Realistic Worst Case for a Severe Space Weather Event Driven by a Fast Solar Wind Stream

Area of Science:

• Space physics
• Satellite engineering
• Plasma physics

Background:

• Satellite charging is a critical orbital risk, potentially causing electrostatic discharge (ESD).
• ESD can result in component damage, phantom commands, service loss, or total satellite loss.
• Geostationary orbit satellites are particularly vulnerable to space weather events.

Purpose of the Study:

• To model the worst-case electron flux during prolonged fast solar wind stream events.
• To assess the risk of electrostatic discharge for satellites in geostationary orbit.
• To determine the shielding requirements against high-energy electrons.

Main Methods:

• Construction of a realistic worst-case scenario for a fast solar wind stream event (≥5 days).
• Utilization of a physical model to calculate maximum electron flux (>2 MeV) at geostationary orbit.
• Comparison of modeled flux with statistical analyses of electron data and NASA guidelines.

Main Results:

• Electron flux reaches ~10^6 cm^-2·s^-1·sr^-1 after 5 days, remaining high for another 5 days.
• This flux level is comparable to a 1-in-150-year event.
• Approximately 2.5 mm of aluminum shielding is needed to meet NASA guidelines, exceeding current usage.

Conclusions:

• Satellites in geostationary orbit face significant risk from prolonged fast solar wind stream events.
• Such events are a greater threat than Carrington-type storms for geostationary satellites.
• Current shielding is insufficient, increasing the likelihood of ESD anomalies and satellite loss.