Indian ASAT Test

Dileep · Post by **Dileep** » 03 Apr 2019 10:51

Get this: The debris from a circular orbit will ALWAYS have a perigee equal to or less than the current orbit. Laws of Fyzziks onlee. So, every darn piece of the debris will de orbit by or before the natural de orbiting period of the satellite.

Some pieces might have got an apogee going to the ISS orbit. But most of them would have got a perigee much lower than the current orbit, to burnt out after a few visits.

The rare few 'lucky' pieces who got the 'kick' exactly in alignment with the orbit would have got the maximum perigee (equal to the circular orbit) and stayed on for longer. But consider the change of them finding the ISS during the few minutes it spends at the altitude.

The probability of ISS being hit by debris is 1 in 300 Trillion. That became 1 in 200 Trillion now. Bigg deal!!

viewtopic.php?f=3&t=7705&p=2338049#p2338049

disha · Post by **disha** » 03 Apr 2019 10:52

ramana wrote:Swarajya writes: https://twitter.com/SwarajyaMag/status/ ... 81857?s=19

Thanks! This is the final statement:

Former DRDO chief and current NITI Aayog member V K Saraswat also termed NASA’s claims of 400 pieces of space debris as “speculative.”

“There is a variation in the space debris figures being put out every day. It is all speculative at this point, till we get a final word from NORAD,” said Dr V K Saraswat.

North American Aerospace Defence Command (NORAD) is a joint US-Canadian initiative that operates a space detection and tracking system (SPADATS), through which it monitors space debris.

More likely it is an internecine agency fight where NASA is losing and had to make a statement to stay in limelight.

disha · Post by **disha** » 03 Apr 2019 10:58

Dileep wrote: The rare few 'lucky' pieces who got the 'kick' exactly in alignment with the orbit would have got the maximum perigee (equal to the circular orbit) and stayed on for longer. But consider the change of them finding the ISS during the few minutes it spends at the altitude.

The probability of ISS being hit by debris is 1 in 300 Trillion. That became 1 in 200 Trillion now. Bigg deal!!

viewtopic.php?f=3&t=7705&p=2338049#p2338049

^There proof in physics- thanks for the repost - I missed it earlier. NASA has to do a brain f@rt though! I am getting increasingly irritated by that space agency.

lakshmanM · Post by **lakshmanM** » 03 Apr 2019 11:03

Does PDV have a clamshell fairing?

Repurposing existing BMD system for ASAT significantly reduced development cost. In the 1980s, development, and induction of ASM-135 cost USA over $3.5 billion dollars. In contrast, XSV-1 cost India less than $150 million to develop and it was done in a relatively short time. Deploying a fully fledged ASAT system, however, would be an expensive affair.
Assessment of threat to Chinese space assets
XSV ASAT weapon (in its current phase of development) is not a threat to Chinese navigation and communication satellites. The BeiDou navigation system consists of satellites in geostationary and medium earth orbit i.e. far out of reach of XSV ASAT (in its existing configuration). XSV, however, can target the bulk of Chinese reconnaissance and electronic intelligence satellites (Yaogan satellite constellation, for instance). A larger first stage or second stage (or combination of both) should allow the kill vehicle to go higher and further.

Test of technology rather than a system
The ASAT weapon tested by India on March 27 was, more or less, a demonstration of the technology. There is a long way to go to operationalize the weapon system. To identify and target enemy satellites, India is going to require a system similar to Space Detection and Tracking (SPADATS) that is used to detect, track, and identify objects in space (which is an expensive affair). On a small scale, however, over the horizon target acquisition by ships like VC-11184 might help India to circumvent SPADATS.
India may continue to test XSV under the guise of BMD test (or simply ASAT point-in-space tests that create no debris cloud). The XSV (in its limited form) might be the cheapest ASAT development to the date, owing to the fact that it makes use of existing BMD infrastructure.

What about space debris created by the ASAT test?
'The test was done in the lower atmosphere to ensure that there is no space debris. Whatever debris that is generated will decay and fall back onto the earth within weeks.'

USA claimed something similar after Operation Burnt Frost in which US-193 satellite was shot down by an SM-3 missile at an altitude of 234 kilometers in order to "prevent toxic hydrazine fuel of the satellite from presenting a danger in case it survived reentry". The U.S. government argued that the interception was designed in such a way as to minimize the amount of debris. A U.S. government press release said, "nearly all of the debris will burn up on reentry within 24-48 hours and remaining debris should re-enter within 30 days."
The reality was quite different- It took more than a month for 50% of the debris to reenter and it was only 18 months later when the final piece of debris re-entered the atmosphere.
The main reason for this was that a large amount of debris was tossed into higher altitude due to the energy of impact. Several pieces of debris were pushed into orbits with apogees above 400 km, and two pieces (the ones that could be tracked) into orbits with apogee above 700 km.
Considering the fact that the Indian ASAT test involved interception at a relatively high altitude, it's pretty safe to assume that it would be years before the final piece of Microsat-R debris reenters the atmosphere.

That article is way too long to be copy-pasted here. source - https://mark20x.blogspot.com/2019/04/st ... -test.html

syam · Post by **syam** » 03 Apr 2019 11:14

Another emperor is naked moment for the high lord now?

NASA was always touted as representative of all humankind. Now it is exposed as another political wing of US. We shouldn't seek approval from any outsider. Let's have faith in our scientists. This guilt tripping is another tactic employed by west to browbeat the 'third world' peeps.

My question is, can US afford this grand high moral posture when their empire itself is under threat? They should focus more on 5G and next Iphone.

Dileep · Post by **Dileep** » 03 Apr 2019 13:49

Here is a realistic article about debris threat
The graph in that article clearly shows what I described.The new perigee is never above the impact point.

ramana · Post by **ramana** » 03 Apr 2019 19:13

Dileep, The SM-3 used against US-193 had a hit to kill warhead or a fragmentation warhead?

Above MV link says

US SM-3 and GMD ballistic missile interceptors are equipped with an H2K warhead.

ramana · Post by **ramana** » 03 Apr 2019 19:15

Disha, Think deeper and don't go by polemics. NASA bleating might have some other message.

ramana · Post by **ramana** » 03 Apr 2019 19:23

I don't get what the bokwas whine is all about using BMD for ASAT?
Which moron will start from scratch when you have a working BMD system?
I am sure US also has done that.
The mention of SM-3 and GMD with HTK confirms that.

sudhan · Post by **sudhan** » 03 Apr 2019 20:02

ramana wrote:Dileep, The SM-3 used against US-193 had a hit to kill warhead or a fragmentation warhead?

Above MV link says

US SM-3 and GMD ballistic missile interceptors are equipped with an H2K warhead.

Saar, the SM-3 has a kinetic warhead, no explosive carried, it is H2K..

SaiK · Post by **SaiK** » 03 Apr 2019 20:13

We have counter NASA on the probabilities of falling back to Earth [focus on these rather NASA feeling unsafe!]. Rest I think are political, and they are intelligent enough [with complete tracking capability] to know ISS safety.

Kakarat · Post by **Kakarat** » 04 Apr 2019 00:07

All You Need To Know About The PDV MK-II: India’s Satellite Killer By Indranil Roy

Rakesh · Post by **Rakesh** » 04 Apr 2019 00:11

Kakarat wrote:All You Need To Know About The PDV MK-II: India’s Satellite Killer By Indranil Roy

Congrats IR! Excellent Article. I will edit the first post - in this thread - to include your article.

nachiket · Post by **nachiket** » 04 Apr 2019 00:24

Great article Indranil! I have posted a question for you in missiles thread.

JTull · Post by **JTull** » 04 Apr 2019 03:12

Why do they need an SSLV for quick replacement satellites when PDV Mk-II can deliver a KKV to 1000kms?

ramana · Post by **ramana** » 04 Apr 2019 03:21

Long ago I hand calculated the weight to orbit for given rocket. Sat launch is energy intensive.
ASAT will not have sufficient energy.

Indranil · Post by **Indranil** » 04 Apr 2019 03:40

JTull wrote:Why do they need an SSLV for quick replacement satellites when PDV Mk-II can deliver a KKV to 1000kms?

The SSLV doesn't deliver KKV to 1000kms. It delivers KKV to 110 kms at suborbital velocity. AFAIK, Agni V can launch 200-300 kgs to 300 km circular orbit.

kit · Post by **kit** » 04 Apr 2019 04:14

lakshmanM wrote:Does PDV have a clamshell fairing?

What about space debris created by the ASAT test?
'The test was done in the lower atmosphere to ensure that there is no space debris. Whatever debris that is generated will decay and fall back onto the earth within weeks.'

USA claimed something similar after Operation Burnt Frost in which US-193 satellite was shot down by an SM-3 missile at an altitude of 234 kilometers in order to "prevent toxic hydrazine fuel of the satellite from presenting a danger in case it survived reentry". The U.S. government argued that the interception was designed in such a way as to minimize the amount of debris. A U.S. government press release said, "nearly all of the debris will burn up on reentry within 24-48 hours and remaining debris should re-enter within 30 days."
The reality was quite different- It took more than a month for 50% of the debris to reenter and it was only 18 months later when the final piece of debris re-entered the atmosphere.
The main reason for this was that a large amount of debris was tossed into higher altitude due to the energy of impact. Several pieces of debris were pushed into orbits with apogees above 400 km, and two pieces (the ones that could be tracked) into orbits with apogee above 700 km.
Considering the fact that the Indian ASAT test involved interception at a relatively high altitude, it's pretty safe to assume that it would be years before the final piece of Microsat-R debris reenters the atmosphere.
That article is way too long to be copy-pasted here. source - https://mark20x.blogspot.com/2019/04/st ... -test.html

If you look at how the ASAT was conducted the HTK warhead manoeuvered above the satellite and impacted from above, such being the case most of the momentum would be towards the earth and even with the high velocity of fragments the trajectory should be facilitating an early re-entry and burn out?

SSridhar · Post by **SSridhar** » 04 Apr 2019 06:03

Indranil, excellent article.

VickyAvinash · Post by **VickyAvinash** » 04 Apr 2019 07:35

Great article Indranil. Thanks for posting.

vera_k · Post by **vera_k** » 04 Apr 2019 09:59

ramana wrote:Disha, Think deeper and don't go by polemics. NASA bleating might have some other message.

I think NASA is confirming hit to kill capability for India. This was previously in doubt, and there was some talk of US sales to India to add that capability.

Haridas · Post by **Haridas** » 04 Apr 2019 12:06

https://twitter.com/HaridasKukkur/statu ... 56673?s=19

Excellent artical Indranil ji.
Please see my tweet above.

FYI, ROCKSIM simulation indicate this ASAT config good to take down sats upto 1500 km altitude.

Haridas · Post by **Haridas** » 04 Apr 2019 12:16

JTull wrote:Why do they need an SSLV for quick replacement satellites when PDV Mk-II can deliver a KKV to 1000kms?

Becoz SSLV delivers payload to orbit (mostly circular orbit), while PDV mk2 delivers payload in sub-orbital trajectory whose apogee is upto 1500 km high, but it's perigee is in depth of earth's core, so KKV needs to at the right place and right time only for a fraction of a second so that target Satellite smashes into the KKV.

siqir · Post by **siqir** » 04 Apr 2019 12:39

china cctv4 put up a show yesterday discussing the asat test

https://www.youtube.com/watch?v=B7KFrHBlk2I

all in chinese no subtitles

the focus was on nasa complaint of debris and iss safety which they accept was true but they also mention usa caused much more space debris themselves
also that usa was pouring cold water on the test since usa does not want competition nor restrictions on itself
they mention russia was saying usa was the reason for indian test by setting up space force etc

on indian claim of entering space league they say it is important step but not in big league yet since commercial launches are less and reliability of our launches is not good which seems a fake claim to me
they say 300km in 3min was normal but claimed the vehicle needed improvements on weight or something
they think this was announced as it was with twitter drama for the election and cite our previous nook tests as examples of such behaviour
they say tweet was day before the announcement rather than just an hour before which i dont know why they lied about this or just got it wrong

zero mention of chinese own asat tests and debris caused or comparison of capabilities or even that they are obvious target of our test
no jingoistic talk at all imo to push the idea that they dont see us as a competitor or threat

the woman analyst seemed to go off script a bit near the end claiming space debris was disaster for humankind or something lol

ramana · Post by **ramana** » 04 Apr 2019 23:09

siqir, thanks for the information.
Good summary.
Very informative about Chinese POV on the test.

syam · Post by **syam** » 05 Apr 2019 10:52

@disha sir, I went through martian meteorite articles. Those reached earth surface because when volcano exploded, some mars rocks gained escape velocity of mars and left the planet gravity. At some time later, these rocks came under earth gravity and pulled in.

In space, gravity is big thing. Our collision happened in leo which still has 9g gravity going on. As per dileep and others, the change in velocity effect only the apogee. It does nothing to perigee of the orbit. I checked regular science simulations. The speed of the object is very high at the perigee and very low at the apogee. It's very similar to swings. So few of the debris might gone little higher but they still come near to earth at perigee, also they will have more speed compared to earlier. The air drag will burn these pieces when it happens.

tl;dr the debris is not big issue. NASA being bigots showing their real colors. I rest my case.

Rakesh · Post by **Rakesh** » 05 Apr 2019 22:03

https://twitter.com/SJha1618/status/1114049970674343937 ---> This is why Dr VK Saraswat said that he would rather wait for NORAD's account than worry about what NASA has to say about debris created by Mission Shakti and the risk it entails.

Mission Shakti: Pentagon backs India, says ASAT debris expected to burn up in atmosphere
https://www.indiatoday.in/world/story/m ... 2019-04-05

Acting US Defense Secretary Patrick Shanahan earlier played down the threat the debris might pose to satellites in space and said it was his understanding the debris would eventually burn up in the atmosphere. Asked on Thursday whether the Pentagon stood by Shanahan's earlier assessment, spokesman Charlie Summers said: "Yes."

disha · Post by **disha** » 06 Apr 2019 05:48

ramana wrote:Disha, Think deeper and don't go by polemics. NASA bleating might have some other message.

Responding after a while, was busy.

NASA is bleating because of loss of potential commerce and of course credentials. In fact NASA is fighting irrelevancy. As an agency, NASA has not been able to adapt to newer paradigms and chotus like ISRO are now stealing the show. Tomorrow they will steal the launch market. What has this to do with ASAT test? Remember at the tactical level, it speaks a lot about India's ability to guide an object in space to precise location very reliably. This is the guidance necessary to send a probe to Mars or to an asteroid or a human to space. At a strategic level, NASA has to now share space with another entity.

Earlier, space had a duopoly with NASA a clear leader. With collapse of Soviet Union, Russian space agency ROSCOSMOS is searching for a mission. Currently it is reduced to ferry humans to space. China itself is facing a design obsolescence and needs something urgent by 2030. While China is developing space based weapons in the guise of civilian space, but can be "co-opted" just like it was co-opted into NSG. In this rosy outlook (for NASA) steps in a declared space power muddying the water (for NASA) and hence the bleating.

All other encumbrances & lawfares like the "outer space treaty to limit weapons" (or rather treaty to limit new entrants in space who can weaponize) are gone or shattered. India has demonstrated that it will use the space peacefully for the advance of humans but will not shy away to protect its own interest unlike the ethically challenged moral infringed neighbour on its NE. That will cause lot of consternation.

It is literally about ceding space.

disha · Post by **disha** » 06 Apr 2019 05:56

syam wrote:tl;dr the debris is not big issue. NASA being bigots showing their real colors. I rest my case.

Syam saar, that is what my point was.*

*Additionally, other points:

1. Yes, some debris will be kicked "upstairs". To be technically correct, some debris will have a higher apogee (same or lower perigee) and in elliptical orbits.

2. No point in arguing that *all* debris will be lower than the target object in current orbit. Just accept the point #1.

3. Most of the debris will burn up in days, some in weeks and very few in months. Some may survive for at most a year (or year and half) which remains to be seen.

4. there is no harm to any other satellites or ISS and if there is any, it can be easily mitigated.

No need to pay attention to itsy-bitsy writers and analcysts who froth at mouth and wag a finger at India talking about space weaponization. They can take a hike.

And congrats DRDO again for job well done.

Amber G. · Post by **Amber G.** » 06 Apr 2019 09:21

Dileep wrote:Get this: The debris from a circular orbit will ALWAYS have a perigee equal to or less than the current orbit. Laws of Fyzziks onlee. So, every darn piece of the debris will de orbit by or before the natural de orbiting period of the satellite.

Sorry but some of the conclusions drawn here (and a few other messages by others I have seen) may be sort of misleading .

FWIW a few basic physics points which may be helpful here. (I may comment more if there is interest as few others have also made a few similar related comments -- not only on debris but orbits in general)

1 - After ASTA collision both energy and momentum are conserved.

Let us assume we know the initial energy of the sat (depends on mass of sat and its orbit), and the projectile. After the collision a lot of energy is turned into destroying the sat (which BTW is more than TNT of similar mass), and putting the debris in new orbit(s). Let us for a short time just think the situation just *after* the collision where debris is in new free fall orbit and decay due to air etc has not yet started).

- Energy is here KE (= sum of (1/2 mv^2 for each debris piece) + PE (=GMm/r). The sum of PE+KE or total energy - if one does the math -here depends depends only on semi-major axis of the new orbit (measured from earth's center) and mass of that debris.

- Sum of the momentum (remember momentum is a vector, so sum here is a vector sum) is conserved. Some debris will be moving *slower*, some will be *faster* and they will be moving in different directions.

So what will be the new orbit(s)?

Assuming the original orbit was circular - new orbit(s) can have larger semi-major axis, smaller semi-major axis, or different inclination - sort of random as there are a large number of debris. (IOW - one can not predict that the new orbit will decay faster/slower etc)

Each piece will return to the same point -- assuming no decay --. The point is not likely to be a perigee (or an apogee). So -

The debris may come closer to earth (and thus spend more time in denser atmosphere) or not in the next orbit.. but the orbit will decay as the orbit becomes smaller and smaller.

How long will it take?

Exact calculation is of course not possible. (I have seen some really absurd calculations). ISRO certainly has much better idea than others but here are few basic points which people sometimes miss-

- Decay depends on MANY factors. Not only shape and size of the debris, its orbit, but even things like sun-spot activities and things like that. For example, if all other things remain same, the decay rate may be many fold (as much as 10 fold) slower now (low solar-activity in 2019) than say 5 years later.

- The time scale (for this particular case) is few months - year or so per simple estimation. 2-6 months is what most people like me will agree.

Hope this helps.

Amber G. · Post by **Amber G.** » 06 Apr 2019 09:33

sudhan wrote:
Saar, the SM-3 has a kinetic warhead, no explosive carried, it is H2K..

To add - Any explosive added really does not matter as KE per mass from KE is quite larger than, say compared to TNT or other explosives.

Indranil · Post by **Indranil** » 06 Apr 2019 09:41

Amber G,

Thank you for writing such great posts every now and then. You asked if there is more interest, you will write more. Let me register my interest. Please keep these coming.

Physics and math are so beautiful if taught properly. It is a pity how science is taught in schools. To this day, most of my friends think Newton “discovered” gravity because an apple fell on his head!!!

Please keep these illuminating posts coming. I absolutely love to read them. For example, there was one line in your posts: All these objects will come back to the point of impact if there was no decay. It is obvious, but only after I read it.

syam · Post by **syam** » 06 Apr 2019 09:54

disha saab, I think this butt-hurt is more to do with the implications rather than space and science. So far lesser countries are put in place by excessive use of newclear mijjile threat. Our ASAT thrown water on these schemes now. Countries like SoKo and Japan held under sword for years, because they don't have credible defence against these. Now enter Indian BMD which is very cheap and no strings attached.

We successfully neutralized second grade paki nuke mijjiles. No wonder equal-equal gang going bonkers over this.

p.s. please no saar for me.

I am still wet behind ears.

Prem Kumar · Post by **Prem Kumar** » 06 Apr 2019 10:19

Even discounting the racism (which certainly exists), U.S is reacting to a change in the equilibrium. MMS was happy with maintaining the equilibrium a.k.a. self-castration. Modi has disrupted it, be it surgical strikes or ASAT.

U.S is going through its 5 stages of grief before they accept the new normal. They will bat for Rahul because it will mean a return to the old equilibrium.

syam · Post by **syam** » 06 Apr 2019 10:22

Amber G. wrote:To add - Any explosive added really does not matter as KE per mass from KE is quite larger than, say compared to TNT or other explosives.

Sir, our ASAT missile is more like Brahmos without the warhead. Collision is not explosion in most cases. It leaves wreckage, not blast.

Coming to the new orbits and stuff. I think we are underestimating gravity here. Orbits are not roads where things travel. It's like you attach a string to an object and throw it out. Once it runs out of the steam it swings back into place. Of course the momentum will be preserved. That's why the object swings to other side.

Our satellite is like that object with gravity itself acting as the string. It 'swings' around earth. That's why we see max speed at perigee. What happened here is, the satellite was hit when it is 'swinging'. It won't create new orbit. It might increase the 'swinging' hight.

Any way that's what I understood by going through space science #101. Please correct me if I am wrong.

arun · Post by **arun** » 06 Apr 2019 14:00

NRao wrote:India's Anti-Satellite Test Created Dangerous Debris, NASA Chief Says

"That is a terrible, terrible thing, to create an event that sends debris in an apogee that goes above the International Space Station," Bridenstine said at the town hall meeting, which was livestreamed on NASA TV. "And that kind of activity is not compatible with the future of human spaceflight that we need to see happen."
India's Anti-Satellite Missile Test Is a Big Deal. Here's Why.

NASA Administrator Jim Bridenstein seems to have been administered a kick on his Musharraf for his ASAT comment and ordered to resume cooperation with ISRO

:

NASA to resume cooperation with ISRO after ‘guidance’ from White House

Kakarat · Post by **Kakarat** » 06 Apr 2019 15:32

https://twitter.com/ShivAroor/status/11 ... 6323593216

Video

The @DRDO_India chief’s briefing on India’s #MissionShakti anti-satellite test is live here:

https://www.pscp.tv/ANI_news/1OwGWkaAWmpGQ

Singha · Post by **Singha** » 06 Apr 2019 16:01

arun wrote: NASA to resume cooperation with ISRO after ‘guidance’ from White House

so a rather sheepish and tame climbdown by NASA, less than week after all fire and fury.

power and money doing the talking, not ideology. the US anyway has no other god to worship than money as my old yahudi buddy used to say.

Kakarat · Post by **Kakarat** » 06 Apr 2019 16:26

https://twitter.com/kakarat2001/status/ ... 8346207232
The final seeker image of #MicrosatR sent by kill vehicle of PDV MkII seconds before hit

nam · Post by **nam** » 06 Apr 2019 17:20

Mashallah, the video of final moments capturing the incoming satellite... just like the Amerikhana one in 2008.

Nothing is going to give sleepless night to the mangoes on the western border than this video. With full fledged khan style kill vehicle with video, god forbid it could have been a Pak "all spectrum" RV instead of a satellite

The Chinis are also loosing out on soft power. What is the point of bush photos, when you need ones like we did!