SOLAR-1 (Space Weather Observations at L1 to Advance Readiness–1)

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The United States has activated SOLAR-1, its first dedicated operational space weather monitoring satellite, to provide early warnings of solar storms that can disrupt GPS navigation, communication systems, satellites, aviation, and power grids.

About SOLAR-1

SOLAR-1 (Space Weather Observations at L1 to Advance Readiness–1) is the first U.S. satellite exclusively designed for continuous operational monitoring of space weather. It is operated by the National Oceanic and Atmospheric Administration (NOAA) and forms a key part of the United States’ efforts to improve resilience against solar storms.

Originally known as Space Weather Follow-On – Lagrange 1 (SWFO-L1), the mission was later renamed SOLAR-1 to reflect its operational role in enhancing space weather preparedness.

Mission and Objectives

The primary objective of SOLAR-1 is to continuously monitor the Sun's activity, particularly solar wind and Coronal Mass Ejections (CMEs), and provide timely warnings before these disturbances reach Earth.

Its data enables governments and industries to protect electric power grids, satellites, communication networks, navigation systems, aviation, and human spaceflight missions from the harmful effects of intense space weather.

Launch Details

SOLAR-1 was launched on 24 September 2025 aboard the SpaceX Falcon 9 launch vehicle.

Orbit and Strategic Location

SOLAR-1 is positioned at the Sun–Earth Lagrange Point 1 (L1), located approximately 1.5–1.6 million kilometres from Earth towards the Sun.

The L1 Lagrange Point provides an uninterrupted view of the Sun, allowing the satellite to continuously monitor solar activity before it reaches Earth. Because the gravitational forces of the Sun and Earth nearly balance at this location, the satellite requires very little fuel to maintain its orbit, making it ideal for long-term observations.

Key Instruments and Capabilities

• SOLAR-1 carries a Compact Coronagraph, a specialised telescope that continuously observes the Sun's outer atmosphere (corona) to detect Coronal Mass Ejections (CMEs).

• In addition, it carries instruments that make real-time measurements of the solar wind, including its speed, density, temperature, and magnetic field.

• A major technological advancement is its ability to transmit CME images to NOAA's Space Weather Prediction Center within just 30 minutes, compared to up to eight hours required by earlier monitoring systems.

Importance of SOLAR-1

SOLAR-1 significantly improves space weather forecasting, enabling earlier warnings of severe solar storms.

Its observations help protect:

• Satellites from radiation damage.

• GPS and navigation systems from signal disruption.

• Power transmission grids from geomagnetic disturbances.

• Communication networks and aviation operations.

• Astronauts and future deep-space missions from harmful solar radiation.

• Aurora forecasting, improving predictions of Northern and Southern Lights.

What is Space Weather?

Space weather refers to the changing environmental conditions in space caused by the Sun's activity, including solar flares, Coronal Mass Ejections (CMEs), and high-speed solar winds.

These events can disturb Earth's magnetic field (magnetosphere), interfere with radio communications, damage satellites, disrupt navigation systems, induce currents in power lines, and increase radiation exposure for astronauts.

What are Coronal Mass Ejections (CMEs)?

A Coronal Mass Ejection (CME) is a massive eruption of plasma and magnetic fields from the Sun's outer atmosphere (corona).

When directed towards Earth, CMEs can trigger geomagnetic storms, resulting in satellite malfunctions, GPS disruptions, radio blackouts, power outages, and spectacular auroral displays.

What are Lagrange Points?

Lagrange Points are five locations (L1 to L5) in a two-body system where the combined gravitational forces of the two bodies balance the orbital motion of an object.

The Sun–Earth L1 point is particularly valuable for solar observation because spacecraft positioned there receive the earliest possible view of solar events before they affect Earth.