South Korean moon probe snaps picture of NASA's powerful lunar orbiter (photo)

Andrew Jones
·3 min read
22
South Korea's Danuri lunar orbiter flew 18 kilometers above the NASA Lunar Reconnaissance Orbiter on April 7, 2023, enabling ShadowCam to capture this dramatic image of LRO.
South Korea's Danuri lunar orbiter flew 18 kilometers above the NASA Lunar Reconnaissance Orbiter on April 7, 2023, enabling ShadowCam to capture this dramatic image of LRO.
South Korea's Danuri lunar orbiter flew 18 kilometers above the NASA Lunar Reconnaissance Orbiter on April 7, 2023, enabling ShadowCam to capture this dramatic image of LRO.
South Korea's Danuri lunar orbiter flew 18 kilometers above the NASA Lunar Reconnaissance Orbiter on April 7, 2023, enabling ShadowCam to capture this dramatic image of LRO.

NASA's Lunar Reconnaissance Orbiter has been caught out at its own game.

The Lunar Reconnaissance Orbiter (LRO) has been studying the moon up close since 2009. It has also imaged other active spacecraft on the lunar surface, such as China's Yutu 2 rover, and even other moon orbiters.

And now, a newcomer to lunar orbit recently spotted LRO from a distance of just 11.2 miles (18 kilometers) as the probes zipped by each other in their respective orbits.

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

A computer-generated image of LRO recreating the precise view seen by NASA's ShadowCam aboard South Korea's Danuri moon orbiter.
A computer-generated image of LRO recreating the precise view seen by NASA's ShadowCam aboard South Korea's Danuri moon orbiter.

The Korea Aerospace Research Institute's (KARI) Danuri spacecraft arrived in lunar orbit in mid-December 2022. Aboard is ShadowCam, a NASA-funded hypersensitive optical imager, which is able to provide views into shadowed areas by collecting light reflected off nearby landforms and light reflected from our planet onto the moon, or "Earthshine."

This time, instead of illuminating shadowed craters, ShadowCam captured a sunlit LRO as both spacecraft passed over a patch of moon shrouded in darkness.

NASA's LRO moon orbiter as seen by South Korea's Danuri spacecraft with spacecraft overlay
NASA's LRO moon orbiter as seen by South Korea's Danuri spacecraft with spacecraft overlay

The stunt required coordination and timing, as the two spacecraft passed each other with a relative velocity of 7,113 mph (11,447 kph). The NASA LRO mission operations team at Goddard Space Flight Center in Maryland oriented the spacecraft relative to Daunri and the sun to allow the radiator and back of the spacecraft to be brightly illuminated, according to a post on the ShadowCam webpages.

The high speed of the near encounter and the exposure time of ShadowCam results in LRO being doubly exposed four times in the final image. An animation from the ShadowCam team illustrates the features of LRO captured in the image, including the spacecraft's solar array, radiator and high-gain antenna, by transitioning from the captured image to a computer-generated high-resolution image.

Related stories:

— Danuri: Facts about the Korea Pathfinder Lunar Orbiter (KPLO)

— Moon facts: Fun information about the Earth's moon

— Wow! Maxar satellite captures up-close look at NASA's Landsat 8 spacecraft in orbit

ShadowCam, which is based on LRO's powerful main camera, is being used to learn about shadowed areas at the lunar south pole ahead of NASA's Artemis 3 mission, mapping out permanently shadowed areas. (Artemis 3 will land astronauts near the south pole, the first crewed return to the lunar surface since Apollo 17 in 1972.) Meanwhile, Danuri has other cameras aboard, which recently captured epic views of iconic lunar features.

Closer to home, a Maxar Earth-observation satellite recently captured an up-close look at NASA's Landsat 8 spacecraft in low Earth orbit, demonstrating how satellite imagery can be used for potentially checking out the health or causes of issues for satellites.

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