The bane of lunar missions
HUMANKIND has always been fascinated by the heavens and wondered about the nature of the objects seen in the night sky. With the development of rockets and the advances in electronics and other technologies in the 20th century, it became possible to send machines and animals and then people above Earth’s atmosphere into outer space. Even before the advent of technology to enable space travel, writers, poets, artists and academics have been using their imagination to depict life on other planets and the thrills of space travel.
Yuri Gagarin, a Soviet pilot and cosmonaut, became the first human to journey into outer space. Travelling in the Vostok 1 capsule, Gagarin completed one orbit of Earth on 12 April 1961. Nine years later, Neil Armstrong and Edwin “Buzz” Aldrin became the first humans ever to land on the Moon. Ever since the conquest of the Moon, scores of space missions have been launched, travelling even beyond the Moon, venturing towards Mars and other planets. Moon being the closest celestial landing ground for humankind, has stimulated the quest for establishing a base on the Moon. The Chinese, who were a late entrant in space research, have not only caught up with the west, but have made good progress.
On 01 December 2020, the Chang’e-5 spacecraft landed a probe on the lunar surface and collected soil and rock samples from the lunar surface and two feet below the surface, after which the spacecraft ascended to Earth. The Chang’e-5 lunar probe concluded an epic Earth-Moon round trip, and managed to carry some 2 kilograms of lunar samples back to Earth on 17 December 2020, making China the third country in the world to achieve such a feat and first in more than four decades.
The significance of this mission is that by 2029, China wants to establish a space station on the Moon to make it easier for humans to travel to the Moon. China launched a mission to Mars called Zhurong, in May 2021, in which a rover or vehicle used for space exploration landed successfully on the Martian surface. The Chinese spacecraft has conducted a detailed survey of Mars, specifically exploring the frozen lakes on the Red Planet. Notably, China plans to send its first crewed mission to Mars in 2033 and wants to build a base there. However, amidst all these exhilarating breakthroughs, there is a bane of it, which till recently, had escaped the notice of space enthusiasts although scientists and government agencies have been worried about it–the debris left behind by space missions around earth as well as the Moon.
Experts opine that the rubble comprises a few dozen pieces of space junk like spent rocket bodies, defunct satellites and mission-related debris orbiting in cislunar space – the space between Earth and the Moon and the area around the Moon. Prima facie this may not be a large amount of litter but becomes hazardous to future space missions owing to the absence of information about locations of the pieces of space debris.
NASA informs of more than 100 planned missions to the Moon in the coming years, making it imperative to take cognizance of the peril. Two planetary scientists have taken up the cudgel to address the issue. Vishnu Reddy and Roberto Furfaro, Professors of Planetary Sciences at the Lunar and Planetary Laboratory and the Director of Space Safety, Security and Sustainability Center (Space 4 Center) at the University of Arizona, in Tucson are using telescopes and existing databases on lunar missions to find, describe and track lunar space debris and build the world’s first catalogue of cislunar space objects.
Vishnu Reddy has authored an eye-opening article titled ‘More lunar missions means more space junk around the Moon – two scientists are building a catalog to track the trash’ in which he informs that historically, NASA and the U.S. military have not closely tracked space debris from the many dozens of crewed and robotic missions to the Moon. He laments the absence of any international agency that has monitored lunar objects, either. He concludes that this lack of oversight is why scientists don’t know the location or orbit of the vast majority of lunar space debris. And these objects won’t simply go away – in the near total vacuum of space, anything left in orbit around the Moon or in cislunar space will likely remain there for at least decades.
The learned scientist informs that this lack of information about human-made objects orbiting the Moon poses many risks for lunar missions. He identifies the first being the risk of collision, which increases manifold, keeping in view the heightened new wave of lunar exploration. With every mission, the risk of a collision with existing debris rises and so, too, does the total amount of debris as missions leave junk behind. Prof. Reddy emphasizes that crash landings onto the surface of the Moon are also a real risk because the Moon does not have a thick atmosphere that can burn up falling space junk.
With both the U.S. and China planning to build lunar bases in the coming years, falling debris could become a real threat to human life and infrastructure on the Moon. The erudite scholar identifies two challenges to preventing the Moon from becoming a cosmic landfill and the need to be able to track cislunar space junk: distance and light. He informs that cislunar space extends about 2.66 million miles from Earth – far past the distance within which the U.S. government currently tracks objects in the massive space, and the objects within which are tiny by comparison.
The second challenge, light, is important because just like the Moon itself, the brightness of an object in cislunar space depends on how much sunlight the object reflects. During a crescent moon, lunar debris appears dim and low in the evening sky, making it hard to find. During a full moon, the same objects are high in the sky and brighter due to more sunlight hitting them, but they blend in with the bright glare that surrounds a full moon creating difficulty in tracking objects within it. The other hazard is threat posed by space junk falling on earth and causing damage to life and property. Thus, the undertaking by Professors Reddy and Furfaro to discover, track and catalogue human-made debris in cislunar space is of immense importance. The next step would be to enforce space law so that it prevents and deters actors from polluting space environment – and holds them accountable if they break these laws – could help overcome bane of future lunar and other outer-space missions.
—The writer is a Retired Group Captain of PAF, who has written several books on China.
