Indian Space Program: News & Discussion - Sept 2016

All threads that are locked or marked for deletion will be moved to this forum. The topics will be cleared from this archive on the 1st and 16th of each month.
Locked
Picklu
BRF Oldie
Posts: 2128
Joined: 25 Feb 2004 12:31

Re: Indian Space Programme Discussion - Sept 2016

Post by Picklu »

There is one after another disaster with the recent launches. Last time, the heat shield didn't open and total loss of sat. This time comm failure and again total loss of sat. Something is not right.
Mort Walker
BRF Oldie
Posts: 10032
Joined: 31 May 2004 11:31
Location: The rings around Uranus.

Re: Indian Space Programme Discussion - Sept 2016

Post by Mort Walker »

Picklu wrote:There is one after another disaster with the recent launches. Last time, the heat shield didn't open and total loss of sat. This time comm failure and again total loss of sat. Something is not right.
You’re mistaken. The last launch of Cartosat 2 was successful in January. In this instance the launch vehicle and Vikas engine were perfect. It was the payload which failed. This is a learning exercise.
Singha
BRF Oldie
Posts: 66601
Joined: 13 Aug 2004 19:42
Location: the grasshopper lies heavy

Re: Indian Space Programme Discussion - Sept 2016

Post by Singha »

when was the last satellite that failed after release? i cant remember...
abhijitm
BRF Oldie
Posts: 3679
Joined: 08 Jun 2006 15:02
Contact:

Re: Indian Space Programme Discussion - Sept 2016

Post by abhijitm »

Need to add a blackbox in sats with autonomous power source just enough to send system log back to ground station. It will help to diagnose and take preventive measures for future missions.
chetak
BRF Oldie
Posts: 32224
Joined: 16 May 2008 12:00

Re: Indian Space Programme Discussion - Sept 2016

Post by chetak »

Hearing from chaiwala that both main and standby power systems are non responsive.

The solar panels have been deployed.

The satellite may be spinning on it's own and there is no telemetry.

It is also non responsive to blind commands.

NASA and ESA have been contacted to see if they have any suggestions to help resolve the situation.

Efforts still continue to try and recover from the situation.
ramana
Forum Moderator
Posts: 59773
Joined: 01 Jan 1970 05:30

Re: Indian Space Programme Discussion - Sept 2016

Post by ramana »

Ashokk wrote:After ‘cardiac arrest’, Rs 270 crore Gsat-6A cruising on silently :roll:
Isro said efforts were on to resume communication with the satellite. Sources said there was no indication of any system malfunction or fluctuations during or after launch. “Every time there is a discrepancy, there are indications. This time, it could not been seen or felt, which is why it is taking more time to establish contact,” Isro chairman K Sivan said.
I cringed when I saw the headline and thought DDM strikes again.
However on reading it the ISRO insider who is quoted in the headline.

I do wish if they are not authorized to talk, to not talk.
Its like that moron who said "Utter failure' after the Nirbhay test failure.

The chairman is more composed and am sure there is a Failure Investigation Team underway looking at the telemetry data till the failure.

And they can replicate the failure on ground with hardware in loop system.

Could be different reasons and will probably end up with most likely causes instead of one single root cause.
ramana
Forum Moderator
Posts: 59773
Joined: 01 Jan 1970 05:30

Re: Indian Space Programme Discussion - Sept 2016

Post by ramana »

Picklu wrote:There is one after another disaster with the recent launches. Last time, the heat shield didn't open and total loss of sat. This time comm failure and again total loss of sat. Something is not right.

Picklu, How are we different than the detractors by airing such comments?

From all reports looks like communication systems failure.
prasannasimha
Forum Moderator
Posts: 1214
Joined: 15 Aug 2016 00:22

Re: Indian Space Programme Discussion - Sept 2016

Post by prasannasimha »

The satellites we lost in orbit were essentially Chandrayaan and GSAT6 A. The others were due to different reasons. Power failure and occurred in both. The first failure was ananlyzed and mistakes were corrected in MOM. The seodn will also undergo a failure analysis in the mockup
kit
BRF Oldie
Posts: 6278
Joined: 13 Jul 2006 18:16

Re: Indian Space Programme Discussion - Sept 2016

Post by kit »

ramana wrote:
Picklu wrote:There is one after another disaster with the recent launches. Last time, the heat shield didn't open and total loss of sat. This time comm failure and again total loss of sat. Something is not right.
Just that the tempo of launches is much higher than in the past .. they would probably do an internal quality assessment
Amber G.
BRF Oldie
Posts: 9263
Joined: 17 Dec 2002 12:31
Location: Ohio, USA

Re: Indian Space Programme Discussion - Sept 2016

Post by Amber G. »

Disclaimer - Has not seen all the messages here or details elsewhere -- have been traveling with little outside communication -- so this may sound like speculation or something already discussed.

-- It is NOT uncommon that communication link gets established after quite some time (many days or longer). ISRO will be working but sometimes it needs time. (For example if loss of lock -- directional antenna lost lock -- is involved it may take some time to establish some kind of communication and then try to debug/reprogram/whatever to get things going.

Time will tell (and some people here may know more) but let us hope so. If it takes about 18-19 hours to orbit it may take few days to find out before giving up.

As far as comments like " ....There is one after another disaster".. ...Something is not right."

Make absolutely NO mistake, this is one field where ISRO and related entries have *every* reason to be proud of *many* fabulous successes... and the world has noticed that too.
Mort Walker
BRF Oldie
Posts: 10032
Joined: 31 May 2004 11:31
Location: The rings around Uranus.

Re: Indian Space Programme Discussion - Sept 2016

Post by Mort Walker »

chetak wrote:Hearing from chaiwala that both main and standby power systems are non responsive.

The solar panels have been deployed.

The satellite may be spinning on it's own and there is no telemetry.

It is also non responsive to blind commands.

NASA and ESA have been contacted to see if they have any suggestions to help resolve the situation.

Efforts still continue to try and recover from the situation.
There was one news article that said ISRO contacted NORAD (North American Air Defense) to verify orbital position and it was correct. That is, GSAT-6A is where it should be after the 2nd lifting operation.
chetak
BRF Oldie
Posts: 32224
Joined: 16 May 2008 12:00

Re: Indian Space Programme Discussion - Sept 2016

Post by chetak »

Mort Walker wrote:
chetak wrote:Hearing from chaiwala that both main and standby power systems are non responsive.

The solar panels have been deployed.

The satellite may be spinning on it's own and there is no telemetry.

It is also non responsive to blind commands.

NASA and ESA have been contacted to see if they have any suggestions to help resolve the situation.

Efforts still continue to try and recover from the situation.
There was one news article that said ISRO contacted NORAD (North American Air Defense) to verify orbital position and it was correct. That is, GSAT-6A is where it should be after the 2nd lifting operation.
It is in the correct position all right.

But, it seems that it's also spinning around it's own axis.
Amber G.
BRF Oldie
Posts: 9263
Joined: 17 Dec 2002 12:31
Location: Ohio, USA

Re: Indian Space Programme Discussion - Sept 2016

Post by Amber G. »

Seeing that the next launch is scheduled for April 12..(per ISRO "upcoming launches will not be affected")

GSAT-6 is still working fine...

GSAT6-A is not going to crash like Tiangong-1 or something like that (not for 20 years of so, at least).
And it is not only possible, but IMO likely that contact would be established and GSAT6-A will not be a failure.

Also please note that it is for military use so they(ISRO, GOI) are not going to please DDM's by releasing all the information or giving press conferences giving last minute updates ... they are busy.

Let us wait to see, till they find out exactly what happened.
SSridhar
Forum Moderator
Posts: 25085
Joined: 05 May 2001 11:31
Location: Chennai

Re: Indian Space Programme Discussion - Sept 2016

Post by SSridhar »

Part of 2012-launched PSLV plummets to Earth, two days after China’s space crash - U Tejonmayam, ToI
CHENNAI: As radars across the world kept an eye on China’s defunct space observatory that crashed into Earth on April 1, their antennas also received signals on a relatively small piece of an Indian rocket reentering the planet over the Atlantic Ocean. The junk, from Isro workhorse PSLV’s fourth stage, weighed about one tonne and had been circling the Earth for nearly six years.

V Adimurthy, advisor to Isro and former Inter-Agency Space Debris Coordination Committee (IADC) chairman, confirmed that the orbital debris re-entered the space atmosphere on April 3 evening.


Astrophysicist Jonathan McDowell of the Harvard Smithsonian for Astrophysics tweeted, “The 1-tonne PS4 rocket stage from @ISRO’s 2012 PSLV C19 launch reentered over the central Atlantic at 1406 UTC Apr 3.”

He was quoted in Space.com, a US-based space news portal, as saying that the debris had been travelling in a circular path around Earth since the launch on April 26, 2012, of RISAT-1, a remote sensing satellite, by PSLV C-19.

The nearly 10-tonne China’s space lab Tiangong-1, launched in September 2011, plummeted to Earth with pieces falling into South Pacific. Most part of the school-bus-sized craft burned up in the Earth’s atmosphere during its uncontrolled reentry. According to an estimate by the European Space Agency, there are about 166 million objects smaller than 1cm, 750,000 objects between 1cm and 10cm and 29,000 objects larger than 10cm in space. Together, they could weigh about 7,500 tonnes. Space faring countries have been tracking space debris through various methods as they pose a danger of colliding with operational satellites or launch vehicles.

Nasa and the space surveillance network of the US Department of Defense alone have catalogued and tracked about 21,000 objects using special ground-based sensors. These are objects as small as two inches in diameter in the circling in the low Earth orbit and about 39 inches in the geosynchronous orbit.

Isro follows a slew of methods to protect its space assets from debris. The space agency is a member of the Inter-Agency Space Debris Coordination Committee, where the agency exchanges information on space debris with 12 other member countries.

The agency also banks on its sophisticated multi-object tracking radar (MOTR), installed in Satish Dhawan Space Centre and has been operational since 2015. “We track debris through the radar for every rocket launch,” an Isro official said.

Officials said the radar can track 10 objects sized 30cmX30cm simultaneously at a distance of 800km and objects 50cmX50cm size at a range of 1,000km.
JayS
Forum Moderator
Posts: 4567
Joined: 11 Aug 2016 06:14

Re: Indian Space Programme Discussion - Sept 2016

Post by JayS »

^^ noob question.All PSLV upper stages linger in decaying orbits dont they..? Is that true for other launch rockets as well..? Or do some of them de-orbit upper stages so they fall down immediately after satellite separation..?
Varoon Shekhar
BRF Oldie
Posts: 2178
Joined: 03 Jan 2010 23:26

Re: Indian Space Programme Discussion - Sept 2016

Post by Varoon Shekhar »

ramana wrote:
Picklu wrote:There is one after another disaster with the recent launches. Last time, the heat shield didn't open and total loss of sat. This time comm failure and again total loss of sat. Something is not right.

Picklu, How are we different than the detractors by airing such comments?

From all reports looks like communication systems failure.
On another forum dealing with space flights, there is a felt negativity about ISRO's recent missions, from some posters. One even praised U.R Rao for his caution, and contrasted that with a couple of ISRO's failures in the last 9 months. Are they/he serious? ISRO now has between 5-9 missions per year, and 2016 was particularly profuse. Can you equate that with the late 80's and early 90's when ISRO was grappling with the ASLV and the very first launch of the PSLV? ISRO was in a beginning phase back then. Of course caution is needed on all missions, but ISRO is on a different stage of its journey at present.
Amber G.
BRF Oldie
Posts: 9263
Joined: 17 Dec 2002 12:31
Location: Ohio, USA

Re: Indian Space Programme Discussion - Sept 2016

Post by Amber G. »

JayS wrote:^^ noob question.All PSLV upper stages linger in decaying orbits dont they..? Is that true for other launch rockets as well..? Or do some of them de-orbit upper stages so they fall down immediately after satellite separation..?
Per basic physics --
Virtually *all* upper stages "linger" in orbits which may decay in years or decades (or centuries) depending on how high (above atmosphere) the orbit is.

To "de-orbit" (a (controlled one) one actually needs fuel which has much better use -- give much needed extra delta-v or put the sat in orbit.

(generally sometimes remaining small fuel is used to push the orbit in a "grave-yard" orbit where it is less likely to encounter other rockets - or push the perigee to a less value so for each passes the orbit decays and the space-junk burns up in the atmosphere - unfortunately there is no standard at present which everyone follows)
Vips
BRF Oldie
Posts: 4699
Joined: 14 Apr 2017 18:23

Re: Indian Space Programme Discussion - Sept 2016

Post by Vips »

RH300 sounding rocket to be launched tomorrow in Kerala.

The RH300 sounding rocket, developed by Vikram Sarabhai Space Centre (VSSC) as part of a study to enrich available atmospheric data, would be launched from Thumba Equatorial Rocket Launching Station (TERLS), here tomorrow.

This will be the 21st launch of RH300 sounding rocket, a release from VSSC said today.

The launch, scheduled at 19.15 hrs, is part of a study undertaken by VSSC under the Sounding Rocket Experiment (SOUREX) programme, which utilises the RH-300 MKII sounding rocket to study the Equatorial E and lower ionosphere regions of the atmosphere, it said.

The study will enrich available atmospheric data and refine the models used for tropical weather prediction, it added.

The skies of state capital and nearby areas will witness a spectacular display of a long trail of interleaved pattern of white and blue light due to chemi-luminescence, a resultant of the experiment.

Photographic capturing of the trail is arranged from four different stations in Thiruvananthapuram, Kollam, Kanyakumari and Tirunelveli, the release said.

The objective of the experiment is to measure neutral wind in the dynamo region (80-120 km) of equatorial ionosphere using the indigenously developed Electron Density and Neutral Wind Probe (ENWi) and perform cross-validation using an independent Tri Methyl Aluminium (TMA) release technique.

Atmospheric studies with TMA were done in the 60's utilizing sounding rockets of foreign countries and the first launch was on May 2, 1965 using a Centaure rocket.

After a long gap, the TMA experiment is now being attempted with indigenously made payload and rocket.
prasannasimha
Forum Moderator
Posts: 1214
Joined: 15 Aug 2016 00:22

Re: Indian Space Programme Discussion - Sept 2016

Post by prasannasimha »

Anyone saw the launch ?
Varoon Shekhar
BRF Oldie
Posts: 2178
Joined: 03 Jan 2010 23:26

Re: Indian Space Programme Discussion - Sept 2016

Post by Varoon Shekhar »

https://www.isro.gov.in/launcher/pslv-c41-irnss-1i

The next launch is very much on, to lift off early hours of Thurs April 12
disha
BR Mainsite Crew
Posts: 8235
Joined: 03 Dec 2006 04:17
Location: gaganaviharin

Re: Indian Space Programme Discussion - Sept 2016

Post by disha »

Picklu wrote:There is one after another disaster with the recent launches. Last time, the heat shield didn't open and total loss of sat. This time comm failure and again total loss of sat. Something is not right.
In space launches, nothing is ever right. Or to put it other way "Something is always wrong". The question is then to identify the "quantum of wrong" and the "impact of the quantum of wrong"!

If you still do not understand the above, then you have not understood space launch or any hi-tech project LCA or Kaveri to name a few.

Here is the deal, space is a risky business. At every launch, there are few tens of thousands of variables that need to be controlled or understood. For example is there a proper pressure in the UDMH tanks? Is the mix proper and flowing at the required parameter (plus or minus within a range?). And variables such as this run into several tens of thousands per launch. Add to that several launches. So now you have hundred thousand of such variables. And some are out of your control, like the chinese spacelab disintegrating the wrong way and maybe causing a space debris field in your path which might not have been properly accounted for.

Hence to come back to say "Something is not right" is wrong. Question should be "Okay, this time what went wrong and how we could cover that variable better?".
SaiK
BRF Oldie
Posts: 36424
Joined: 29 Oct 2003 12:31
Location: NowHere

Re: Indian Space Programme Discussion - Sept 2016

Post by SaiK »

What is the 70v bus this time (first time)? Any possibilities that played in?
JTull
BRF Oldie
Posts: 3113
Joined: 18 Jul 2001 11:31

Re: Indian Space Programme Discussion - Sept 2016

Post by JTull »

We now know the exact location of GSAT-6A communication satellite, says Isro chief
Indian Space Research Organisation (Isro) now knows the exact location of communication satellite GSAT-6A with which the signal link got snapped soon after its launch from Sriharikota on March 29.

Talking to TOI, Isro chairman Dr K Sivan said, “With the help of the satellite tracking system and other sources, we now know the exact location of GSAT-6A. Earlier, we were searching in the dark. But now we know the exact position of the satellite and keeping a close watch on its movement round-the-clock.

We are hopeful that at a particular orientation, it will capture the signal from the ground station and communication will be restored. Currently, GSAT-6A is moving in the geo transfer orbit at perigee of around 26,000km and apogee of about 33,000km.”

On the power front, Dr Sivan said, “We expect that the satellite has the power as its solar panels are fully deployed and getting recharged.” He said, “Currently, two teams are working simultaneously in Isro. One is busy restoring the link with GSAT-6A and the other in preparation of the launch of navigation satellite IRNSS-1I on Thursday.” IRNSS-1I, the eighth satellite to join the constellation of navigation satellites, will be launched at 4.04am on Thursday from Sriharikota by PSLV-C41 and the countdown will start from Tuesday night.

On addition of any new safety mechanism in IRNSS-1I to avoid power failure, the chairman said, “Power systems used in GSAT-6A and IRNSS-1I are totally different. The power system being used in IRNSS-1I is very simple and proven as all seven navigation satellites launched earlier are working successfully.”

IRNSS-1I is being launched to replace first navigation satellite IRNSS-1A, whose three Rubidium atomic clocks (meant to measure precise locatioal data) had stopped working two years ago. The launch of the first replacement satellite IRNSS-1H on August 31 last year was a failure as the satellite got stuck in the heat shield soon after its launch.

To avoid the heat shield glitch again, Dr Sivan said, “The glitch in the heat shield opening has been sorted out. The successful launch of Cartosat-2 series satellite in January this year and GSAT-6A on March 29 showed the improved system for the heat shield opening mechanism is working fine.”

On upcoming launches this year, the Isro chairman said, “Before the Chandrayaan-2 launch in the first week of October, we will launch three to four launches. After IRNSS-1H launch on Thursday, we will be busy in the launch of heaviest satellite GSAT-11 weighing over 5 tonne from the Guiana space centre. Thereafter, we will launch GSLV Mk III D2 (Isro’s ‘fat boy’). We are targeting to launch nine satellites after IRNSS-1I launch on Thursday. Almost, one launch every month.”

Isro has been increasing its frequency of launches in recent years in order to meet the national requirement of satellites in the areas of communication, earth observation and navigation.
Haridas
BRFite
Posts: 878
Joined: 26 Dec 2017 07:53

Re: Indian Space Programme Discussion - Sept 2016

Post by Haridas »

JTull wrote:We now know the exact location of GSAT-6A communication satellite, says Isro chief
Indian Space Research Organisation (Isro) now knows the exact location of communication satellite GSAT-6A with which the signal link got snapped soon after its launch from Sriharikota on March 29.

Talking to TOI, Isro chairman Dr K Sivan said, “With the help of the satellite tracking system and other sources, we now know the exact location of GSAT-6A. Earlier, we were searching in the dark. But now we know the exact position of the satellite and keeping a close watch on its movement round-the-clock.

We are hopeful that at a particular orientation, it will capture the signal from the ground station and communication will be restored. Currently, GSAT-6A is moving in the geo transfer orbit at perigee of around 26,000km and apogee of about 33,000km.”

On the power front, Dr Sivan said, “We expect that the satellite has the power as its solar panels are fully deployed and getting recharged.” He said, “Currently, two teams are working simultaneously in Isro. One is busy restoring the link with GSAT-6A and the other in preparation of the launch of navigation satellite IRNSS-1I on Thursday.” IRNSS-11
Great !! good to know. We will make contact and recover it via boot-strap recovery mechanism. I fondly recall satellite communication Under-grad class.

As I expected a week ago.
Haridas wrote:^^ re acquisition of the signal via low gain wide angle antenna for secondary control channel might take longer time due to long orbital period of current orbit, and unknown tumble rate (if any).

There is hope in next 10 days window imho.
SSridhar
Forum Moderator
Posts: 25085
Joined: 05 May 2001 11:31
Location: Chennai

Re: Indian Space Programme Discussion - Sept 2016

Post by SSridhar »

If ISRO can pull it off and I hope they do, it will be nothing short of miraculous.
Ashokk
BRFite
Posts: 1116
Joined: 11 Aug 2016 06:14

Re: Indian Space Programme Discussion - Sept 2016

Post by Ashokk »

Isro set to launch first privately built satellite tomorrow
India could see its first privately built satellite in space this week as Indian Space Research Organisation (Isro) gears up for a launch to boost its Navic fleet.

A consortium of mid- and smallsized firms led by Bengaluru-based aerospace firm Alpha Design Technologies has built IRNSS-1L, the backup navigation satellite with a new atomic clock, under the watchful eyes of Isro. It is also the first satellite to be built at a special Isro facility for private firms.

The satellite will be launched on Thursday from Sriharikota by the home-grown polar satellite launch vehicle (PSLV) rocket.

This is the second satellite the private team has built for Isro. The previous one was lost in August last year, when the heat shield of the rocket failed to open and let out the spacecraft. An inquiry later found an explosive had failed to detonate fully, to break the latch of the heat case or conical top of the PSLV, where satellites are housed as they are carried into space.
Image
Prithwiraj
BRFite
Posts: 264
Joined: 21 Dec 2016 18:48

Re: Indian Space Programme Discussion - Sept 2016

Post by Prithwiraj »

Liftoff Narmal!! 430am launch
Sagrawal
BRFite
Posts: 152
Joined: 08 Jan 2010 14:33

Re: Indian Space Programme Discussion - Sept 2016

Post by Sagrawal »

Mission successfully accomplished
thammu
BRFite -Trainee
Posts: 79
Joined: 29 Mar 2007 08:16

Re: Indian Space Programme Discussion - Sept 2016

Post by thammu »

SSridhar wrote:If ISRO can pull it off and I hope they do, it will be nothing short of miraculous.
This is the normal strategy of management to give hope to stakeholder, till the incident fades away from memory. So don't expect any miracle!

Having said that, ISRO has achieved phenomenal success through the years and a few glitches are always expected, especially when you are trying out new things. Risks have to be taken to keep on developing and catch up with the rest.
SriKumar
BRF Oldie
Posts: 2243
Joined: 27 Feb 2006 07:22
Location: sarvatra

Re: Indian Space Programme Discussion - Sept 2016

Post by SriKumar »

thammu wrote:
SSridhar wrote:If ISRO can pull it off and I hope they do, it will be nothing short of miraculous.
This is the normal strategy of management to give hope to stakeholder, till the incident fades away from memory.
I dont know if the implication is that ISRO is trying to mislead public or give false hope. Who is the 'stakeholder' you have in mind in your statement above?

Far from trying to 'give hope' falsely, ISRO has actually given very limited statements on this, and the content of their limited statements is mostly technical.

Unlike politicians and some management in companies, ISRO cannot brush things under a carpet. They absolutely need to find the cause of a (any) problem, and fix it; or else it will come up again in future launches ......for the entire world to see, and they know it.
juvva
BRFite
Posts: 380
Joined: 20 Oct 2008 17:34

Re: Indian Space Programme Discussion - Sept 2016

Post by juvva »

^^wow. Just 2 posts for the entire launch.
Prithwiraj wrote:Liftoff Narmal!! 430am launch
Sagrawal wrote:Mission successfully accomplished
PSLV launches have become so routine.
No need to wake up early in the morning for what is anyhow given,
SSridhar
Forum Moderator
Posts: 25085
Joined: 05 May 2001 11:31
Location: Chennai

Re: Indian Space Programme Discussion - Sept 2016

Post by SSridhar »

thammu wrote:
SSridhar wrote:If ISRO can pull it off and I hope they do, it will be nothing short of miraculous.
This is the normal strategy of management to give hope to stakeholder, till the incident fades away from memory. So don't expect any miracle!

Having said that, ISRO has achieved phenomenal success through the years and a few glitches are always expected, especially when you are trying out new things. Risks have to be taken to keep on developing and catch up with the rest.
thammu, your response makes no sense to me.

What is this preaching that you are resorting to?
Mukesh.Kumar
BRFite
Posts: 1242
Joined: 06 Dec 2009 14:09

Re: Indian Space Programme Discussion - Sept 2016

Post by Mukesh.Kumar »

thammu wrote:
SSridhar wrote:If ISRO can pull it off and I hope they do, it will be nothing short of miraculous.
This is the normal strategy of management to give hope to stakeholder, till the incident fades away from memory. So don't expect any miracle!

Having said that, ISRO has achieved phenomenal success through the years and a few glitches are always expected, especially when you are trying out new things. Risks have to be taken to keep on developing and catch up with the rest.
@thammu: !!!!!! What?

Would appreciate if we can avoid these management motherhood quotes.
Amber G.
BRF Oldie
Posts: 9263
Joined: 17 Dec 2002 12:31
Location: Ohio, USA

Re: Indian Space Programme Discussion - Sept 2016

Post by Amber G. »

SSridhar wrote:If ISRO can pull it off and I hope they do, it will be nothing short of miraculous.
SSridhar - As I pointed out earlier (see this apri 4th post <link> going by past data, there is always a very good possibility that this may happen. It may take time. From what I know some of the ISRO engineers are top notch and resourceful.

Past quote:
It is NOT uncommon that communication link gets established after quite some time (many days or longer). ISRO will be working but sometimes it needs time. (For example if loss of lock -- directional antenna lost lock -- is involved it may take some time to establish some kind of communication and then try to debug/reprogram/whatever to get things going.
Haridas
BRFite
Posts: 878
Joined: 26 Dec 2017 07:53

Re: Indian Space Programme Discussion - Sept 2016

Post by Haridas »

juvva wrote:^^wow. Just 2 posts for the entire launch.
PSLV launches have become so routine.
No need to wake up early in the morning for what is anyhow given,
What is news/information content (info entropy) if someone reports today sun rose from the East?
I say pleasant and naarmal day only. :D
chetak
BRF Oldie
Posts: 32224
Joined: 16 May 2008 12:00

Re: Indian Space Programme Discussion - Sept 2016

Post by chetak »

Amber G. wrote:
SSridhar wrote:If ISRO can pull it off and I hope they do, it will be nothing short of miraculous.
SSridhar - As I pointed out earlier (see this apri 4th post <link> going by past data, there is always a very good possibility that this may happen. It may take time. From what I know some of the ISRO engineers are top notch and resourceful.

Past quote:
It is NOT uncommon that communication link gets established after quite some time (many days or longer). ISRO will be working but sometimes it needs time. (For example if loss of lock -- directional antenna lost lock -- is involved it may take some time to establish some kind of communication and then try to debug/reprogram/whatever to get things going.
Per inputs, the satellite is spinning around its own axis, just like a top. That has complicated things.
SriKumar
BRF Oldie
Posts: 2243
Joined: 27 Feb 2006 07:22
Location: sarvatra

Re: Indian Space Programme Discussion - Sept 2016

Post by SriKumar »

If this thing does not get sorted out in an year or so, perhaps one could consider launching a 'relay communication' satellite with a GSLV launch (in addition to the scheduled payload). This 'relay comm' satellite should be brought to the same orbit and in proximity to the disabled satellite to establish communication. (alternatively, a pre-scheduled payload going via the same intermediate orbit could be programmed to do some relay communication functions in the orbit of the disabled satellite before it goes on to its final orbit).

At a minimum, it can send pictures of the orientation of the GSAT6 satellite and determine how the satellite is spinning/antenna is oriented w.r.t time etc. Once the spin rate/antenna attitude is known, the relay satellite could be positioned to transmit a signal. All of the above applies if it is 'only' a matter of getting a signal into the disabled satellite, which per public domain information is the problem. (If there are other issues, then I dont know). It is not clear what has caused the (i) power loss, and (ii) communication loss (loss of earth lock obviously). The solar panel is deployed, so it does have power from an active power source. Some circuit issue perhaps.
vasu raya
BRFite
Posts: 1658
Joined: 11 Aug 2016 06:14

Re: Indian Space Programme Discussion - Sept 2016

Post by vasu raya »

to stabilize the 'relay' sat which is possibly a microsat,

http://www.thehindu.com/news/internatio ... 716332.ece
Mr. Lapeyrere and his team are trying to reduce PicSat’s spin by providing torque through on-board magnetorquers. Picsat is expected to become stable in two weeks
....
In order to stabilise the satellite, an electrical current is run through the copper coils using on-board batteries and a solar array. “The current creates a magnetic field around PicSat which is already inside Earth’s magnetosphere. The magnetic field created by the coils align with Earth’s magnetic field. That’s how we are keeping PicSat stable,” said Mr. David, who was at Sriharikota to witness the January 12 launch.
Locked