The minimum distance between both Russian and Indian satellite was 224 meters. Both satellites are meant for Earth's remote sensing.
India's Cartosat 2F weighing over 700kg dangerously approached the Kanopus-V spacecraft at 1.49 UTC, on Friday, according to the Russian Space Agency. In a tweet, Roscosmos has said that the minimum distance between both Russian and foreign satellite was 224 meters. Both satellites are meant for Earth's remote sensing.
How significant and dangerous is this?
According to a source that spoke to Zee Media, 1 kilometer is an ideal distance between satellites in orbit, whereas 224 meters is scary and can be counted as a near miss. Generally, when two satellites are predicted (based on calculations) to make a close pass, a decision is taken to manoeuvre one of them away in advance(usually days ahead).
It is notable that low Earth orbit (500-2000km) is the most congested, with satellites of various sizes - ranging from 10cm cubes to ones that are the size of a car or larger.
However, the decision to manoeuvre is not very easy. Especially, when the satellite is performing a strategic role that requires it to be at a particular spot. Because the manoeuvre would affect the schedule of the pre-planned operation of surveillance (in whatever form).
In this case, Roscosmos has said that both are remote sensing satellites, which implies that they in all likelihood used for strategic purposes.
The space community has been divided over the prediction models for tracking satellites in orbit. The existing ones are the European Model, American model, Russian model, whereas the Indian model is under development. The reason that the space community hotly debates the efficiency of the models is that there are differences between the calculations made using each model.
Let's assume, in this case, the Indian model said that the satellites would be 1 km apart, whereas the Russian model would have predicted that they would be 500 m apart. It is also highly likely that in reality, both models went wrong and the satellites get closer than the prediction showed.
Hence, there is no single model that works accurately, as each one can provide a different result. Another factor that could impact prediction models in low earth orbits is the impact of the drag from the Earth's atmosphere.
Some interesting questions in this scenario are--how or why did the respective agencies allow the satellites to get this close? Were there predictions that both sides performed? Given the close Indo-Russian cooperation on space technology, did the agencies foresee this close shave and coordinate?
Most importantly, why would the Russian agency go public with this information, rather than discuss with ISRO officials. Or did both the agencies have critical strategic functions that required the satellites to remain exactly in their respective orbits, despite knowing that they would make a close pass. Is it possible that the agencies wanted to allow a close pass and then take a call on any possible manoeuvre in future?
The real danger posed by a possible collision of satellites would be the debris of varying sizes scattered across space in all directions, in high-speeds with high potential of harming other satellites.
The last large collision of satellites happened in 2009, when a US commercial Iridium spacecraft hit a defunct Russian satellite over Siberia, producing thousands of pieces of debris.
As of January 2020, there are around 2,000 active satellites orbiting the earth. There are also more than 23,000 pieces of debris larger than 10cm (4inches) in orbit, according to NASA.
India's Cartosat-2F, Russia's Kanopus-V satellites barely miss collision
India's 700 kg cartography satellite Cartosat-2F and Russia's 450 kg Kanopus-V satellite had a near miss in the outer space on Friday morning
India's 700 kg cartography satellite Cartosat-2F and Russia's 450 kg Kanopus-V satellite had a near miss in the outer space on Friday morning, said Roscosmos, Russia's state space corporation.
Both the satellites were as close as 224 metres.
Roscosmos said in a statement that as per the TsNIIMash main information and analytical centre of the Warning Automated System of Hazardous Situations near the earth space-part of Roscosmos, at 1.49 UTC (IST 7.19 a.m.), Cartosat-2F, an active Indian satellite, dangerously approached Russia's Kanopus-V satellite.
According to the TsNIIMash calculations, the minimum distance between the Russian and the foreign satellite was 224 metres.
Both the spacecraft are designed for Earth's remote sensing.
Kanopus is an Earth observation sattelite with a launch mass of 450 kg mini-satellite mission of the Russian Space Agency.
The overall objective is to monitor Earth's surface, atmosphere, ionosphere, and magnetosphere to detect and study the probability of strong earthquake occurrence.
On the other hand, Cartosat-2F is the eighth in the Cartosat-2 series launched in January 2018.
While Roscosmos made the matter public, the Indian Space Research Organisation (ISRO) has maintained silence on the issue so far.
However, it is not known how the Indian satellite came so close to the Russian satellite.