There are many things about the measurement technique, pressure, interface, and performance are presented in the paper. Inside the paper you can read description about measurement technique, microgravity, and gauge pressure.
The paper tells you information regarding measurement, pumping performance, pressure sensors, and schematic diagram. Here are excerpted from the paper:
A measurement technique for obtaining the pumping performance of a centrifugal collector under microgravity has been developed and evaluated through microgravity experiments. These tests have been conducted under conditions such that the pressure sensors cannot easily detect the pressure rise of the liquid working ﬂuid. These conditions have a pressure increase smaller than 400 Pa. The characteristic of the head produced in a centrifugal collector calculated from experimental data agrees well with that predicted theoretically from the velocity and the pressure generated by rotation of the centrifugal collector.
Also, this paper contains information about centrifugal collector, collector pump performance, and the centrifugal collector.