NASA’s Lunar Reconnaissance Orbiter (LRO) has been orbiting and studying the Moon for the past 15 years. And yet, it’s not every day that the LRO manages to capture images of another spacecraft in lunar orbit.
During the period of March 5 and 6, 2024, the LRO, travelling in a nearly parallel orbit, managed to capture a series of images of Danuri. This was no simple task. The two spacecraft were moving in opposite directions, making the timing of the images crucial.
To capture these images, the LRO operations team at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, had to ensure that the LRO’s camera was pointing to the right place at the right time. The relative velocities between the two spacecraft were approximately 7,200 miles (or 1,500 kilometers) per hour. Despite the short camera exposure time (only 0.338 milliseconds), Danuri appears smeared in the images due to the high relative velocities.
Danuri, the Republic of Korea’s first spacecraft to reach the Moon, has been in lunar orbit since December 2022. One of the images shows Danuri (streaked across the middle) from 3 miles (or 5 kilometers) above it. During the next encounter, LRO was closer to Danuri, about 2.5 miles (or 4 kilometers), and oriented 25 degrees toward it. In the final photo, LRO was reoriented by 60 degrees to catch a glimpse of Danuri when it was 5 miles (or 8 kilometers) below it.
Interestingly, Danuri also had an opportunity to photograph the LRO. Its ShadowCam instrument, which was provided by NASA, took a photo of the LRO as the Korean spacecraft passed about 11 miles (18 kilometers) above it on April 7, 2023.
Launched on June 18, 2009, the LRO has made significant contributions to our knowledge about the Moon. Its seven powerful instruments have collected a wealth of data, supporting NASA’s mission of returning to the Moon with commercial and international partners to expand human presence in space and bring back new knowledge and opportunities.