Indian Space Programme Discussion

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nTripathi
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Re: Indian Space Programme Discussion

Postby nTripathi » 09 Mar 2016 18:26

kit wrote:once the INRSS is in place would it be possible to block all GPS signals in India ? at times of war for example ?


well, GPS is operated by USA so in a situation of war they can selectively block the coverage of their positioning service in any region of the world and for any duration! However, I believe IRNSS can be used very efficiently to block GPS. The orbit of the Indian satellites is higher than that of GPS ones given that IRNSS can generate signals in similar frequency range as the GPS satellites. In a state of war, IRNSS satellites can use a fraction of their transponders to jam GPS signals an rest of the transponders to beam on strategic authorized users like the military...

(But I must say, in all cases if USA is not involved, jamming the GPS can create major international crisis.)

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Re: Indian Space Programme Discussion

Postby Varoon Shekhar » 09 Mar 2016 18:32

"The first satellite IRNSS-1A was launched in July 2013, the second IRNSS-1B in April 2014, the third on October 2014, the fourth in March 2015, and the fifth in January this year.

The seventh satellite-IRNSS-1G- is expected to be launched in the second half of 2016.

Once the regional navigation system is in place, India need not be dependent on other platforms."

Whoa, is this accurate, or is it "DDM strikes again". ISRO was first pretty certain that they would launch 2 satellites in the same month, March. That's likely not going to happen, but another news item mentions an April launch for IRNSS-1G, the last of the 7. If 1G is really going to be launched only in the second half of 2016, that's either a grotesque miscalculation or blatant misinformation. Not a credit to ISRO either way!

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Re: Indian Space Programme Discussion

Postby nTripathi » 09 Mar 2016 18:45

ranjan.rao wrote:Will the chinese and pakistanis be able to access the IRNSS? Could it be turned up against us in any fashion?


Yes, people in China and Pakistan will be able to use IRNSS but only the standard positioning service (accuracy of 10-20 metres) not the sub-30 cm authorized service. However, China and Pakistan have access to Beidou so no need to worry about that!

But there are two other things that must be noted: first, they cannot access IRNSS signal use/user data (if they come to access that somehow, then it will be disastrous for India). Second, take the example of Sri Lanka... Suppose they want to invade India, since they do not have access to any military positioning service they are at a loss here. However, there is free availability of GPS, Glonass, Beidou and IRNSS in the area: they can easily combine these services to decrease the signal to noise ratio and errors, hence creating an augmented system of sub-metre level accuracy!

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Re: Indian Space Programme Discussion

Postby member_22733 » 09 Mar 2016 18:45

GPS jammers are available in market. Very easy to spoof the commonly known GPS signals. What is unknown is whether there are non-public (secret) military modes. So even if you spoof the public GPS signals, you maybe unsuccessul in jamming the military ones. GPS jamming in the US can get you a long prison sentence.

However, GPS jamming over India should not be a problem (and IMO must be regularly tested out).

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Re: Indian Space Programme Discussion

Postby kit » 10 Mar 2016 00:00

I think denial of any positioning signals GPS or Beidou to any country over India, other than IRNSS should/would a core objective at the outbreak of any hostilities ..

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Re: Indian Space Programme Discussion

Postby disha » 10 Mar 2016 06:53

nTripathi wrote:are you talking about merging beidou and irnss coverage areas?... well that is far from becoming a reality.


No. I was just being sarcastic. Even though chinese would want the general use of Beidou-2 in the asia-pacific., specific countries will definitely have reservations using chinese gps.

it has since been retired. from 2007 to 2014 was beidou-2/compass (it covers whole of china, india, australia, asia pacific). this one is operational.


Yes I am aware of Beidou-2 and in general I am skeptical of any Chinese space endeavors. Including their plan to offer a competitive GPS coverage for the whole world.

Now this is what i hope that happens. I believe if India places the similar configuration of GEO/GSO sats between 25 degree west to 32 degree east, the whole of africa can be covered using four extra satellites! one way to go about India-Africa relationship... 8)


Of course it will help more if it is at MEO. Of course caching it as India-Africa relationship is a good thing., but it will provide more commercial opportunities.

India must consider both Indo-China and Africa as its extended backyard with footprints in Oceania.

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Re: Indian Space Programme Discussion

Postby disha » 10 Mar 2016 06:59

kit wrote:once the INRSS is in place would it be possible to block all GPS signals in India ? at times of war for example ?


Not block, but jam. Yes., one can have selective jammers in place that blocks out civilian GPS, Glonass and Beidou signals to GPS devices on the ground. Of course millitary GPS signals is jam resistant but then one needs specialized GPS devices to operate with millitary GPS.

So to Tripathi'jis point., even if a baki uses civilian GPS, Glonass and Beidou to get millitary level accuracy, they will run into vast 'holes' in the coverage because of strategic jammers at critical areas.

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Re: Indian Space Programme Discussion

Postby nTripathi » 10 Mar 2016 10:30

disha wrote: No. I was just being sarcastic. Even though chinese would want the general use of Beidou-2 in the asia-pacific., specific countries will definitely have reservations using chinese gps.


I noticed the sarcasm disha... but look at the picture here: you have more than 4000 posts and i have less than 20! So I felt it was my moral obligation and utmost duty to answer to it (m still a trainee, right!). :wink:

Answering to this quote, keeping the matter of south china sea aside, why would any country have reservations using BDS (beidou... one thing i like about them: they cannot stick to one name!)? navigation is purely a civilian issue and of great importance in today's world... Stating some figures here, china has generated over 31 billion dollars in revenue using BDS since its inception in 2003.

Yes I am aware of Beidou-2 and in general I am skeptical of any Chinese space endeavors. Including their plan to offer a competitive GPS coverage for the whole world.


Okay, they do a lot of reverse engineering but I believe they have a strong space policy. heck.. they are far ahead of our country in both vision and achieving goals. We must accept here that China is moving towards world supremacy and they understand the importance of a strong space programme!

Of course it will help more if it is at MEO. Of course caching it as India-Africa relationship is a good thing., but it will provide more commercial opportunities.

India must consider both Indo-China and Africa as its extended backyard with footprints in Oceania.


ummm.. why MEO? Africa lies between 40 degree N to 40 degree S which can easily be covered by GEO and so will Oceania... plus the added benefit of whole day coverage. MEO is more logical for far North and far South latitudes.

So to Tripathi'jis point., even if a baki uses civilian GPS, Glonass and Beidou to get millitary level accuracy, they will run into vast 'holes' in the coverage because of strategic jammers at critical areas.


So children, that is why India created a baby called IRNSS!

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Re: Indian Space Programme Discussion

Postby SSridhar » 10 Mar 2016 11:28

Live webcast starting at 15:30 IST will be available here

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Re: Indian Space Programme Discussion

Postby SaraLax » 10 Mar 2016 12:11

It is not exactly a clear blue sky day today but it's quite possible that people in Chennai & areas nearby Sriharikota could well be able to see in normal eye sight as well as capture pictures of today's launch of the PSLV rocket. I believe this happened during a rocket launch some months before.

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Re: Indian Space Programme Discussion

Postby SaraLax » 10 Mar 2016 12:42

nTripathi wrote:
disha wrote:
So to Tripathi'jis point., even if a baki uses civilian GPS, Glonass and Beidou to get millitary level accuracy, they will run into vast 'holes' in the coverage because of strategic jammers at critical areas.


So children, that is why India created a baby called IRNSS!


When it comes to real war situations - I was of the idea that Chinese & Americans have the capability to shoot down Satellites of other countries via some powerful LASER emitting machine or something similar and thus prevent their enemies from exploiting GPS technology to gain advantages for their missiles, armies, aircrafts, ships & etc. I believe none of the satellites have the capability on their own to avoid war time destruction possibilities such as these ground based damaging techniques. India can also do the same to the satellites of its adversaries but I am not sure if we have such a capability already (IIRC, there used to be some technology being developed ... and possibly called as KALI or so ?).

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Re: Indian Space Programme Discussion

Postby srin » 10 Mar 2016 13:45

There is a corollary to that: we should be able to launch IRNSS satellites at very short notice as replacements in case of such ASAT attacks. We need a batch of ready and lightweight IRNSS satellites that can be mated with Agni-5 based launch vehicle to quickly launch replacements into MEO or highly elliptical orbit.

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Re: Indian Space Programme Discussion

Postby manjgu » 10 Mar 2016 14:40

saraLax...its not normal eyesight but narmal eyesight.... launch was narmal not normal.

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Re: Indian Space Programme Discussion

Postby MN Kumar » 10 Mar 2016 14:51

ISRO site goes offline :-( and Airtel stopped DD


JTull
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Re: Indian Space Programme Discussion

Postby JTull » 10 Mar 2016 14:57

Lift off

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Re: Indian Space Programme Discussion

Postby nirav » 10 Mar 2016 14:57

Lift off naarmal !!

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Re: Indian Space Programme Discussion

Postby JTull » 10 Mar 2016 14:58

+70secs groundlift strapons separated

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Re: Indian Space Programme Discussion

Postby JTull » 10 Mar 2016 14:59

+92 secs airlift strapons separated
xx stage 1 separated
stage 2 ignition normal
Last edited by JTull on 10 Mar 2016 15:00, edited 1 time in total.

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Re: Indian Space Programme Discussion

Postby Bob V » 10 Mar 2016 15:00

parfarmance naarmal

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Re: Indian Space Programme Discussion

Postby nirav » 10 Mar 2016 15:00

Image

JTull
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Re: Indian Space Programme Discussion

Postby JTull » 10 Mar 2016 15:00

heat shield/payload fairing separated

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Re: Indian Space Programme Discussion

Postby JTull » 10 Mar 2016 15:02

260.9 secs: stage 2 separated. stage 3 ignited - naarmal

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Re: Indian Space Programme Discussion

Postby JTull » 10 Mar 2016 15:03

stage 3 burnout

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Re: Indian Space Programme Discussion

Postby JTull » 10 Mar 2016 15:08

+655.3secs : stage 3 separated
+666 secs: PS4 engine started

SSridhar
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Re: Indian Space Programme Discussion

Postby SSridhar » 10 Mar 2016 15:10

Could see trail of the rocket and PS1 separation from my house top.

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Re: Indian Space Programme Discussion

Postby rsingh » 10 Mar 2016 15:12

^^
Lucky you. Meanwhile all is narmal

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Re: Indian Space Programme Discussion

Postby nirav » 10 Mar 2016 15:14

Apogee counter picking up crazy speed ..

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Re: Indian Space Programme Discussion

Postby SSridhar » 10 Mar 2016 15:16

Looks like excellent orbit achieved

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Re: Indian Space Programme Discussion

Postby JTull » 10 Mar 2016 15:17

1175.3 secs: PS4 shutoff

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Re: Indian Space Programme Discussion

Postby JTull » 10 Mar 2016 15:17

1212.4 secs: Mission complete!

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Re: Indian Space Programme Discussion

Postby member_28579 » 10 Mar 2016 15:18

Congrats ISRO....One more to Go to complete IRNSS... :)

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Re: Indian Space Programme Discussion

Postby nirav » 10 Mar 2016 15:18

Congratulations to ISRO and desh .. Yet another successful launch !

Image

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Re: Indian Space Programme Discussion

Postby SSridhar » 10 Mar 2016 15:21

The orbit achieved is so precise that the life of 1F could be extended by 2 years ! ISRO Mission Director

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Re: Indian Space Programme Discussion

Postby member_27581 » 10 Mar 2016 15:36

nTripathi wrote:
ranjan.rao wrote:Will the chinese and pakistanis be able to access the IRNSS? Could it be turned up against us in any fashion?


Yes, people in China and Pakistan will be able to use IRNSS but only the standard positioning service (accuracy of 10-20 metres) not the sub-30 cm authorized service. However, China and Pakistan have access to Beidou so no need to worry about that!


Thanks nTripathi Sir,
Is it only a software encryption issue or there is some hardware aspect to it. I was wondering how much secure we can keep this service from ChiPakus. If it's just an encryption issues, I am sure it will be a matter of time before they get their hands to it.

I didn't consider the coverage of their bidu2.

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Re: Indian Space Programme Discussion

Postby sudhan » 10 Mar 2016 15:54

Yaaawn! ISRO is making it boring! For another naarmal launch of a textbook happened onlee! Guess one has to wait for LVM missions to go back to good old nail-bitey launches..

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Re: Indian Space Programme Discussion

Postby SaiK » 10 Mar 2016 15:58

congrats..!

now toilet says only 20 meters accuracy.

getting closer to GPS?

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Re: Indian Space Programme Discussion

Postby nTripathi » 10 Mar 2016 16:18

SaraLax wrote:When it comes to real war situations - I was of the idea that Chinese & Americans have the capability to shoot down Satellites of other countries via some powerful LASER emitting machine or something similar and thus prevent their enemies from exploiting GPS technology to gain advantages for their missiles, armies, aircrafts, ships & etc. I believe none of the satellites have the capability on their own to avoid war time destruction possibilities such as these ground based damaging techniques. India can also do the same to the satellites of its adversaries but I am not sure if we have such a capability already (IIRC, there used to be some technology being developed ... and possibly called as KALI or so ?).


It is true that anti-satellite weapons are the nuclear counterpart when we talk about space. USA and china definitely have this technology. However, the mechanism they openly use is the direct kinetic hit method; successful use of high energy laser is unconfirmed. A few proper hits by anti-satellite weapons can win you a war, but the debris-fallout is catastrophic for all the other satellites in the region and this could very well trigger world war 3.

So ASATs are scary weapons... Should India have them? Of course! With our growing fleet of satellites, they can act as a deterrent just like the nuclear weapons do. But we must also understand here that with current ASATs which of the Indian satellites are vulnerable and which are not! Our IRNSS system and communication satellites lie in GEO orbits: and i don't think someone will use ICBMs to launch a satellite attack. However, those laser system you talk about can be very effective in this case!

So what i think is that India should work on these unconventional means like laser, EMPs, etc. to develop their ASAT capabilities. Think about it: India is at war; India tactically points its laser on one of the enemy's satellites; satellite fried; no debris; "little" international crisis! (well, truly speaking there will be crisis: more like everybody will be afraid over what India can do rather than what India has already done as in case of conventional means which create debris.)

At last, if DRDO is too adamant about developing missile attack system on satellites, I suggest they do the tests on objects below 300 km altitude whose orbits are already decaying to avoid causing the debris problem like China created back in 2007!!

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Re: Indian Space Programme Discussion

Postby SaiK » 10 Mar 2016 16:41

well if not debris, the disabled satellite loses control and must fall into the atmosphere. would that be a controlled risk that we Earthians can take?

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Re: Indian Space Programme Discussion

Postby member_22733 » 10 Mar 2016 16:50

nTripathi wrote:It is true that anti-satellite weapons are the nuclear counterpart when we talk about space. USA and china definitely have this technology. However, the mechanism they openly use is the direct kinetic hit method; successful use of high energy laser is unconfirmed. A few proper hits by anti-satellite weapons can win you a war, but the debris-fallout is catastrophic for all the other satellites in the region and this could very well trigger world war 3.


A KE hit usually changes the orbit of the sattelite (along with doing damage ofcourse), and the debris will usually go from circular to eliptical with microscopic eccentricity (i.e. will be barely even different from the original orbit) and therefore will not impact any other satelite.

Unless the KE hit is extremely energetic, the above would be true. A highly energetic KE hit needs a high power (possibly two stage) rocket itself. The problem with that is that it increases launch time, since it needs a higher energy budget and most things are power constrained. So with limited power reaching higher energy levels takes a longer, time consuming trajectory. Such launches can be detected by almost any decent military satellites and therefore can be evaded easily.

So an ASAT weapon has to be launched fast,and if we are power constrained it means highly energetic KE hits are improbable and unlikely to be used in a real scenario.

If there a successful high energy KE hit, there will be fragmentation and the slower fragments will deorbit (very slowly) and the higher velocity fragments will continue in elliptical orbits following approximately the same orbital period. It wont pose a statistically large enough threat for any nearby sattelite.

Even if the debris fall back, they will usually disintegrate before hitting earth.


PS: The movie "Gravity" is bullsheet and I learned this while trying to research whether that movie was acccurate or not.


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