Indian Space Programme Discussion - Sept 2016

The Military Issues & History Forum is a venue to discuss issues relating to the military aspects of the Indian Armed Forces, whether the past, present or future. We request members to kindly stay within the mandate of this forum and keep their exchanges of views, on a civilised level, however vehemently any disagreement may be felt. All feedback regarding forum usage may be sent to the moderators using the Feedback Form or by clicking the Report Post Icon in any objectionable post for proper action. Please note that the views expressed by the Members and Moderators on these discussion boards are that of the individuals only and do not reflect the official policy or view of the Bharat-Rakshak.com Website. Copyright Violation is strictly prohibited and may result in revocation of your posting rights - please read the FAQ for full details. Users must also abide by the Forum Guidelines at all times.
vasu raya
BRFite
Posts: 1599
Joined: 11 Aug 2016 06:14

Re: Indian Space Programme Discussion - Sept 2016

Postby vasu raya » 10 Sep 2017 05:44

vasu raya wrote:They have predicted two months of orbiting before the last stage hits the lower atmosphere, so instead of helplessly watching, can they use the exo version of the ABM, the PAD to pepper special sharpnel so they get embedded into the payload fairing which is mostly random, special in the sense they are charges with accelerometers that can be triggered from a ground station.

once attached one can study the accelerometers data from each charge and try to correct the tumbling as well as split open the fairing by selectively choosing the charges to explode. In the next stage they can use the electric thrusters as I believe the fuel is depleted, even if it takes 6 months to a year to reach its designated spot.


At its perigee of about 120km it is with in reach of the PDV, and the sat is in a known orbit, if this perigee happens to be over the ocean at a specific time one has to place the OPV there provided the PDV can be fired from the OPV and you have two months time to sail to position

one can make it a ASAT with the resultant debris closer to the atmosphere which has a lesser lifetime

or if one can manage a custom warhead on the PDV, there is nothing like it

srinebula
BRFite
Posts: 123
Joined: 12 Oct 2016 13:36

Re: Indian Space Programme Discussion - Sept 2016

Postby srinebula » 10 Sep 2017 21:17

Someone on twitter was suggesting a similar approach, saying this is our god given opportunity to test an ASAT. Apparently there is precedence: US knocking out one of their sats because it was "misbehaving" and would have become "harmful" for other satellites.

Prasad
BRF Oldie
Posts: 6804
Joined: 16 Nov 2007 00:53
Location: Chennai

Re: Indian Space Programme Discussion - Sept 2016

Postby Prasad » 10 Sep 2017 21:41

Indranil wrote:^^^ Will the above movie also have Liv Tyler, If yes, I will love to watch it too.

:rotfl: :rotfl:

vasu raya
BRFite
Posts: 1599
Joined: 11 Aug 2016 06:14

Re: Indian Space Programme Discussion - Sept 2016

Postby vasu raya » 10 Sep 2017 21:53

Xi Eleven should offer to use his ASAT to take down the tumbling Indian sat, that will settle it :rotfl: :rotfl: :rotfl:

disha
BR Mainsite Crew
Posts: 6330
Joined: 03 Dec 2006 04:17
Location: gaganaviharin

Re: Indian Space Programme Discussion - Sept 2016

Postby disha » 11 Sep 2017 03:50

Indranil wrote:^^^ Will the above movie also have Liv Tyler, If yes, I will love to watch it too.


Definitely not with her dad singing. Maybe Lana Del Ray singing nasally will make it more interesting.

IMHO., ISRO will treat this as another space debris and will calculate its re-entry and see if the real values match the calculations. This will give ISRO ample chance to fine tune its re-entry algorithms. In this particular case., the space-debris will be more interesting., since the heat-shield may still end up doing a good job on re-entry!!!

Indranil
Forum Moderator
Posts: 6656
Joined: 02 Apr 2010 01:21

Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 11 Sep 2017 04:06

^^^ Did not think about it. That is a problem. But only if it enters in a particular orientation. Otherwise the structural loads/temperature will get too high, won't it?

vasu raya
BRFite
Posts: 1599
Joined: 11 Aug 2016 06:14

Re: Indian Space Programme Discussion - Sept 2016

Postby vasu raya » 11 Sep 2017 20:13

talking about building blocks, here are some proven concepts that should aid in exploration

3D printed miniature sat to talk to ground stations
http://indianexpress.com/article/technology/science/india-creates-history-as-nasa-launches-worlds-lightest-satellite-designed-by-tamil-nadu-student-4717886/

the comet lander design, carries a solar powered reaction wheel too
https://en.wikipedia.org/wiki/Philae_(spacecraft)

the exo kill vehicle, one hopes the DRDO is working on it in secret, can be used to stabilize the spacecraft, random placements of the landers may need gimbaled thrusters
https://www.youtube.com/watch?v=KBMU6l6GsdM

if the atmospheric touchdown isn't within the range of the radar at Bylalu, here is tracking ship in support of BMD phase 2

https://www.livefistdefence.com/2017/01/revealed-indian-navys-next-advanced-technology-vessel.html

if one doesn't believe that these can be put together in a short timeframe, we will have to wonder where the ASAT stands since it was said all building blocks exist for it and its a matter putting them together.

and if one can manage changing a sats orbit from step 3, ASAT would be about nudging a sat towards the earth's atmosphere and not worry about debris of in place explosion

SSridhar
Forum Moderator
Posts: 22670
Joined: 05 May 2001 11:31
Location: Chennai

Re: Indian Space Programme Discussion - Sept 2016

Postby SSridhar » 23 Sep 2017 14:47

Pyro devices to blame for PSLV failure: ISRO - The Hindu
The Indian Space Research Organisation (ISRO) has come round to the inference that the PSLV C-39 mission on August 31 was doomed by the failure of the pyro devices that actuate the separation of the heat shield encasing the satellite from the rocket.

A high-level meeting chaired by ISRO chairman A.S.Kiran Kumar held at the VSSC here on Friday came to the conclusion on the failure of the pyro devices. The meeting was informed that simulation exercises were on to ascertain the reason for the malfunctioning of the pyro devices.

‘Component isolated’

“We have isolated the component responsible for the failure of the mission but it remains to be established why it failed to function,” VSSC Director Dr. K.Sivan said. “We are testing various versions and hope to arrive at a consensus in seven to 10 days”. The exercises are expected to help the scientists analyse the failure from various angles.

ISRO had declared the PSLV- C39 mission unsuccessful after the heat shield refused to open and release the IRNSS-1H navigation satellite on board. The failure review committee set up by ISRO had zeroed in on the electrically-operated pyro devices as the culprit after it was found that the command for separation had gone through but failed to trigger the mechanical process that pops open the heat shield.

Pyro devices use small charges to actuate the release mechanism that forces the fairings apart.


Mort Walker
BRF Oldie
Posts: 6821
Joined: 31 May 2004 11:31
Location: The rings around Uranus.

Re: Indian Space Programme Discussion - Sept 2016

Postby Mort Walker » 23 Sep 2017 23:57

So this means the fairing separation mechanism is working correctly and it’s just pyro devices. I’m not familiar as to how these pyro devices are actuated. The signal comes in and activates an electro mechanical switch to ignite the pyro charges?

Kartik
BRF Oldie
Posts: 3861
Joined: 04 Feb 2004 12:31

Re: Indian Space Programme Discussion - Sept 2016

Postby Kartik » 26 Sep 2017 03:55

From AW&ST

India considers dedicated satellite or satellites to monitor Chinese border

India Considers Satellite To Aid Border Patrol Missions

After a summer of scuffles with China along the Tibetan border, India is considering development of a satellite to improve surveillance.

“It is just a preliminary idea. The government has shown interest in having a dedicated satellite bandwidth for the Border Security Force and Indo-Tibetan Border Police, among others, for improved border observation,” says an official at the state-run Indian Space Research Organization (ISRO).

[India may add to its set of weather satellites to develop one that can keep closer watch over its border with China. Credit: ISRO]
India may add to its set of weather satellites to develop one that can keep closer watch over its border with China. Credit: ISRO

The purpose is to support the armed forces, check infiltration, map terrain and communicate effectively in remote areas, he explains.

“Concerned parties” are discussing whether to use a single satellite or multiple ones to monitor activities along the border, the ISRO scientist adds.

To step up surveillance, the Indian government also is providing night-vision devices, thermal imagers, surveillance radars, direction finders, unattended ground sensors and high-powered telescopes.

—Jay Menon in New Delhi

ramana
Forum Moderator
Posts: 49799
Joined: 01 Jan 1970 05:30

Re: Indian Space Programme Discussion - Sept 2016

Postby ramana » 26 Sep 2017 09:47

ramana wrote:The PSLV issue looks like ordnance for shroud separation failure. Could be in installing the ziptube in the shroud.



My own post on 31 August.

sum
BRF Oldie
Posts: 9763
Joined: 08 May 2007 17:04
Location: (IT-vity && DRDO) nagar

Re: Indian Space Programme Discussion - Sept 2016

Postby sum » 08 Oct 2017 14:23

Saw a FB post on ISRO joining hands with Raman institute (RRI) to develop a quantum comms satellite

Any more info on this and how far are we in this field?

saumitra_j
BRFite
Posts: 330
Joined: 24 Dec 2005 17:13
Location: Pune, India

Re: Indian Space Programme Discussion - Sept 2016

Postby saumitra_j » 08 Oct 2017 14:29

sum wrote:Saw a FB post on ISRO joining hands with Raman institute (RRI) to develop a quantum comms satellite

Any more info on this and how far are we in this field?

Sirji, check Sourav Jha's twitter for more info.

prasannasimha
Forum Moderator
Posts: 738
Joined: 15 Aug 2016 00:22

Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 08 Oct 2017 23:25

Seems the quantum enanglement thing has also been reproduced by ISRO/Raman research Institute

Amber G.
BRF Oldie
Posts: 6014
Joined: 17 Dec 2002 12:31
Location: Ohio, USA

Re: Indian Space Programme Discussion - Sept 2016

Postby Amber G. » 10 Oct 2017 02:50

^^^ I have seen little technical details except tweet:
From Raman Research Institute "joins hands with ISRO to develop satellite based secure quantum communications for the first time in India!"
I like this text-book by Mermin, (used in graduate-level course in Cornell) and think it is very good for:
- someone who is a computer scientist (with little background in Quantum Physics).
- Or someone who knows quantum physics but is does not know what quantum computing is)

SSSalvi
BRFite
Posts: 581
Joined: 23 Jan 2007 19:35
Location: Hyderabad
Contact:

Re: Indian Space Programme Discussion - Sept 2016

Postby SSSalvi » 10 Oct 2017 21:53

Even GSLV Mk III-D1/GSAT-19 mission brochure did not ever mention about a 3D printed antenna. But it does seem to have one.

https://www.facebook.com/indianspaceinvestigators/posts/403893833359396

( Careful .. no references given .. only reproduction of contents )

BTW this seems to be a test antenna because there is no 300mm antenna aboard as per brochure. ( There is a 1.4M and a 2M antenna as per brochure ).

======

Update : after communication, they have given following source : https://m.all3dp.com/india-space-resear ... ter-orbit/

Amber G.
BRF Oldie
Posts: 6014
Joined: 17 Dec 2002 12:31
Location: Ohio, USA

Re: Indian Space Programme Discussion - Sept 2016

Postby Amber G. » 14 Oct 2017 02:25

Slightly OT but may be this discussion may come here in 5 years from now - announcing the launch of an observatory !

You heard it here first!

My Paanwala says: Chandra X-ray observatory (Named after S. Chandrasekhar) is going to be in News BIG time..

If I am right about the rumors I am hearing - wait for the announcement by LIGO Team at 7 AM (California Time) on October 16.
(It seems that CXO noticed a pulse when two Neutron stars merged and which may be officially confirmed by Gravitational Wave team and may be even by another optical telescope)... Stay tuned.

If true, and I think it it, it is really a BIG Deal.

(Chandra x-ray observatory initially launched with a life expectancy of 5 years but it is still going strong after almost 20 years. I hope the next version is launched by ISRO or ISRO/NASA..Specially when ESA/NASA/JAXA have been a canceled few times, I think they plan it for 2028 - May be ISRO offers to launch it's own advance version of such telescope before this. )

Small tidbit for those who may not know this - Chandra's original name was AXAF( Advanced X-ray Astrophysics Facility) it got renamed Chandra X-ray Observatory (CXO), after a naming contest- after the Nobel Prize winner S. Chadrasekhar. Naming contest was won by, IIRC, a high-school student. (I still have a nice poster from MIT depicting the observatory :)

VenkataS
BRFite
Posts: 235
Joined: 02 Apr 2010 03:38

Re: Indian Space Programme Discussion - Sept 2016

Postby VenkataS » 14 Oct 2017 02:47

Amber G. wrote:If I am right about the rumors I am hearing - wait for the announcement by LIGO Team at 7 AM (California Time) on October 16.
(It seems that CXO noticed a pulse when two Neutron stars merged and which may be officially confirmed by Gravitational Wave team and may be even by another optical telescope)... Stay tuned.

If true, and I think it it, it is really a BIG Deal.


Layman question here, why is noticing a pulse of two neutron stars merging such a big deal?

Amber G.
BRF Oldie
Posts: 6014
Joined: 17 Dec 2002 12:31
Location: Ohio, USA

Re: Indian Space Programme Discussion - Sept 2016

Postby Amber G. » 14 Oct 2017 03:25

VenkataS wrote:

Layman question here, why is noticing a pulse of two neutron stars merging such a big deal?

I will answer this in Physics dhaga in more details and discussion may move there.. But few points...

Gravitational waves, for which Nobel Prize was awarded this year, is certainly one of the biggest discovery of modern times -- A new way to see universe. (If more details needed - check out Gravitational Waves or LIGO in wiki or things like that). It is akin to discovery of the first telescope 400 years ago -- to look at the sky using light (Electro-magnetic waves). First time in history of human kind, we can use another fundamental force (gravitational waves) to explore the universe.

Up till now, all gravitational waves discovered have been due to merging of two black holes - which you can not see directly using a telescope.

Merging Neutron stars also produces gravitational waves. They can also be seen via x-ray (or gamma-ray) telescope, or even optical telescope (Hubble might too have confirmed this particular event). So if LIGO detected it, and it is confirmed by Chandra.. it is a big deal.. (Means more confidence in LIGO).

Anyway let us wait till October 16.. then every newspaper will be talking about this :).

Edited later: This may be helpful - talks about neutron stars and why this is exciting news .. Astronomy without light
Last edited by Amber G. on 14 Oct 2017 03:50, edited 1 time in total.

Amber G.
BRF Oldie
Posts: 6014
Joined: 17 Dec 2002 12:31
Location: Ohio, USA

Re: Indian Space Programme Discussion - Sept 2016

Postby Amber G. » 14 Oct 2017 03:29


Amber G.
BRF Oldie
Posts: 6014
Joined: 17 Dec 2002 12:31
Location: Ohio, USA

Re: Indian Space Programme Discussion - Sept 2016

Postby Amber G. » 14 Oct 2017 06:33


Layman question here, why is noticing a pulse of two neutron stars merging such a big deal?

Have to post this answer from recent Wired Magazine -- !!!!

WHAT HAPPENS WHEN TWO NEUTRON STARS COLLIDE? SCIENTIFIC REVOLUTION
“If the detection is true, it would be transformative for the field and probably one of the greatest discoveries in astronomy,” said Enrico Ramirez-Ruiz of the University of California, Santa Cruz, who refused to discuss any specific results.

This is why I was saying it is a BIG deal!

ArjunPandit
BRFite
Posts: 1114
Joined: 29 Mar 2017 06:37

Re: Indian Space Programme Discussion - Sept 2016

Postby ArjunPandit » 14 Oct 2017 07:37

Why Indian astrosat is not used for this

Amber G.
BRF Oldie
Posts: 6014
Joined: 17 Dec 2002 12:31
Location: Ohio, USA

Re: Indian Space Programme Discussion - Sept 2016

Postby Amber G. » 14 Oct 2017 10:21

ArjunPandit wrote:Why Indian astrosat is not used for this

I knew some one will mention this!! :) I think it is being used. It is ideal in the sense that it gives Indian scientists faster and guaranteed access to the information as I think they have privileged access and some are excited about studying neutron stars from India (without having to wait for international support). Also according to some experts in one particular case Astrosat may be better than Chandra for detecting short-lived bursts of X-rays -- the kind LIGO is looking for.

Actually rumors are there and speculation is there for Astosat . LIGO team is tight-lip about it, and in all fairness we can wait in our speculation. (More optical /x-ray telescopes may be involved - we will know soon enough. :)


Also I believe, one of the things Astrosat is being used is to do "timing studies" of X-ray binaries..difference in timing is another way to study Gravitational waves ... more of this can be continued in physics dhaga.

(BTW IIRC it was in Indian newspapers - recent massive coronal explosion on the nearest planet-hosting star was observed by Astrostat (along with Chandra and Hubble)

disha
BR Mainsite Crew
Posts: 6330
Joined: 03 Dec 2006 04:17
Location: gaganaviharin

Re: Indian Space Programme Discussion - Sept 2016

Postby disha » 14 Oct 2017 22:33

VenkataS wrote:Layman question here, why is noticing a pulse of two neutron stars merging such a big deal?


Let's say., we are all cave people huddled in a cave on a stormy night and thunder claps are going around. There is the sudden light and sound, but several going around there is sound and light show or light and sound show depending on who you ask.

Several theories come through. Like there is the god of thunder like Indra wielding his vajra and fighting against asuras or Thor welding his hammer etc. For each theory., there should be a logical explanation to validate it. Now the search is on for finding the logical explanation. Is it Indra or is it Thor?

Imagine the excitement *you* will feel if you have a theory either which way and then the tools come through (or people going in search and report on their findings) which will lead to a conclusion.

Now add to it that the thunder claps are rare but when they do occur they are awesome and powerful to the observer. You are super-excited.

That is the excitement physicists are having. Currently we observe gamma ray bursts. They are powerful., very very powerful events. There were several theories on this but one of the leading theory (and now confirmed) is that two neutron stars colliding cause this event. You will observe gamma ray burst and simultaneously observe gravitational waves.

Imagine you observe a thunder followed by clap and are able to calculate relative speed of sound to light., that knowledge is revolution. But for the rest., they wonder what the hoo-ha is all about.

Similarly now you have a theory which is confirmed logically. More importantly observing this events is rare and here you have two simultaneous and different type of observation for the same event. Hence the excitement.

Amber G.
BRF Oldie
Posts: 6014
Joined: 17 Dec 2002 12:31
Location: Ohio, USA

Re: Indian Space Programme Discussion - Sept 2016

Postby Amber G. » 20 Oct 2017 11:07

Amber G. wrote:Slightly OT but may be this discussion may come here in 5 years from now - announcing the launch of an observatory !

You heard it here first!

My Paanwala says: Chandra X-ray observatory (Named after S. Chandrasekhar) is going to be in News BIG time..

If I am right about the rumors I am hearing - wait for the announcement by LIGO Team at 7 AM (California Time) on October 16.
(It seems that CXO noticed a pulse when two Neutron stars merged and which may be officially confirmed by Gravitational Wave team and may be even by another optical telescope)... Stay tuned.

If true, and I think it it, it is really a BIG Deal.

<snip see the post above>


Of course!

Announcement did happen on October 16, and it was the biggest scientific news of our time! It has been the front page news of virtually every newspaper, science magazines, etc[ .

On August 17, Chandra X-ray observatory, (along with others) noticed the GRB (Gamma Ray Burst) 2 seconds after the GW event as expected, soon the word got around. 70 other observatories, in every spectrum (from visible, xray, UV, Radio) were able to notice the same event. Thousands of Scientists worked as a team, and when everything checked out, announced the big news on October 16th.

Physics dhaga has more details, so many good links, such as:http://www.gw.iucaa.in/news/gw170817/
(Nice article from IUCAA from Indian perspective (thanks Badeji) is above. )

Of course, contribution from Astrosat (as I said it's very nice CZTI), and other Several Indian telescopes like the AstroSat, Giant Meter wave Radio Telescope, Himalayan Chandra Telescope each played a very powerful and significant role. Congrats to all.

Several scientists, including friends, specially from IIT (Various IIT's) CMI , ICTS-TIFR, IISER IUCAA-Pune, RRCAT-Indore, TIFR-Mumbai, just to name a few deserves kudos!

***

India's Astrosat deserves special mention here, as I have not seen this in Indian newspapers (Scientific papers came out after October 16, has a lot more details)

- In previous big GW event (Feb 2017), optical telescopes saw something which was in the same general area as GW prediction but Astrosat's said a firm NO - It detected GBR (thus proving that it's CZTI is quite good) but GBR it detected was after 21 later than GW event. (and not within seconds of GW). Pointing the fact that the bright source noticed by optical telescopes was unrelated to black hole merger.

- Last event - was different story - History is made!
- GW detectors in US registered a very long and strong signal. (suspecting that it was neutron star merger)
- Around the same time (within seconds) Fermi satellite had detected a GRB at the same time: in fact within a couple of seconds of the GW event. So did INTEGRAL. Astorosat did not - although CZTI was good enough to record it - so conclusion was it was not visible from Astrosat (Earth was blocking the gamma rays). This help localized to source.
- Around this time, data was analyzed from VIRGO, which helped more..
- Within hours dozens of other telescopes saw and pinpointed the exact location. (With that info, a good amateur telescope would have been able to see the merged NS).
India's Astorsat has been quite impressive.

manish singh
BRFite -Trainee
Posts: 59
Joined: 10 Dec 2007 13:20

Re: Indian Space Programme Discussion - Sept 2016

Postby manish singh » 20 Oct 2017 15:09

Apologies if posted earlier:

http://www.isro.gov.in/update/17-oct-2017/astrosat-contributes-to-saga-of-gravitational-wave-astronomy

Oct 17, 2017
AstroSat contributes to the saga of Gravitational Wave Astronomy


On August 17, 2017, scientists seeking the holy grail of gravitational wave (GW) astronomy struck gold. The elusive and long sought after GW signals from merging binary neutron stars were found and multi-messenger observations provided tell-tale signs of this merger to clinch the issue without any qualms. Two of the GW detectors in the US picked up the signal and a third, working in Europe, confirmed it. Several of the satellites in the sky detected signals from this event across various bands of the electromagnetic spectrum, and a vast array of optical and radio telescopes worldwidetrained their vision into this new phenomenon, finding a variety of corroborating signals.

The AstroSat scientists, who pitched in with their efforts, today stand shoulder to shoulder with a few thousand scientists across the globe (including three Nobel Prize winners and a few scores of other Indian scientists) to announce this momentous discovery and an `open sesame’ moment of staring at the huge cache of scientific discovery that this new era of`multi-messenger, time-domain astronomy’ opens up.

Gravitational Wave Astronomy: the last frontier


Any accelerated electronic charge emits electromgnetic radiation: scientists routinely use this to generate and send electromagnetic waves like radio waves, optical light, and X-rays. Any moving mass disturbs the space time and a `quadropole’ moment in the moving mass should generate gravitational waves: theorised Albert Einstein a hundred years ago. Einstein’s words are treated as Veda Vakya or Gospel Truth, and astronomers routinely use this to understand the dynamics of compact large masses in the cosmos. Russell A. Hulse and Joseph H. Taylor, Jr discovered two radio pulsars going around each other, slowly hurtling towards each other, and they invoked Einstein’s gravitational wave theory to understand their behavour: they were duly awarded a Nobel Prize for this work. This opens up an interesting question-shouldn’t astronomers, who use every branch of electromagnetic radiation from radio to gamma-rays to prise open the secrets of the Universe, use gravitational waves to understand exotic features of the cosmos- like the ripples of the Big Bang or merging of black holes when galaxies collide ?

Well, they should,but the catch lies in the fact that the gravitational force is extremely weaker than the electromagnetic force, and common sense deems that even the most sensitive detectors that humans can build cannot detect the most exotic gravitaional wave sources that we can imagine. However, during the past few decades, a huge number of dedicated scientists have built the most sophisticated detectors capable of measuring infinitesimal movement of mass corresponding to a tiny fraction of a nanometer in kilmoter sized objects so that they would be sensitive to the gravitational waves from outer space. Year after year, they kept looking for signs of merging neutron stars, but the quest was in vain !

Mother Nature usually likes to keep surprises up her sleeve! When the GW detectors with highly improved sensitivity were switched ON in 2015, they found something: not a neutron star-neutron star merger, but a totally unexpected event of two massive black holes merging and spewing out energy equivalent to the complete burning out of mass corresponding to two Suns. This is indeed a momentous discovery, and the architects of this humongous human effort, Kip Thorne, Rainer Weiss, and Barry Barish, duly got this year’s Nobel Prize.

What about the elusive case of the merger of two neutron stars anticipated from the discovery of Messers Hulse and Taylor?During the past two years, four GW events were discovered, however, they were all due to mergers of black holes. The problem with merging black holes is that they are, as apparent from the name, `black’;i.e., apart from the GW events,there are no tell tale signs of the merger in any other branch of electromagnetic radiation. So, we cannot determinewhere they are coming from, or what are their progenitors. This is not the case for neutron star mergers. It was firmly believed that when GW events are discovered from neutron star mergers, they would be accompanied by huge amounts of electromagnetic radiation, which will help us pin down the sources of these events.

The whole scientific community was eagerly waiting for this much anticipated event.

CZT Imager of AstroSat pitches in

AstroSat was launched on September 28, 2015 and the CZT Imager (CZTI) instrument of AstroSat was the first instrument to be made operational. On October 6, 2015, the first day of operation, CZTI detected a gamma-ray burst (GRB) and proved to be an efficient GRB detector. The scientists working with the CZTI data realised that it would be a wonderful instrument to detectany gamma-ray events accompanying the GW sources.

The problem with detecting such gamma-ray events is that they are rare, unpredictable, and can come from any direction in the sky. Hence, the detectors need to have all sky sensitivity, and generally, there is a trade off in their observing capabilities. Currently, there are three sensitive operating GRB monitors, along with a few more less sensitive detectors, each having their own capabilities and limitations. The most sensitive GRB monitor currently operating is the Swift satellite, however, it can observe only one tenth of the sky at any given time. CZTI and the Fermi satellite, on the other hand, are sensitive to much larger regions in the sky, but have very limited capability to localise these events. The anti-coincidence shield of the INTEGRAL satellite, too, can act as a GRB monitor.

Each of these instruments played their part in the race to detect gamma-ray signals accompanying the GW events. During the very first GW event on September 14, 2015 (before the launch of AstroSat), Fermi claimed that it had detected a GRB like event within 0.4 s of the GW event. Observations from theINTEGRAL satellite, however, disagreed: the consensus was that this could be some unrelated spike in the background. During another GW event detected in January 2017, optical astronomers saw, the very next day of the event, some source gradually diminishing in brightness. Could this be the tell-tale signs of something happening in the GW source? CZTI chipped in with a firm No! It had detected a GRB, 21 hours after the GW event. The fading optical source was shown to be this GRB, unrelated to the GW event.

Aug 17, 2017: a red letter day


On August 17, 2017, the much anticipated event occurred.

The GW detectors in US registered a very long series of signals, or `chirps’, closely resembling what the scientists have simulated for decades to be coming from neutron star coalescence. Even before they could announce this discovery, the Fermi satellite had detected a GRB at the same time: in fact within a couple of seconds of the GW event. Could this also be an unrelated background fluctuation event? Very unlikely, because, at exactly the same time, the anti-coincidence shield in the INTEGRAL satellite had also detected this GRB. What about Swift and CZTI? They didn’t detect any! The event should probably be outside the narrow field of view of Swift. What about CZTI? It was active and operating and the GRB should have been detected. The only way to reconcile was to assume that the source was blocked by the Earth: this helped to narrow down the possible source regions of the GW event.

Soon, the GW detectors from Europe too pitched in, and the region of the sky responsible for the GW event and GRB was narrowed down to a small region. Optical telescopes around the world scanned each and every galaxy in this region and, lo and behold, there indeed was a bright optical object, not seen before, near a galaxy called NGC 4993.

The rest, as they say, is history. Soon, infra-red and ultraviolet emissions were seen from this source. Nine days later, an X-ray source was detected, and fifteen days later, radio emission was also observed. From such vast multi-wavelength data, the physics of colliding and merging neutron stars were studied in depth. An exciting find is that the material ejected in the event is rich in heavy elements, so much so that, colliding neutron stars can account for the entire supply of precious metals, like gold, platinum and silver, in the universe. Production of these elements have been difficult to understand, and now the source has been found!

The story of GW170817 bears testimony to the amazing outcome possible when all the world’s best instruments are combined for a single purpose. The collaborative efforts of a number of teams worldwide lends an added credibility to this exciting and substantial discovery and ushers in a new era in multi-messenger, time-domain astronomy!

Scientific curiosity: never satiated

The GW detectors are taking a year off to return with an improved sensitivity. Neutron star merger events and the accompanying `kilonova’ should be fairly common observations during the next run. There should be more of black hole merger events as well. Scientists are already dreaming about the rich future harvests:

Can we get any tell-tale signatures of black hole mergers to identify where they are coming from? Perhaps more sensitive all sky detectors would help with an answer.

Can these events be used as a tool for distance measurement to refine cosmology? A massive collaboration between GW theorists and kilonova observers should be able to do it.

Can we learn anything about the regions close to black hole? Possible.

Are there some strange stars among the neutron stars? Certainly more such objects will tell us. Finally, has Mother Nature more surprises up her sleeve? Only the future will tell us!

What next? Significant next steps will involve making detectors more sensitive, improving localisation capability and most importantly, continued collaboration of observatories worldwide spanning all electromagnetic bands, neutrinos and gravitational waves.

In the Indian space science context, the capability of CZTI would certainly be improved through better algorithms and simulations: it should be possible to independently confirm and localise gamma-ray events for future GW associations. Perhaps, even a much improved CZTI like all sky monitor could be designed and flown!

Multi-messenger studies of GW170817 incorporating the contribution of AstroSat CZTI are published in the journals Science and Astrophysical Journal Letters.

Papers

Illuminating gravitational waves: A concordant picture of photons from a neutron star merger - Science 10.1126/science.aap9455 (2017).
Multi-messenger Observations of a Binary Neutron Star Merger - The Astrophysical Journal Letters, 848:L12 (59pp), 2017 October 20

Amber G.
BRF Oldie
Posts: 6014
Joined: 17 Dec 2002 12:31
Location: Ohio, USA

Re: Indian Space Programme Discussion - Sept 2016

Postby Amber G. » 20 Oct 2017 22:44

manish singh wrote:Apologies if posted earlier:

http://www.isro.gov.in/update/17-oct-2017/astrosat-contributes-to-saga-of-gravitational-wave-astronomy

Oct 17, 2017
AstroSat contributes to the saga of Gravitational Wave Astronomy




Thanks for posting this. Nice write up.
(I did some googling, and did see the above article but not much else in main-stream Indian Media. In fact while newspapers here in US had this news as front-page news, form what I saw, there is/was, very little coverage in Indian Media. I saw some good stories in Gujarti, and Telgu papers but nothing much in Hindi, and English media.)

Please post here, if there are nice articles like this. Thanks.

Amber G.
BRF Oldie
Posts: 6014
Joined: 17 Dec 2002 12:31
Location: Ohio, USA

Re: Indian Space Programme Discussion - Sept 2016

Postby Amber G. » 20 Oct 2017 23:34

Here is press release, of one event which I mentioned a few posts above ..(About how Astrosat was able to help identify a false source. LIGO team of course took all data into account and reported what should have been reported)
(Note that this about the previous GW event, and not the present Neutron Star collision where the GBR source turned out to be correct)
http://astrosat-ssc.iucaa.in/?q=press-release-gw170104Press Release: India's AstroSat catches astronomical imposter
Press Release: India's AstroSat catches astronomical imposter
India’s AstroSat catches astronomical imposter Download PDF

Indian scientists leading an international team of astronomers showed that a new object discovered in the sky, believed to be related to the latest gravitational wave discovery, was in fact an unrelated gamma ray burst.

The LIGO scientific collaboration’s discovery of GW170104 led to a frenzy of activity among partner astronomers around the world, each trying to find any associated explosions in the sky. The Hawaii-based ATLAS group found a source that was in the right place in the sky, and was fading fast – causing excitement all around. But was it really associated with GW170104? Was it the first discovery of an optical source related to a gravitational wave detection? No, according to a study by the AstroSat CZTI team and the international GROWTH collaboration.

While studying observations of the source – named ATLAS17aeu – the team noticed something odd about how fast it was fading. “Analysing the data, I concluded that ATLAS17aeu must be related to some explosion on 5th January, not the 4th”, says Varun Bhalerao (IIT Bombay), the lead author in this study. The team had already used CZTI to look for X-rays coming from GW170104, and not seen any. CZTI (Cadmium Zinc Telluride Imager), a gamma ray telescope on ISRO’s maiden space observatory AstroSat, proved to be the most sensitive instrument in the world to find transient sources with sub-second durations. So if there was another burst in the sky, they were sure they would find it in CZTI data. Varun continues, “I shot off an email to my student Sujay, asking him to search for a burst in CZTI data in the calculated time window. And then I noticed an email from Vidushi (another student) in my inbox: she had found the burst I was looking for!”

The culprit seemed to be a gamma ray burst GRB 170105A – that exploded in the same part of the sky 21 hours later. But to be sure of this, astronomers needed more data. Enter GROWTH: Global Relay of Observatories Watching Transients Happen. This multi-national team had already swung into action, observing ATLAS17aeu with optical, X-ray and radio telescopes. Team member Dipankar Bhattacharya (IUCAA) said, “The team studied the source with radio, optical and X-ray telescopes for a few days, till it faded away into oblivion. Based on its behaviour we concluded that this event signalled the birth of a new black hole when a massive star imploded in a galaxy several billion light years away.”

This gamma ray burst was missed by several other international satellites which were pointing at other parts of the sky at that instant. It was detected only by the Cadmium Zinc Telluride Imager (CZTI) on AstroSat, and by the Chinese-European POLAR instrument. “This is the result of insightful instrument design, imaginative onboard software, and collaborative data analysis from a nationwide team”, says A.R. Rao (TIFR). But the team has its eyes on the prize: finding the first electromagnetic counterpart to a gravitational wave source. And the highly sensitive CZTI might not be enough. Rao adds, “We need wide angle detectors scattered over interplanetary space to discover X-rays from LIGO sources. The CZTI team has proposed a small sized instrument called MOTIVE to ISRO as a likely payload for a future interplanetary mission. Together, CZTI and MOTIVE can revolutionize the field!”

-----------------------------------------------------------------------------------------------------------

CZT-Imager is built by a consortium of Institutes across India. The Tata Institute of Fundamental Research, Mumbai, led the effort with instrument design and development. Vikram Sarabhai Space Centre, Thiruvananthapuram provided the electronic design, assembly and testing. ISRO Satellite Centre (ISAC), Bengaluru provided the mechanical design, quality consultation and project management. The Inter University Centre for Astronomy and Astrophysics (IUCAA), Pune did the Coded Mask design, instrument calibration, and Payload Operation Centre. Space Application Centre (SAC) at Ahmedabad provided the analysis software. Physical Research Laboratory (PRL) Ahmedabad, provided the polarisation detection algorithm and ground calibration. A vast number of industries participated in the fabrication and the University sector pitched in by participating in the test and evaluation of the payload. The Indian Space Research Organisation funded, managed and facilitated the project.

This work was supported by the GROWTH project funded by the National Science Foundation under Grant No 1545949. GROWTH is a collaborative project between California Institute of Technology (USA), Pomona College (USA), San Diego State University (USA), Los Alamos National Laboratory (USA), University of Maryland College Park (USA), University of Wisconsin Milwaukee (USA), Tokyo Institute of Technology (Japan), National Central University (Taiwan), Indian Institute of Astrophysics (India), Inter-University Center for Astronomy and Astrophysics (India), Weizmann Institute of Science (Israel), The Oskar Klein Centre at Stockholm University (Sweden), Humboldt University (Germany). GROWTH is supported by the Science and Engineering Research Board, Department of Science and Technology, India.

More information about the discovery of the gravitational wave source GW170104 can be obtained at https://www.ligo.caltech.edu/page/press ... e-gw170104, and in the IndIGO press release.

Amber G.
BRF Oldie
Posts: 6014
Joined: 17 Dec 2002 12:31
Location: Ohio, USA

Re: Indian Space Programme Discussion - Sept 2016

Postby Amber G. » 22 Oct 2017 00:49

xposting simply because I think it is beautiful!
>>
HAPPY DIWALI!

This amazing image is of our sun taken from SDO on this Diwali.


On Oct 19, the Moon photobombed @NASASun observatory that typically watches the Sun 24/7. For more info and amazing view on this Diwali see http://go.nasa.gov/2xVZm0s


Image

kit
BRF Oldie
Posts: 2534
Joined: 13 Jul 2006 18:16

Re: Indian Space Programme Discussion - Sept 2016

Postby kit » 22 Oct 2017 04:04

Amber G. wrote:^^^ I have seen little technical details except tweet:
From Raman Research Institute "joins hands with ISRO to develop satellite based secure quantum communications for the first time in India!"
I like this text-book by Mermin, (used in graduate-level course in Cornell) and think it is very good for:
- someone who is a computer scientist (with little background in Quantum Physics).
- Or someone who knows quantum physics but is does not know what quantum computing is)


some laughed when i mentioned quantum communications in India :roll:

Ashokk
BRFite
Posts: 311
Joined: 11 Aug 2016 06:14

Re: Indian Space Programme Discussion - Sept 2016

Postby Ashokk » 23 Oct 2017 10:56

Isro to launch Cartosat 2 sat with 30 nano sats in mid-December
NEW DELHI: After the unsuccessful launch of navigation satellite IRNSS-1H, Indian Space Research Organisation (Isro) is gearing up to launch a remote sensing satellite of Cartosat-2 series along with 30 nano satellites of foreign countries in the second half of December.

Vikram Sarabhai Space Centre (VSSC) director Dr K Sivan said, "Isro will be busy in launching a series of satellites from December onwards. We are targeting to launch Cartosat along with 30 nano satellites of foreign countries in the second half of December."

He said, "The replacement satellite for IRNSS-1A (the first navigation satellite whose three atomic clocks, meant to provide precise locational data, had stopped working last year) will be launched soon thereafter. Both these launches will be from the first launchpad at Sriharikota as the second launchpad will be busy in launching three GSLV rockets, including the Chandrayaan-2 mission in March. "If for any reason, Cartosat launch is delayed in December, it will also stall the launch of replacement satellite IRNSS-1I as both these launches have been planned from the first launchpad."

The three GSLV launches, which will involve two GSLV Mk II and one GSLV Mk III (Isro's fat boy), will be from the second launchpad at Sriharikota. Instead of PSLV (which was used for launching Chandrayaan-1 mission in 2008), Isro is using GSLV Mk II for the second lunar mission as the payload is heavier this time (combined launch mass 3,250 kg). The payload will constitute orbiter, lander and rover.

Dr Sivan said, "After the IRNSS-1H satellite failure, corrective measures will be taken in all rockets before the launches." Though the inquiry into reasons for the heat shield glitch is still going on, "initial findings suggested a defect in the pyro elements of the rocket which deal with the stage separation mechanism". The VSSC director said the committee probing the failure of IRNSS-1H launch will submit its investigation report much before the upcoming launches.

He said the faulty satellite stuck inside the heat shield is still orbiting the outer space and is "unlikely to fall into the Pacific Ocean anytime soon". On August 31, PSLV-C39 could not deliver the 1.4-tonne IRNSS-1H in the geo orbit as its heat shield did not get separated minutes after the rocket's lift-off from Sriharikota.

JayS
Forum Moderator
Posts: 3375
Joined: 11 Aug 2016 06:14

Re: Indian Space Programme Discussion - Sept 2016

Postby JayS » 23 Oct 2017 11:22

Ashokk wrote:
He said the faulty satellite stuck inside the heat shield is still orbiting the outer space and is "unlikely to fall into the Pacific Ocean anytime soon". On August 31, PSLV-C39 could not deliver the 1.4-tonne IRNSS-1H in the geo orbit as its heat shield did not get separated minutes after the rocket's lift-off from Sriharikota.


Good opportunity to test ASAT, I say.

abhik
BRF Oldie
Posts: 2168
Joined: 02 Feb 2009 17:42

Re: Indian Space Programme Discussion - Sept 2016

Postby abhik » 24 Oct 2017 18:11

Is PSLV currently 'grounded', when is the next scheduled launch? ToI article doesn't seem clear.

Varoon Shekhar
BRFite
Posts: 1679
Joined: 03 Jan 2010 23:26

Re: Indian Space Programme Discussion - Sept 2016

Postby Varoon Shekhar » 24 Oct 2017 19:03

Next scheduled launch is in December. About 30 satellites will be launched from one PSLV

Prem
BRF Oldie
Posts: 20784
Joined: 01 Jul 1999 11:31
Location: Weighing and Waiting 8T Yconomy

Re: Indian Space Programme Discussion - Sept 2016

Postby Prem » 27 Oct 2017 05:47

https://www.nextbigfuture.com/2017/10/i ... -2018.html
India will Orbiter and Rover to the moon in 2018

India will make its second mission to the moon in 2018, the Indian Space Research Organization announced this week.The Chandrayaan 2 spacecraft consists of an orbiter, lander and rover configuration “to perform mineralogical and elemental studies of the lunar surface,” the ISRO said.Chandrayaan 2, India’s second mission to the Moon, is an advanced version of the previous Chandrayaan-1 mission. It consists of an Orbiter, Lander and Rover configuration. It is planned to be launched as a composite stack into the Earth Parking Orbit (EPO) of 170 X 18,500 km by GSLV-Mk II. The Orbiter carries the combined stack up to moon till the Lunar Orbit Insertion (LOI). The combined stack is then inserted into a lunar orbit of 100 km x 100 km. The Lander is separated from the Orbiter in this orbit.The Orbiter with scientific payloads will orbit around the moon. The Lander will soft land on the Moon at a specified site and deploy the Rover. The scientific payloads onboard the Orbiter, Lander and Rover are expected to perform mineralogical and elemental studies of the lunar surface.The Lunar Lander development would be done by ISRO and Chandrayaan-2 will be totally an Indian mission.


https://youtu.be/80YB-Gmq-FQ?t=3

Yugandhar
BRFite -Trainee
Posts: 64
Joined: 28 Jun 1999 11:31
Location: Bendakaalooru

Re: Indian Space Programme Discussion - Sept 2016

Postby Yugandhar » 27 Oct 2017 06:14

As the heat shield is intact, it may protect the satellite during reentry. Is there any chance of recovering a functioning satellite? . There is the issue of impact with the ocean and then the whole thing disintegrating. But is this even remotely possible?

Singha
BRF Oldie
Posts: 62446
Joined: 13 Aug 2004 19:42
Location: the grasshopper lies heavy

Re: Indian Space Programme Discussion - Sept 2016

Postby Singha » 27 Oct 2017 10:33

http://www.news18.com/news/india/cia-im ... 58579.html

Nambi narayan releases autobiography. suspects CIA hand in setting him up for a fall.

Amber G.
BRF Oldie
Posts: 6014
Joined: 17 Dec 2002 12:31
Location: Ohio, USA

Re: Indian Space Programme Discussion - Sept 2016

Postby Amber G. » 27 Oct 2017 12:18

Yugandhar wrote:As the heat shield is intact, it may protect the satellite during reentry. Is there any chance of recovering a functioning satellite? . There is the issue of impact with the ocean and then the whole thing disintegrating. But is this even remotely possible?

A few general points..
Generally true for all such satellites - they will remain in orbit for 10-20 years (or even longer)..if/when the orbit decays (due to air resistance - which is very small but as orbit decays becomes more) it is will probably burn up - even with the heat shield. Any way, even if it does not, one can not predict where it will fall at present.

Also 'cost' of satellite is mainly due to the energy and money spent in putting it into orbit - so if one puts the sat in space again, you still have to spent lot of money.

Of course, 10-20 years from now - closer to final decay one will be able to predict what will happen to sat, and then one can recover it, if it is of value.

Philip
BRF Oldie
Posts: 19316
Joined: 01 Jan 1970 05:30
Location: India

Re: Indian Space Programme Discussion - Sept 2016

Postby Philip » 27 Oct 2017 12:39

Ind-thra...Thor.Thra-Thor .See the similarities in the words. In ancient times many Gods were the same for diff. civilisations,pronounced with small differences.Some were representations of planets. Time,cosmic disasters affecting the planet destroyed these super-civilisations around 11000-12000 BC.The Indian coastline on the east was 30Km further out to sea where the sunken remains of Poompuhar are,carbon dated to around 12-20,000BC!
Take two other words/Gods. Jehovah In Judaism/Christianity.Say it quickly several times and what do you hear? Shiva!

The req. from the services is increasing rapidly.The media today said something about more dedicated sats to monitor the border with China. How are we going to meet this challenge of increased launches and what would be the optimum launch vehicles for such milsats? Would we need extra launchpads/infra at SHK or even a new launch site?

JayS
Forum Moderator
Posts: 3375
Joined: 11 Aug 2016 06:14

Re: Indian Space Programme Discussion - Sept 2016

Postby JayS » 27 Oct 2017 13:49

Yugandhar wrote:As the heat shield is intact, it may protect the satellite during reentry. Is there any chance of recovering a functioning satellite? . There is the issue of impact with the ocean and then the whole thing disintegrating. But is this even remotely possible?


This heat shield is designed for going up. The loads will be too high while reentry. I highly doubt the heat shield can last re-entry loads. Plus it will be a uncontrolled reentry. Without very precise attitude control even with proper heat shield there are next to no chance of survival.


Return to “Military Issues & History Forum”

Who is online

Users browsing this forum: Indranil and 20 guests