WASHINGTON, D.C. –
At 0808 on Dec. 2, 1995, the European Space Agency (ESA) and NASA’s joint Solar and Heliospheric Observatory (SOHO) satellite launched from NASA Kennedy Space Center in Cape Canaveral, Fl. Among the 15 instruments aboard the spacecraft was the U.S. Naval Research Laboratory’s (NRL) Large Angle and Spectrometric Coronagraph (LASCO).
Today, LASCO celebrates 30 years of on-orbit expeditions that have unveiled scientific phenomena that have extended far beyond the aspirations of the original developers and heralded a new era in space weather science.
LASCO’s advanced engineering, special location in space, and the scientific leadership of NRL, have transformed solar observation and established the foundation for modern space weather operations. Its findings continue to inform naval and defense readiness with accurate forecasting of solar-driven disruptions across the electromagnetic spectrum. LASCO remains a testament to NRL’s role in advancing science in direct service to national security.
What is LASCO
LASCO provides continuous, high-fidelity observations of the solar corona – the Sun’s outer atmosphere – marking a cornerstone achievement in heliophysics. It is a three-telescope coronagraph system that blocks direct sunlight and captures the faint visible light scattered by energetic electrons and charged particles around the sun. NRL is the principal investigator institute for LASCO, leading the original proposal for the instrument and an international consortium in its construction.
Positioned nearly one million miles from Earth, LASCO continuously observes the near-Sun environment where solar eruptions originate and start propagating through interplanetary space. Its nested telescopes image coronal structures from approximately 0.5 to 14 million miles above the solar surface, providing an unprecedented view of the dynamics that drive solar activity.
LASCO has revealed the mechanisms behind coronal mass ejections (CMEs), solar wind acceleration, large-scale magnetic disturbances, and more. These phenomena are the primary sources of space weather.
Impact of Space Weather Forecasting
Space weather describes the dynamic conditions in our solar system, and the primary driver of its most hazardous impacts on Earth is the “geomagnetic storm”.
A geomagnetic storm is a major disturbance of Earth's magnetosphere triggered by the efficient transfer of energy from the solar wind into the planet’s surrounding space environment. The most intense storms are typically linked to CMEs.
The repercussions can range from causing permanent damage to satellites, disrupting communication and navigation systems, affecting missile detection sensors, and threatening ground-based power grids. In low-Earth orbit, heightened atmospheric drag can alter spacecraft trajectories and accelerate orbital decay, while high-frequency radio signals used for civilian and military purposes can experience severe interference or blackout conditions.
“One of LASCO’s major contributions has been advancing the heliophysics community’s modeling capabilities,” said Karl Battams, Ph.D., a computational scientist in NRL's Space Science Division and LASCO principal investigator. “By observing how fast coronal mass ejections move in LASCO images and determining their direction, researchers can estimate when these events will impact Earth.”
This capability became possible only through the development of LASCO, which has revolutionized the continuous observation of the solar corona. Its success has demonstrated to both the scientific community and decision makers that maintaining a persistent space-based coronagraphic imaging capability is vital—much like the way meteorological satellites are essential for monitoring Earth’s weather.
National Security Impact
What began as a pioneering research experiment has become a cornerstone of national security infrastructure. LASCO continues to deliver near-real-time observations essential for predicting geomagnetic storms that can hinder defense operations.
“Such disturbances can compromise situational awareness, obstruct command and control, affect precision-guided systems, and even impact the electrical power grid, directly affecting military readiness and operational effectiveness,” Battams said.
Observations from LASCO are paramount for operational space weather monitoring, allowing forecasters to predict the timing of the event's arrival at Earth and the potential geomagnetic storm it could induce. While precisely predicting the severity, exact timing, and duration of a geomagnetic storm remains challenging, these advance warnings are vital for enabling the Department of War (DoW) and other agencies to prepare.
The potential impacts of severe geomagnetic storms on DoW and Department of the Navy missions are significant and far-reaching. These events can disrupt or degrade critical systems and capabilities, including satellite communications, Global Positioning System (GPS) navigation and timing, and various remote sensing systems.
“LASCO demonstrated that continuous, operational observations of the Sun are not just scientifically interesting—they are essential,” Battams said. “Space weather impacts can cause direct consequences to our national security. That importance has since been recognized at the highest levels of policy, including legislation aimed at strengthening our nation’s space weather resilience. LASCO didn’t just contribute to heliophysics—it launched a new era of space weather monitoring and preparedness.”
Impact on Science
LASCO is on board the joint
NASA/ESA SOHO spacecraft, which was designed to study the sun from its interior to its dynamic atmosphere and corona and its interaction with the entire solar system. LASCO remains a vital asset for heliophysics researchers and solar physics. It has unveiled a plethora of advances in our understanding of the Sun and its dynamic corona, now spanning almost three complete 11-year
solar cycles.
“NRL’s history in space science, space weather, and heliophysics is unparalleled,” Battams added. “While LASCO is known for its big, headline achievements, it’s also a foundational piece of a much larger system. It’s a crucial ingredient in how NRL’s Space Science Division strives to observe, understand, and predict space weather on a global scale by understanding the fundamental processes of the Sun itself.”
From the launch of the SOHO mission to LASCO’s first images of the Sun’s corona, LASCO became the catalyst for a new era in solar physics and space weather research.
“When LASCO was launched, no one had any idea its data would become one of the most scientifically prolific archives in history,” Battams said. “The sheer volume and impact of discoveries that have come from this instrument have exceeded even our most ambitious expectations.”
The SOHO project was nominally a two-year mission and has now stretched to nearly 30 years. This unprecedented spacecraft lifetime was driven substantially, particularly in the past decade, by the reliance of the research and operations communities on LASCO’s data stream. Accordingly, LASCO has set the stage for the next advancements in space weather monitoring technologies, which have begun their operations in space.
“LASCO opened the door to an entirely new way of studying the Sun and space weather,” Battams said. “Once scientists could see solar eruptions in real time, they could finally begin to develop accurate models and determine what instruments were needed next. LASCO has helped reveal the questions—and the tools—we needed to answer them and has directly driven the development of next-generation instruments.”
In 2024 the NOAA GOES-19 satellite was launched into a geostationary Earth orbit, carrying the first ever purely operational compact coronagraph, known as CCOR-1. This instrument was designed and built by NRL and supplied to NOAA as a demonstration of the technology to design a more compact coronagraph telescope. This was followed in 2025 by the launch of the NRL-built CCOR-2 coronagraph, flying on the SWFO-1 mission, which will take up permanent residence at the L1 Lagrange point in space, and provide uninterrupted images of the solar corona, starting in March 2026.
CCOR is a spaceborne solar imaging sensor that continuously searches for massive, large scale, and fast-moving concentrations of Earth-directed solar plasma. Analysis of CCOR image plasma concentration content is used to predict geomagnetic storm severity and onset times.
Historical background
“NRL has been a pioneer in heliophysics and space weather research since the very inception of the field, dating back to the first discovery of CMEs through NRL space-based observations in 1971,” Battams said. “Since then, NRL has consistently maintained its position at the forefront of coronal imaging with a portfolio of groundbreaking instrumentation that has driven heliospheric and space weather studies.”
Prior to LASCO, studies of the Sun and its connection to space weather were disjointed.
“Scientists knew the Sun was doing something, and then—hours or days later—something would happen at Earth,” Battams explained. “The two were clearly connected, but we didn’t have the means to observe that process in real time. LASCO provided that first clear view. It gave us the baseline understanding that allowed this entire field of space weather modeling and forecasting to develop.”
LASCO’s design was built on NRL’s decades-long heritage of studying the Sun, from the V-2 rocket experiments in the late 1940’s that first linked solar emission to the state of Earth’s ionosphere; to the first ever observations of large solar eruptions, or CMEs, in the early 1970s; to the first rudimentary catalog of CMEs from NRL’s P78-1/SOLWIND telescope. These pivotal milestones laid a foundation for an instrument package that would become the global benchmark for studying solar storms.
Notable Achievements
In 1997 the LASCO team received the NRL Group Achievement Award, recognizing the exceptional technical and scientific accomplishments.
Over its lifetime, LASCO has achieved a series of transformative scientific breakthroughs that have defined the modern field of heliophysics and space weather forecasting. Among the most significant milestones are:
- Definitive demonstration of the significance of CMEs. LASCO provided the first comprehensive and continuous observations confirming that CMEs are the dominant drivers of large-scale space weather disturbances.
- Revelation of the three-dimensional structure of CMEs. LASCO’s multi-scale imaging enabled the first realistic models of CME geometry, dynamics, and evolution in three dimensions.
- Identification of the halo CME and its geoeffectiveness. LASCO was the first instrument to definitively demonstrate that “halo” CMEs, observed when directed toward Earth, are key causes of geomagnetic storms and can directly impact orbiting spacecraft and ground-based systems.
- Quantitative characterization of CME occurrence and energetics. The LASCO dataset provided the first statistically robust measurements of CME frequency, velocity, kinetic energy, and mass over multiple solar cycles.
- Discovery of the streamer-blowout CME phenomenon. LASCO identified a distinct class of coronal ejections associated with large-scale restructuring of the solar corona, improving understanding of long-term solar magnetic field evolution.
- Unprecedented discovery of near-Sun comets. LASCO has become the most prolific comet-finding instrument in history, identifying thousands of sungrazing and near-Sun comets that are otherwise invisible from Earth-based observatories.
The Future
"LASCO truly set the stage, and demonstrated the necessity, for a permanent presence of an operational coronagraph,” said Arnaud Thernisien, Ph.D., a research physicist from the Advanced Sensor Technology Section within NRL's Space Science Division. “It is the perfect demonstration of the effectiveness of NRL’s research-to-operations chain and our world-leading capability at designing and building these optically complex instruments.”
From its foundational basic scientific principles to the design, testing, and data analysis, and subsequent operational replacement, LASCO has cemented its place as a landmark of heliophysics that epitomizes the value and success of NRL’s research-to-operations pipeline. The impact of LASCO, both from the perspective of heliophysics science as well as protecting critical Navy and DoW assets and operations, will continue to reverberate for decades to come.
About the U.S. Naval Research Laboratory
NRL is a scientific and engineering command dedicated to research that drives innovative advances for the U.S. Navy and Marine Corps from the seafloor to space and in the information domain. NRL, located in Washington, D.C. with major field sites in Stennis Space Center, Mississippi; Key West, Florida; Monterey, California, and employs approximately 3,000 civilian scientists, engineers and support personnel.
NRL offers several mechanisms for collaborating with the broader scientific community, within and outside of the Federal government. These include Cooperative Research and Development Agreements (CRADAs), LP-CRADAs, Educational Partnership Agreements, agreements under the authority of 10 USC 4892, licensing agreements, FAR contracts, and other applicable agreements.
For more information, contact NRL Corporate Communications at
NRLPAO@us.navy.mil.