Plasma irregularities at the equator mission concept: a VLEO CubeSat investigation of ionospheric irregularities

We present a Very Low Earth Orbit (VLEO) mission concept to investigate the formation mechanisms of equatorial plasma bubbles (EPBs) and the characteristics of medium-scale traveling ionospheric disturbances (MSTIDs) in the low to mid-latitude ionosphere. The mission utilizes two 6U CubeSats with complementary instrumentation at a perigee of 250 km to make direct observations of the bottom-side F-region ionosphere. The first CubeSat, Pecan, carries electric and magnetic field probes, a Langmuir probe, and an impedance probe. The second CubeSat, Peach, carries a Langmuir probe, impedance probe, and radio occultation (RO) receiver. The satellites fly in sun-synchronous orbit at 19LT with a longitudinal separation of 200 km and altitude difference of 10 km at perigee. This configuration allows simultaneous measurement of in-situ plasma parameters and subsequent detection of bubble formation. Through this architecture, the mission addresses two critical questions: (1) whether the evening sector is primarily dominated by atmospheric gravity wave-driven MSTIDs or electrified nighttime MSTIDs, and (2) the relative importance of Rayleigh-Taylor Instability growth rate versus MSTID seeding in controlling day-to-day variability of EPB formation. The mission’s unique capability to measure both the precursors and outcomes of ionospheric irregularity formation will provide valuable insights into space weather phenomena that affect communication and navigation systems.