Green comet seen from space by Artemis 1 moon mission cubesat (video)

Comet C/2022 E3 (ZTF) imaged by the Japanese Equuleus cubesat that is orbiting the moon.
Comet C/2022 E3 (ZTF) seen traversing the sky on Feb. 12 by the Japanese Equuleus cubesat that orbits the moon. (Image credit: Equuleus project team)

Japan's cubesat EQUULEUS, which hitched a ride to the moon aboard NASA's Artemis 1 mission in November last year, took a video of Comet C/2022 E3 (ZTF) earlier this month, about two weeks after the ice ball's closest approach to Earth. 

The comet — also called the green comet for its hue or the Neanderthal comet, as it hasn't visited Earth since the era of the Neanderthals — can be seen in the video sequence shared on Twitter as a fuzzy white dot traversing a star-studded black-and-white background.

"EQUULEUS successfully photographed Comet ZTF (Comet C/2022 E3) from space!" the EQUULEUS team said in a tweet accompanying the image sequence shared on Tuesday (Feb. 21). 

Related: Amazing photos of gorgeously green Comet C/2022 E3 (ZTF)

The 6U cubesat , built by the Japanese Aerospace Exploration Agency (JAXA) and the University of Tokyo, imaged the comet for six hours on Feb. 12. At that time, the cubesat was about 43 million miles (69.5 million kilometers) from the comet and 211,000 miles (340,000 km) from Earth. 

"These series of images were taken by calculating the timing and direction from the relative orbits of the comet and EQUULEUS," the team said in the tweet.

EQUULEUS is currently sailing toward the Lunar Lagrange point 2, a gravitationally stable point in the Earth-moon system, which is about 38,000 miles (61,347 km) behind the moon on the side away from Earth. 

The mission is testing low-energy propulsion techniques, including a low-thrust water propulsion system that uses very little propellant to control the spacecraft's trajectory. The spacecraft also carries sensors to make measurements of Earth's plasmasphere, the inner region of the magnetosphere a few thousand miles above the planet that contains cool plasma  —  gas in which atoms have been stripped of electrons.

As for Comet C/2022 E3 (ZTF), the object is still visible in the sky with amateur telescopes but is quickly fading as it hurtles back toward the outer solar system, where it came from. It may pay Earth and the sun another visit in 50,000 years, but some astronomers think it will actually never return again, as the gravitational kick it received from our life-giving star may fling it out of the solar system altogether. 

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Tereza Pultarova
Senior Writer

Tereza is a London-based science and technology journalist, aspiring fiction writer and amateur gymnast. Originally from Prague, the Czech Republic, she spent the first seven years of her career working as a reporter, script-writer and presenter for various TV programmes of the Czech Public Service Television. She later took a career break to pursue further education and added a Master's in Science from the International Space University, France, to her Bachelor's in Journalism and Master's in Cultural Anthropology from Prague's Charles University. She worked as a reporter at the Engineering and Technology magazine, freelanced for a range of publications including Live Science,, Professional Engineering, Via Satellite and Space News and served as a maternity cover science editor at the European Space Agency.