[Malyaj]

My first reaction on reading the news about India destroying a satellite using A-SAT was “What happens to the debris?”

https://www.ndtv.com/india-news/us-s...home-topscroll

Read the above article today on NDTV and it does not address the issue in entirety. Do the debris get burnt completely when they enter the atmosphere? The Ministry of External Affairs own statement (or part of it) says that the remnants would “decay and fall back on to the Earth within weeks”

So where do they fall back? Who decides whether that area is safe? Even if the target satellite was above the ocean and hence ‘deemed safe’, it could always hit some ship or aircraft on the way. Considering what the smallest fragment can do to an airborne aircraft, I consider this a clear risk.

My concern is not just regarding India’s test but all such tests done by any country in the past or planned in the future. This is very different from missile tests which are controlled, the missile destination is clearly known and preventive measures taken both in the skies and on ground/water.

The opening scene from the movie “Gravity” and how one of the astronauts gets killed by a fragment of a destroyed satellite was very gruesome and haunting. I am nowhere close to being an expert on space matters so would love to hear others’ views on this.

All along I had thought debris would remain in space but MEA’s comments have me confused.

[beast_within]

Originally Posted by Malyaj

My first reaction on reading the news about India destroying a satellite using A-SAT was “What happens to the debris?”

https://www.ndtv.com/india-news/us-s...home-topscroll


So where do they fall back? Who decides whether that area is safe? Even if the target satellite was above the ocean and hence ‘deemed safe’, it could always hit some ship or aircraft on the way. Considering what the smallest fragment can do to an airborne aircraft, I consider this a clear risk.

Even though I am not an expert in this field, however these particles or debris will catch fire due to friction with air and burn-down completely in the higher atmospheric layers before reaching the altitudes (~35,000 feet) where the air crafts fly.

[GeneralJazz]

Originally Posted by Malyaj

So where do they fall back? Who decides whether that area is safe? Even if the target satellite was above the ocean and hence ‘deemed safe’, it could always hit some ship or aircraft on the way. Considering what the smallest fragment can do to an airborne aircraft, I consider this a clear risk.

My concern is not just regarding India’s test but all such tests done by any country in the past or planned in the future. This is very different from missile tests which are controlled, the missile destination is clearly known and preventive measures taken both in the skies and on ground/water.

The opening scene from the movie “Gravity” and how one of the astronauts gets killed by a fragment of a destroyed satellite was very gruesome and haunting. I am nowhere close to being an expert on space matters so would love to hear others’ views on this.

All along I had thought debris would remain in space but MEA’s comments have me confused.

They don't 'fall back', in the true sense of the word. Satellites need precise orbits and occasional course corrections to remain in space. Else they will fall back to the earth. And when it does, it completely burns up during re-entry as the heat will be extreme. When regular meteors enter earth's atmosphere, the heat generated is sufficient to vaporize it (and remember the meteors are mostly made of metals). Plastics and glass from our tiny man made satellites dont stand a chance.

Another point to note is that the altitude of commercial air crafts are very very low (compared to orbital height of satellites). Commercial aircraft fly at around 30000 ft, while most meteors burn up above 400000 ft. If only a minuscule percentage of meteors make it beyond this height, chances of a piece of satellite hitting an aircraft are even smaller.

Another thing is that satellites are spaced wide apart, and that too in 3-D. The chances of debris striking another satellite are small. However, there have been talks of killer satellites that can take out enemy spy satellites, not sure how much of this is imagination. However, if a particular satellite is to be taken out, I assume the countries, whose satellites are in close proximity, will be notified. After all, its not some dumb politician who crunches the tough numbers (no matter how much credit they try to usurp), but experienced rocket scientists!

[pkulkarni.2106]

BTW, here is an article which shows the damage caused by debris of a size of an eraser: https://curiosity.com/topics/check-o...-do-curiosity/

[anjan_c2007]

There is an Outer Space Treaty to which India is a signatory. The treaty is of 1967 that was ratified in 1982. It prohibits use of Weapons of Mass Destruction (WMD) in the outer space, but does not ban ordinary weapons.

Here are two links from the news that have appeared in the Economic Times two days ago and today, respectively.

https://economictimes.indiatimes.com...w/68594835.cms

The above news says that being a test case conducted in the lower atmosphere, there will be no space debris generated and all the debris so generated will decay and fall back onto the earth within weeks.

https://economictimes.indiatimes.com...w/68610627.cms

The next link published in the Economic Times today says that the US has taken note of India's ASAT and that it will continue its pursue its shared interests with New Delhi in space and technical cooperation, even as the US expressed concern over the issue of space debris. While India asserts that test was designed to address space debris issues.

[Miyata]

From what I know of it, there are no accurate models at the moment that predict with "good confidence" where the remnants might fall. The hope is that most of the lower orbit debris would crash towards earth and burn up on the way down. A fairly acceptable hope. The worked out probabilities of someone getting hit by the any such debris is minuscule.

I presume there are other dangers associated with it too - chain reaction of collisions and damages in space with other satellites.

The higher orbit ones will get pushed further away from earth's gravitational influence to not be much of a worry anymore.

I think it's probably more purposeful and constructive to sort of hack that satellite in ways to enable it to do work for you instead of destructively blasting it away! Really speaking there is no much scientific/technological challenge is blasting things off in space considering the amount of precision and accuracy we have developed for such things as docking, landing, deploying various satellites at different altitudes etc.

Presumably, they must have ways to hack as well as seek-and-destroy. More intelligence in the process.

[Prowler]

One can't be too sure about the falling debris causing no damage to aircraft or people/property on earth. There was a close call when the American satellite Skylab went defunct and fell in 1979. The US embassy kept notifying the local press about the probable area where it would land. Fortunately whatever fuel was left in it, they used it to steer it to fall harmlessly in the Indian Ocean.

[Mukund]

A relevant article pertaining to the ASAT test, quoting portions of it below.

India's ASAT missile test created 400 pieces of debris, endangering ISS: NASA
The head of National Aeronautics and Space Administration (NASA) on Tuesday branded India’s destruction of one of its satellites a “terrible thing” that had created 400 pieces of orbital debris and led to new dangers for astronauts aboard the International Space Station.

Not all of the pieces were big enough to track, Mr. Bridenstine explained. “What we are tracking right now, objects big enough to track — we’re talking about 10 cm (six inches) or bigger — about 60 pieces have been tracked.”
But 24 of the pieces “are going above the apogee of the International Space Station,” said Bridenstine.

“That is a terrible, terrible thing to create an event that sends debris at an apogee that goes above the International Space Station,” he continued, adding: “That kind of activity is not compatible with the future of human spaceflight.”

“It’s unacceptable and NASA needs to be very clear about what its impact to us is.”

Source.

[navin]

Originally Posted by Malyaj

My first reaction on reading the news about India destroying a satellite using A-SAT was “What happens to the debris?”

Originally Posted by Miyata

From what I know of it, there are no accurate models at the moment that predict with "good confidence" where the remnants might fall. The hope is that most of the lower orbit debris would crash towards earth and burn up on the way down. A fairly acceptable hope. The worked out probabilities of someone getting hit by the any such debris is minuscule.

There are already organizations like Asgard S.L. (based in Barcelona Spain) tracking some of the "space junk". https://asgard-space.com/

We can all hope that
a. Any junk that falls toward Earth should burn up in the atmosphere
b. Any junk that does not fall into Earth's orbit (or any other orbit) will slowly drift so as to make space collisions a very rare occurrence but they do occur as related in the articles below.
https://www.nature.com/news/2009/090...l/457940a.html
https://www.seeker.com/evasive-maneu...770028827.html

So yes there is a real problem and there are efforts being taken to deal with this. However given the myriad of governments and agencies involved don't expect quick results. (see link below).
https://www.nature.com/articles/d41586-018-06170-1

[V.Narayan]

Originally Posted by Mukund

A relevant article pertaining to the ASAT test, quoting portions of it below.
Source.

What the article says is true. But some how these journals and journalists pipe up only when India or China do a demonstration test like this. Their concern for the ISS(International Space Station) is fully warranted. I assume ISRO would have factored risk to other satellites and the ISS when deciding where in its orbit our target satellite should be destroyed. In Low Earth Orbit, where the target was, any object revolves around the earth in approximately 2 hours.

When the US did this, in 1985 and again 2008, they wrote things to the effect that (and I write from memory) -'utmost care was taken to ensure it was a low orbit demolishment which will result in most if not all pieces gradually burning out in the atmosphere...blah, blah, blah .... all care has been taken..... USA of all the countries cannot say much. They are the only country to have exploded a nuclear device in space - Operation Fishbowl - in this case near space at an altitude of around 80 kms over the Pacific in 1962. We don't even know what damage to the atmosphere that could cause. This was of 11 hydrogen bombs the largest of which was 1.4 megatonnes!!

When China demonstrated its ability to destroy a satellite, in 2007, there was sharp criticism of the 3000+ pieces of debris created. And now India. Each such instance creates debris. All debris, regardless of which nation's, poses some risk to operational satellites or manned stations. Most debris in low earth orbit (below 2000 kms up from the earth's surface) eventually falls to earth and burns out - though that takes several weeks, months, years or decades depending on the altitude and speed of revolution.

We don't need to demonstrate our capability more than once. And that should cap the issue from our side. Countries that have satellites up there - Japan, UK, Germany, France, Brazil etc and have remained non-military have a right to complain. But not USA.

[Malyaj]

Originally Posted by V.Narayan

They are the only country to have exploded a nuclear device in space - Operation Fishbowl - in this case near space at an altitude of around 80 kms over the Pacific in 1962. We don't even know what damage to the atmosphere that could cause. This was of 11 hydrogen bombs the largest of which was 1.4 megatonnes!!

I never knew about this. They must have been supremely confident about the safety of such a test. Somehow the thing with space matters is that so few know the real stuff and so less can be verified by commonfolk, one is inclined to believe whatever the experts claim about safety or hazard.

[V.Narayan]

Originally Posted by Malyaj

I never knew about this. They must have been supremely confident about the safety of such a test. Somehow the thing with space matters is that so few know the real stuff and so less can be verified by commonfolk, one is inclined to believe whatever the experts claim about safety or hazard.

At the time in 1962 I don't think they cared enough about the environmental effects of nuclear explosions. In 1962 both the Americans and the Soviets indulged in high altitude explosions as a form of sabre rattling. We do not have precise data on damage to the upper atmosphere and its components such as the ozone layer, Van Allen belt etc from these explosions. Photo below of what one such explosion in 1962 looked like from Hawaii, 1300 kms away. The 11 American upper atmosphere tests were conducted at least partly as anti-satellite weapons as in those days precise stellar navigation was in its infancy.

[Iyencar]

Originally Posted by Mukund

A relevant article pertaining to the ASAT test, quoting portions of it below.
Source.

Here is a better article which actually tells the whole story.

Source

Originally Posted by V.Narayan

What the article says is true. But some how these journals and journalists pipe up only when India or China do a demonstration test like this.

I assume ISRO would have factored risk to other satellites and the ISS when deciding where in its orbit our target satellite should be destroyed. In Low Earth Orbit, where the target was, any object revolves around the earth in approximately 2 hours.
USA of all the countries cannot say much.
Most debris in low earth orbit (below 2000 kms up from the earth's surface) eventually falls to earth and burns out - though that takes several weeks, months, years or decades depending on the altitude and speed of revolution.

As always, well said Sir. From the article I have linked above (I am going to paraphrase):

NASA: But he acknowledged that this risk was comparatively small and would “dissipate” with time.


India: We expect all the debris from the test to either decay or fall down to earth’s atmosphere within a maximum period of 45 days. The bigger pieces should start decaying much earlier. We don’t think there is any real threat of collisions from these pieces

NASA again: While the risk went up 44 per cent, our astronauts are still safe. The ISS is still safe. If we need to manoeuvre it, we will. But probability of that, I think, is low.

Folks, this is politics plain and simple. The fact is no one likes a new kid on the block to muscle their way into the room. The sad part is our own journalists are simply lapping up what NASA is saying instead of countering it with facts. The statement from NASA is concealed and presented in a way that the issue seems much bigger than it is. 44% rise of risk does not equate to a 44% chance of a hit. Yet all the headlines are stating this number in an effort to sensationalise. These percentages are worthless unless the actual odds are clearly stated. I read somewhere that this translates to a 0.01% chance of being hit.


Link: https://xkcd.com/1252/
Finally,here is an article from Russia Today to end my rant.
End of Rant

• “It is indeed hypocritical for the US to complain since the Pentagon has created more space debris than any other nation on the planet,” says Bruce K. Gagnon, coordinator of the Global Network Against Weapons & Nuclear Power in Space.
• “The debris from the Indian test, because it is in low orbit, will burn and fall back onto the Earth in the coming months, if not weeks. But the debris from the US and Chinese actions will persist for many years,”
• But the latest 60 trackable bits represent a tiny number compared to the total of 21,000 pieces larger than 10cm that NASA is already watching. A third of those were created in previous anti-satellite weapons tests by Russia, China and the US itself.

It seems space is no longer that vast, silent, void. Humanity's pettiness and political noise is now echoing there as well.

[Iyencar]

Well, well, well it seems great minds do think alike

[V.Narayan]

Originally Posted by Iyencar

Well, well, well it seems great minds do think alike
Attachment 1865534

And you can trust some Indian channels and journalists to promptly go around quoting the 'objective' western media without a drop of homework or background knowledge.