A lean satellite is equivalent to a small/micro/nano/pico satellite that utilizes untraditional risk-taking development approaches to achieve low-cost and fast-delivery. Lean satellites have demonstrated great ability to be used for the study of space plasma and Earth’s ionosphere which has helped in the prediction of many astrophysical phenomena and forecasting of geophysical changes on ground. Several methods have been employed in the measurement of space plasma parameters over the years using the Langmuir Probe. These methods employed different techniques using single probes or double probes. Single probe requires a well-defined reference which is difficult in small spacecraft. Moreover, high current flow in the saturation mode may destroy the probe and on-board circuitry. A low cost double Langmuir probe made of gold with its measurement circuit has been designed and tested inside RF generated Argon plasma in the pressure of 1.4×10^-2 Pa that confirms the electron density from 10¹⁰ to 10¹² m^-3. Important design considerations such as operability of the designed system in low earth orbit grade plasma, mitigation of probe contamination and sputtering of the electrode surface were analysed in the paper to ensure that the developed system can provide high fidelity plasma measurement data throughout the life span of HORYU-IV (Arc Event Generator and Investigator Satellite) which is a 13 kg, 40 cm cubic lean satellite under development at the Kyushu Institute of Technology.