Langmuir probes are ubiquitously used for in-situ measurements of plasma parameters. These probes have been placed on many different platforms, including experimental sounding rockets for measurements in mesosphere-lower-thermosphere, and also onboard satellites to obtain data sets over an extended period of time in the ionosphere. To accommodate such different situations, many different variations of the Langmuir probe design have been made. This thesis covers two such implementations, as well as the data analysis and issues that can arise with such instruments. The first of these implementations is a set of sweeping Langmuir probes on the Floating Potential Measurement Unit (FPMU) that is deployed on-board the International Space Station. We compare the output of NASA’s current data processing algorithm for FPMU to that of our own algorithm. This work shows how instruments degrade overtime, and how data analysis can partially work around such degradation. Our analysis also demonstrated how various environmental effects need to be accounted for to get an accurate measurement during data analysis of Langmuir probes. The second implementation considered in this thesis is a new multi-needle Langmuir probe (mNLP) design as recently flown aboard some German sounding rockets. Our work confirms that mNLP instrument shows great promise, but also cautions in its data processing algorithms which can easily lead to 50% errors unless appropriately dealt with. We then present a new way to analyze mNLP data that can bring the measurement error to within 10%
