In 2009, NASA launched the Lunar Reconnaissance Orbiter (LRO). Its current mission is to map the lunar surface in detail, identifying potential landing sites, resources and features of interest such as lava tubes. The continued success of this mission is another example of NASA’s excellence. The map covers approximately 98.2% of the lunar surface, excluding deeply shadowed areas in the polar regions.

But recently the LRO team’s ingenuity was on display for another reason: It took photos of another satellite zipping past the Moon’s surface.

The Republic of Korea, or what most of us call South Korea, launched the Danuri lunar orbiter in August 2022. It is the nation’s first lunar orbiter and its mission is to develop and test technologies including space-based Internet and create topographic mapping. lunar surface.

The map will help select future landing sites and identify resources such as uranium, helium-3, silicon, aluminum and water ice. Danuri has a number of instruments, including a spectrometer, a magnetometer, and various cameras. More importantly, it includes a camera that will allow LRO to capture shadowy polar regions beyond its capabilities.

NASA contributed to the Korean Aerospace Research Institute’s (KARI) Danuri mission. NASA has created a Shadowcam device that captures shadowed areas at the Moon’s poles. LRO took photos of Dhanuri as he passed under LRO as a sort of high-five to his fellow astronauts.

On March 5 and 6, the two orbiters passed each other at a combined speed of 11,500 km/h (7,200 mph). There were three orbits that allowed LRO to capture images of the fast-moving Danuri. The vertical distance between them was different during each orbit.

In the first image, LRO was 5 km (3 mi) above Dhanuri. LRO had to change the angle. To catch Danuri, he had to aim at an angle 43 degrees below his normal angle.

During the second orbit, only 4 km (2.5 mi) separated the pair of orbiters.

In the third and final orbit, the distance between the two spacecraft was greater: 8 km (5 mi). This time the LRO was directed at a 60 degree angle.

It’s hard to see Danura in the last image.

This isn’t the first time a pair of orbiting ships have played the visual game. In April 2023, it was Danuri’s turn to photograph the LRO. At that time, the Korean spacecraft passed about 18 km (11 mi) above LRO and imaged it with its ShadowCam instrument.

This isn’t the first time Lunar ships have taken portraits of each other. In 2014, the LRO was captured by NASA’s Lunar Atmosphere and Dust Environment Exploration Instrument (LADEE) before it was sent to impact the lunar surface.