Curating the catalog
Because of the difficulty and lack of adequate resources to track objects near the Moon, there is no group or organization consistently doing so today. So, in 2020, Furfaro and I took on the challenge to discover, track and catalog human-made debris in cislunar space.
First, we linked historical observations from various telescopes and databases to each other to identify and confirm what cislunar objects were already known. Then, realizing there were no dedicated telescopes scanning the night sky for cislunar objects, my students at the University of Arizona and I built one. In late 2020, we finished building a 24-inch-diameter (0.6-meter-diameter) telescope, which is at the Biosphere 2 Observatory near Tucson.
The first object we tracked was Chang’e 5, China’s first lunar sample return mission. The large rocket launched on Nov. 23, 2020, headed toward the Moon. Despite the powerful lunar glare, my students and I were able to track Chang’e 5 to a distance of 12,354 miles from the Moon, deep into the Cone of Shame. With this success, we started tracking newly launched cislunar payloads and adding them to our nascent catalog. With this success, we started tracking newly launched cislunar payloads so we can calculate and predict their orbits to prevent them from getting lost.
To characterize both old and new space debris, once we figure out where an object is, we use optical and near-infrared telescopes on Earth to capture the object’s spectral signature – the specific wavelengths of light that bounce off an object’s surface. By doing this, we can figure out what material an object is made out of and identify it. This is how we identified the mystery rocket booster that crashed into the Moon in 2022. We can also measure changes in the light bouncing off the object over time to determine how fast that object is spinning, which can also help with identification.
Over the last two years, we have become better and better at finding and identifying objects in cislunar space. While at first we were happy to identify the school bus-sized Chang’e 5 spacecraft, now we are able to track CubeSats no bigger than a cereal box – like NASA’s Lunar Flashlight.
To date, my team has been able to identify a few dozen pieces of debris in cislunar space and are continuing to add to our ever-expanding catalog. The vast majority of the work ahead comprises continued observations and matching objects to known missions to confirm what objects are out there and where they came from.
While there is still a long way to go, these efforts are designed to ultimately form the basis for a catalog that will help lead to safer, more sustainable use of cislunar orbital space as humanity begins its expansion off of the Earth.
