Rockets are the only means to observe the small-scale motions in the mesosphere and lower thermosphere (60-120 km). Langmuir probes are common rocket instruments to measure the electron or ion density in this region, and fluctuations in the plasma density are often indicative of motions in the neutral atmosphere. A current NASA rocket program will utilize this and other techniques to study waves, wave sources, and turbulence.

To ensure the accuracy of the Langmuir probe current measurements, the electrometer amplifiers and following analog-to-digital converters need to calibrated and checked regularly during payload integration and before launch. At Western Kentucky University, and in collaboration with Penn State University, we are designing a calibration device for this purpose, which will send an automatic sequence of precise currents (0.01 to 1000 nA) when connected to the rocket instrument. The unit will be used during payload testing and integration at NASA Wallops Flight Facility and later at the launch sites in Northern Scandinavia.