A NASA spacecraft spotted something weird orbiting the moon. It was just a lunar neighbor (photos)

Samantha Mathewson
·2 min read
A dark streak over the moon as seen by a NASA spacecraft.
A dark streak over the moon as seen by a NASA spacecraft.

NASA's Lunar Reconnaissance Orbiter (LRO) snapped a perfectly timed photo as it crossed paths with another spacecraft orbiting the moon.

The LRO, which has been orbiting the moon for 15 years, captured several images of the Korea Aerospace Research Institute's Danuri lunar orbiter as the two spacecraft, traveling in nearly parallel orbits, zoomed past each other in opposite directions during three orbits between March 5 and March 6, according to a statement from NASA.

Danuri, the Republic of Korea's first moon-explorer, has been in lunar orbit since December 2022. At the time the photos were taken, Danuri was orbiting below the LRO, which was flying 50 miles (80 kilometers) above the moon's surface.

Related: Amazing moon photos from NASA's Lunar Reconnaissance Orbiter

Relative velocities between the two spacecraft were about 7,200 miles per hour (11,500 kilometers per hour), NASA officials said, making it challenging for the LRO's narrow angle camera  to hone in on Danuri. The LRO's camera exposure time was roughly 0.338 milliseconds, causing Danuri to appear smeared across the image and stretched 10 times its size, as it traveled swiftly in the opposite direction of the LRO.

"The LRO operations team at NASA's Goddard Space Flight Center in Greenbelt, Maryland, needed exquisite timing in pointing LROC to the right place at the right time to catch a glimpse of Danuri," NASA officials said in the statement.

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A dark streak over the moon as seen by a NASA spacecraft.
A dark streak over the moon as seen by a NASA spacecraft.

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A white box surrounds an area of the moon in which NASA's LRO spacecraft spotted the Danuri probe from South Korea.
A white box surrounds an area of the moon in which NASA's LRO spacecraft spotted the Danuri probe from South Korea.

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Side by side photos show glimpses of South Korea's Danuri spacecraft as pixelated smears in photos photos from NASA's LRO.
Side by side photos show glimpses of South Korea's Danuri spacecraft as pixelated smears in photos photos from NASA's LRO.

NASA's LRO had three opportunities to snap photos of Danuri during close flybys. For the first snapshot, LRO was 3 miles (5 kilometers) above Danuri and oriented down 43 degrees from its typical position looking down at the lunar surface. In capturing the orbiter with its new positioning, Danuri appeared sort like a disk-shaped streak across the middle of the image.

For the second image, LRO was closer to Danuri, about 2.5 miles (4 km), and oriented 25 degrees toward it. Then, on the last flyby, LRO was reoriented by 60 degrees to catch a final glimpse of Danuri as it flew 5 miles (8 km) below.

This isn't the first time the two spacecraft have crossed paths. Using its ShadowCam instrument, provided by NASA, Danuri photographed LRO from a distance of about 11 miles (18 km) on April 7, 2023.