[Lakshay Beniwal is a student at School of Law, Christ University]
Introduction
The first satellite was launched into Earth's orbit by Russia in 1957. Since then, the space scenario has changed a lot; thousands of missions have been undertaken by space agencies worldwide. These space missions have proved to be very important for the global economy as the satellites provide critical services like communication, navigation, meteorology, national defence and scientific investigations. About nine thousand satellites have been launched till date, and more than five thousand of them are still in space. Out of these five thousand satellites, about one thousand nine hundred and fifty satellites are still functioning while others are derelict. These derelict satellites stay in Earth's orbit for a very long period of time before they finally make reentry into Earth's atmosphere and fall back to the Earth's surface. Waste disposal is essential to a satellite's functioning, and therefore the orbit also contains small sensors, nuts and bolts, chips of paint from satellites, separated rocket boosters, etc. An official, legal definition of orbital debris has not been internationally adopted. The Scientific and Technical Subcommittee (STSC) of the United Nations Committee on Peaceful Uses of Outer Space (COPUOS) came up with a definition. According to the STSC, "Space Debris are all man-made objects, including their fragments and parts, whether their owners can be identified or not, in Earth orbit or re-entering the dense layers of the atmosphere that are non-functional with no reasonable explanation of their being able to resume their intended functions or any other functions for which they are or can be authorized."
Problem of Space Debris
As of 2019, there are more than twenty-two thousand trackable objects hurtling around the Earth at speeds upto 12 kilometres per second. This translates to 15,000 miles per hour, even a small object measuring about 1-2cm in diameter can prove to be catastrophic for a satellite's mission. The energy that will release from a collision at such a high speed will be boundless. While small pieces of debris pose a considerable risk, large defunct satellites present a greater future risk of fragmentation. Antisatellite (ASAT) missile tests, orbital collisions (such as the Cosmos-Iridium crash), and separated capsules are among the largest sources of these materials. So why not send up the space vacuums and conduct debris remediation. It sounds simple, but there are a host of technicalities and legal issues that arise.
Usually, technology expands rapidly, very similar to Moore's law, as it continuously pushes its own boundaries. Such exponential growth is usually not matched with the legal framework that governs it. The governing space law treaties are a hindrance in addressing contemporary problems because of their outdated nature. Article IX of the Outer Space Treaty (OST) condemns the harmful contamination of space. However, there are no enforcement mechanisms to implement the same. Articles VI and VII impose an overwhelmingly high degree of liability on states (launching states). The liability convention further complicates the question of fault, as it is nearly impossible to determine liability in case of a collision between two satellites. In the current scenario, advanced tracking equipment does exist to monitor and track orbital debris, but negligence still has to be determined. There is no clear answer to the question of causation and the liability convention fails to provide the same. A functional satellite can always maneuver small distances. If a derelict satellite collides with an operational satellite that did not maneuver itself out of the way, is that contributory negligence? Till date, there are no firm answers to questions like this. Another major issue that proves to be a hindrance in remediating space debris is the problem of jurisdiction. Anything launched into space remains the property of the entity that launched it, even if that entity breaks into thousands of pieces. Therefore, it is illegal to move or remove any object in space that does not belong to the launching state. This is considering the fact that states can even identify who owns a certain piece of debris. It is evident form the above observations that Debris Remediation in space is still a far cry, legally and technologically. An alternate solution to this problem must be found immediately.
Mitigation of Space Debris
The COPOUS introduced guidelines for space sustainability in 2007. These guidelines are one of the first acts done together by spacefaring nations to reduce and control space debris and ensure the long-term sustainability of outer space. The guidelines also suggest limiting debris during operations, minimizing the potential for breakups in orbit and avoiding destruction or harmful activities that may further create space debris. The importance of communication between countries and non-governmental entities to manage space debris has also been emphasized upon. The COPOUS must set up an Information platform that would result in all countries gaining access to tracking software and improving coordination among each other. Another suggestion is to ensure that all satellites use active or passive tracking aids, including Radio Frequency Identification (RFID). It is largely for the countries with an emerging space program because they tend to use more primitive satellite designs.
Satellites often encounter small forces, while orbiting a planet. This is why many satellite propulsion systems have to deliver exact impulses to facilitate the satellite's accurate positioning. Reliability is vital in these systems because there is no real opportunity to service these systems over their entire lifetime. Traditionally, chemical propulsion systems use monopropellant (single fluid) and bipropellant (two fluids) liquid thrusters, however, these propulsion systems are expensive to maintain and use, therefore not all satellites are equipped with efficient thrust propulsion systems. A French startup ThrustMe was recently successful in conducting on-orbit tests of iodine fueled electric propulsion system, proving its ability to change a satellite's orbit. This propulsion system was sent into space aboard 12U CubeSat developed by a Chinese Space firm Spacety. This could be a huge step towards space sustainability. It allows a satellite to lower its altitude, reduce its time in orbit, and re-enter Earth's atmosphere, thereby reducing space debris in lower Earth orbit. The propulsion system serves two purposes; it reduces the satellite's time in the LEO, and provides excellent maneuvering ability to avoid the existing space debris. According to ThrustMe, using iodine as a propellant is a huge step forward in satellite propulsion technology. It allows propulsion systems to be delivered completely prefilled to customers, and for the satellite integration process to be significantly simplified and streamlined. Conversely, most conventional electric propulsion systems use rare, expensive xenon or krypton which also require storage under high pressure. When heated, the solid iodine turns to gas without progressing through a liquid phase. The company will be delivering systems to several clients this year along with in-orbit demonstrations of two new and improved propulsion systems which generate more thrust.
Conclusion
Space debris is a significant hindrance for all space missions, and any mishap can be catastrophic in nature. International cooperation and mutual consensus is essential to eliminate this problem. However, getting all spacefaring nations onboard to accept a single definition of space debris, agree to a debris remediation program and follow space sustainability guidelines is a lengthy process. One can't afford to wait as the Earth's orbit is becoming more and more clustered with each passing year. Debris remediation is an expensive, complicated and dangerous process. While we find more efficient means to do the same, it is essential that an alternative method to reduce space debris must be devised. Reducing a satellite's time in the Earth's orbit goes a long way in decluttering the LEO. The only possible way of doing so is through satellite propulsion systems. Satellite propulsion systems help change the orbit of a satellite, in this case lowering the orbit so that it can re-enter the atmosphere. As of now, satellite propulsion systems are rare and expensive but ThrustMe's achievement is a significant one. It is a great leap in technology and is expected to improve the accessibility of satellite propulsion systems to smaller players.
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