Indian Space Program: News & Discussion - Sept 2016

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Re: Indian Space Programme Discussion - Sept 2016

Postby Varoon Shekhar » 03 May 2017 02:41

"Idiot reporter says, that the GSLV Mk III cryogenic engine is a re-engineered version of the Russian Cryo engine"

I was about to mention that, I think it is a case of bad editing. It did say earlier that the engine was wholly Indian designed and produced. Maybe what he meant to write was that the Mark 2 engine is essentially Indian re-engineered version of imported Russian cryo, but the arrangement of the paragraphs was messed up. Trying to be charitable!

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Re: Indian Space Programme Discussion - Sept 2016

Postby Singha » 03 May 2017 09:27

A simple cheap pslv replacement to put say 2.5t into mediu orbits would be good. That and the mk3 gslv can be our workhorse rockets for a couple of decades with smaller and bigger outliers for specific use cases.

The current pslv is heavy and complex for its payload.

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Re: Indian Space Programme Discussion - Sept 2016

Postby disha » 03 May 2017 20:56

^^ That would be GSLV Mk III core alone - that is, minus the solid boosters. Anyway., GSLV Mk III is the ULV - it can be scaled up or scaled down.

Going from UDMH/NO4 to Semi-Cryo is to reduce the usage of toxic impact & increase safe handling of UDMH/NO4*. Semi-Cryo is a work in progress and can be integrated into ULV as and when it qualifies.

*With multiple launch pads and monthly launch schedule., it will be a very busy launch port and just modifying one's propellants will increase safety and decrease risk. Imagine a rocket on LP1 and it leaks UDMH (which is hypergolic with NO4 and a potent carcinogenic). This will put all other activities if not to pause definitely a major slow down.

**I do not think Semi-Cryo gives a major advantage in terms of ISP over say UDMH/NO4 and UDMH/NO4 has been understood very well and ISRO has multi-decade experience with it. And ISRO has a staged combustion cryo and still will use relatively inefficient gas generator for Mk III. And ISRO have been stating that it went with GG-Cryo for Mk III so that it can be tested independently and multiple times (and hence covering more test points, safety rating is higher than Staged Combustion Cryo). Following that and given ISRO's own statements in its annual budgets the move towards semi-cryo is to increase the range safety by using less toxic and more safe propellants.

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Re: Indian Space Programme Discussion - Sept 2016

Postby RonyKJ » 03 May 2017 21:50

There is an advantage in specific impulse, but more in vacuum than sea level,
so the penalty of using it in lower stages is not as much.
LOX-Kerosene Isp is 300 at sea level and 353 in vacuum
UDMH-N2O4 Isp is 285 at sea level and 333 in vacuum

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Re: Indian Space Programme Discussion - Sept 2016

Postby disha » 04 May 2017 00:04

RonyKJ wrote:There is an advantage in specific impulse, but more in vacuum than sea level,
so the penalty of using it in lower stages is not as much.
LOX-Kerosene Isp is 300 at sea level and 353 in vacuum
UDMH-N2O4 Isp is 285 at sea level and 333 in vacuum


Exactly., the efficiency on average of semi-cryo over UDMH-N204 is 6%. Does not warrant an entire set of technology to be created (and a entire set of petroleum refinement process) for a mere 6% efficiency.

At the same time as India's economy has progressed and is one of the leader in petrochem refinement with large scale refining capacity and very skilled workforce to refine oil into required grade petroleum.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Gagan » 04 May 2017 05:02

ISRO is boosting the capacity to produce UDMH-N2O4, as National Fertilizers is going to mass produce this in Madhya Pradesh

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Re: Indian Space Programme Discussion - Sept 2016

Postby SSSalvi » 04 May 2017 06:06

GSLV F 09 Launch:
28 Hr Countdown staring @ 12:57 IST ( 07:27 GMT ) 4th May
Launch @ 16:57 IST ( 11:27 GMT ) 5th May

http://epaper.deccanchronicle.com/articledetailpage.aspx?id=8020855

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Re: Indian Space Programme Discussion - Sept 2016

Postby Singha » 04 May 2017 07:03

What is the advantage of liquid engine in 3rd stage vs a solid motor? Does lack of O2 up there means only liquid is possible?

How then do icbm use solid motor in 3rd stage?

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 04 May 2017 08:12

The specific impulse is higher with cryo semicryo that is needed for higher injection velocity to maintain orbits or escape earth in single shot. The weight penalty is higherwith solids in higher stages. ICBM's are ballistic or fractional orbita at the most. Not orbital and generally throw weights are less and suborbital. Dnepr is liquid based and can put small satellites only. Not heavy telecommunication satellites

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Re: Indian Space Programme Discussion - Sept 2016

Postby RonyKJ » 04 May 2017 08:18

Singha wrote:What is the advantage of liquid engine in 3rd stage vs a solid motor? Does lack of O2 up there means only liquid is possible?

How then do icbm use solid motor in 3rd stage?


If you are referring to GSLV Mark 2, the third stage is the 7.5 ton cryo engine which uses liquid oxygen and liquid hydrogen. This engine has several advantages over a solid motor. First of all, the specific impulse (which is a measure of its efficiency) is much higher, almost double that of a solid motor.
Secondly the thrust of the engine can be throttled to adjust its performance to achieve the closest possible match to orbital velocity and insertion parameters. None of the rocket engines used by ISRO or for that matter any other space agency uses oxygen from the air. It is all carried onboard as oxidiser. In future rockets may carry only the fuel and acquire oxygen from the air for the initial part of the trajectory. These are called air-breathing rockets.
Their trajectory will be different from the present rockets which try to spend the least amount of time in the atmosphere. Instead air-breathing rockets will try to spend the most possible time in the atmosphere gathering oxygen and building up speed until orbital velocity is reached. Air breathing rockets will have much higher payload than regular rockets since they don't need to carry oxygen. ICBM's are essentially rockets, but they generally only use solid motors since they need to be ready to launch at any instant. Liquid rockets are only fuelled just before launch and hence are unsuitable as ICBM's.


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Re: Indian Space Programme Discussion - Sept 2016

Postby abhik » 04 May 2017 17:53

Most of the delta v is provided by the upper stage(s), in two stage rockets it is around 2/3 ballpark. Having a high specific impulse engine especially liquid hydrogen will mean a smaller upper stage and a cascading reduction in lower stage mass.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Gagan » 04 May 2017 18:19

Hope they have high res onboard cameras and a broadband datalink and will telecast the feed live.

Please ISRO !

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Re: Indian Space Programme Discussion - Sept 2016

Postby SSSalvi » 04 May 2017 19:55

Strange, No brochure yet reg launch profile.

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Re: Indian Space Programme Discussion - Sept 2016

Postby arshyam » 04 May 2017 20:36

Gagan wrote:Hope they have high res onboard cameras and a broadband datalink and will telecast the feed live.

Please ISRO !

They've always had cameras on-board, just that they didn't release the visuals till recently. Per a recent talk given by an ISRO engineer.

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 04 May 2017 20:52

^ Yes I have seen at times on their screens the live video feed for just a fraction of a second. I recognized the video of the previous GSLV launch that was being displayed live on the monitor. They do not have an obligation to release it but doing it is good PR

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Re: Indian Space Programme Discussion - Sept 2016

Postby SSSalvi » 04 May 2017 23:11

May be now they want to change their image from a scientific organization to an operational entity by not releasing the Launch brochure.

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 04 May 2017 23:33

^ The investigational flights did not have launch brochures

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Re: Indian Space Programme Discussion - Sept 2016

Postby disha » 05 May 2017 00:09

Singha wrote:What is the advantage of liquid engine in 3rd stage vs a solid motor? Does lack of O2 up there means only liquid is possible?

How then do icbm use solid motor in 3rd stage?


Several members have already answered it., but one thing we must be aware and need to be clear on - ICBM and Orbital rockets are different categories. Both are rockets in that they follow the 3rd law of motion and both carry payload and the similiarities end there.

ICBMs did not start out as solid., in fact Titan II was all liquid. And could still launch a 2tonne payload to polar orbits., but again its prime use was ensuring that the payload comes back to earth in a precise location versus PSLV/GSLV which needs the payload to be injected into precise orbit.

All Solid ICBMs came about for road mobility and quick reaction and storage and concealment etc. No modern strategic missile is liquid.

All missiles have 3 distinct phases - boost phase., sub-orbital space flight and re-entry. A liquid engine at re-entry gives precise injection but again modern strategic missiles have several different innovation that it does not require a liquid engine for precision. Of course if one takes out the re-entry phase., one can use a missile to orbit a payload. This is just to demonstrate immediate launch capability in case one needs it. Or use up the ICBMs in their retirement. Not for regular launches.

For the launch rockets., I would put only two phases - boost phase and a kick phase. Boost phase is when the most thrust is required - to take the entire stack up and out of atmosphere - here massive thrust is favored over efficiency in the lower stages and efficiency (since one requires a good sharp kick to the payload to inject into precise orbit) at a higher stage. Cryo gives the most efficient kick.

Another advantage of liquid engines is the ability to throttle precisely. Solids do not have that ability. Take a look at the CUS of GSLV MkII., it is throttled for a brief duration at a higher thrust to 82 KN before throttling back to 73 KN.

One more is engine restarts. Well MOM had so many start/stops to do gravity pumping (which was *stupidly* portrayed in martian) to cite an example.

And BTW, all rocket engines carry their own oxidizers - it is either liquid oxygen or N204 or NH4CL04 (ammonium per chlorate).

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Re: Indian Space Programme Discussion - Sept 2016

Postby sohamn » 05 May 2017 03:16

Singha wrote:What is the advantage of liquid engine in 3rd stage vs a solid motor? Does lack of O2 up there means only liquid is possible?

How then do icbm use solid motor in 3rd stage?


All solid motors have their own solid fuels and solid oxidizers. No ICBM and SLVs are air breathing, none depend on atmospheric oxygen. Some motors infact dont need oxidizers at all as they may be electric and mean't for final stage.

Liquid engines have better specific impulse Ispv than solid motors as they are more energy efficient. And specific impulse matters a lot on upper stages as the specific impulse in vacuum for liquids is even more than solid. But solid motors are not complicated, provides a lot of thrust and is cheap to build.

Hence, ISRO prefers solids for 1st stages or boosters ( because thrust is more important for liftoff ) and earth storable liquids in second and cryo in upper. Its a tradeoff with thrust/efficiency and cost. For some western countries where cost is not so important, they might use cryo in first or booster stage as well - for e.g. delta 5 - but it requires really complicated engine and may be clustering to achieve same level of thrust as solids generate. But because of very high Isp - they have greater payload capacity than a similar sized ISRO rocket.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Gagan » 05 May 2017 07:31

Any links to the launch?

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Re: Indian Space Programme Discussion - Sept 2016

Postby Gagan » 05 May 2017 07:37

Ariane 5 is back and GSLV launches for India! | kNews W.18/2017

https://www.youtube.com/watch?v=iGxTUf9zSEY

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Re: Indian Space Programme Discussion - Sept 2016

Postby Neshant » 05 May 2017 08:05

Excellent idea for space science.

Much better bang for the buck than spending tons of money on a space station with zero commercial value & limited returns on science/tech.


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Re: Indian Space Programme Discussion - Sept 2016

Postby SSridhar » 05 May 2017 08:21

Gagan wrote:Any links to the launch?


No media glare for South Asia Satellite - The Hindu
A communication spacecraft, the South Asia Satellite, which will serve India and six of its regional neighbours, is set to lift off from Sriharikota off Andhra Pradesh on Friday evening.

Some bare information on this regional diplomatic overture apart, mystery shrouded the civil mission until late on the eve of the launch. The 2230-kg spacecraft will be launched on a GSLV, the Indian Space Research Organisation’s medium-lift rocket, numbered F09.

A normally transparent ISRO has been unusually reticent about a less than routine launch. The time of the launch has a cryptic clue - one must infer it as 4.57 p.m. from the duration of the countdown. There will be no live telecast. Brochures that would be routinely released about five days ahead of a mission are still to be uploaded on the ISRO website.

Three earlier exceptions

Mediapersons will not cover a launch for the first time in a decade; normally ISRO would ferry about 200 reporters from different places to Sriharikota to witness a launch.

Among the three earlier exceptions was the launch of of Israel’s spy satellite, TecSAR, on a PSLV in January 2008.

ISRO functionaries said, “This is our mandate. We don’t know much about all this, either.”


GSAT-9 was planned years ahead to augment Internet broadband and DTH activities within the country.

It is not known if Prime Minister Narendra Modi, who offered the spacecraft for the region, or dignitaries from those nations will witness the launch.

This much is known: a 28-hour countdown began for the GSLV mission at 12.57 p.m. on Thursday, along with other pre-launch activities, according to the space agency’s one-liner put out in the afternoon.

GSLV-F09 is slated to take off with the 2,230-kg satellite at 4.57 p.m. on Friday.

The communication spacecraft carries 12 Ku-band transponders that can drive telecommunication, disaster management, broadcasting and direct to home TV, Internet activities, tele-education and telemedicine across the region. It was first announced as SAARC Satellite by the Prime Minister in July 2014 as India's gift to regional neighbours. After Pakistan declined to participate, Afghanistan, Bangladesh, Bhutan, The Maldives, Nepal and Sri Lanka remain in the plan to reap its uses.

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Re: Indian Space Programme Discussion - Sept 2016

Postby naruto » 05 May 2017 08:24

ToI reports that the launch is predominantly in-house affair with no major representatives​ from​ saarc except some diplomats​ from Delhi. Doordarshan it seems is not covering the launch. They're​ deliberately keeping it a low key affair. PM is not available for launch even from his office.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Gagan » 05 May 2017 08:28

No Live telecast!
Very sad... :evil:
Because this is a developmental flight?

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Re: Indian Space Programme Discussion - Sept 2016

Postby SwamyG » 05 May 2017 09:24

TV channels are talking about this in their news segment.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Neshant » 05 May 2017 09:26

An interesting documentary on British efforts at building a space lander for Titan

Something of importance for India's space lander efforts to Mars.

Admin note: deleted inline video. post such links in international aerospace thread

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Re: Indian Space Programme Discussion - Sept 2016

Postby hnair » 05 May 2017 12:16

Neshant wrote:An interesting documentary on British efforts at building a space lander for Titan

Something of importance for India's space lander efforts to Mars.



If you have something to elaborate why it is important for India, please do. Simply posting a link to a non-ISRO story on an ISRO thread and saying it is related is not helpful

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Re: Indian Space Programme Discussion - Sept 2016

Postby juvva » 05 May 2017 14:17

Gagan wrote:No Live telecast!
Very sad... :evil:
Because this is a developmental flight?


This may be a blessing in disguise. If the recording is raw audio/video from the control room, without any DD commentary. We may finally get to hear the controller call outs clearly.

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Re: Indian Space Programme Discussion - Sept 2016

Postby juvva » 05 May 2017 14:22

Not sure if this will be a live or delayed stream:

https://www.youtube.com/watch?v=4Tbi4W9m5BY

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Re: Indian Space Programme Discussion - Sept 2016

Postby Kakarat » 05 May 2017 15:53

As per my Airtel DTH schedule Live telecast of GSLV launch to start at 4:30 PM in DD Pothigai

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Re: Indian Space Programme Discussion - Sept 2016

Postby Gagan » 05 May 2017 16:12

Hajaar dhanyavaads

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Re: Indian Space Programme Discussion - Sept 2016

Postby Singha » 05 May 2017 16:46

for unknown reasons launch is in total secrecy mode. is it because of some suspected sabotage attempt on the 2nd launch pad or assembly building for the GSLV mk3 which is upcoming?

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Re: Indian Space Programme Discussion - Sept 2016

Postby JTull » 05 May 2017 16:48

Shiv Aroor on twitter

"India Roars In Space, Paranoid Pak Sulks! LIVE coverage of India's new 'Spacegiri' - launch of GSAT-9 coming up on 5IVE LIVE from 4.55pm."

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Re: Indian Space Programme Discussion - Sept 2016

Postby Ashokk » 05 May 2017 16:49


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Re: Indian Space Programme Discussion - Sept 2016

Postby Gagan » 05 May 2017 16:52

No telecast anywhere !

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Re: Indian Space Programme Discussion - Sept 2016

Postby Singha » 05 May 2017 16:53

amazing!

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Re: Indian Space Programme Discussion - Sept 2016

Postby Singha » 05 May 2017 16:54

hope its not another CBM with TSP!

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Re: Indian Space Programme Discussion - Sept 2016

Postby uddu » 05 May 2017 16:56

Podigai live: Eat millet's more than rice, because it gives more nutrients and do have less carbohydrates. :D
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