Mars Express (MEX) Analyser of Space Plasmas and Energetic Atoms (ASPERA-3) data is providing insights into atmospheric loss on Mars via the solar wind interaction. This process is inﬂuenced by both the interplanetary magnetic ﬁeld (IMF) in the solar wind and by the magnetic ‘anomaly’ regions of the martian crust. We analyse observations from the ASPERA-3 Electron Spectrometer near to such crustal anomalies. We ﬁnd that the electrons near remanent magnetic ﬁelds either increase in ﬂux to form intensiﬁed signatures or signiﬁcantly reduce in ﬂux to form plasma voids. We suggest that cusps intervening neighbouring magnetic anomalies may provide a location for enhanced escape of planetary plasma. Initial statistical analysis shows that intensiﬁed signatures are mainly a dayside phenomenon whereas voids are a feature of the night hemisphere.