NASA’s Perseverance Mars rover captured Earth briefly vanishing behind the Martian moon Phobos during an evening twilight observation on July 2. Recorded from Jezero Crater on the 1,907th sol of the mission, the rare celestial occultation shows our distant planet as a single pixel disappearing behind the lumpy satellite.
More than 140 million miles away from home, NASA’s robotic explorer captured a twilight alignment that astronomers call an occultation. The sequence reveals Earth appearing as a tiny, bright speck of light as it slowly passes behind the irregularly shaped Martian moon Phobos in the evening sky of Mars. The observation marks the first time humanity has recorded Earth disappearing behind another object from the surface of a different planet.
Mastcam-Z Captures Twilight Occultation from Jezero Crater
Perseverance recorded the sequence using its Mastcam-Z instrument at approximately 7 p.m. local solar time on July 2, corresponding to the 1,907th Martian day, or sol, of the mission. In the resulting composite view, Earth moves diagonally from the upper left toward the lower right while Phobos travels in the opposite direction from the lower left to the upper right. By the third image in the sequence, the two objects line up, and Earth temporarily vanishes behind the shadowed edge of the small moon.
NASA applied image processing to filter out background light, highlighting the celestial pairing against fading twilight in an annotated version released that spans just 40 seconds of progression. The natural orbital path of Phobos causes it to appear to drift upward in the frame while Earth moves downward before slipping out of view.
Scale and Distance in the Martian Sky
From the rover’s position along the rim of Jezero Crater, Earth and Phobos present a sharp contrast in size and distance. Phobos is a lumpy, potato-shaped moon measuring about 17 miles or 27 kilometers across at its widest. Because it orbits just 4,850 miles or 7,800 kilometers from Mars, the moon appeared about one-third as wide as Earth’s Moon appears from our home planet. Earth, by contrast, was roughly 195 million miles or 314 million kilometers away, appearing in the camera frames as a single-pixel-sized point of light.
Phobos crosses the Martian sky three times a day, and Earth is visible for months at a stretch, but catching one directly behind the other takes planning and a little luck,
said Mark Lemmon, a Mastcam-Z co-investigator at the Space Science Institute in Boulder, Colorado, who planned the observation and assembled the composite.
Distinguishing Occultations from Solar Eclipses
Astronomers categorize the event as an occultation, which occurs when a closer object that appears larger from the observer’s perspective completely blocks a more distant object behind it. This differs from an eclipse, where an object enters the shadow of another, or a transit, where a smaller-appearing object crosses the face of a larger-appearing one.
Perseverance has observed similar phenomena during its mission, including occasions when Phobos or Deimos passes across the Sun as viewed from the Martian surface, events informally referred to as Martian solar eclipses.
Mission Operations and Instrument Management
NASA’s Jet Propulsion Laboratory, managed by Caltech in Southern California, built Perseverance and oversees mission operations for the agency’s Science Mission Directorate in Washington. Arizona State University leads operations for the rover’s Mastcam-Z instrument, working alongside Malin Space Science Systems in San Diego on the design, fabrication, testing, and operation of the camera hardware.
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