Space-Based Observations of Plasma Waves During Conjunctions Between Host Sensors and Space Objects

Area of Science:

• Space Physics
• Plasma Physics
• Orbital Mechanics

Background:

• Space debris poses a growing threat to operational satellites.
• Detecting smaller debris is challenging with current methods.
• Ion density rarefactions in the wake of space objects offer a potential detection signature.

Purpose of the Study:

• To investigate the feasibility of detecting space objects via their plasma wave signatures.
• To determine if Very Low Frequency (VLF) plasma waves can indicate the presence of space debris.
• To analyze data from satellite conjunctions for evidence of ion density rarefactions.

Main Methods:

• In-situ measurements of VLF plasma waves (1-35 kHz) using the CASSIOPE satellite's Radio Receiver Instrument (RRI).
• Recording electric field data during conjunctions with other space objects (e.g., Starlink, Iridium, OneWeb).
• Analyzing 35 conjunction events for correlated broadband noise indicative of ion density rarefactions.

Main Results:

• Three conjunctions showed weak correlation between VLF broadband noise and closest approach.
• One event exhibited a strong temporal correlation, potentially indicating traversal of a Starlink satellite's wake.
• No clear, repeatable signatures of ion density rarefactions were consistently identified.

Conclusions:

• Sensing ion density rarefactions in space object wakes appears impractical for debris detection with current methods.
• The study did not identify clear, repeatable wave signatures from known space object conjunctions.
• Further research may be needed to refine detection techniques or explore alternative signatures.