The OSIRIS CubeSat Mission: A System of Satellites for Investigating the Response of the Stimulated Ionosphere

The proposed OSIRIS (Orbital System for Investigating the Response of the Ionosphere to Stimulation and space weather) CubeSat mission will provide in situ measurements of the spatial and temporal characteristics of stimulated (heated) ionosphere, which will be correlated with ground-based measurements to better understand variable space weather conditions and phenomena such as ionospheric irregularities. As its primary objectives OSIRIS will 1) provide in situ measurements of the stimulated (heated) ionosphere produced by ground-based heaters; 2) correlate in situ heated ionosphere measurements with ground-based measurements including incoherent scatter radars and ionosondes; and 3) investigate spatial and temporal characteristics of the heated ionosphere by measuring plasma properties as the satellites gradually separate. The use of ionospheric heaters such as HAARP, Arecibo, and EISCAT will allow the OSIRIS mission to mimic natural ionospheric irregularities at defined locations and times, as well as perform research on active experiments. The OSIRIS mission is a constellation of three CubeSats, each carrying a Hybrid Plasma Probe, which is compresed of a combination Langmuir probe, plasma frequency probe, fixed-biased probe, and Druyvesteyn fast temperature probe. Using three spatially separated, simultaneously measured data segments with an identical sensor on each satellite, it becomes possible to distinguish between spatial and temporal phenomena. The OSIRIS satellites will spread out into slightly different orbits, experiencing an average separation rate of 50 km between satellites over the first 6 months, slowly changing the constellation’s multi-point measurement resolution from a finer scale to a larger scale. The OSIRIS mission is designed to function in a circular or low-eccentricity orbit between 300 and 450 kilometers with inclination of higher than 65°. OSIRIS electron density measurements permit observations of the densities outside the narrow line-of-sight provided by UHF radar collocated at ionospheric heaters. OSIRIS will address the question: where does the plasma go when large ionospheric bite-outs are produced in the F-region by high power radio waves? The large HF depletion region will be scanned with the in situ plasma probes on OSIRIS to yield measurements of the elevated electron temperatures produced by the HF waves and the electron density reductions that accompany these high plasma temperatures. The data collected by OSIRIS will be incorporated into existing ionospheric models to provide a consistent physical picture of ionospheric modification by high power radio waves. The second question addressed is: what are the spatial and frequency characteristics of low frequency ion-acoustic waves excited by high power electromagnetic waves? The in situ probes are advantageous over radar probes of the plasma by measuring the ion acoustic density structures at all wavelengths.