Indian Space Program: News & Discussion - Sept 2016

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prasannasimha
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Re: Indian Space Programme Discussion - Sept 2016

Post by prasannasimha »

50% is impossible. The net pressure increase was 6% The statement was that with 5(L40 +GS2) and other improvements the payload can be increased up to 3 Tons from 2.5 Tons which would be an 16% approx. Each Vikas engine upgrade would lead to a 70 Kg increment of the final payload mass (ie 350 Kgs and using electrohydraulic actuators another 100 kg has been reduced. Otheer methods to cause a dry mass reduction and the CUS stage upgradation all together would allow an increase to 3.2 Tons from the original design for 2-2-2.4 tons to GTO.
This is the configuration that will be used for Chandrayaan 2
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Re: Indian Space Programme Discussion - Sept 2016

Post by Indranil »

JayS wrote:
Varoon Shekhar wrote:
Great launch, congrats. Is the electromechanical actuator system made by ISRO? That is not clear, though it is powered by ISRO developed Lithium Ion batteries. Also, would the full utilisation of the propellant lead to noticeable improvement in accuracy and/or payload.
ISRO developed actualtors for LCA. If they have the tech for electomechanical actuators now, AMCA can use them, giving significant edge to it.
And all Agni and K-series. It is a publicly stated improvement going from Agni-5 to Agni-6.

Current payload capacity is 2.25 tons. Changing all the 5 Vikas engines will take the payload up to 2.5 tons. Going to 3 tons will require the upgradation of the CUS: from the current 7.5 Tons to 9.5 tons and propellant mass from 12.8 tons to 15 tons.
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Re: Indian Space Programme Discussion - Sept 2016

Post by SSridhar »

SaiK wrote:I heard the improvement for greater than 2.5 ton validations. Can anyone tell more details of how much tonnage now we can launch? 4T?
4T requires C25 Cryogenic stage. That is GSLV-Mk. III. The GSLV-Mk. II, yesterday's launch, can place 2.5 Tonnes in GTO.
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Re: Indian Space Programme Discussion - Sept 2016

Post by SSridhar »

I think one can hear the whirring of the turbopumps of the CU Stage in the video. Or, is it the background music?
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Re: Indian Space Programme Discussion - Sept 2016

Post by SSridhar »

The other things that were mentioned in the post-launch speeches were
  • IRNSS 1i will be launched in two weeks time from first launch pad (first time another launch takes place within such a short duration of a previous one)
  • The GSLV Mk III campaign is on-going
  • There will be ten launches this year
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Re: Indian Space Programme Discussion - Sept 2016

Post by Mort Walker »

That's actually a good shot considering the distance and amount of water vapor in the air. You may want to borrow or rent a 400mm lens next time.
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Re: Indian Space Programme Discussion - Sept 2016

Post by Mort Walker »

Image

Artist concept of GSAT-6A in orbit.
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Re: Indian Space Programme Discussion - Sept 2016

Post by Mort Walker »

A few seconds (3-4) prior to the launch there appears to be some sort of panel that fell off, and we see several panels fall off a few seconds (2-3) after liftoff. Can someone please explain again?
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Re: Indian Space Programme Discussion - Sept 2016

Post by SSridhar »

These are frangibles that provide insulation etc. Normal occurrence in all launches.
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Re: Indian Space Programme Discussion - Sept 2016

Post by Mort Walker »

^^^Thanks. Presumably needed for the LOX and other cryogenic fuels.
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Re: Indian Space Programme Discussion - Sept 2016

Post by prasannasimha »

Not just for LOX-H2 but also during loading of the hyperbgolic liquid propellant . You will see the same insulator foam dropping off during launch of PSLV if you carefully look. The foam cover is made to look like the rockets external surface so it is not obvious but us seen when dropping off at launch.
Last edited by ramana on 02 Apr 2018 22:01, edited 1 time in total.
Reason: Fixed auto correct. ramana
prasannasimha
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Re: Indian Space Programme Discussion - Sept 2016

Post by prasannasimha »

Image
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Re: Indian Space Programme Discussion - Sept 2016

Post by prasannasimha »

^ you can see the foam layer dropping off. You can see one foam panel near the rocket near the PSLV logo actually dropping off and like the quick change in magic shows the lower painted PSLV is seen. (They paint both the foam layer and the actual rocket in the same manner.(Liquid stages only)
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Re: Indian Space Programme Discussion - Sept 2016

Post by prasannasimha »

Image



See between the P and S and you can see the joint of the foam panel in this picture

Zoom in after clicking the URL

https://www.isro.gov.in/sites/default/f ... cility.jpg

In the zoomed version see the L and you can see a vertical joint line through it too
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Re: Indian Space Programme Discussion - Sept 2016

Post by prasannasimha »

Mar 30, 2018 : The first orbit raising operation of GSAT-6A Satellite has been successfully carried out by LAM Engine firing for 2188 sec from 09:22hr IST on March 30, 2018.

Orbit Determination results from this LAM firing are:

- apogee X perigee height was changed to 36412 km X 5054 km.

- Inclination is 11.93 deg.

- Orbital period is 12hr 45min.
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Re: Indian Space Programme Discussion - Sept 2016

Post by jaysimha »

Department of Space
GSLV Successfully Launches GSAT-6A Satellite
Posted On: 29 MAR 2018 8:15PM by PIB Delhi

India's Geosynchronous Satellite Launch Vehicle (GSLV-F08) successfully launched GSAT-6A Satellite into Geosynchronous Transfer Orbit (GTO) today (March 29, 2018). Today’s launch of GSLV was its twelfth and took place from the Second Launch Pad at Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota, the spaceport of India. This is the fifth consecutive success achieved by GSLV carrying indigenously developed Cryogenic Upper Stage.

In its oval shaped GTO, GSAT-6A is now orbiting the Earth with a perigee (nearest point to Earth) of 169.4 km and an apogee (farthest point to Earth) of 36,692.5 km with an orbital inclination of 20.64 deg with respect to the equator.

Few seconds before the launch countdown reached zero, the four liquid propellant strap-on motors of GSLV-F08, each with nearly 43 tons of liquid propellants, were ignited. At count zero and after confirming the normal performance of all the four strap-on motors, the 139 ton solid propellant first stage core motor was ignited and GSLV lifted off at 16:56 IST, as scheduled. The major phases of the flight occurred as intended. About seventeen and a half minutes after lift-off, GSAT-6A was successfully placed in GTO.
.
Soon after separation from GSLV, the two solar arrays of GSAT-6A were automatically deployed in quick succession and the Master Control Facility (MCF) at Hassan in Karnataka assumed control of the satellite. .

GSAT-6A is a communication satellite built by ISRO to provide mobile communication services through multi beam coverage. For this, it is equipped with S and C band transponders.

In the coming days, the orbit of GSAT-6A will be raised from its present GTO to the final circular Geostationary Orbit (GSO) by firing the satellite's Liquid Apogee Motor (LAM) in stages. The Satellite will be commissioned into service after the completion of orbit raising operations and its positioning in the designated slot in GSO following in-orbit testing of its payloads.

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vasu raya
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Re: Indian Space Programme Discussion - Sept 2016

Post by vasu raya »

Glad to hear about the repeat success of the cryo engine stage.
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Re: Indian Space Programme Discussion - Sept 2016

Post by Hiten »

ISRO publishes renders of a new reusable rocket

Image

http://www.spansen.com/2018/03/does-isr ... sable.html
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Re: Indian Space Programme Discussion - Sept 2016

Post by shynee »

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Re: Indian Space Programme Discussion - Sept 2016

Post by Singha »

could be something with the new power umbrella thing. it looks fairly complex. a genius design would be something that uses pyrobolts or cold gas to desegment and release anything that fails to deploy, leaving the basic simpler antenna intact....there are certain videos going around of self deploying IOT "insects" and such

one never knows where inspiration can come from
https://www.youtube.com/watch?v=9M1zNIVGrjM
https://www.youtube.com/watch?v=vlXh8RvvcuI
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Re: Indian Space Programme Discussion - Sept 2016

Post by srin »

Being reported on other sources too ...

https://timesofindia.indiatimes.com/ind ... 565033.cms
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Re: Indian Space Programme Discussion - Sept 2016

Post by Hari Seldon »

#ISRO #GSAT6A Faces Serious Glitch In Power System, Scientists Say Communication Lost

https://t.co/qsePGXYAeS
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Re: Indian Space Programme Discussion - Sept 2016

Post by Singha »

Happens ... we learn from failure too
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Re: Indian Space Programme Discussion - Sept 2016

Post by suryag »

Saddening but it’s okie, ananth aka tarmak had signaled this yesterday on Twitter :(
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Re: Indian Space Programme Discussion - Sept 2016

Post by Singha »

Couple months ago a classified spy payload on a falconx was lost
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Re: Indian Space Programme Discussion - Sept 2016

Post by Austin »

Did the solar panels got deployed , Intial power is from sat battery till it deploys solar panels
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Re: Indian Space Programme Discussion - Sept 2016

Post by RKumar »

Some guru can correct me ...I guess solar panels should be deployed only when satellite is in its final position. Its would have given us advantage but we will recover from it. Sh*t happens :((
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Re: Indian Space Programme Discussion - Sept 2016

Post by Singha »

comms was lost during third & final orbit raising manouver so I dont think it had reached stage of deploying solar panels.
it may well have exploded due to some fuel leak or fuel leak or electrical malfunction may have shorted the electronics.
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Re: Indian Space Programme Discussion - Sept 2016

Post by srin »

One fantastic thing about ISRO is whenever they've had setbacks (GSLV CUS comes to mind), they've taken a step back, investigated the issues thoroughly and then fixed them at the root.
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Re: Indian Space Programme Discussion - Sept 2016

Post by Mort Walker »

From ToI:
The agency received data from the satellite for about four minutes after the second orbit raising operation, after which the it went blank, a source said.

BENGALURU: In what is a disappointment for both citizens and the armed forces of the country, the Indian Space Research Organisation (Isro) on Saturday lost contact with the GSAT-6A + , India’s most powerful communication satellite, in less than 48 hours after it launched it on Thursday. While Isro says it is trying re-establish link, sources attributed the failure to a power system failure.
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Re: Indian Space Programme Discussion - Sept 2016

Post by Mort Walker »

So this is NOT a launch vehicle failure, but rather the satellite itself. Need to trace back to who and when did the power and communication sub-systems. ISRO, BEL, or contracted out.
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Re: Indian Space Programme Discussion - Sept 2016

Post by SSridhar »

How sad after such a magnificent launch! Hope they somehow succeed in re-establishing contact.
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Re: Indian Space Programme Discussion - Sept 2016

Post by prasannasimha »

Supposed to be a power overload problem. Got nothing to do with the launcher etc.
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Re: Indian Space Programme Discussion - Sept 2016

Post by jaysimha »

If I were pm, I would say,,,,, postpone chandrayaan,,,, re-build the satellite & launch.
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Re: Indian Space Programme Discussion - Sept 2016

Post by PratikDas »

I wonder if the satellite was using indigenous lithium ion batteries - perhaps similar to that used successfully for the launcher.

“GSLV F-08 used electro-mechanical actuators in its second stage for the first time. And these were driven by indigenously developed lithium-ion batteries.”

https://twitter.com/SJha1618/status/979325207436546048?s=20

Of course, I’m presuming these batteries are new based on this: http://www.thehindu.com/sci-tech/science/bhel-to-make-li-ion-cells-with-isro-technology/article23333131.ece
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Re: Indian Space Programme Discussion - Sept 2016

Post by Ashokk »

GSAT-6A glitch: No contact with satellite, but we're hopeful, Isro chief says
What exactly transpired after the 2nd orbit-raising operations?

Everything went on as prescribed, a picture-perfect launch and two textbook orbit raising manoeuvres and then the satellite suddenly stopped communication. We are yet to determine what exactly went wrong.

When a satellite gets de-linked, it goes into a ‘safe mode’, is that the case here?

Generally the spacecraft returns from ‘safe mode’ in a matter of minutes, it returns in about one to five minutes. This is, however, very unusual as it did not happen. We are unable to establish any contact with the satellite, but our teams are on the job continuously.

What are the chances of recovery?

We are hopeful, but as of now there is no contact with the satellite. If we are just able to speak with the satellite, we can get it back to working as there are several redundancy mechanisms including back-up power. But everything hinges on re-establishing contact.
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Re: Indian Space Programme Discussion - Sept 2016

Post by saip »

According to this harami link, India seems to have launched a Naval Frigate into orbit.
The satellite -- an indigenous model weighing more than 2,000 tonnes --
Link
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Re: Indian Space Programme Discussion - Sept 2016

Post by ramana »

So it's a satellite raising issue.
Could be a battery short that drained it.
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Re: Indian Space Programme Discussion - Sept 2016

Post by prasannasimha »

There probably was an issue with power requirements. This satellite had a higher power requirement than the previous one.
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