The Indian Space Research Organisation (ISRO) launched earth observation satellite Cartosat-2 series and 30 co-passenger satellites from Sriharikota in Andhra Pradesh. The number of spacecraft missions launched by the space agency till now will go up to 90. However, not all these spacecrafts are operational now but are still in space.
ISRO has made major strides in recent times capitalizing on the ability of its Polar Satellite Launch Vehicles (PSLV) to launch massive payloads.
Though ISRO’s main objective is to make satellites functional once placed in orbit, protecting them from space debris is also the top priority of the agency.
Space debris, junk, waste, trash, or litter is the collection of defunct man-made objects in space old satellites, spent rocket stages, and fragments from disintegration, erosion, and collisions including those caused by debris itself. As of December 2016, five satellite collisions resulted in space waste.
These space debris can really be dangerous as they travel at a speed of up to 30,000 km an hour, which turns even tiny pieces of junk into deadly shrapnel that can damage satellites, space shuttles and even space stations.
As of 5 July 2016, the United States Strategic Command tracked a total of 17,852 artificial objects in orbit about the Earth, including 1,419 operational satellites. However, these are just objects large enough to be tracked.
As of July 2013, more than 170 million debris smaller than 1 cm (0.4 in), about 670,000 debris 1–10 cm, and around 29,000 larger debris were estimated to be in orbit. Collisions with debris have become a hazard to spacecraft; they cause damage akin to sandblasting, especially to solar panels and optics like telescopes or star trackers that cannot be covered with a ballistic Whipple shield unless it is transparent.
ISRO relies on a slew of methods to safeguard its assets in space. The agency is a member of Inter-Agency Debris Coordination Committee (IADC), which makes global efforts to reduce man-made and natural space debris.
The primary objective of IADC is to exchange information on space debris among member space agencies, to facilitate opportunities for cooperation in space debris research and identify debris mitigation options.
Tapan Misra, director of Ahmedabad based Space Applications Centre (SAC), said, ‘IADC alerts a respective space agency when any satellite of that space agency is in danger due to space debris’.
ISRO also banks on its sophisticated Multi-Object Tracking Radar (MOTR), operational since 2015, to track space debris. Tapan Misra said, “The state-of-the-art radar, developed at our centre, can track 10 objects simultaneously of size 30cm by 30cm at a distance of 800km. In case of objects of 50cm by 50cm size, the radar can track at a range of 1,000km.”
The SAC director Tapan Misra said, “With use of one rocket for multiple satellites, ISRO is actually helping reduce space debris”, as each rocket spent in space adds to space junk.
Tapan Misra is an Indian scientist who is an incumbent director of Space Applications Centre, Indian Space Research Organisation and Physical Research Laboratory. He also heads the Office of Innovations Management, ISRO, Bangalore. Since June 1, 2016, he is also having additional charge of Director, Physical Research Laboratory, Ahmedabad.
The Space Applications Centre (SAC) is an institution of research in Ahmedabad under the aegis of the Indian Space Research Organisation (ISRO). It is one of the major centres of ISRO that is engaged in the research, development and demonstration of applications of space technology in the field of telecommunications, remote sensing, meteorology and satellite navigation. This includes research and development of on-board systems, ground systems and end user equipment hardware and software.
Explaining the process of rockets becoming space debris, Dr K Sivan, director of Thiruvananthapuram based Vikram Sarabhai Space Centre, said, “The fourth stage of rocket once launches a satellite into its respective orbit becomes useless. This fourth stage, which contains some propellant, could be dangerous as it could explode and add to space debris. But we ensure this stage doesn’t explode as we have fitted a mechanism whereby this stage automatically deactivates and de-pressurises itself after it places a satellite in its orbit and completes its mission.”
Dr K Sivan is an Indian scientist with the Indian Space Research Organization. He currently serves as Director, Vikram Sarabhai Space Centre, Thiruvananthapuram.
The Vikram Sarabhai Space is a major space research centre of the Indian Space Research Organisation (ISRO), focusing on rocket and space vehicles for India’s satellite programme. It is located in Thiruvananthapuram, in the Indian state of Kerala.
The centre had its beginnings as the Thumba Equatorial Rocket Launching Station (TERLS) in 1962. It was renamed in honour of Dr. Vikram Sarabhai, often regarded as the father of the Indian space program.
The Vikram Sarabhai Space Centre is one of the main research and development establishments within ISRO. VSSC is an entirely indigenous facility working on the development of sounding rockets, the Rohini and Menaka launchers, and the ASLV, PSLV, GSLV and GSLV Mk III families of launch vehicles.