GOLDEN, Colorado – The growing amount of space hardware flying through cislunar space and around the Moon is, among experts, a growing concern. Even a single fragmentation event can have far-reaching and calamitous consequences for future lunar exploration, driving the need for appropriate debris characterization tools.
That's the view of two Purdue University researchers who warn that space domain awareness is lacking at a time when cislunar activity is intensifying. Orbital debris now surrounding Earth has been generated primarily through collisions, propellant tank explosions, battery detonation, or the deterioration of aging or damaged spacecraft, among other causes.
Studies indicate that disintegration events in the cislunar domain can transport fragments far beyond their original orbits, even to Earth. What is needed, they conclude, is a better evaluation of the behavior of the possible cislunar disorder.
Having space debris in cislunar space (the region between the Earth and the Moon) or orbiting the Moon itself would be cause for concern. In terms of debris orbiting the Moon, there is no natural cleanup mechanism like the drag induced by Earth's atmosphere on orbiting flotsam. The fragments surrounding the airless moon simply remain there, held together by lunar gravity.
chaotic nature
Arly Black and Carolin Frueh of Purdue University in West Lafayette, Indiana, raise the cislunar debris warning flag. Black is a graduate research assistant in the Frueh Spatial Information Dynamics Group in the university's School of Aeronautics and Astronautics. The team identified a number of problems in your researchrecently published in Advances in space researchthe magazine of the Committee for Space Research.
They note that multinational lunar and cislunar exploration is already underway. However, there is still a lack of more knowledge and modeling of spacecraft disintegrations in the cislunar environment. For example, China's series of lunar orbiters, landers and rovers, Israel's first Beresheet lunar landing attempt, India's Chandrayaan-3 mission to the lunar south pole, as well as the POT CAPSTONE Pioneer Missionnow in extended mission mode in the Earth-Moon L2 near-rectilinear halo orbit (NRHO).
Additionally, NASA's Commercial Lunar Payload Services is contracting with private American companies to deposit the space agency's science and technology payloads on the surface of the moon.
NASA's Artemis effort also involves the small multipurpose outpost Gateway, visited by the crew, being placed in an NRHO to support missions to the lunar surface, scientific missions in lunar orbit, and the eventual return of human crews to restart the moon .
Black and Frueh explain that point solutions for individual spacecraft breakups in particular cislunar orbits can and have been modeled in the past. However, more work is needed to comprehensively predict rupture behavior on a global scale, “without requiring new simulations for every possible permutation, which is computationally expensive and dependent on precise parameter information,” they write. in the article.
It is necessary to take into account the movement of spacecraft in the Earth-Moon system. Then relevant forces are at play, such as the pressure of solar radiation and the gravitational influences of Jupiter and the Sun.
“Given the chaotic nature of the system dynamics in this region, orbits and nearby cases may exhibit completely different behavior,” the university researchers explain in their journal article, adding that many relevant debris scenarios remain. unexplored.
Complex dynamics
Near-Earth space situational awareness remains a work in progress, says Black SpaceNews“and even after so many decades of space activity, we have yet to fully combat the problems of debris in a simple two-body system.”
The complex dynamics of a three-body system, applied to a space object near the Moon, for example, poses a much greater challenge, Black said.
“Given the renewed fervor for lunar exploration, the cislunar population is expected to increase significantly in the coming years,” Black said. “And if we have learned anything from the analysis of near-Earth fragmentation, it is that we cannot wait until a critical capacity is achieved to address debris-related problems.”
Black added that the research work aims to take a proactive approach to analyzing cislunar debris, “before a catastrophic fragmentation event occurs,” in order to understand the consequences of such an event at multiple cislunar locations and highlight areas mitigation potentials.
Not if, but when
Fragments of man-made objects in the cislunar region are harmful, says Frueh SpaceNewsas pieces can return and impact the Moon, or Earth and near-Earth space, potentially interacting with satellites there.
“Some fragments will continue to travel and traverse the region between the Earth and the Moon, posing a danger to active space missions in that region,” Frueh observed. Even debris that leaves the Earth-Moon system toward the Sun could return decades later, he said.
In fact, such a scenario appears to have involved Snoopy, a lunar ascent module discarded from the manned Apollo 10 mission in May 1969. It was jettisoned and launched into orbit around the sun, later discovered as an Earth-crossing object for a amateur. astronomers who said with almost certainty that it was Snoopy. Frueh and his colleagues also examined the re-entering object in 2015 and “related it reasonably well to the Snoopy hypothesis,” he said.
“With the increase in space in the region, it is not a question of whether “We will see fragmentations of man-made objects in cislunar space, but when,” Frueh emphasized. “With the best efforts of spatial situational awareness, we hope to extend that time into the future.”
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