Ian DesJardin, University of Maryland, College Park; Christine Hartzell, University of Maryland, College Park
Keywords: Plasma soliton, space debris, sub centimeter debris, space weather, ionosphere, radio sensing.
Abstract:
Detection of space debris below the size limits of optical and radar-based methods ( < 1 cm) is an open question. All previous detection attempts in this size range have relied on in situ measurements, limiting the results to qualitative surveys, not operational catalogs. A new method of detecting orbital debris is being developed that detects debris-ionosphere interactions as a proxy for detecting the debris directly. Natural stable plasma wave emissions, known as solitons, are generated by these interactions. Fortunately, the spatial locations where these interactions are strongest are at commonly congested orbits (i.e., the F layer of the ionosphere which often corresponds to low Earth orbit) [1]. Existing proposed detection approaches of plasma solitons include incoherent scatter radar (e.g. EISCAT 3D [2]), spacecraft measurements (e.g. Swarm-E RRI instrument [3]), and active ionospheric research stations (e.g. HAARP). We propose a new detection method for plasma solitons based on measurements of GNSS carrier frequency or another known radio transmission. This approach uses passive ground-based receivers that makes it amenable to continuous surveying. Plasma waves locally modify the electron density which is known to distort radio waves in a highly frequency dependent manner. This phenomenon is described by the Appleton-Hartree equation. For frequencies above the ionospheric plasma frequency, this manifests as phase scintillation at the receiver where the amount of scintillation depends on the integral of electron density, known as the total electron count (TEC), in the beam. A plasma wave emitted from debris passing through the radio beam path will modify the TEC and scatter the radio signal. In this paper, we use scattering theory derived from the Appleton-Hartree equation for the plasma wake behind an ideally shaped spacecraft to predict the power received at a ground receiver. For sub-centimeter debris, we show that the scattering cross section from the ionized trail is larger than the Rayleigh cross section. We also estimate the magnitude of refractive modification to the TEC by a characteristic plasma wake of the International Space Station superimposed on the International Reference Ionosphere (IRI) model and identify GPS receivers capable of detecting the effects. This would be an experiment could be used to test the physics of the technique. The expected outcome of this paper is a candidate radio receiver network design that observes distortions of existing space-to-ground radio transmissions. This will include properties of the receiver(s) including system noise and network geometry. We explore the possibility of using existing GNSS receiver networks and radio telescopes to observe these effects. References: [1] Truitt, A. S., & Hartzell, C. M. (2020). Simulating Plasma Solitons from Orbital Debris Using the Forced Kortewegde Vries Equation. Journal of Spacecraft and Rockets, 57(5), 876897. [2] Connor M. Wilson and Christine M. Hartzell. "Simulated Propagation of Ion Acoustic Solitary Waves from Orbital Debris Contrasted with Simultaneous Observations of the Ionosphere by an Incoherent Scatter Radar," AIAA 2023-2617. AIAA SCITECH 2023 Forum. January 2023. [3] Bernhardt, P. (2022). Space Object Identification by Measurements of Orbit-Driven Waves (SOIMOW). Bulletin of the American Physical Society. Date of Conference: September 19-22, 2023
Track: SDA Systems & Instrumentation