Danuri examines the Lunar Reconnaissance Orbiter during their rendezvous in the orbit of the Moon

NASA’s lunar reconnaissance vehicle was “caught” in the Moon’s orbit. The Lunar Reconnaissance Orbiter (LRO) has been studying the Moon since 2009. It has also taken images of other active spacecraft on the moon’s surface, such as the Chinese Mars rover Yutu 2 and even other orbiters. Now LRO saw another spacecraft – the South Korean “Danuri”, which flew past at a distance of only 18 kilometers. During this approach, Danuri could photograph the Lunar Reconnaissance Orbiter and sent a photo to NASA.

The Danuri lunar orbiter of the Korean Aerospace Research Institute (KARI) flew at an altitude of 18 kilometers above NASA’s Lunar Reconnaissance Orbiter on April 7, 2023, which allowed the ShadowCam camera to capture this impressive LRO image. The relative velocity between the two spacecraft was 3180 m/s. Image: NASA/KARI/Arizona State University

The picture was taken using the ShadowCam camera on board the Danuri. But the rapprochement took place over a dark-shrouded section of the Moon. Performing the trick additionally required coordination and time, as the two spacecraft passed each other at a relative speed of 11,447 km/h. The NASA LRO Mission Task Force at the Goddard Space Flight Center in Maryland oriented the spacecraft relative to the “Danuri” and the Sun so that the radiator and the back of the spacecraft were well illuminated. 

An enhanced LRO computer image reproducing the exact view that the ShadowCam camera saw at the time of photographing. Image: NASA/KARI/Arizona State University

The high speed of approach and the exposure time of the ShadowCam leads to the fact that the LRO is exposed four times in the final image. In the original image, the spacecraft is extremely complicated to see, because it occupies only a few tens of pixels. Therefore, the ShadowCam team improved the image thanks to computer algorithms to make the photo with the LRO clearer, in which individual details became visible, including the solar panel, radiator and antenna with a high gain. 

A reproduced view of the LRO in high resolution using a computer simulation, as seen by the ShadowCam camera. Image: NASA/KARI/Arizona State University

The Danuri spacecraft of the Korean Aerospace Research Institute (KARI) arrived in lunar orbit in mid-December 2022. On board is the ShadowCam, NASA’s ultra-sensitive high-resolution optical camera. ShadowCam is being used to study shaded areas at the Moon’s south pole ahead of NASA’s Artemis III mission. Meanwhile, there are other cameras on board the Danuri that have recently captured epic views from the Moon’s orbit.

Animation of gradual improvement of the LRO image
LRO silhouette recreated by computer

Earlier we reported on how the lunar ice hunter took the first picture.

Follow us on Twitter to get the most interesting space news in time