Indian ASAT Test

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V_Raman
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Re: Indian ASAT Test

Postby V_Raman » 09 Apr 2019 04:47

I would rather have a PM who does something important/useful and boasts about it even it is timed for elections than have a PM who will not do anything to truly advance the nation!
Last edited by V_Raman on 09 Apr 2019 05:21, edited 2 times in total.

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Re: Indian ASAT Test

Postby SaiK » 09 Apr 2019 05:17

I'd rather not listen to anyone who is against vikas or swindles the nation on vikas. vikas is the core engine :) for growth!

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Re: Indian ASAT Test

Postby disha » 09 Apr 2019 05:55

Questions for the physics gurus here:

1. Orbit direction of satellites as viewed from Hasaan MCF, Bengaluru Kerala for all PSLV launches for SSO is from North to South. PSLV launches south and releases the Sat on a general North-South axis.

2. If the orbit direction is NS axis, then any ASAT launched from Balasore will be in a tail-chase mode. Given that the sat is at 7.0km/sec and the HTK is at 3.5 Km/Sec (approximates, to remember as thumb rules!) there will be no point in which HTK can catch up with the sat and even gently bump it!

3. ASAT videos clearly confirm that it was a head on collision. Further the collision occurred over Bay of Bengal and further the NOTAM was issued in that area.

4. Ergo, the sat was travelling on South-North Axis. That is, it was a polar satellite allright - but it was not going from North to South, but reversed direction and was going South to North. That is almost a complete 180* turn in orbital plane!

SO - Here is the question:

1. How come the orbital plane of Micro Sat was rotated 180* to go from NS axis to SN axis?

2. One can say that the microsat-R was placed in a quasi-GTO orbit and at apogee it carried out LAM firings. True, but the overall energy required is still tremendous*

*From my thumb rule calculation the delta-V required will be something like (2vSin(180/2)) => (2vSin90) => (2v) => (3.5x2) => 7 km/sec. Assuming the same orbit. (such a calculation as again is very imprecise, but gives an insight)

That is, intuitively you have to zero out the NS velocity and then send it back in opposite direction. There could be optimizations like throw the microsat at a higher orbit and then trade PE for VE. Still it will require lot of energy to initiate a 180* change in orbital plane.

Of course, if it can be done with the microsat-R, I would be glad to know how. Otherwise we have to assume that it is not microsat-R.

Implications are different if the sat is not microsat -R

1. Microsat-R might indeed have been launched for ASAT, but *not* as a target, but as an observer? So satellite taken out is *not* microsat-R

2. So which satellite is taken out? Or rather, which satellites in Polar orbit are launched in SN direction and *not* NS direction traditionally?

Bakistanis do not have a sat launch industries hence their satellites are ruled out (Bakistani Satellites are oxymorons, if not morons). Russian satellites are in molniya orbits. Japan and US are friendly countries.

Chinese satellites are launched from Taiyuan space center in Shanxi province located in northeastern China. One was launched at 98.7* inclination to equator. https://spaceflightnow.com/2017/11/14/chinese-weather-satellite-launched-into-polar-orbit/

The Fengyun 3D satellite lifted off at 1835 GMT (12:35 p.m. EST) Tuesday from the Taiyuan space center in Shanxi province located in northeastern China.

A three-stage Long March 4C rocket boosted the approximately 2.5-ton satellite toward the south from Taiyuan, where launch occurred at 2:35 a.m. local time Wednesday

The Long March 4C’s three liquid-fueled stages placed the Fengyun 3D satellite in a 500-mile-high (800-kilometer) polar orbit tilted 98.7 degrees to the equator, according to tracking data released by the U.S. military.


The above launch site will drop its stages in the dense chinese south west if the article is to be believed or will launch north where mongolia and siberia is sparsely populated.

China has another launch centre at Jiuquan which is at the edge of Gobi desert NW of Tibet. Of course it is not clear if any sun synchronous SN directed polar sats are launched from here. So putting this one in plausible for now.

Here are the remaining ones that can launch potentially in SN directed polar sats:

1. Xichang Satellite Launch Center : it is at 28.24646, 102.02814 and google maps puts it between Chengdu and Kunming in Sichuan province. This is an ideal launch site for spy satellites. Located near Chengdu, and can launch in Polar SN axis. On its North, entire Tibet and Mongolia and further Siberia is available for China to dump its polar rocket stages without worrying about pollution or hitting dense urban areas.

South of that, it will end up dumping stages on Laos, Vietnam, Thailand, Malaysia and Indonesia !!

2. Wenchang Satellite Launch Center: 19°36′52.17″N 110°57′4.08″E, this is on Hainan Island and ruled out for Polar launches in South->North (SN) axis.

3. Jingyu, 42.0°N 126.5°E - Very remote and ideal for Polar launches in SN axis.

So yes, China can launch spy sats in both NS and particularly SN axis.

----

I think we must entertaining the plausibility that if microsat-R did not change its orbital plane then the sat taken down was a Chinese spy-sat.

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Re: Indian ASAT Test

Postby Najunamar » 09 Apr 2019 06:03

Dishaji, this could explain some of the bizarre reactions not only from Chipanda but Khan also. However, it seems improbable that such a public rebuke would be made in the current climate this close to elections.

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Re: Indian ASAT Test

Postby disha » 09 Apr 2019 06:04

Cain Marko wrote:b) I want to understand the reasoning behind the hoopla created by Namo before announcing the result. Seemed to me that the standard format response via a PTI release could have done the trick. Was it some veiled message (that I surely didn't catch) or was it purely political showbaazi?


What if the test was more than just a test? Also, the nation is at an undeclared war against not one but two adversaries. In such situations, certain deterrence needs to be backed by political will (otherwise that is not a deterrence but a science experiment) and what better way to show political will than the PM himself announcing it? There is no ambiguity when an elected leader of 20% of humanity states that India is a space power and will take all steps to protect its space assets. And it was demonstrated (PM stressed twice on 3 mins. publicly) that India has fielded this and it is quasi-operational. It is not a one-off science experiment.

The task at hand may not be technical difficulty (like bombing Balakot), but the will (which the previous government utterly lacked). So to frame the question on why a PM statement is needed on a seemingly technical less difficult task is to *purposely* miss the entire forest while searching for saplings.

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Re: Indian ASAT Test

Postby disha » 09 Apr 2019 06:20

Najunamar wrote:Dishaji, this could explain some of the bizarre reactions not only from Chipanda but Khan also. However, it seems improbable that such a public rebuke would be made in the current climate this close to elections.


Election could be a factor if the nation was not in an undeclared war from Bakistan aided by China.

BRF Ramana conjecture is that Risat-I was a target of Chinese attack (through some debris). I am veering around his view. See the cryptic tweet from NORAD

https://twitter.com/18SPCS/status/783812350860140544

16 pieces of debris and 15 decayed.

And this one from NASA is more explicit -> https://orbitaldebris.jsc.nasa.gov/quarterly-news/pdfs/odqnv20i4.pdf

Indian RISAT-1 Spacecraft Experiences Possible Fragmentation

The Indian Radar Imaging Satellite (RISAT)-1 Earth observation satellite experienced a possible fragmentation event on 30 September 2016 between 2:00 and 6:00 GMT due to an unknown cause. The spacecraft (International Designator 2012-017A, U.S. Strategic Command [USSTRATCOM] Space Surveillance Network [SSN] catalog number 38248), operated by the Indian Space Research Organization (ISRO), carries a C-band microwave synthetic aperture radar. The spacecraft had been on-orbit 4.4 years and was in a 97.6° inclination, 543 by 539 km orbit at the time of the event. Stored energy sources include batteries and nine 11 N thrusters for orbit and attitude control. No debris had entered N the SSN catalog as of
early October


This explains the cryptic statement from US on "No more mess in space will be tolerated", the intended audience was likely Panda Pokers. And from my POV also the NASA admin going ballistic, since he would have assumed that ChiPanda would start taking out Indian Sat assets in 400 Km+ orbit in retaliation starting a space war and proving that NASA is toothless and nanga (nekid). Or proving that NASA knew about the "possible fragmentation" event in advance and did not inform its counterparts in ISRO.

Either way, the timelines check out - late 2016 is when Risat-I gets encountered and PMO authorizes ASAT test and 2-years later a satellite in SN axis is taken out of equation.

PS: Looks like conjectures are adding up to a seeming plausibility.

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Re: Indian ASAT Test

Postby Singha » 09 Apr 2019 06:43

For polar sats orbit one half is ns and other half is sn
Sometimes india will be in the sn part due to rotation of earth

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Re: Indian ASAT Test

Postby Karan M » 09 Apr 2019 07:01

The reason Modi went public is because he made it a policy imperative that now India will operationalize this capability and hence it was now overt backed by GOI etc.

Any other Govt thereafter will find it tough to change course. Before he demits office he would have signed off on the relevant paperwork as well.

This is different from a subdued test which remains a TD with no.political ownership.

This is also likely a lessons learnt from the Indian strategic community which sat seething with frustration as leader after leader in the Indian firmament kept our nuke capabilities under wraps and did not operationalize them in time.

War capable ops capability is fundamentally different from test beds and LSP runs.

What Modis announcement of having the NSA operationalize this capability means is that paperwork and funding will now be put in place for an ASAT capability which is operational, a minimum deterrent so to speak.

A BARC bigwig mentions his frustration in an account of approaching Rajiv Gandhi about operationalizing the bomb. Gandhi instead of even giving him a pep talk, responded we have lived with a Chinese nuclear capability for 30 years so what difference does a few more years make, besides I intend to ask for disarmament in the UN etc. With such political leadership says the scientist, what were we to do?

Vajpayee broke that jinx by testing at least and finally operationalizing our deterrent. Now we have proper command and control, safety interlocks, SFC, missiles tasked for this purpose, not some village level small scale industry.

Similarly, Modi has done the same for ASAT capability before any other peacenik Govt took over and lost us this opportunity by just sitting on an ASAT proposal.

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Re: Indian ASAT Test

Postby UlanBatori » 09 Apr 2019 07:33

Cain Marko wrote:
UlanBatori wrote:The message was to Pakis, and it was clearly that there is an existing BMD infrastructure, so don't even think of trying anything.

Pleej to phorgive impertinent question but why not just conduct an ABM test then? Message would be a lot clearer no?
It is a very carefully nuanced message, and I hope Pakis have good scientists explaining it to their netaship. I am sure Parveen Hoodbhuoy can figure it out.

Pakis and nuance? Good scientists? To expect TSP establishment to understand that this was an underhanded way of showing ABM capability to castrate their mijjile seems convoluted.

Message is that there is infrastructure, not just a tech demo. ASAT components were carefully explained as being COTS from ABM infra (quite an unnecessary revelation), also common with Prithvi motors I suppose. IOW, mass-produced. This is the point that I see in the very public PR about such a system.
ASAT is visible to all: the debris cloud is unmistakable and radar of several nations will show that it was generated by the missile, not a Sergeant York type on-board explosion of the target.
ABM tests have been done from sriharikota etc numerous times, barely rates mention in the newspaper any more.
Message was intended to go out not only to TSP establishment but to their sponsors. Would u invest in TSP missiles given this demo?

Of course I am not saying that the ASAT was INTENDED solely to send a message, but the go-ahead for this test at this time had a clear and urgent purpose. Point is that it is not an election gimmick.
Look at the evidence of the Dog That Didn't Bark: TSP IRBM test was not conducted, after NOTAM closing air space citing IRBM test. Sponsors must have pulled out. Someone got the message.

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Re: Indian ASAT Test

Postby UlanBatori » 09 Apr 2019 07:45

Does a northward launch from SHAR have time to drop stages in the sea b4 crossing BD coast, or is the coast too close?

Reversing orbit direction requires twice the kinetic energy, so it would require a much bigger launcher: very wasteful. What point is proven by hitting a S-N rather than N-S? As I said, all u have to do is to get in the way. Sounding rocket would do just as well to produce a 7.5+ kps collision. With the right controls and terminal-stage guidance of course.

The CT of the target being dlagon-sat is a bit improbable since all launches are tracked by kids all over the world. A Chinese-launched object disappearing after a kiss from an Indian mijjile, would certainly not go unremarked.

The other point of the national announcement was to stop the DS (dhoti-shivering) about Paki new clear detergent, after Balakot jhapad.
V r having anti-mijjile mijjile onlee

BTW, was there any explanation of NaMo's 45-min delay? Was that exactly when the test occurred?

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Re: Indian ASAT Test

Postby Amber G. » 09 Apr 2019 09:07

Have not had chance to go through messages in details here.. some comments, more to come as I get a chance. (Plan to respond to Tanaji and Cain Marko later) but few quick responses:

disha wrote:
1. Orbit direction of satellites as viewed from Hasaan MCF, Bengaluru Kerala for all PSLV launches for SSO is from North to South. PSLV launches south and releases the Sat on a general North-South axis... [and related questions..]

The sat as you know (and is public knowledge now) was in a sun - synchronous orbit. This means it is *almost* polar but not quite - it is retro-grade ( West to East - that is opposite direction than our communication sats orbits)

For background - Most Indian Earth-observing satellites use retrograde sun-synchronous orbits to ensure that observations are performed at the same local time each pass of any given location. While almost all communication satellites we use are in prograde (East-to West) orbits.

As you know, they are *almost* polar (that is inclination > 80 degrees) so retrograde motion's component in equatorial direction is quite small.
For ASAT this means - depending on time-window there are two options of azimuth angle(s). The "head-on" option (that is going in opposite direction of sat - or having ASAT in pro-grade orbit) also has a benefit of getting extra velocity due to earth's rotation..but this benefit for polar orbit is quite small.

To be clear, the ASAT can be launched in either Northwards (approximately - azimuth angle has to be calculated accurately) or in South-wards direction (depending on time-window) and still be "head-on" mode (and not tail chase mode).



4. Ergo, the sat was travelling on South-North Axis. That is, it was a polar satellite allright - but it was not going from North to South, but reversed direction and was going South to North. That is almost a complete 180* turn in orbital plane!


As noted before - yes, sat is polar (or almost polar) but it goes North-to-South for half the orbit and then goes South-to-North.


(Some clarity - when sat crosses the equator going south-to-north - the technical term is "node" - is fixed wrt to stars but since earth is spinning, the land below this "node" is NOT fixed wrt to ground. IOW over time - 24 hours - position of this point on equator fixed to earth changes)

Another point I want to make here that collision relative velocity of about 10 Km or so, one can estimate fairly accurately by just knowing the altitude of sat from basic physics and some simple assumptions)

So now hope the answers are clear - but just for the record:

SO - Here is the question:

1. How come the orbital plane of Micro Sat was rotated 180* to go from NS axis to SN axis?


No orbit change of Micro-sat was done (it simply can't be done - as you said due to energy requirement).. This I think answers other related questions too.



Implications are different if the sat is not microsat -R
[/quote]
N/A as it WAS microsat-R.

Hope this clears a few things.

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Re: Indian ASAT Test

Postby disha » 09 Apr 2019 09:33

Singha wrote:For polar sats orbit one half is ns and other half is sn
Sometimes india will be in the sn part due to rotation of earth


Missed this. :eek: :(

{retiring in cave feeling dumb]

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Re: Indian ASAT Test

Postby Prem Kumar » 09 Apr 2019 09:57

I always had a suspicion the RISAT-1 was a Chinese ASAT sabotage but now I am convinced:

1) Surgical Strike 1.0 on Sept 29, 2016
2) NORAD reports a debris-causing event on Sept 30, 2016
3) In 1 month, RISAT-1 is officially declared dead
4) Our ASAT test took 2 years of preparation. That means the clearance must have been given by the PMO around Dec 2016. Right after RISAT-1's death

Too much coincidence!

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Re: Indian ASAT Test

Postby Indranil » 09 Apr 2019 10:38

If anything, this proves that even if RISAT was lost to an ASAT, it was not because of surgical strikes. It takes a little preparation to launch an ASAT. The satellite has to be at the right place at the right time.

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Re: Indian ASAT Test

Postby disha » 09 Apr 2019 11:17

Due to snafu in the technical part of the brain, squeaking from a cave on political undertones (this I did not post since I was feeling :oops: earlier)

Cain Marko wrote:b) I want to understand the reasoning behind the hoopla created by Namo before announcing the result. Seemed to me that the standard format response via a PTI release could have done the trick. Was it some veiled message (that I surely didn't catch) or was it purely political showbaazi?


The nation is at an undeclared war against not one but two adversaries. In such situations, certain deterrence needs to be backed by political will (otherwise that is not a deterrence but a science experiment) and what better way to show political will than the PM himself announcing it? There is no ambiguity when an elected leader of 20% of humanity states that India is a space power and will take all steps to protect its space assets. And it was demonstrated (PM stressed twice on 3 mins. publicly) that India has fielded this and it is quasi-operational. It is not a one-off science experiment.

The task at hand may not be technical difficulty (like bombing Balakot), but the will (which the previous government utterly lacked). So to frame the question on why a PM statement is needed on a seemingly technical less difficult task is to *purposely* miss the entire forest while searching for saplings.

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Re: Indian ASAT Test

Postby UlanBatori » 09 Apr 2019 17:29

RISAT as I heard it was taken out by a Chinese kiss-vehicle (KV): it came up nearly alongside and then boom. I think this was the "co-orbit" thing mentioned either in DRDO report or elsewhere. If it was an ASAT missile it would have been a big news item I think. IOW no great closing velocity, but like James Bond SPECTER concept for swallowing satellites. Must have been a very small thing, to have been nearly undetected.

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Re: Indian ASAT Test

Postby ArjunPandit » 09 Apr 2019 18:56

UlanBatori wrote:RISAT as I heard it was taken out by a Chinese kiss-vehicle (KV): it came up nearly alongside and then boom. I think this was the "co-orbit" thing mentioned either in DRDO report or elsewhere. If it was an ASAT missile it would have been a big news item I think. IOW no great closing velocity, but like James Bond SPECTER concept for swallowing satellites. Must have been a very small thing, to have been nearly undetected.

This is total CT domain, what is the timing
https://www.deccanchronicle.com/science ... -isro.html
US space agency Nasa has reported that India’s earth observation satellite Risat-1 had experienced a “fragmentation event” in September last year, when pieces appeared to have broken off


Risat-1 (Radar Imaging Satellite) was launched on April 26, 2012, on board a PSLV rocket. It had been in space for 4.4 years when the incident reported by Nasa occurred. The magazine said Risat-1 experienced the fragmentation event between 0200 and 0600 GMT (7.30 am and 11.30 am IST). Over 12 fragments were observed by the Space Surveillance Network of the US, it said. By November 8, only one piece, designated SSN 41797, had entered the catalog, having decayed — from orbit on October 12, 2016. The other pieces had decayed — moved away from the satellite — as well. Eventually, space debris in the near earth orbit tends to enter the earth’s atmosphere and burn up.





2. https://en.wikipedia.org/wiki/RISAT-1

Code: Select all

On 30 September 2016, Joint Space Operations Center identified a debris generating event near RISAT-1.[14][15] The event created 16 pieces out of which 15 decayed and one was catalogued on 6 October 2016 under NORAD ID: 41797 and COSPAR ID: 2012-017C and decayed on 12 October 2016. Cause of this event remains unknown. A month later on 3 November 2016, RISAT-1 data was declared unavailable on ESA's Copernicus Space Component Data Access portal due satellite outage. Satellite was experiencing anomalies but ISRO denied they were related to fragmentation event

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Re: Indian ASAT Test

Postby UlanBatori » 09 Apr 2019 19:17

Thx. Now that AP has declared it CT I can voice UBCN's real concern that the RISAT problems are nothing to do with external intervention. Simple reason: If there had been a collision with another object, the process is very simple: Announce it, try to get help tracking the piece of junk that came and hit, and ascribe responsibility. You can claim that it was because your yak drank too much Zam Zam Cola, but there is no escape. Space Law is very clear on this: If your yak dumps on my yakmobile that is YOUR responsibility. YOU pay for it. There are no ifs and buts and no "accidental onlee, baccha chota hain, what 2 do".
So the FIRST thing to do would be to announce the "fragmentation event" and blame it on something owned by Unknown Nation. Then let amateurs, professionals/ national agencies whatever trace it. Keep ur own findings kind-of low-profile unless the probability is high that it is due to satellite or debris from so-and-so, and gently mention it to them.
Because 99% of the time, they are going to say accident onlee, and have insurance pay. If someone says: "Yeah, I did it" that is an act of war, and at least clear violation of Space Law. Major propaganda gain if nothing else.

NOTHING of the sort happened with the RISATs, so until the second event I don't think there was even a suspicion.

And you can forget about any real long-distance laser beaming etc to drill a hole and blow up the fuel tank: those things require enormous energy and massive satellites, AFAIK. So either there was another satellite within a kilometer or so when the "event" occurred, or there wasn't.

Now IF u want to do a "co-orbit kiss" here is how to do it: Send a soosai coke-can sized can-sat up, filled with dirt for all I care. Do a small burn at the other end of the orbit from where you want the event to occur: it sends the can into an elliptic orbit with a much higher apogee, IOW the orbit where you want to kiss. This is half of a Hohmann Transfer. When you get there you are moving much slower than the speed you need to maintain a circular orbit there. Along comes the Kissable Satellite, moving at orbital speed. That gives you a good, say, 2 km/s differential, equivalent to hitting with a warhead traveling at Mach 7. "Head-on collision".
End of Kissable. No one sees it because cansats are probably undetectable unless you have your Bada Telescope zoomed in to them.

If u miss, the can-sat burns up in the atmosphere because it is in a steep elliptic trajectory. No one the wiser.

But if the event occurs, someone will trace back and see the flash of the rocket burn that occurred at the right moment, far away. And then you are under deep suspicion at the very least. In any case, the Kissable's daddy screams murder.

****Which did not occur with RISAT-1 or 2. Why not? What did ISRO have to gain by keeping quiet? ****
Last edited by UlanBatori on 09 Apr 2019 19:48, edited 2 times in total.

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Re: Indian ASAT Test

Postby ArjunPandit » 09 Apr 2019 19:25

^^my definition of CT is very simple, if it runs against the govt (my fav) narrative ;-). So it was my definition.
Coming to this, there's no Indian govt narrative. Orbits are not traffic in jaipur that anyone can come from any side anytime and then escape by saying "o saab, galti ho gai. Here i believe you more than the I did for gravitational waves. :evil:

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Re: Indian ASAT Test

Postby Prem Kumar » 09 Apr 2019 23:19

Indranil wrote:If anything, this proves that even if RISAT was lost to an ASAT, it was not because of surgical strikes. It takes a little preparation to launch an ASAT. The satellite has to be at the right place at the right time.


Risat-1 had a 12 day revisit cycle. So, right after surgical strike would be a good time to hit. Or wait 12 more days. Of course, this assumes the Chinese were ready-to-launch on short notice.

Regarding whether it was observed: if our BMD was not yet operationalized and it wasn't tracking all objects in space, we wouldn't have known what hit Risat. Amir Khan might know because he is watching space as well as Chinese BM/ABM launches.

This is yet another reason to operationalize BMD+ASAT. So that we have eyes on our assets, our enemy's assets & his actions. If we don't know what hit us, someone could declare stealth war on us and we have to run to Amir Khan for verification.

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Re: Indian ASAT Test

Postby Indranil » 09 Apr 2019 23:56

Prem Kumar wrote:
Indranil wrote:If anything, this proves that even if RISAT was lost to an ASAT, it was not because of surgical strikes. It takes a little preparation to launch an ASAT. The satellite has to be at the right place at the right time.


Risat-1 had a 12 day revisit cycle. So, right after surgical strike would be a good time to hit. Or wait 12 more days. Of course, this assumes the Chinese were ready-to-launch on short notice.

If surgical strikes was a surprise attack, that took Pakistan (and China) by surprise, then we have to assume that China took the decision to take out Risat on the 30th. And, Risat, by chance was revisiting China on exactly the same day! Also, considering the fact that China whose ASAT capabilities are just starting to get operationalized would wait the 12 days and make sure shot rather than hurriedly make a mess?

Risat could have been taken down by hostile action. But, it is unlikely that it was in response to surgical strikes.

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Re: Indian ASAT Test

Postby Indranil » 10 Apr 2019 00:02

UB,

You brought out a point that I have been wanting to ask for a while now. What is the meaning of co-located orbits? How can two objects co-located in the same orbit ever come to touch each other?

Intersecting orbits, I get it. Could this be a way to hit satellites in much higher orbits. Basically, put the KV in an highly elliptical orbit whose apogee is coincidental with the perigee of the satellite orbit? Time it so that the KV reaches its apogee at the same time as the satellite reaches its perigee, and Kaboom!

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Re: Indian ASAT Test

Postby negi » 10 Apr 2019 00:02

Well it need not be an ASAT missile right , may be some sort of laser/directed energy weapon was used and why do we have to assume only lizard would do that maybe someone else could also do it , someone who doesn't like our growing capabilities .

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Re: Indian ASAT Test

Postby Indranil » 10 Apr 2019 00:19

Even more unlikely. China has a fairly advanced DEW program. But if you use a DEW, you don't blow up a satellite.

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Re: Indian ASAT Test

Postby UlanBatori » 10 Apr 2019 02:14

Indranilji, obviously in Space one cannot just accelerate in the same orbit and hit from behind (for those confused by this: if you accelerate, you will move to a different orbit). So I feel that the "co-located orbits" is more or less what I described (easiest). But as the Indian ASAT showed, these also need not be in the same plane. I feel that they refer to a situation where you have satellites in orbit already, and then one day you feel the need to kiss someone. So there is no Launch Warning (no big fire to be seen that day from Space). Just a collision (or a short-range laser/microwave beam aka DEW) with no warning. The "co-located" implied a low relative-velocity event, like for a rendezvous, but then you have to fly close for a fairly long time to do mischief, and may be detected. DARPA Something Express showed how one could go around another satellite, also reach out and grab something with a wrench (or drill...) for "repair and maintenance".

I think it would be EZ, by the same token, to go toss a Burkha over someone's camera lens. End of $B Imaging Array, as far as effectiveness, but no physical damage done. Or hit it with a paint spray that evaporates after a couple of days... enough to hide whatever event you don't want it to see.

Someone mentioned BMD systems detecting objects: But AFAIK there is no way to detect passive things that are only the size of a coke can (or grenade). And that is enough with the large relative velocity that can be achieved with a high-eccentricity orbit.

Those interested may want to look up "Molyna Orbit". This was the Soviet Union's attempt to get a telecomm satellite located above a far northern place like Vladivostok where the standard equatorial GEO satellite would be too low on the horizon. These were extreme-ellipse orbits, so they spent a LOT of time going through the apogee. I think Mullah Kepler's Fatwa dictates that area of pizza pie slice swept at the focus per unit time is constant or something like that. So at the apogee the "speed" is pretty slow.

In the ASAT application this is like standing still and "mooning" a satellite arriving in a circular orbit. Catastrophic collision with something that is in a circular orbit.

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Re: Indian ASAT Test

Postby UlanBatori » 10 Apr 2019 02:44

But like I said (and got into all sorts of trouble....) all this is unnecessary. Pls see this statement:

Why is this so much better?
A circular orbit at 500km requires a "speed" of around 7600 m/s. So Kinetic Energy per unit mass is like 288 million per kilogram (Madarssa Math: 0.5*7600^2). A sounding rocket that reaches 500 km, and falls down, expends all its kinetic energy converting it to potential energy against gravity, so it has a potential energy at the top, of 500,000*9.8 = 49 million per kg. This is only 17% of the orbital energy, which means a FAR smaller rocket to launch. Here the launcher can be mobile - IF you have a fixed landmass that you want to defend.

The destruction occurs because of the kinetic energy of the target.

So the Indian ASAT is a defensive BMD.
The Co-Orbit Kisser is a much larger offensive weapon, launched into Space with the intent to kill someone much later.
U c Y India has been arguing to ban the latter, but allow the former. But others argue that OK, throwing a ball onto a busy Interstate Hwy is not exactly defensive...

Viewed another way, the Rohini has since 1967 been fundamentally capable of hitting something up to 500km above Thumba, at least accidentally. What is new is the fancy maneuvering with the fast-responding, ultra-precise thrusters (wonder what those are in reality: pulsed solid thrusters? Activated by what? Valves and liquids cannot move that fast, can they?)
The thing that my Paki mind saw - and ran to the pakistan as a result - is the shiny Tata Transporter/Erector and the truck cab pulling it. That says Mobile Infrastructure all over it.
Plus the big brag was about the computing speed and power built into the small gizmo for terminal-stage guidance. If you read the Brilliant Pebble thing, **THAT*** was always the big obstacle in Star Wars, and it looks like India has not only achieved it, but miniaturized into something that can survive the very high-G launch from a tube and the atmospheric buffeting and all, and perform with the cool precision of an IAF ground controller sending a Sopwith Camel after a fleeing Paki F-16.
This is what I was trying to convey before (never mind). :roll:

BTW, the Brilliant Pebbles as originally proposed, were a large number of KVs of the first kind (already in orbit) against a swarm nuclear attack. But the same could be done from a large number of mobile launchers as well. So the advantage is with the defender, against any ballistic missile attack.

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Re: Indian ASAT Test

Postby UlanBatori » 10 Apr 2019 02:57

Indranil wrote:if you use a DEW, you don't blow up a satellite.

Interesting thought, but I think it can be done. A couple of shots from a pulsed microwave may heat up and rupture a propellant tank and heat the propellant to ignition. Isn't that the idea of the Airborne Laser for Boost-Phase Intercept? But yes, that seems to be too much trouble.
Trouble with DEW is that the mass of the gizmo becomes too large for the needed energy. So it is very expensive to launch and impossible to hide. Plus you really don't want it to be nearby when the target explodes - like what happened to WCdr Abhi.

There is a potentially more elegant way. Most space thingies spin, I believe, to keep from melting on the sunny side (no convective heat loss). So if you were to sidle up and open a reflective umbrella from "below" and warm up the shady side, the operating temperature of the electronics will rise pretty fast and they will die. Quiet, no contact, no external damage or fragmentation.
*******

Thinking about it, I guess the "Co-located" is the best way to kill a GEO sat because the required Molnya vehicle would anyway be too large to be mobile ground-launched. So again, India is totally against that. Very bad, to militarize Space.

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Re: Indian ASAT Test

Postby Indranil » 10 Apr 2019 03:28

If you use a DEW, all you need to do is make the satellite in operational. Why spend orders of magnitude higher energy to blow it up?

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Re: Indian ASAT Test

Postby UlanBatori » 10 Apr 2019 04:07

Yes, the Solar Umbrella is a "Gentle Passive DEW". But it takes a long time, which means long co-located time, meaning too detectable. Laser mass per unit beam energy is still too large I think, so it means a chemical energy system to generate the pulse. Blindling the Imaging Array of the camera using a laser may be the best bet, if you know exactly where to point it, but consider that the camera may pick up and transmit a picture of the killer in its last moments. So maybe disabling the transmitting antenna is smarter, but it may be a large thing.

These are all reasons why a small "pebble" moving much slower is the best killer of all. Got to think of the Burkha though. :mrgreen:

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Re: Indian ASAT Test

Postby Amber G. » 10 Apr 2019 07:49

Okay .. anybody still wants to take a stab at this. if you have not seen this before it will help to understand basics of

This is NOT a trick questions. Neglect air-resistance etc.. assume well-known values for physical constants like g etc.

If one "threw" a "ball" ** straight up with 1 km/second speed from Mumbai will it:

a) land back exactly into "your hand" (the place where the ball was thrown)? If not how far away in which direction will it will land?
b) How high will it go?
c) at the "top" will the speed be zero? if not how much? (wrt to person on the ground in Mumbai)


(** Note - okay ball is rather fast but just think of this as a thought experiment)

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Re: Indian ASAT Test

Postby Amber G. » 10 Apr 2019 07:54

disha wrote:
Singha wrote:For polar sats orbit one half is ns and other half is sn
Sometimes india will be in the sn part due to rotation of earth


Missed this....]

Yes, also this is why I was talking about right "time-window" and "two-sets of azimuth choices" in my message above.. and actually in other dhaga on talking about the choice for launch point for various types of orbits.

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Re: Indian ASAT Test

Postby sudeepj » 10 Apr 2019 08:05

Amber G. wrote:Okay .. anybody still wants to take a stab at this. if you have not seen this before it will help to understand basics of

This is NOT a trick questions. Neglect air-resistance etc.. assume well-known values for physical constants like g etc.

If one "threw" a "ball" ** straight up with 1 km/second speed from Mumbai will it:

a) land back exactly into "your hand" (the place where the ball was thrown)? If not how far away in which direction will it will land?
b) How high will it go?
c) at the "top" will the speed be zero? if not how much? (wrt to person on the ground in Mumbai)


(** Note - okay ball is rather fast but just think of this as a thought experiment)


It certainly wont land back in your hand because of Earths rotation. I think it should land in the Arabian ocean.. :-D sorry, its been a long while since I tried to consider a 'frame of reference' in my mind. :-)

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Re: Indian ASAT Test

Postby Amber G. » 10 Apr 2019 08:26

Cain Marko wrote:
Amberji, can you please explain in plainspeak if the ASAT test was more or less challenging than a BMD test? I ask because:

a) I was always under the impression that the latter is more difficult considering the possibility of maneuvering reentry vehicles but am not sure anymore
b) I want to understand the reasoning behind the hoopla created by Namo before announcing the result. Seemed to me that the standard format response via a PTI release could have done the trick. Was it some veiled message (that I surely didn't catch) or was it purely political showbaazi?


ASAT test was a BIG (Very big deal) in many ways. Best way to summarize is how one very respectable prof put it while some discussion about this was going on and some was a little skeptical.

"If this is not that hard why other countries have not done this" !!!

There was a US BMD test - one person, who knows quite a bit about such things, remarked that many technologies (not all) were very similar to India's ASTA test. If one can do ASAT one is surely capable of doing the other.

Main thing, as I said before, 1 mili-second translates into missing a target by 10 meters.
Think about that!
And the accuracy (.1 m) was 100x better than that. Technologies need incredibly fast sensors and hardware. Also orbit-computation needs *very fast* (real-time) computers. This actually makes it a very big deal.

(Yes it may be true that BM can employ decoys - or have sheer many numbers of them - so that may be a challenge (but not that big IMO, as hitting a fast sat). As to " maneuvering reentry" it is not likely that the Missile will have luxury of precious fuel, sensors, - even more important fast software to track and "dodge" the BMD.. by attempting to doing so, it is most likely that the hostile missile will miss the target.
(Maneuvers are desirable for relatively slower moving planes with smart pilots and software - not so much for Ballistic missiles which just wants to go fast to the target)
-
As to Modi's announcement - My take - Such a BIG deal has to be announced in a suitable way. Letting the world know that we not only have world class scientists but leaders who support them 100%. The success of ASAT test can not be kept a secret (and India does not want to keep it a secret) world can have solid data to confirm and validate India's claim. The fact that GoI has equally brilliant leadership could be shown only if Modi announced the results to the world. After all it is a BIG deal. And GoI wants to tell the world that leadership also understands it fully.

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Re: Indian ASAT Test

Postby NRao » 10 Apr 2019 08:36

Amber G. wrote:Okay .. anybody still wants to take a stab at this. if you have not seen this before it will help to understand basics of

This is NOT a trick questions. Neglect air-resistance etc.. assume well-known values for physical constants like g etc.

If one "threw" a "ball" ** straight up with 1 km/second speed from Mumbai will it:

a) land back exactly into "your hand" (the place where the ball was thrown)? If not how far away in which direction will it will land?
b) How high will it go?
c) at the "top" will the speed be zero? if not how much? (wrt to person on the ground in Mumbai)


(** Note - okay ball is rather fast but just think of this as a thought experiment)


a) Yes, it will land exactly into "your hand" (not accounting for wind, etc.
b) You know v and v0, so use v = v0 + at to compute t ( a= 9.8 ), then use x - x0 = v0t + 1/2at^^2 to get the height
c) yes, the verticle speed at the top will be 0. wrt to the person on the ground, whatever speed the earth is spinning at?

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Re: Indian ASAT Test

Postby UlanBatori » 10 Apr 2019 08:46

Dear Adminullahs: OT, I am sure, but ..
There IS still a pissicks thread for kindergarten discussions, isn't there? Plus a Math Thread? Plus a Poll on Whether 2 Have a Pissicks and Math thread? What is the point of the above posts here except to impress children with Pompous (never mind) please? (seems to render the poll Q.E.D..)

Confucius say:
He hu throw dung straight up
Wise to oil bald head


The funny thing is that (never mind, no point in explaining funny things in presence of ppl who get offended easier than 2-year-olds).

If postors need help with 6th grade problems I suggest with all due respect that they use real numbers, with real wind effects and cylinder cross-flow drag coefficients in the Earth's atmosphere, and use Wikipedia or the NASA K-12 portal to help them understand why a sounding rocket with guidance and good calculation can destroy a satellite at 300km altitude. Estimate the error that they make in neglecting wind effects etc rather than waste time and bandwidth doing the Churchillian Mouth-Opening Demonstration.

Reminds me of the old story:
The physics student and engg. student were sitting on a bus (according to the narrator who was sitting behind).
Phy: "I can't satisfy this Physics Teacher no matter how hard I try. He asked us to calculate the height of the Administration Building, given a Mercury Manometer and a String and a Scale. First I told him I would take the Manometer to the roof and lower it to the ground with the string, and measure our the length of the string. He (Physics Teacher, of course) got mad and gave me an F. Then I told him I would hold the Manometer straight up and mark the shadow of it on the ground, use the string to measure out the distance and scale it by the length of the Manometer's shadow. He gave me an F and told me I was a fool, not paying attention in class. I am at my wit's end

Engr: U R going about it all wrong. Take the Manometer, scale and string down to the basement of the Admin. Bldg. Give those to the old gent sitting in dingy room b4 a desk, surrounded by filing cabinets. Ask him to get you the blueprint for the Admin Building, and get the real answer.


Of course that would have got an F as well from the types of Physics Mullahs who tried to educate me, because their stupid Expected Correct Answer would have been to measure the tiny change in manometer column height due to the difference in altitude between the ground and roof, and measure it using an (inaccurate) scale. Like the effect of 300 km on a radius of 6378km, the first 100 km of that rotating like a solid body with the 6378km.
Last edited by UlanBatori on 10 Apr 2019 09:11, edited 2 times in total.

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Re: Indian ASAT Test

Postby Ravi Karumanchiri » 10 Apr 2019 08:53

Related (perhaps) reading on the topic (I just read about): The "Laser Broom", which could perhaps also be replicated with a MW device.

DEWs are definitely a possibility (though I haven't followed this thread or topic that closely).

Regarding a different topic raised by a remark above; (while imagineering an ASAT) it occurs to me: The degree to which an orbital platform is detectable, is directly related to its RCS and visual appearance; which need not necessarily, comport directly with its physical size. Space is a vacuum, and inflatable objects are old-hand. A tiny package (nano-sat) with a very small RCS could contain something that inflates into a very large "catcher", yet it need not be highly visible, or have any appreciable RCS. Imagine something made of matte black space-safe rubber, that inflates into an enormous catcher with 10000 fingers, all coated with a sticky epoxy/glue to adhere-to the target. A small gas generator could inflate it, and it would be very hard to see even with telescopes, and have no RCS. The kinetic energy of the impact, causes the ensnarement of the target satellite, which could then be de-orbited in one piece.

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Re: Indian ASAT Test

Postby UlanBatori » 10 Apr 2019 08:57

Raviji, attaching a nylon tether can kill the satellite equally well, causing momentum transfer and a swift demise by atmospheric entry with no visible explosion/fragmentation. But even that requires getting close to the speed of the satellite. The sounding rocket mooning the satellite using a tiny payload is much more effective. Yes, position accuracy need is extreme, but look at it this way: you can keep trying on a couple of orbits until you succeed: only one hit is needed.

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Re: Indian ASAT Test

Postby Theeran » 10 Apr 2019 09:00

NRao wrote:
Amber G. wrote:Okay .. anybody still wants to take a stab at this. if you have not seen this before it will help to understand basics of

This is NOT a trick questions. Neglect air-resistance etc.. assume well-known values for physical constants like g etc.


(** Note - okay ball is rather fast but just think of this as a thought experiment)


a) Yes, it will land exactly into "your hand" (not accounting for wind, etc.
b) You know v and v0, so use v = v0 + at to compute t ( a= 9.8 ), then use x - x0 = v0t + 1/2at^^2 to get the height
c) yes, the verticle speed at the top will be 0. wrt to the person on the ground, whatever speed the earth is spinning at?


Ok the calc flew over my head. But common sense the ball will land to the west? With the earth rotating you will be long gone before the ball lands.

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Re: Indian ASAT Test

Postby Prem Kumar » 10 Apr 2019 09:07

UB: regarding tracking tiny objects, both Amir Khan and we seem to possess it. Khan was tracking centimeter sized ASAT debris. We also had recently built a BMD radar that can detect small objects from 1000+ Km range. This was used during the ASAT testtoo.

Question is: can the tiny objects be detected in a scan mode while scanning wide swaths of space? Or can these be tracked only if you know where to look? Plus we have the geographical coverage issue. Can we track who's near our Cartosat when its flying over Finland?

Right now, Khan might be the only one with resources to keep track of all their space assets & objects of interest near them.

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Re: Indian ASAT Test

Postby UlanBatori » 10 Apr 2019 09:14

Space-based cameras claim to be able to read the newspaper held in someone's hand etc, but apparently looking the other way is not so EZ. AFAIK, the claim is that even asteroids can't be detected unless they are several meters in diameter though they may be in nearly same orbit as Earth. So Space debris I think the threshold is maybe about 1 foot dia, IF one is zooming in on it, otherwise finding is random. So I think a grenade is quite undectable.

There MUST be some signal return if you scan with a high-frequency where the wavelength is nearly as small as 30cm, but how much one can trace each such object is a good question. So you may realize that a satellite got hit by SOMETHING, but from debris of what? Pinning blame will be very hard.
Last edited by UlanBatori on 10 Apr 2019 09:16, edited 1 time in total.


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