the heliophysics
community, have collected an abundance of observations of the terrestrial bow
shock, instrument and mission-level limitations have made it impossible to
quantify this partition, to establish the physics within the shock layer
responsible for it, and to understand its dependence on upstream conditions.
This paper stresses the need for the first ever spacecraft mission specifically
designed and dedicated to the observation of both the terrestrial bow shock as
well as Interplanetary shocks in the solar wind.
