Abstract <p>Measurement instruments onboard satellites are susceptible to various disturbances that can affect not only the accuracy of the measurements but also the entire satellite mission. Of particular concern are disturbances associated with Earth’s magnetic field, which arise when field lines intercept the spacecraft (S/C) body or one of the Langmuir probes dedicated to measuring electric field disturbances, as is the case for the Demeter satellite. We analyze this effect for a Langmuir double probe, which provides ambient electric field measurements on low-orbit satellites with altitudes of approximately 650 km. The electric field disturbances arise when the sheath surrounding at least one of the probes is connected to the S/C body and/or solar panel through a magnetic field line (also known as a tube of force). We found that for certain orbits, this disturbance can be significant in strength and can last approximately 10 min, regardless of whether the orbit is nighttime or daytime.</p>