Shock waves are common in the heliosphere and beyond. The collisionless
nature of most astrophysical plasmas allows for the energy processed by
shocks to be partitioned amongst particle sub-populations and
electromagnetic fields via physical mechanisms that are not well
understood. The electrostatic potential across such shocks is frame
dependent. In a frame where the incident bulk velocity is parallel to
the magnetic field, the deHoffmann-Teller frame, the potential is linked
directly to the ambipolar electric field established by the electron
pressure gradient. Thus measuring and understanding this potential
solves the electron partition problem, and gives insight into other
competing shock processes. Integrating measured electric fields is space
is problematic since the measurements can have offsets that change with
plasma conditions. The offsets, once integrated, can be as large or
larger than the shock potential. Here we exploit the high-quality field
and plasma measurements from NASA's Magnetospheric Multiscale mission to
attempt this calculation. We investigate recent adaptations of the
deHoffmann-Teller frame transformation to include time variability, and
conclude that in practise these face difficulties inherent in the 3D
time-dependent nature of real shocks by comparison to 1D simulations.
Potential estimates based on electron fluid and kinetic analyses provide
the most robust measures of the deHoffmann-Teller potential, but with
some care direct integration of the electric fields can be made to
agree. These results suggest that it will be difficult to independently
assess the role of other processes, such as scattering by shock
turbulence, in accounting for the electron heating.