Ambient space plasma can induce electrostatic noise in a linear antenna onboard a spacecraft. The resulting quasi-thermal noise (QTN) intensity spectrum as a function of frequency depends on the plasma parameters. The phenomenon can be utilised for inferring the plasma parameters if one measures the induced noise by a sensitive radio receiver. This is called QTN spectroscopy and it has been demonstrated and validated in several space missions that the technique is able to uncover the correct plasma parameters. In PIANOS project we assess to what extent the noise measurement technique could be used to monitor key parameters of space weather in various relevant regions at low cost. We review the properties of the target plasmas, consider different antenna geometries and their deployment strategies as well as data analysis methods and algorithms. To enable low-cost space weather monitoring by the QTN method, we recommend a roadmap of technology developments activities including CubeSat demonstrations.