Indian Space Programme Discussion

[SSSalvi]

Now all things appaear to have been sorted out about orbit, KE, PE, g, m etc .. just A real life examples of MOM and MAVEN entering the respective orbits around Mars ( One approached from North while the other from South of ecliptic. ) may be in order.

A bit dated posts . But the graphs throw light on the intricasies involved.

http://indiaspaceactivity.blogspot.com/ ... rtian.html

http://indiaspaceactivity.blogspot.com/ ... maven.html

[SSridhar]

Look at orbitals of electrons. The lower the orbital (closer to the nucleus), the lower the energy of the electron.

[SriKumar]

The phyiscs of the two systems- at the quantum level and at a planetary are different in very major ways and not comparable.

For example, one cannot even determine the position and velocity of an electron simultaneously- the famous Heisenberg uncertainty principle that all have learnt. Whereas we can track the position and velocity of a satellite routinely (even brouchures and websites provide it).

Also, an orbital of an electron is not the same as an orbit of a satellite. The most fundamental aspect being that you dont know exactly where an electron will be- you just get a probability function that says with 95% (?) probability that an electron is at a certain location. It is not deterministic- whereas this is clearly not the case in a satellite.

The shape of an orbital is different in many ways compared to shape of a satellite orbit. While an 's' oribtal is roughly circular, p-orbital is not- it is dumbell shaped. And the famous sp3 hybridized orbital seen in diamond, for example, nothing close to that exists in satellite orbits- it has a really funny shape with a small lobe at one end and a larger one at the other. Also, satellites can orbit in any orbit i.e. at any height but electrons have to go into specific quantum 'slot' orbitals.

I looked at the ionization energies of various orbitals and the innermost orbitals have a larger value for the ionization energy, so I am not sure about what you mean by lower orbitals have lower energy unless you mean that a -ve sign makes it numerically a lower energy; but in any case the physics of the two- quantum physics at an atomic scale and planetary physics at a macrosopic scale are very different. Gotta run now but if there is interest we can continue this in the physics thread. I did not look at the various components that constitute the energy of an electron, which one needs to do in order to figure out the sources and magnitude of energies, but I am quite sure that it will not affect/change above discussion on energies of satellite orbits.

[gakakkad]

shape orbitals reflect probability distribution of finding an electron....while in case of satellite ,we exactly know where they are...a lot of stuff that is applicable to an electron is not applicable to a satellite....for instance electrons are present around a nucleus and the interactions between electrons and nucleus are electrostatic..(they don't technically rotate because the orbitals which are probability distributions are not circular)...

[shyamoo]

Newton's laws do not apply at quantum level

[sanjaykumar]

Trouble is back in the old days, the "unprepared" Munnas were given a school system where they would write a 400 word essay on the launch of Apollo to the moon in the Physics paper , where actual physics was zero, but long wind verbal vomit which would be shelved under "Science History" (which is more literature and writing skills) , for an answer worth 10% of the total marks and the "unprepared " Munnas would march in to state engg colleges, while "prepared" Munnas like us who were repelled by "Science History" writing and couldn't do it had to take a high stakes chance at the JEE, which was the only route for us to actually become engineers or to end up as pool typists in a Govt office.



Very interesting. The implication being that somehow the intrinsic intellectual merit of memorising formulae and textbooks in physics is superior to, oh let's say, Karl Popper's essays on the history of science.

Such cannot possibly understand reason but may well understand text-books.

[gakakkad]

^^ OT but I am not really sure if one can memorize physics and do well in JEE...but most people ,even with an iq of 80/90 can understand Karl Popper's essays...maybe they can even plug in the value in F=(Gm1m2)/r^2 ...but they ll not be able to solve the jee mains problem simply by plugging and chugging ..A common leftist argument is to equate math/science to social science and literature...they argue that ability in calculus is given an oopri hath over ability in puking bile in ny toilet paper..(ie literature ,sociology etc)...most of us STEM folks are too shy to tell them things the way they actually are...that math/science abilities are tougher to acquire (ie have more intrinsic merit as u said) than writing abilities ...and infinitely more useful ...shakespeare was not going to send us to moon or cure cancer...

[sanjaykumar]

Hmmmm.....In fact if one examines the IQ of those in the natural sciences vs those in non-science fields at the professorial level, they are quite similar except for the very top people doing physics and math. Now unless one is representing oneself as the elite in physics or math, one is merely a number cruncher. I doubt the Newtons or Ramanujans are hanging around BRF.

Karl Popper is certainly digestible or perhaps one can state one does not need to rote memorise formulae to access him, but it is odd that some of his insights were not formulated by those in STEM.

Finally it is originality in insight that must be held in premium, regurgitating 400 year old concepts in orbital mechanics is perhaps more for journeymen.

[gakakkad]

^^we had a nobel laureate physicist once...iirc it was saul perlmutter who was his colleague...was brought in by one of the members...even made a couple of posts...

[SriKumar]

ISRO's successes in satellite technology and rocketery is a result of the work of journeymen, engineers and mechanics and technicians. There are no Nobel laureates working in ISRO.

[sanjaykumar]

That's why I say bless 'em. These are people who don't claim to be super geniuses, but are a shining light for mankind, given what they have to work with in terms of resources.

[shiv]

Ok folks thanks for all the inputs about payload separation and orbits and energy. However I get one more doubt - it would be easier to ask with a diagram but I will try.

For any orbiting body - the total energy (KE+PE) would be constant. If you then "split" the body into 2 parts (like a launcher and payload separating) then the total energy of the two bodies would still be constant - but the energy that was stored in the spring or payload separation jet would be added to the KE of both bodies.

So here's the question. If the two split parts are of unequal masses then one will be accelerated more and the other less. The one that gets greater acceleration should then rise to a slightly higher orbit and the other (heavier mass, less acceleration) should also rise - since it gains KE from the spring - but to a slightly lower orbit than the other mass. But then both bodies would continue to orbit near each other with some altitude (from earth) and perhaps some lateral separation which may have occurred in the time it takes for both bodies to stabilize in their new orbits based on the extra energy imparted by the separation spring.

What I want to know is whether the two bodies would then gradually move apart over time because they are both in separate orbits or would they end up orbiting at a constant distance from each other?

[vina]

Very interesting. The implication being that somehow the intrinsic intellectual merit of memorising formulae and textbooks in physics is superior to, oh let's say, Karl Popper's essays on the history of science.

Such cannot possibly understand reason but may well understand text-books.

Lets be very clear here. Asking someone to write a full descriptive 400 words of the launch of Apollo to the moon (with irrelevant details on when the 1st stage fell off at what height, what was the burn length of the second stage, how many circles around the earth did the Apollo did around the earth before it went off towards the moon, how the lunar module separated and did a 180 deg turn and attached itself again.. who was the 1st man to land on the moon, who was the 2nd man and who stayed behind in lunar orbit etc, with marks for each of these details), is NOT PHYSICS and to give a huge percentage of marks (around 95%) of the paper towards those kind of questions, precisely to enable people who can memorize these details in rote and spit it back verbatim and to decide if that is the required skill for you to take a course in Physics or Engineering at college is a TRAVESTY . Bottomline , no need to actually think folks , just memorize what is there in the text book (which reads like a newspaper article / press hand out brochure about Saturn V and Apollo ) and spit it out again, and you get into college, while a guy who can actually put pen on paper work out how much thrust will be required in the 1st stage engines , what should be the escape velocity to go to moon and how much it should be decelerated to enter lunar orbit is told, but recoils from writing or is unable to write that inane prose about of some totally irrelevant details ,is told to go try passing the JEE (with a 1% probability as in those days), or you are welcome to line up to become the pool typist in the local Govt office.

There is no need to conflate that travesty with different kinds of knowledge and some "IQ" or whatever. It is as if suddenly MetaPhysics and "Science History" entrance skills and criteria are the ones to decided whether one becomes actual scientist or not , or you end up with a farce where a student of "Science History" (like the late Rohit Vemula was, nothing wrong with that) gets to be described as a "Scientist" by the idiotic media.

Finally it is originality in insight that must be held in premium, regurgitating 400 year old concepts in orbital mechanics is perhaps more for journeymen.

As if, reguritating some random essay masquerading as a Physics lesson on some rocket's journey to the moon is profoundly original, or even if you ignore that, regurgitating and putting on pedestal some ancient "Philosophy" (Plato, Aristotle) or some "Philosophy" and Poetry and Play stuff from the middle ages or 400 years ago is the epitome of originality.

Anyways, very very OT. Start another thread on the Epistemology or Theory of Science if you want to take this forward.

[SriKumar]

For any orbiting body - the total energy (KE+PE) would be constant. If you then "split" the body into 2 parts (like a launcher and payload separating) then the total energy of the two bodies would still be constant - but the energy that was stored in the spring or payload separation jet would be added to the KE of both bodies.

I'll give a qualitative answer....if anyone wants to put in numbers is more than welcome.

So here's the question. If the two split parts are of unequal masses then one will be accelerated more and the other less.

If a spring pushes apart two masses that are glued to each other and orbiting as a single mass with a velocity 'v', I would expect one mass- the one in the 'front', to accelerate to a velocity higher than 'v'; and the mass 'behind' to decelerate to a velocity less than 'v'. If you push against a heavy box that moves forward, the box pushes you backward. Same thing happens to the mass 'behind' the spring. So, one mass goes 'higher' and the other 'lower'.

The one that goes lower than the original orbit, my position is that its orbit would decay and it would fall to earth unless it is accelerated at this point to its orbital velocity for that lower orbit (which needs to be a higher value than 'v').

But then both bodies would continue to orbit near each other with some altitude (from earth) and perhaps some lateral separation which may have occurred in the time it takes for both bodies to stabilize in their new orbits based on the extra energy imparted by the separation spring...... What I want to know is whether the two bodies would then gradually move apart over time because they are both in separate orbits or would they end up orbiting at a constant distance from each other?

Couple of caveats- when a satellite in a circular orbit is given an infusion of energy to accelerate it, either via a spring or a rocket thruster, the orbit becomes 'higher' but it is more accurate to say that it becomes elliptical, with the point of acceleration being the perigee of the elliptical orbit. So while there is some (minor) gain in height after acceleration, the maximum gain in height occurs at the 'other end' of the elliptical orbit, i.e. apogee. Mangalyaan's orbit-raising maneuvers when around earth was performed the same way, with the LAM or other thrusters being fired when it was the closest to earth. ALL those 5 (or 6) orbit-raising maneuvers were elliptical orbits.

I dont know how satellites would move laterally relative to each other in elliptical orbits that are 'concentric'. It can be deduced from Kepler's law of areas, but it has been a long day so far, so I am not googling right now. For the discussion below, I will assume that a satellite, after an infusion of energy from spring and moving to a 'higher' orbit is re-energized/re-directed to a circular orbit, but with a larger radius. And the one going lower is re-accelerated to stably orbit at a lower, circular orbit.

Yes they would drift apart over time. I would venture that this part can be deduced independent of above discussion. A satellite orbiting in a low earth orbit revolves around earth once every 90 minutes (about) and the one in geo-stationary orbit once every 24 hours. So, their lateral separation will increase over time, significantly. The degree of the lateral separation should be lower if the orbits are closer, as described in your scenario.

Added later:
Another way to think about lateral separation is to see if the angular velocities of orbiting satellites are the same or not. Now orbital velocity = sqrt (GM/R) (derived by equating mv^2/R = GmM/R). now, v = R*omega where omega = angular velocity.

If angular velocity of two satellies are the same, then their lateral separation will not change over time.

R*omega = sqrt(GM/R); therefore omega = sqrt(GM/R^3). So, angular velocity varies as the inverse cube of radius, so there will be a very clear increase in lateral separation over time.

(I did not re-check above proposition- if anyone finds anything wrong, feel free to correct it).

[sanjaykumar]

A final data point. Linus Pauling could have, should have won another Nobel. He was eminently equipped to determine DNA structure. A giant of the chemical bond, collagen structure etc.

Francis Crick should have had the insight into base pairing, he certainly was intellectually equipped for it. But it was left to an obnoxious 22 year old bird watcher, Watson, to provide the crucial insight. I have learnt from this alone to never disparage anyone.


(Genes for intelligence are apparently constant across different fields/specialisations. We must look elsewhere to determine what makes an Edward O. Wilson, Harvard sociobiologist/entomologist get a C in calculus).

[vina]

For any orbiting body - the total energy (KE+PE) would be constant. If you then "split" the body into 2 parts (like a launcher and payload separating) then the total energy of the two bodies would still be constant - but the energy that was stored in the spring or payload separation jet would be added to the KE of both bodies.

HakimJi, the total energy is conserved alright, but note however that total energy need not be just KE and PE. Take the case of a shell doing soosai and splitting in half. In addition to the energy of the two halves, it generates noise, creates shock wave, generates light etc, so you need to account for all that in the energy equation .

That is why, if in the Shell Soosai example, if you take the law of conservation of energy , but take total energy to mean PE + KE alone (without accounting for all forms of energy some examples I mentioned) , you will get the wrong answer. However, note that Momentum is conserved as well and since that is purely a function of velocity and impulse , applying that will give the correct answer for the Shell Soosai problem, since it is "complete" in itself.

Just as in shell soosai, applying conservation of energy in the spring separating the two halves case would be erroneous. The spring when it expands probably experience temperature change, some energy loss due to vibration etc. etc and you can't account for all that in your energy balance equation. However, momentum is conserved as well, and applying conservation of momentum will give you the right answer.

[disha]

Ok folks thanks for all the inputs about payload separation and orbits and energy. However I get one more doubt - it would be easier to ask with a diagram but I will try.

What I want to know is whether the two bodies would then gradually move apart over time because they are both in separate orbits or would they end up orbiting at a constant distance from each other?

Without going into complex equation etc., just want to give a different context. Let us say you shoot a bullet from the center of earth to center of moon. You are precise sharpshooter, but on that particular day - you are off by 1 cm (0.01 m). How far do you think you will be off from the center of the moon when your bullet hits it? By several kms. Just keep that in perspective. Similarly the orbits even for a small delta-V will have large distances.

Also in your question - assuming, the mass and velocity are imparted in such a way that both the orbits are circular then yes - they will be constant distance from each other.

However, all orbits have different dynamic pressures acting on them. Gravitational anamolies (there is one right under Sri Lanka), expansion of earths' atmosphere for LEO, pressure from solar wind etc will degrade the orbits and hence it will never be constant unless compensating forces are applied to keep it constant.

That is why, 40-50% mass of all satellites have propellants/engines for 'orbit maintenance'. This determines the life of the satellite. And hence research in electric motors (ion thrusters for ex) since they have a very high Isp compared to chemical motors. This will save considerable weight of the satellites.

This is interesting., for example with current tech - GSAT is say 2000 Kg and 800kg of it is propellants and engines (conservatively)., now if it is replaced by say a NEXT class of Ion thrusters (assuming 20x ISP compared to chemical rockets), the same upkeep engine will now be 40 kgs! So now for the same capacity GSAT, it is 1240 Kg. launchable by PSLV. Or with heavy lift vehicles - a more capable (say more transponders) can be packed in.

[disha]

One of Buzz Aldrin's seminal papers in MIT was to establish the method for orbital rendezvous. If you impart velocity to an object in orbit it will not approach another body but will instead obtain a higher orbit. The reverse occurs during slowing. That us why for orbital rendezvous if you want to catch up to another body in space you must either be at a lower orbit and increase your velocity to approach the body at ... You cannot approach or eject in a straight line ie point or shoot. That is why you have vbar and zbar approaches.

In other words., even in orbit-to-orbit maneovres, the trajectories are parabola (not a straight line)*

The reason is simple, both the bodies are still falling towards the earth, and hence whatever they shoot, follows a parabolic trajectory under the gravitational influence of earth.

*PS: That is why I never liked the movie Gravity. All wrong sciences. So was Martian.

Added later: The way solar system depicted with planests laid down horizontally is wrong. It should be depicted as planets falling towards the sun with sun at the base (or a vertical representation). This also makes it easier to understand how the trajectory of inter-planetary vehicles is determined. For example, think of MOM being thrown "up" to mars and if it does not slow down near mars and starts falling towards mars, it starts falling back towards sun. The trajectory from earth to mars of Mom was elliptical and never a straight line.

*PPS: There is no true up or down in space. Up or down is always relative.

[JayS]

This is interesting., for example with current tech - GSAT is say 2000 Kg and 800kg of it is propellants and engines (conservatively)., now if it is replaced by say a NEXT class of Ion thrusters (assuming 20x ISP compared to chemical rockets), the same upkeep engine will now be 40 kgs! So now for the same capacity GSAT, it is 1240 Kg. launchable by PSLV. Or with heavy lift vehicles - a more capable (say more transponders) can be packed in.

Precisely for this reason GSLV will be very well placed for launch market for communication satellites in coming future, in my opinion. The 4ton class satellites are expected to come to 2ton class with next gen propulsion systems. There will be choice of keeping same weight with high on-station life or reducing weight significantly for same life. GSLV could perhaps launch 2 of these next gen satellites at a time.

BTW Martian was still better than Gravity. I was laughing like crazy while watching Gravity.

[shyamoo]

The audio book was even better.

Returning back to the question regarding the effect of forces on the satellite and the launcher, it was mentioned that the effect on the launcher would be negligible. But in space, nothing is negligible. If you can have an ion thruster accelerate satellites across space, wouldn't the spring provide a lot more accelerate. I understand the fact the it would not be a sustained one one, but nevertheless, the is a finite amount of energy imparted to the launcher. Essentially, only the potential energy in the spring is converted into kinetic energy and should transferred to both the objects equally.

Moi is no tfta iit jee fundoo nor could have eligible to be one. But, is my question valid or is my assumption of how ion thrusters work incorrect

[member_28108]

Ion thrusters lsp is slow but steady a spring gives one shot and that's it.ion thrusters are to fire for much longer time and that is how they can theoretically reach stupendous velocities but not rapidly but over a very vetylong time

[Gyan]

GTO satellites using ION thrusters (called all electric sats) are half the weight of normal satellites but take 6 months to reach their earmarked position.

[disha]

The audio book was even better.

Returning back to the question regarding the effect of forces on the satellite and the launcher, it was mentioned that the effect on the launcher would be negligible. But in space, nothing is negligible. If you can have an ion thruster accelerate satellites across space, wouldn't the spring provide a lot more accelerate. I understand the fact the it would not be a sustained one one, but nevertheless, the is a finite amount of energy imparted to the launcher. Essentially, only the potential energy in the spring is converted into kinetic energy and should transferred to both the objects equally.

Moi is no tfta iit jee fundoo nor could have eligible to be one. But, is my question valid or is my assumption of how ion thrusters work incorrect

No sir., not just valid but you bring up an important question.

A spring loaded mechanism will give it a short burst of huge initial accelaration and the body is on a sustained velocity with no new addition of accelaration. While an ion engine gives a very small accelaration, but continues to do so and the net gain in accelaration over time is more than the huge initial accelaration provided by the spring loaded mechanism. This gives it more velocity than the spring loaded mechanism.

And hence I mentioned earlier, that sats are 'kicked out'. But once the sats are kicked out, they come under other pressures that degrade their orbit and they need to get back into the right orbit. So either Sats fire chemical based rocket engines from time-to-time and correct their orbit or they continuously fire their ion engines to maintain their orbit!

Also check out a thrusters Isp or specific impulse or just 'efficiency measure'.

Writing it this quick (and the iit-jee wallahs will tear it apart, but again the goal is to convey this in simple language). Put it this way., you take a rock and hit it hard. You are imparting some force that will either shatter or crush the rock. Or you put the rock in a clamper and every day, you just put a small additional sustained force positively increasing by a small margin everyday. The rock will still shatter or get crushed. Now for the former case you might have to spend say F to bring down the hammer hard., but for the later case you might just have to put a very smaller 'f' to turn the clamper. The later becomes more efficient. Again this analogy is just to highlight various approaches.

In case of rockets, if engine A spends X amount of fuel to impart A accelaration and another engine B spends x (where X>x) to impart the same A accelaration., which is efficient? (engine . Specific impulse is just a measure of that efficiency.

Specific impulse of the latest research (4-grid electrostatic) ion thruster is around 20,000 sec while that of a liquid motors (LAMs on sats) is around 400 s. The difference is 50x! Or a NEXT ion-thruster is 4000s (which is 10x better than LAM).

One of the downsides is the actual thrust from ion engines. For example NEXT ion engines give you only 200 mN while the space shuttle booster produced 15 MN. Basically, the ion engine will give you bahut-chota-dhaka (like a baby's punch) while that of space shuttle booster will give you bahut-bada-dhaka (like a gabbar singh's punch., note the scale is still disproportional).

[disha]

Upcoming launch schedules to watch for:

1. September GSLV-Mk-II-F05
2. December 2016/Q1 2017 - GSLV-MKIII-D1

[SSSalvi]

Whooa MODs.
Hats off to you. It must have been a daunting task to restore so much activity over the years.
Glad to get the daily manna back. Thanks

[Varoon Shekhar]

Yes, the GSKV with Insat 3d is upcoming, and eagerly awaited! Though it has been delayed, without comment, from August 28th.

The "Scatsat" launch with PSLV was also supposed to be launched in August( originally, July) and that too has been delayed until Sept.

What happened to Resourcesat 2A? Has that been sidelined until further notice? There was originally supposed to be two PSLV launches in the summer, one with Scatsat, the other with Resourcesat. Or will both these go up in a single mission?

Also, the RH-560/ATV scramjet test should have taken place by now. Perhaps the An-32 wreckage search in the Indian Ocean has a lot to do with its delay.

[Mollick.R]

It's being more than 3 months that last sat of IRNSS being launched successfully. I guess final orbit raising maneuvers are also finished by now & the satellite is in it's final desired orbit.
However presently there is no news about incorporating (mandatory or otherwise) IRNSS compatible chips in mobile handsets sold in India. Is there anything happening on that front ? Any guidelines/whitepapers or proposed legislatures ????

I think if ISRO/GOI can play it's card well & bargain with proper "stick" they they may manage to bring Reliance Jio (i.e their LYF brand) on board in the issue & make them start selling their upcoming handsets with inbuilt IRNSS chips.
Any updates ??

[Mollick.R]

In continuation to above post following are my observations :-

1. It's a great technological achievement that India being able to conceive,develop & successfully put in place a complex satellite navigation system like IRNSS, however it is equally important for organisation (here state) to push with all might for its deployment in market. i.e proper marketing , arm twisting & lobbying tactics.
We see same example in case of VHS vs Betamax, GSM vs CDMA, HDDVD vs BlueRay & Android vs Windows.
I was not the format/standard which was technically superior which won, but those battle were won by the one which used above mentioned tricks.

2. In this regard China provides some clue to us, look at the way they have created & promoted Baidu & Weibo (goggle & twitter substitutes respectively). I'm sure when their Compass system is fully ready they will use same tricks again & promote it & thus retain control over use of this tech in their territory.
3. I hope ISRO/GOI/Antrix corp. is working with a long term vision & proactively in this issue & we see some concrete movement in upcoming days.

[Bheeshma]

Other than china no where are their crappy baido or weibo used. Its easy when you censor everything. In outside world it fails miserably. But agree with first point.

[Mollick.R]

Sir, i do accept your point & know technically there can be no comparison between power/effectiveness of Goggle's algo & that of Baidu, or user experience of twitter vs Weibo. Neither those two services I refered have any global user base. Yes they are very limited & specific to China.
However my point was for the time being China being able to use sham-dam-dand-bhed to promote & guard their homegrown tech & thus due to market dominating position of them retains bargain power with western companies. In the mean time it is allowing them to refine & polish their tech too, perhaps in future if they ever choose to or forced to open their market they may play with western companies on equal terms.

In India too in recent past we have seen what we can achieve with proper backing power of state in case of RuPay cards (promoted by NPCIL). It did forced Visa/MsterCard to come to negotiation table.

http://articles.economictimes.indiatime ... han-yojana

http://www.ibtimes.co.in/mastercard-vis ... WHrf46J.97

Here I was discussing about using same arm twisting & state backing for promotion of IRNSS. With our huge 1.25 bn market already opened for tech giants we must have some say for support of our homegrown tech.
Even playing by WTO rules there must have different innovative methods (tariff or non tariff based barriers etc) to seek their (chip & handset manufactures) support for IRNSS.

Just my 2 paisa.

[Bheeshma]

I am not disagreeing but I am just saying I would like IRNSS not just limited to India but atleast entire SAARC and even South east asia and middle east/Gulf.

[Kakarat]

NAVIC as IRNSS is called now should be expanded to cover from Iran to south china sea and eventually Global. I feel NAVIC will be definitely backed by the current government and is needed by our Armed forces also

[Mollick.R]

As per this IRNSS coverage map, present constellation with 7 sats is sufficient for covering Iran, however i doubt whether it can cover entire of SCS.
Sir, what you say SCS is in full reach of IRNSS ??

[Ashokk]

Russia passed a law in 2013 forcing the mobile handsets producers to incorporate GLONASS support in all handsets sold in Russia. We should do the same.
GLONASS to Be Required for Phones Sold in Russia

Phones sold in Russia will have to use GLONASS or GLONASS + GPS as of 2014, according to a report from the Voice of Russia. Phones with only GPS will be illegal in Russia, and any mobile devices imported will have to support GLONASS.

[Kakarat]

As per this IRNSS coverage map, present constellation with 7 sats is sufficient for covering Iran, however i doubt whether it can cover entire of SCS.
Sir, what you say SCS is in full reach of IRNSS ??

To my understanding thats the map of satellite signal availability region and some ground stations are required for positioning and Navic is currently available only in India and 1500km around it. Please correct me if I am wrong

[Mollick.R]

I'm also not sure whether mil grade signals of IRNSS further requires ground stations to improve its accuracy or not. Perhaps disha garu, vina garu or any other senior member can throw some light on the topic.

http://pib.nic.in/newsite/PrintRelease. ... lid=137666

According to above press release India is on the path of establishing a satelight tracking centre at Hanoi Vietnam.

India, is working towards the establishment of a Satellite Tracking & Data Reception Station and Data Processing Facility in Vietnam for ASEAN Member countries. This facility is intended to acquire and process Indian Remote Sensing Satellite data pertaining to ASEAN region and disseminate to ASEAN Member countries.

This only mentions about satellite tracking centre, there is no mention about whether it could be an IRNSS ground station or not.

Another One --------

http://in.reuters.com/article/india-vie ... NKCN0V309W

The Reuter report however raises questions about possibility of this centre having any notable military value.

Chinese Foreign Ministry spokeswoman Hua Chunying told a regular briefing that Beijing hoped the facility "will be able to make a positive contribution to pushing forward relevant cooperation in the region". China's Defence Ministry said the proposed tracking station wasn't a military issue.

May be the underlined part being said by lizard spokesperson to downplay the incident & save their H&D.
But i do think once India builds such a facility at Vietnam, in future if requirement arises we may (easily ??) get permission to build IRNSS ground station too.

[ManSingh]

For what it's worth..

The below shows the coverage of IRNSS on June 30th ( before BR went offline ) at around 12.00 AM EDT. Created using publicly available satellite location data from NORAD and gpredict software.

http://imgur.com/Eximbjk

Some interesting observations( though I am no expert ):

1) China does not seem to be fully covered, atleast not at this time.

2) American continent has no reception at all.

Note to mods: Please help modify the post for the image is not showing correctly with img tag. This is my first post with an image. Hopefully I can get it correct next time.

[prasannasimha]

There was some data from one of the periarctic countries (I think it was Finland) where they used the IRNSS data to determine acuracy and the area and range is much larger than what ids depicted because of the accuracy obtained by the data .

[kit]

has india any ongoing research into quantum communication tech ? satellites?

[prasannasimha]

The decrease in launches may be due to the monsoon. The scramjet test was delayed because of the searhc operations after the naval aeroplane crash.