This paper introduces the recent testing results of the University of Southampton porous electrospray thruster. The thruster was manufactured using low-cost techniques, manufactured in-house at the University of Southampton. Previous studies on this thruster suggested it can achieve a high specific impulse with relatively high thrust. In this paper, the plume properties of the thruster were further studied. The distribution of particles' retarding potentials in the plume was characterised, and the plume energy distribution was measured and analysed. Measurements of the plume angle were completed. A long-term operation test was attempted, suggesting the thruster was able to operate for 18 hours with reasonable performance variations.