The multi-needle Langmuir probe system on VISIONS-2 35.039 consists of four cylindrical Langmuir probes with different bias potential (3V, 4.5V, 6V, and 7.5V). The currents measured allow to calculate the electron density at a high sampling rate (6250 Hz).

The 4-NLP experiment and the University of Oslo participation in the Grand Challenge Initiative Cusp rocket campaign were funded through the Research Council of Norway grant 275653.