Space debris due to A-Sat test won’t affect Monday launch: Ex-DRDO scientist

NEW DELHI: With Indian Space Research Organisation (Isro) gearing up to launch an advanced electronic intelligence satellite EMISAT and 28 foreign satellites with its PSLV-C45 rocket on Monday, concerns are being raised whether the space debris created by the Defence Research and Development Organisation-led anti-satellite missile (A-Sat) test last Wednesday will pose a danger to the mission. There are also reports that the US’s Joint Force Space Component Command is tracking 250-270 objects of debris in space generated due to India’s A-SAT test at the 300 km altitude in the lower earth orbit.


Setting to rest all fears and concerns, former DRDO scientist Ravi Gupta told TOI, “Whenever a country is launching a satellite, it calculates all the risk involved in the mission by considering each and every object, whether space debris or any other satellite, that may come in the path of the satellite. The country finds a safe window for its satellite launch by knowing the real-time position of all space debris in the respective orbit either through its own means or by getting commercial data from international agencies, which are constantly monitoring the real-time position of all space debris.”



The DRDO veteran said the debris due to the A-Sat test won't pose a danger to other satellites “as they are at the low-earth orbit (LEO) and ultimately will enter the earth’s atmosphere and burn out”. He said, “India can’t be held responsible for space debris as big countries like the US had already conducted innumerable A-SAT tests and that too at higher altitude that had generated a lot of space debris”.
On danger from space debris, Isro chairman K Sivan told TOI, “Based on the information from the international agency on space debris, all the space agencies, including ours, after launching a satellite manoeuvre it in order to avoid collision. This has been the global practice which we have been following and continue to do so.”



The PSLV-C45 mission is significant for Isro as the rocket will launch payloads in three different orbits in a single mission, a first in India’s space history. The rocket will first launch the 436-kg DRDO-developed EMISAT, which will be used to detect enemy radars and sensors, at an altitude of 763km, and thereafter it will spew 28 foreign satellites at 504km altitude. The last stage (PS-4) of the rocket carrying three experimental modules will then be released at 485km where it will act as an experimental platform.

In space, Isro relies on a slew of methods to safeguard its assets. The agency is a member of Inter-Agency Space Debris Coordination Committee (IADC), which makes global efforts to reduce man-made and natural space debris. IADC’s key objective is to exchange information on space debris and alert members if their satellite is in danger due to space debris. Isro also banks on its sophisticated multi-object tracking radar (MOTR) to track space debris. The radar 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.

According to United Nations Office for Outer Space Affairs (UNOOSA), only 1,400 of the 19,000 artificial objects currently being tracked in the earth’s orbit are functional satellites. The remaining objects are collectively known as “space debris”.

According to an estimate by the European Space Agency, there are over 34,000 pieces of debris in orbit that are larger than 10cm in size, close to a million pieces between 1cm and 10cm, and 128 million pieces of debris less than a centimetre in size.

With every launch of a satellite, the number of space debris grows as there are several components of rockets which become useless in space after releasing the satellite and turn into debris. Therefore, the number of space debris is bound to grow as the frequency of launches is increasing every year.