The enigma of beyond has been a fundamental pursuit of thinkers since the earliest forays into philosophy. As early as the 2nd millennium BC, Vedic scholars imparted knowledge on the cyclic nature of the universe. It was only in 1957 that humans physically ventured into space with the launch of the Soviet Union’s Sputnik satellite. And hence, the space race was transformed forever at the peak of the Cold War.
Space Debris
In over six decades since Sputnik, there have been an average of 100 launches a year, with 2021 surpassing all previous records at 144 space launches with a whopping 122 successful. With all these launches, one wonders whether they remain in operation perpetually? If not, what happens to them?
Regarding space launches, we send various objects with a greater variety in the objective, destination and life. For example, the backbone of communication technology is the constellation of satellites that orbit the Earth. Usually, they are launched into higher orbits so that they appear at the same position in the sky at all times. These are the longer-lasting satellites with a life of 8-10 years. In contrast, the satellites that map various climatic phenomena are placed much closer to the Earth’s surface so that they can map the entire globe within a day, every day. However, these do not last more than five years. Other than satellites, the launches include various space explorations and interplanetary missions that eventually leave the immediate space of Earth. Still, they often leave parts of earlier stage rockets in orbit, which should ideally burn up on reentry and leave minimal waste in orbit.
However, the Earth’s orbit has been choking given the 9300 tonnes of space hardware, a lot of which is space debris. Space debris is resultant of a large number of non-functional space hardware, as well as fragments of smaller space particles suspended. These are usually from the unsuccessful flights that unfortunately explode into a million pieces. Now, all of these uncontrollable objects have increasingly posed a threat to putting new satellites in space as well as preventing new endeavours at a record pace. Much like Earth’s various reservoirs, space, too, is at risk of being unusable for future generations.
Sizing up the Threat of Space Debris
Over 6000 launches till now have resulted in more than 55000 tracked objects in the Earth’s orbit, of which only about 28000 remain in space. Hardly one-seventh of these are intact, operational satellites – pegging the total space hardware in orbit at 9300 tonnes. As we enter the space renaissance, Kessler syndrome forewarns devastating consequences of space debris. Propounded by NASA scientist Donald J. Kessler in 1978, Kessler syndrome is a scenario in which the density of objects in Earth’s orbits reaches a critical mass such that collisions between objects could cause a cascade.
Monitored space debris includes satellites, upper stages and mission-related objects, such as launch adapters and lens covers. Over 500 fragmentation events have been held accountable for generating space debris of more than 1 cm in size to 9 lakhs. Such incidents are attributed to fuel-caused explosions. Harsh space environments take a toll on the mechanical integrity of space hardware and promulgate such fragmentation events.
Managing Space Debris
Even if, in lieu of space debris, all future launches are halted, there is already a great build-up of space debris. Images captured by JAXA clearly show how severe this is, especially in the Low Earth Orbit (LEO).
This gives impetus to actively devising strategies for dealing with space debris and managing it. To this effect, various programmes focus on monitoring and tracking space debris. The concerted international effort is spearheaded by Inter-Agency Space Debris Coordination Committee (IADC), comprising space agencies of 10 countries, including ISRO. Independently, many space agencies run their monitoring programs, as well. Notably, NASA’s Orbital Debris Program Office uses modelling for tracking various space objects. India also stepped into this domain with Mission NETRA to build Space Situational Awareness for Indian satellites. ESA and JAXA have also built capabilities.
Not only from the government side do we see all the effort. Various startups have now forayed monitoring and tracking space objects, including space debris. Most recently, an Indian startup, Digiantra Research and Technology (DRT), developed India’s first In-orbit Space Debris Monitoring and tracking system, which will provide global real-time earth coverage.
The usage of such capabilities is in the planning phase of a launch that models the trajectory of the satellite throughout its life and models data from such monitoring tools to gauge and further mitigate collisions once launched.
Mitigating Space Debris
From monitoring, the next natural step is to strategise for reducing space debris. This translates to two approaches: one, to minimise the impact of future launches on space debris; two, to build capabilities to remove or eviscerate space debris. The former is addressed through monitoring and modelling of space debris. The latter is the piece de resistance that will see its first launch through ESA’s ClearSpace-1, an active debris removal mission.
Underlying approaches to managing space debris, the concept is to rely on deorbiting and forcing the burn up of space hardware upon reentry. The various technologies implement this in a variety of ways.
For debris like lens caps, Earth-based Lasers are shone on the debris, which exerts enough pressure to force it towards the Earth. A 5-10 kilowatt laser, in two hours, can clear an 80 centimetres lens cap which would be about 5 kg heavy. On the other hand, active debris removal refers to missions that send a removal orbiter towards the target. Upon approach, it captures and oversteers the target and deorbits it. This is planned to be achieved in a few ways: using a harpoon, a tether or a net. Under its RemoveDEBRIS mission, the UK even tested a drag sail technology to remove space debris.
Over 100 startups worldwide are working towards implementing one or many of the above active debris removal technologies. They also offer in-orbit servicing to extend the life and delay replacement launches.
Building A Sustainable Future
As more countries begin to expand their space capabilities, such as Brazil and Bhutan, it is a moral responsibility to ensure aspirations are not marred by unchecked choking of the global commons of space. To this effect, only space laws can ensure regularity in missions and communication of a larger philosophy. The United Nations Committee on the Peaceful Uses of Outer Space has written down guidelines for space debris mitigation at the international level. It also required that nations formulate their space laws focusing on space debris.
A space law must ensure that various feasibility checks and proper protocols are followed to bake into satellites a deorbiting mechanism to ensure post-life decluttering of space. Through a concerted effort towards reducing the current debris, minimising the addition of debris by future missions and being mindful of space debris from the get-go of planning a mission, the increasing threat of the space debris can be mitigated to a large extent.
– The writer is an Aerospace and Defence Analyst & Director ADD Engineering Components (India) Pvt Ltd (An Indo- German Company). The views expressed are of the author and do not necessarily reflect the views of Raksha Anirveda
-The author is a Defence, Aerospace & Political Analyst based in Bengaluru. He is also Director of ADD Engineering Components, India, Pvt. Ltd, a subsidiary of ADD Engineering GmbH, Germany. You can reach him at: girishlinganna@gmail.com. The views expressed are personal and do not necessarily carry the views of Raksha Anirveda
