How EPIC Captured the Moon Passing Earth from a Million Miles Away

EPIC Vision

In July 2015, a camera one million miles from Earth captured something extraordinary: the Moon passing in front of our vibrant, cloud-streaked planet. The image, taken by NASA and NOAA’s Earth Polychromatic Imaging Camera (EPIC) aboard the DSCOVR satellite, offered an awe-inspiring view of our cosmic neighborhood. Suspended between Earth and the Sun at a gravitational balancing point known as L1, DSCOVR has since delivered stunning visuals and vital data on Earth’s climate and atmosphere.

This post explores how EPIC works, the significance of its location, a brief history of Earth observation satellites, and a look at some of today’s key orbiting observatories.

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What Is EPIC?

The Earth Polychromatic Imaging Camera (EPIC) is a 10-channel imaging spectroradiometer. It captures full-disk, true-color images of Earth every two hours, viewing only the sunlit side from its unique vantage point in space.

What EPIC Measures:

• Cloud height and dynamics

• Atmospheric aerosols (e.g., dust, smoke, pollution)

• Ozone levels and UV reflectivity

• Surface vegetation

• Global albedo (reflectivity)

With this data, scientists can assess air quality, monitor climate trends, and study Earth’s energy balance—all while generating captivating images that put our home planet into cosmic perspective.

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️ Meet DSCOVR

DSCOVR (Deep Space Climate Observatory) was launched in 2015 as a joint mission between NASA, NOAA, and the U.S. Air Force. Its primary mission is to:

• Monitor space weather, especially solar wind,

• Provide early warnings for geomagnetic storms,

• And support climate science through EPIC’s imagery and the onboard NISTAR radiometer.

But what makes DSCOVR unique is where it lives in space…

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L1: A Perfect Place to Watch Earth

DSCOVR is positioned at the first Lagrange point (L1), about 1 million miles from Earth toward the Sun.

What Are Lagrange Points?

Lagrange Points are locations in space where the gravitational forces of two large bodies—like the Earth and Sun—create regions of stable equilibrium. There are five such points (L1 to L5), and they’re used by satellites to “hover” in a fixed position relative to Earth and the Sun.

Why L1?

• Always sees the full sunlit Earth.

• Ideal for space weather monitoring and continuous Earth imaging.

• Allows for stable solar observation, with minimal orbital correction.

EPIC, riding at L1, can stare at Earth’s sunlit face without interruption—a view no satellite in low Earth orbit can achieve.

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A Brief History of Earth Observation Satellites

Humanity’s effort to observe Earth from space began with a Cold War-era curiosity: could we spy on our planet as easily as we did on each other?

Key Milestones:

• 1959 – Vanguard 2: The first satellite designed for cloud cover observation.

• 1960 – TIROS-1: The first successful weather satellite, launching the modern era of meteorology.

• 1972 – Landsat 1: Pioneered land use and environmental monitoring from space.

• 1999 – Terra (EOS AM-1): A NASA flagship Earth-observing satellite focusing on climate science.

Since then, we’ve launched a fleet of satellites to study oceans, ice, forests, pollution, temperature trends, and even the subtle color changes in vegetation.

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Today’s Active Earth Observation Satellites (Partial List)

Here are a few current missions—each offering distinct capabilities:

Each satellite has a unique orbital pattern, resolution, and suite of instruments. Together, they give us a real-time mosaic of our changing planet.

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When the Moon Passed in Front of the Earth

In that famous 2015 image, EPIC captured the Moon passing between it and Earth—a visual alignment only possible from L1. The stark contrast between the Moon’s ashen gray and Earth’s vibrant blues and greens evokes a sense of scale, beauty, and fragility.

What’s especially striking is how the Moon appears motionless and dark, while Earth bursts with life and color—a silent visual poem about our place in the cosmos.

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Why It Matters

EPIC isn’t just a pretty picture machine. It helps:

• Track pollution and climate indicators.

• Provide daily real-time views of Earth for education and outreach.

• Connect us emotionally and scientifically with our planet.

In an age where Earth’s systems are under growing stress, having a million-mile vantage point helps us see not only where we are—but where we’re going.

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Want to explore EPIC images for yourself?
https://epic.gsfc.nasa.gov