Indian Space Program: News & Discussion - Sept 2016

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Re: Indian Space Programme Discussion - Sept 2016

Postby srin » 27 Oct 2017 13:56

The heat shield may still be attached, but it doesn't have a parachute, no? Even assuming that the payload doesn't burn up at all on reentry (hard to believe), impacting the ocean at hypersonic terminal speeds means, there probably won't be anything left to indicate it was even part of the satellite.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Ashokk » 30 Oct 2017 21:57

Make in India: Joint venture of Isro and private firms to launch rocket by 2020
Isro chairman AS Kiran Kumar on Monday said that inadequate pressure in the bellow pump resulted in the heat shield not separating from the satellite, resulting in a failure of the mission on August 31.
The PSLV C-39 was carrying the IRNSS-1H was then declared an unsuccessful mission. The committee looking into the failure analysis, Kumar said, has found that the automated commands were performed accurately.
"There was no fundamental problem, that's clear. A system that has performed so well on so many occasion could not just go wrong. The failure happened because there was not enough pressure in the bellow pump, which resulted in the non-separation," Kumar said.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Amber G. » 07 Nov 2017 01:09

India's Astrosat and its CZTI (Cadmium Zinc Telluride Imager) was in limelight in its role about the recent big LIGO/Neutron Start inspiral discovery. (see many posts here or in Physics dhaga around October 20). Kilonova which was detected here on earth by LIGO and 70+ observatories around the world in many EM spectrum as well as Gravitational waves .

There is another significant achievement by Astorsat and CZTI - which ought to be a major news item.

It's sensitive CZTI has measured X-ray polarization of Neutron star - Famous pulsar in Crab Nebula remnant of super-nova (SN 1054). For those, not familiar with this event which happened in 1054 AD was recorded by astronomers, and people, all over the world. One can not miss it as this was the most bright event (apart from moon) in night sky -- one can see this even in daylight.

Anyway for such a short time ( year or so) of operation," CZTI has recorded several gamma-ray bursts, measured the phase resolved hard X-ray polarization of the Crab pulsar, and the hard X-ray spectra of many bright Galactic X-ray binaries. The excellent timing capability of the instrument has been demonstrated with simultaneous observation of the Crab pulsar with radio telescopes like GMRT and Ooty radio telescope." VERY IMPRESSIVE!

Here is the Arxiv paper:
Cadmium Zinc Telluride Imager onboard AstroSat : a multi-faceted hard X-ray instrument

A. R. Rao, D. Bhattacharya, V. B. Bhalerao, S.V. Vadawale, S. Sreekumar

The AstroSat satellite is designed to make multi-waveband observations of astronomical sources and the Cadmium Zinc Telluride Imager (CZTI) instrument of AstroSat covers the hard X-ray band. CZTI has a large area position sensitive hard X-ray detector equipped with a Coded Aperture Mask, thus enabling simultaneous background measurement. Ability to record simultaneous detection of ionizing interactions in multiple detector elements is a special feature of the instrument and this is exploited to provide polarization information in the 100 - 380 keV region. CZTI provides sensitive spectroscopic measurements in the 20 - 100 keV region, and acts as an all sky hard X-ray monitor and polarimeter above 100 keV. During the first year of operation, CZTI has recorded several gamma-ray bursts, measured the phase resolved hard X-ray polarization of the Crab pulsar, and the hard X-ray spectra of many bright Galactic X-ray binaries. The excellent timing capability of the instrument has been demonstrated with simultaneous observation of the Crab pulsar with radio telescopes like GMRT and Ooty radio telescope.


There are a few regular papers mentioning this (more may follow) but as someone said "Indian astronomers obtain the most precise hard X-ray polarization measurements of the Crab pulsar so far" -- which will help understand Neutron (this pulsar).

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Re: Indian Space Programme Discussion - Sept 2016

Postby Amber G. » 08 Nov 2017 11:14

^^^^
Amber G. wrote:India's Astrosat and its CZTI (Cadmium Zinc Telluride Imager) was in limelight in its role about the recent big LIGO/Neutron Start inspiral discovery. (see many posts here or in Physics dhaga around October 20). Kilonova which was detected here on earth by LIGO and 70+ observatories around the world in many EM spectrum as well as Gravitational waves .

There is another significant achievement by Astorsat and CZTI - which ought to be a major news item.
<snip>
.

Here is one newspaper article from today:
Isro’s multi-wavelength space telescope AstroSats’ breakthrough discovery
AstroSat measurement of polarisation of X-ray emission from the Crab Pulsar
Image
CHENNAI: Isro’s multi-wavelength space telescope AstroSat has made a breakthrough discovery in X-ray emission while helping the Indian scientists to solve one of the puzzles in astronomy that is to measure the elusive properties of high energy X-rays. These properties of high energy X-rays can throw more light on their sources which include neutron stars (pulsars) and black holes. In a paper published in ‘Nature Astronomy’, a team of scientists has documented the results of their study of the Crab pulsar in the Taurus constellation.

Using data from the CZT Imager instrument of the AstroSat, the scientists have performed the most sensitive measurement of X-ray polarisation of the Crab pulsar, the rotating pulsar which is the main energy source of the nebula. The measurements have for the first time enabled the study of polarization at different rotation phases of the pulsar. It has revealed the strange polarisation of Crab Pulsar which challenges the prevailing theories of high energy X-ray emission from pulsars. “This new paradigm can throw new light on our understanding of pulsars. This is fully an Indian discovery involving Indian scientists and telescopes,” said Professor Santosh Vadawale of Physics Research Laboratory, Ahmedabad and the lead author of this paper.

“Current theories say all emissions are coming from inside the light cylinder. But, these results suggest that it cannot come from inside, so it has to come from outside. So, that new theoretical understanding of pulsars has to be developed,” he added. “In X-ray polarisation, we observed the emissions even when the beams are not pointing towards us which also known as off pulse duration,” Professor Dipankar Bhattacharya of IUCAA, Pune, and co-author of this paper told Deccan Chronicle. He gave an example of the lighthouse to explain the discovery. ““Like a lighthouse, it was believed, the rotating pulsars emit radiation when the beams are pointing towards us. But, in our X-ray polarization we have discovered that the Crab Pulsar emit radiation even beams not pointing towards us,” he explained.

This discovery potentially redefines the concept of how pulsars emitting the X-rays. X-ray polarisation measurement is very difficult and so far the only reliable measurement obtained worldwide is for the pulsar in the Crab Nebula – the ghostly remains of a massive stellar explosion known as the supernova, observed in 1054 AD. To get the micro-second accuracy required for combining the data, the AstroSat team sought help from radio telescopes – the Indian Giant Meterwave Radio Telescope (GMRT), at Khodad near Pune and Ooty Radio Telescope. The team monitored radio pulsations from Crab and meticulously corrected for all known anomalies. The scientists after spending several months on the data came up with the best measurements of Crab X-ray polarisation in the world.

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Re: Indian Space Programme Discussion - Sept 2016

Postby abhik » 22 Nov 2017 08:37

Isro's plan: A rocket that can be made in 3 days
As per this ISRO is developing a 100t launcher which will cost "1/10 of original manufacturing cost of PSLV", payload of 500-700kg and will be ready to launch by end of 2018 or early 2019. Was there reports of this earlier or did ISRO just pull a rabbit out of the hat?

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 23 Nov 2017 06:46

This is very interesting.

The PSLV-3s was proposed low-cost/low payload variant to lift 500-700 kg to LEO (2000 km?). It was to be achieved by removing the boosters and the second stage. Such a config would be around 200 Tons.

This is something new. This is an even lighter version with an even lighter payload capacity What could this possible configuration be?
First stage: PS 2 (current second stage) + 2/3 PSOMs
Second stage: PS 3 (current 3rd stage)
Third stage: PS 4 (current 4th stage)

But will this config with the L40 stage be cheap? Any other config that you guys can think of?

First stage: 6 PSOMs + PS 3 (current 3rd stage)
Second stage: PS 4 (current 4th stage)

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Re: Indian Space Programme Discussion - Sept 2016

Postby abhik » 23 Nov 2017 10:11

I was hoping for new launcher of this size but to quickly develop/demonstrate technologies like all liquid stack, horizontal integration, first stage (maybe even second stage) reusability etc.
BTW any reason not to use a cryogenic upper stage, may be the CE 7.5 - too expensive?

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 23 Nov 2017 11:53

I think this will be all solid affair if everything has to go in 3 days and the price is 1/10th that of PSLV. The first stage of PSLV is over 140 Tons, so that is out of the picture.

The Rohini RH-560/300 Mk II sounding rocket can already lift 100 kgs to such an orbit.

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Re: Indian Space Programme Discussion - Sept 2016

Postby symontk » 23 Nov 2017 12:34

Indranil wrote:This is very interesting.

The PSLV-3s was proposed low-cost/low payload variant to lift 500-700 kg to LEO (2000 km?). It was to be achieved by removing the boosters and the second stage. Such a config would be around 200 Tons.

This is something new. This is an even lighter version with an even lighter payload capacity What could this possible configuration be?
First stage: PS 2 (current second stage) + 2/3 PSOMs
Second stage: PS 3 (current 3rd stage)
Third stage: PS 4 (current 4th stage)

But will this config with the L40 stage be cheap? Any other config that you guys can think of?

First stage: 6 PSOMs + PS 3 (current 3rd stage)
Second stage: PS 4 (current 4th stage)


Technically, you can use Agni5 first stage for the purpose

Or another one is to use 1 segment (60 - 70 tons) from LVM3 strapons (200 tons in total), with PS3 and PS4. Since it is only a single segment there is no time wasted for costly integration as for PSLV / GSLV (Each of the 5 segments of the first stage of these rockets needs to be integrated)

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 23 Nov 2017 17:01

Agni-V will be a 50-ton launcher.

The thrust of the S200 engines will be too much for a 100 ton launcher. If a stage has to be modified to obtain the launcher, the easiest path would be to modify the S139 (first stage of PSLV) of the PSLV-3S config.

Alternatively, substitute the first stage of the PSLV-3s config with 4 PSoms strapped directly to its second stage. The boosters act as the first stage, peel off, and the second stage takes over.

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Re: Indian Space Programme Discussion - Sept 2016

Postby JE Menon » 23 Nov 2017 18:02

Nambi Narayanan, speaking about his framing as a spy by as yet unknown parties through local agencies...

https://www.youtube.com/watch?v=M_fNzUjO8ks

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Re: Indian Space Programme Discussion - Sept 2016

Postby JTull » 23 Nov 2017 21:55

Seems they're looking to develop capability to replace IRNSS sats in a hurry due to their strategic nature. A modern version of ASLV!.

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Re: Indian Space Programme Discussion - Sept 2016

Postby symontk » 23 Nov 2017 23:10

Indranil wrote:Agni-V will be a 50-ton launcher.

The thrust of the S200 engines will be too much for a 100 ton launcher. If a stage has to be modified to obtain the launcher, the easiest path would be to modify the S139 (first stage of PSLV) of the PSLV-3S config.

Alternatively, substitute the first stage of the PSLV-3s config with 4 PSoms strapped directly to its second stage. The boosters act as the first stage, peel off, and the second stage takes over.


Yes its a good config actually more efficient than solid one, Only hitch being 3 day prep time, it may not be possible with a liquid engine

Actually if 2 of the Agni3/5 first stages can be used instead of current PSOM's better thrust can be obtained. Also instead of PS3 and PS4, CE7.5 can be used. But again cost and time taken will not change from current PSLV

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 24 Nov 2017 00:08

Agni 5 in its entirety can launch a 200-300 Kg satellite as per some reports if I can recollect correctly.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 24 Nov 2017 02:10

Actually, I have been thinking why is ISRO waiting for the SC-160 stage to start with the ULV?

Won't replacing the S200 strapons on the GSLV Mk3 with S139 strapons give an GSLV Mk2 equivalent? In fact, I am guessing that the payload capacity will be between 3.0-3.5 Tons to GTO.

Similarly, won't replacing them with 6 PSOMs give us a PSLV-XL equivalent? Only its LO mass will be 240 Ton mark.

Whenever the SC160 arrives, swap it in with the L110.

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Re: Indian Space Programme Discussion - Sept 2016

Postby ArjunPandit » 24 Nov 2017 02:16

prasannasimha wrote:Agni 5 in its entirety can launch a 200-300 Kg satellite as per some reports if I can recollect correctly.

Interesting perspective, i always wondered about it, will the other way be true sir?

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 24 Nov 2017 09:22

The L110 is an interim arrangement till the semicryo engine is validated. L110 was and is an interim arrangement done for 2 reasons one because we don't have a semicryo engine and two we did not have knowledge of clustering of engines. The latter was achieved with L110. Once we get our semicryo working things will change. So also our LOXmethane program. The semicryo facility has been constructed ,valudation and tests must be going on.
One must not forget the complex geopolitical play in these. Think why the original testing in another country was abandoned and we had to urgently establish facilities in India. People deride the GSLV Mk2 but while it was well known to be inefficient it was the best we could make with what technology we had. When some essential steps are mastered the next step evolves and that's what ISRO does

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 24 Nov 2017 09:28

ArjunPandit wrote:
prasannasimha wrote:Agni 5 in its entirety can launch a 200-300 Kg satellite as per some reports if I can recollect correctly.

Interesting perspective, i always wondered about it, will the other way be true sir?

I did not understand though if you think of it it precisely means a fractional orbital path with a lower payload may be possible but the issue will be size of re-entry vehicle

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 24 Nov 2017 09:35

Indranil wrote:Actually, I have been thinking why is ISRO waiting for the SC-160 stage to start with the ULV?

Won't replacing the S200 strapons on the GSLV Mk3 with S139 strapons give an GSLV Mk2 equivalent? In fact, I am guessing that the payload capacity will be between 3.0-3.5 Tons to GTO.

Similarly, won't replacing them with 6 PSOMs give us a PSLV-XL equivalent? Only its LO mass will be 240 Ton mark.

Whenever the SC160 arrives, swap it in with the L110.

The core for the ULV family will be the semicryo +cryo stack and what you mentioned is what has been articulated decades ago. The issue is that you have to get your stack components first. We now have CE20 ( incidentally the most powerful or rather longest firing upper stage today due to our launch constraints ) So when we get SC stage things will change.
One thing though space research and implementation is about reliability first so mix and match is easier said than done. Just wonder why GSLVMk3 booster nose cones were changed from a delta4 type to an Ariane type ? If you see CAREexperiment flight path you will get an idea. Small changes can have big repurcussions

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 24 Nov 2017 12:26

I understand the purpose of the L110. That is not my question.

According to the latest dates given out by LPSC chief SC160 will flight-ready by end of 2021. Add a year or two to that. Till then, the L110 and the cryo stages already in place. We can start testing out the ULC configs. 6 PSOMs for PSLV equivalent. 2 S139s for GSLV Mk2 equivalent and 2 S200s for GSLV Mk3. The last one has already been flight tested twice.

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 24 Nov 2017 12:51

The GSLV Mk2 depends on an outer liquid strapons for starting precisely to avoid solid rocket initiation in case of launch abort situation as solids cannot be shut off when started so option 2 is not practical in the GSLV Mk2 .

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 24 Nov 2017 12:54

The gslvmk3 is still a D configuration ie still developmental. I don't they will tinker that till it is stabilized and completely validated

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 24 Nov 2017 14:35

prasannasimha wrote:The GSLV Mk2 depends on an outer liquid strapons for starting precisely to avoid solid rocket initiation in case of launch abort situation as solids cannot be shut off when started so option 2 is not practical in the GSLV Mk2 .

I am not speaking about modifying Mk2. Take GSLV Mk3, remove the S200s, add S139s. Is this possible? If not. Why?

prasannasimha wrote:The gslvmk3 is still a D configuration ie still developmental. I don't they will tinker that till it is stabilized and completely validated

After 2 more developmental flights?

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 24 Nov 2017 16:10

d2 IS IN 2018 TO LAUNCH GSAT 29. Any major revisions of a launch vehicle can only be done after significant trials. Even the PSLV XL was made after the lauch of the original PSLV was stabilized.
Incidentally the mini PSLV is likely to be

3-stage PSLV
- 2nd stage of the 4-stage version removed
- Capable of placing 500 kg to LEO

https://web.archive.org/web/20110710163553/http://www.earth2orbit.com/pdf/PSLV.PDF

http://spl.gov.in/nsss2016/Program/web/SPS/SPS-1-2.pdf[url]
[/url]
https://web.archive.org/web/20110524225122/http://www.ias.ac.in/currsci/dec252007/1697.pdf

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 24 Nov 2017 16:13

From the article by Dr Sivan

A three-stage configuration without strap-on motors and
liquid stage will offer lower launch cost of 500 kg class
of satellites into LEO.

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 24 Nov 2017 16:17

Image

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 24 Nov 2017 16:28

So eliminating second sage refueling essentially means using solid rockets for primary lift and the only liquid stage will be the neo 3rd (old 4th stage) allowing a quicker turnover and launch campaign as solid rockets will be available "off the shelf"

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 24 Nov 2017 16:38

wrt replacing and mixing and matching wrt SC200 that is the plan as per reports but now nose cone modifications may have to be done.In fact with a C50 and two s250 the heavy launcher will be able to lift 9 Tons to GTO. Also the core alone will be able to lift 3.5 Tons so for lower weights it will still be PSLV

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 25 Nov 2017 06:55

Prasanna sir, please see my first post on this subject
Indranil wrote:The PSLV-3s was proposed low-cost/low payload variant to lift 500-700 kg to LEO (2000 km?). It was to be achieved by removing the boosters and the second stage. Such a config would be around 200 Tons.

I wonder if they did design the S60 stage that they had discussed as a booster for the ULV.

For the future, it will b e ULV/HLV combination. PSLV, GSLV Mk2 and GSLV Mk3 will be retired and replaced by the ULV-L, ULV-M and ULV-H respectively. ULV-H will eventually be replaced by TSTO core only.

The caps are not that difficult a problem to solve.

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 25 Nov 2017 07:11

The caps were actually a signifcant problem to solve but they did it. Remember the flight deviation in the LVM3/CARE experiment. Our on-board correction closed loop guidance saved the day but the open truss under the cryo engine with vertical cones was mostly the cause. If you see the subsequent launch all that was changed .
Space agencies are loath to change what works so till the ULV family is validated they will not mix and match. Why will they spend millions on flight validation of an interim temporary solution .
Making a required solid booster like S60 per we will not be a problem. Changing the cone will not be a manufacturing problem .Validating it with the added launcher combo will be the problem requiring simulations etc and validating it with observed values. Currently we dont have enough data to reliably set our baseline values versus modeled values so I presume they will be careful and cautious. Space industry is loath to change what works and just imagine what our detractors and our own people would be screaming of we have blow ups like space X that latitude will not be given to us. Remember how things were when our cryo program was in trouble. That will haunt anyone.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 25 Nov 2017 07:25

Yes, there is no substitute to validation through flight testing. And that is the most time and money-wise expensive part. So, why not start early? We have a very good test vehicle which differs from the ULV in only one stage.

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Re: Indian Space Programme Discussion - Sept 2016

Postby disha » 25 Nov 2017 08:11

Indranil wrote:I understand the purpose of the L110. That is not my question.

According to the latest dates given out by LPSC chief SC160 will flight-ready by end of 2021. Add a year or two to that. Till then, the L110 and the cryo stages already in place. We can start testing out the ULC configs. 6 PSOMs for PSLV equivalent. 2 S139s for GSLV Mk2 equivalent and 2 S200s for GSLV Mk3. The last one has already been flight tested twice.


Why? The reverse is even a better path - S140s can be retired and S200 can be used in place for GSLV Mk 2.

GSLV Mk2 without the liquid boosters can become the "stick rocket".

PSLV 'low cost' variant (500-700 Kg to LEO) indicates that the market for reliable "pocket rockets" is alive and kicking. What happened to the idea of bigger and bigger and even bigger payloads?

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 25 Nov 2017 08:21

The L110 conformation is not the same as the semicryo. This L110 a flatter two pack cluster whereas the Semicryo is cylindrical so how will the data match? One truss or fin causes enough problems so this itself will be major.
As far as bigger and bigger now it is two ways bigger and bigger for telecom (more trandponders) but even that is changing with better electronics but smaller and more efficient for others. The 4 ton class will be replaced by more efficient 2 ton class in the coming decades.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 25 Nov 2017 08:35

Except for the business end of the L110, everything is perfectly circular.

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 25 Nov 2017 09:40

That is perfectly enough to change the flow parameters precluding a simple swap without realisation.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 25 Nov 2017 10:08

disha wrote:
Indranil wrote:I understand the purpose of the L110. That is not my question.

According to the latest dates given out by LPSC chief SC160 will flight-ready by end of 2021. Add a year or two to that. Till then, the L110 and the cryo stages already in place. We can start testing out the ULC configs. 6 PSOMs for PSLV equivalent. 2 S139s for GSLV Mk2 equivalent and 2 S200s for GSLV Mk3. The last one has already been flight tested twice.


Why? The reverse is even a better path - S140s can be retired and S200 can be used in place for GSLV Mk 2.

GSLV Mk2 without the liquid boosters can become the "stick rocket".

PSLV 'low cost' variant (500-700 Kg to LEO) indicates that the market for reliable "pocket rockets" is alive and kicking. What happened to the idea of bigger and bigger and even bigger payloads?

I did not go down that path because ISRO is unlikely to. ISRO has clearly stated that the future is ULV and HLV designs. All I am saying is that everything for the ULV except the SC160 stage is ready. So start flight testing! Infact, GSLVMk3 core + 2 S130s will most likely going to have a payload fraction close to 0.7% instead of GSLVs 0.5%. I can be accused of undue haste as GSLV-Mk3 has to go through 2 more developmental flights before, it can be considered for tinkering.


None-the-less, the stick model of GSLV with S200 is a nice mental exercise. How much do you think, it will outperform PSLV-XL by? Essentially the S139+6 PSOMs have the same mass as the S200. They just burn faster and would provide the PSLV a faster initial acceleration. But the later stages of the GSLV are more efficient. So, I don't know how much will the GSLV-core alone version will come ahead by.

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 25 Nov 2017 14:13

In lower stages as mentioned by Von Braun you want more thrust while penetrating the dense atmosphere. Later you want lsp. So core alone GSLV will have that issue so while doable will probably be costlier. That is why even the space shuttle relied on SRB's. Probably when me master fully semicryo and multiple clustering we may move in that direction

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Re: Indian Space Programme Discussion - Sept 2016

Postby disha » 27 Nov 2017 12:24

Indranil wrote:I did not go down that path because ISRO is unlikely to. ISRO has clearly stated that the future is ULV and HLV designs. All I am saying is that everything for the ULV except the SC160 stage is ready. So start flight testing! Infact, GSLVMk3 core + 2 S130s will most likely going to have a payload fraction close to 0.7% instead of GSLVs 0.5%.


I think ULV is still a proposal., basically on the drawing boards. It may happen or it might still remain on drawing board till SCE comes on board.

Put it this way., if most of the building blocks are available and already tested., why strap them together into a new design while waiting for the key SC 160 which will change the design anyway!

Take GSLV MkIII - it is designed for 2xS200 + L110 + C25. The flight algorithm is optimized for that design. What is the point on strapping in 2 x S139s to the design., since the entire design changes. The L110 has to start burning earlier and that means the C25 also burns earlier., there is a penalty in payload. But again to what purpose? The S139s are already tried and tested and works!

So when the SC 160 comes., then one can as well replace the L110 and call it GSLV Mk 3.2 or ULV 1.0 and go from there. That will be new line of ULV with SC-160+C25 as stick and progressively going with 6 PSOMs or 2 S139s or 2 S200s with a different flight profile.

In effect., one cannot "hurry the ULV" project since for the ULV the proposal is to use the SCE (as in SC-160) as the core., the rest of the pieces hanging on the core or sitting on top of the core is already validated! Only the core remains., and till the SC-160 stage is validated (first the SCE itself needs to be validated!)

Now coming to GSLV-Mk II - "Stick model"., the pieces are already there.

Here is the current spec of GSLV - Mk II (ignoring the liquid boosters): S 139/Diameter 2.8m + GS 2 Vikas / Dia 2.8 m + Cus 12 / Dia 2.8 m.

My point is that the tankage of GS 2 Vikas and CUS 12 can be increased from 2.8 m diameter to 3.2 m diameter. The engines remain the same., and this will give additional burn time for the engines. Now one can slew the S200 (diameter 3.2 m) to this Stick only GSLV - Mk II.2 and have an uprated rocket. Of course., liquid boosters can be added back in if required. Let's call this fattened GS2 Vikas and CUS12 as extended GS2 and extended CUS12

Here the engines are already tried and tested., the stages need to be validated (new tankage & trusses) but that is an easier path.

GSLV Mk2 will be in use for another decade or so., and this will provide an upgrade to GSLV Mk2 capabilities. Further between PSLV - Stick model and GSLV Mk-III., there is a dire need of a launch vehicle that takes some 5 to 7 tonnes to LEO. This is also the vehicle for research sats like chandrayaan/mangalyaan/astrosats etc., where PSLV does not suffice and GSLV - Mk3 is an overkill.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 27 Nov 2017 13:22

If you remember, I had proposed a 3.2 mtr dia GSLV long back. But, the stick model won't work. But, I don't think the stick model will have enough oomph at lift off. We are speaking of TWR of 1.2 to 1.3 only.

The same goes for ULV. Its stick model will definitely not work. That's only 2000 kN for a rocket which weighs over 200 Tons. Boosters will always be needed.

Image

The stick model will only come with TSTO or HLV 1.0 where 5 of the SC200 engines are clustered for the first stage.

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Re: Indian Space Programme Discussion - Sept 2016

Postby symontk » 27 Nov 2017 13:58

disha wrote:
Indranil wrote:Now coming to GSLV-Mk II - "Stick model"., the pieces are already there.

Here is the current spec of GSLV - Mk II (ignoring the liquid boosters): S 139/Diameter 2.8m + GS 2 Vikas / Dia 2.8 m + Cus 12 / Dia 2.8 m.

My point is that the tankage of GS 2 Vikas and CUS 12 can be increased from 2.8 m diameter to 3.2 m diameter. The engines remain the same., and this will give additional burn time for the engines. Now one can slew the S200 (diameter 3.2 m) to this Stick only GSLV - Mk II.2 and have an uprated rocket. Of course., liquid boosters can be added back in if required. Let's call this fattened GS2 Vikas and CUS12 as extended GS2 and extended CUS12

Here the engines are already tried and tested., the stages need to be validated (new tankage & trusses) but that is an easier path.


These are significant changes and basically a new rocket. ISRO's direction is to move vehicles in the LVM3 architecture of strapon boosters, with engines in the main body. This is gives the engine start flexibility for various variants, orbits and missions. Also the current PSLV / GSLV designs greatly successful are not optimal. ISRO needs to move to an efficient design otherwise countries like South Korea might come up with better designs in near future (impacts of Korean crisis)

GSLV Mk2 will be in use for another decade or so., and this will provide an upgrade to GSLV Mk2 capabilities. Further between PSLV - Stick model and GSLV Mk-III., there is a dire need of a launch vehicle that takes some 5 to 7 tonnes to LEO. This is also the vehicle for research sats like chandrayaan/mangalyaan/astrosats etc., where PSLV does not suffice and GSLV - Mk3 is an overkill.


This is the exact reason why there is requirement of ULV type of vehicles with proven variants. Lets wait for that. But two variants that ISRO can very well test is that of 2*S60 + L110 + PS4 and 2**S60 + L110 + CE7.5 which will effectively replace PSLV as we see now. maybe not PSLV-3S

For GSLV replacement, ULV variants can do

2**S60 + SC160 + CE7.5
2**S60 + SC160 + CE25
2**S139 + SC160 + CE25
2**S200 + SC160 + CE25
2**S200 + SC160 + CE60


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