Space junk or debris poses an increasing threat to assets in space, as it consists of spent rocket stages, dead satellites, fragments of space objects and debris resulting from Anti-satellite (ASAT) System (ASAT). These objects, travelling at an average speed of 27,000 kmph in Low Earth Orbit (LEO), can cause lethal collisions, even with small fragments. This potential hazard is known as Kessler Syndrome. In response to this, the Indian Space Research Organisation (ISRO) is developing an effective surveillance and tracking network under the Network for Space Objects Tracking and Analysis (NETRA) project.
Understanding Space Junk
Space junk is a term for defunct man-made objects in space, such as old satellites and spent rocket stages. It includes fragments from their disintegration and collisions. At high velocities, even small-sized debris in space can damage or destroy satellites and spacecraft. Donald Kessler first proposed the Kessler Syndrome in 1978, suggesting that the density of space junk in orbit could create a chain reaction, leading to the creation of even more space junk. This “domino effect” can potentially render Earth’s orbit unusable.
The NETRA Project: An Early Warning System in Space
Project NETRA aims to be an early warning system in space to detect debris and other hazards to Indian satellites. It will provide India with independent space situational awareness (SSA), analogous to other space powers. Given the increasing number of satellites launched by various countries, each one a strategic or commercial asset, collision avoidance may pose a future challenge. ISRO had to perform 19 Collision Avoidance Manoeuvres (CAM) in 2021 alone for the protection of its space assets.
How Will NETRA Operate?
ISRO plans to establish various observational facilities under NETRA. These include interconnected radars, telescopes, data processing units, and a control centre. NETRA will be capable of spotting, tracking, and cataloguing objects as small as 10 cm, up to a range of 3,400 km and equivalent to a space orbit of around 2,000 km. Besides tracking and warning about space debris, NETRA will contribute significantly to India’s overall security by detecting threats from air, space, or sea.
The Current State of SSA
Currently, India uses a Multi Object Tracking Radar at the Sriharikota range in Andhra Pradesh for SSA but its range is limited. India depends on data from the North American Aerospace Defence Command (NORAD) and other publicly available sources for its SSA needs. However, these sources often lack comprehensive or accurate information. ISRO’s SSA efforts are coordinated by the SSA Control Centre in Bengaluru and managed by the Directorate of Space Situational Awareness and Management at the ISRO headquarters.
Global Initiatives Against Space Debris
Global initiatives against space debris have been gaining momentum. One such initiative is Clearspace-1, a project by the European Space Agency, scheduled to launch in 2025. It aims to be the first space mission dedicated to removing debris from orbit.
Previous Year Questions (PYQs)
In the UPSC Civil Services Examination 2016, a question was posed about the Mangalyaan mission launched by ISRO, also known as the Mars Orbiter Mission. The question clarified that India was the only country to successfully place a spacecraft into Mars orbit on its first attempt. Meanwhile, another question from 2010 asked about “Bhuvan”, a geoportal developed by ISRO that offers high-resolution imagery of the Indian region.