Technology Requirements

• Solar sail propulsion and navigation
• Autonomous operation
• Miniaturized instrumentation
• Real-time solar wind data from 0.95 AU

Societal Benefits

• Understanding CMEs enables improved space
  weather forecasts
• Real-time data enables several-hour warning of
  geomagnetic storms
• Warnings of shock-acclerated particles enable
  occupants of Space Station to take protective
  measures

• Determine the three-dimensional structure of CMEs
• Study the evolution of CMEs during their transit from Sun
• Investigate stream interactions and interplanetary shocks in three-dimensions
• Investigate particle acceleration by CME-driven shocks and solar wind turbulence

Mission Description

• Delta launch to L1
• Three solar-sail spacecraft navigate to stations well inside L1
• Sentinel spacecraft orbit Sun with a 1-year period and adjustable separation
• Continuous operation, including real-time solar wind data

Measurement Strategy

• Solar wind plasma
• Interplanetary magnetic field
• Energetic particles
• Coordinated measuremetns at L1, L4, and L5 would be valuable