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Indian Space Programme Discussion - Sept 2016

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Indian Space Programme Discussion - Sept 2016

Postby dhiraj » 25 Aug 2016 09:34

old thread
viewtopic.php?f=3&t=6652&start=3920
============================

http://www.thehindu.com/sci-tech/airbre ... 027578.ece

According to ISRO Chairman A.S. Kiran Kumar, while the test would take place on August 28, the GSLV-F05 rocket with an indigenous cryogenic engine would lift-off on September 8. A Polar Satellite Launch Vehicle (PSLV) will lift off on September 26. While these three missions would take place from Sriharikota, an Ariane-V launch vehicle from Arianespace will put India’s communication satellite, GSAT-18, into orbit from Kourou in French Guiana on October 4.

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Indian Space Programme Discussion - Sept 2016

Postby Varoon Shekhar » 28 Aug 2016 07:16

I think the scramjet test was successful! Can't provide link due to some silly problem with 'adblocker'. From Timesofindia.

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Re: Indian Space Programme Discussion

Postby Varoon Shekhar » 28 Aug 2016 07:28

http://www.ndtv.com/india-news/isro-to- ... eststories

But lousy editing brought Insat 3DR into the picture. What does that have to with the scramjet test? "Bring down the cost of weather satellite.."' Yah maybe in some future launch, not in some impending one. Geeez!

ISRO Successfully Conducts Scramjet Engine Test Today

Indian weather satellite launch has now been postponed to September 8.
Chennai:
Highlights

The test was conducted at Satish Dhawan Space Centre early in the morning
The Indian weather satellite launch was postponed to September 8
The weather satellite will be mounted on to the rocket in 3-4 days

The Indian Space Research Organisation (ISRO) successfully conducted scramjet engine test today at Satish Dhawan Space Centre (SDSC) in Sriharikota in Andhra Pradesh around 80 km from Chennai.

The rocket took off at 6 am today.

The scramjet engine, used only during the atmospheric phase of the rocket's flight, will help in bringing down the launch cost of weather satellite INSAT-3DR by reducing the amount of oxidiser to be carried alo

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Re: Indian Space Programme Discussion

Postby SaiK » 28 Aug 2016 09:01

try not to refer undietv here. just a request onree.

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Re: Indian Space Programme Discussion

Postby shiv » 28 Aug 2016 09:28

http://www.thehindu.com/news/national/i ... 042486.ece
The test-flight of the indigenously-developed supersonic combustion ramjet engine took place from the Satish Dhawan Space Centre in Sriharikota at 6 a.m.

India on Sunday morning successfully tested its own scramjet or the air-breathing engine with the launch of a big sounding rocket, said a senior official of Indian Space Research Organisation.

“The mission was successful. Two scramjet engines were tested during the flight. The finer details about the test will be known later,” the official not wanting to be quoted told IANS.

He said that as scheduled the two stage/engine RH-560 sounding rocket took off from the rocket port located at Satish Dhawan Space Centre in Sriharikota.

He said the two air-breathing engines were like hugging the rocket on its sides and normally when the rocket reaches a height of 11 km the scramjet engines would start breathing air.

“The scramjet engines were ignited 55 seconds into the rocket’s flight. The engines were tested for six seconds,” he added.

The scramjet engine, used only during the atmospheric phase of the rocket’s flight, will help in bringing down the launch cost by reducing the amount of oxidiser to be carried along with the fuel.

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Re: Indian Space Programme Discussion

Postby Ashokk » 28 Aug 2016 12:51

Successful Flight Testing of ISRO's Scramjet Engine Technology Demonstrator
After a smooth countdown of 12 hours, the solid rocket booster carrying the Scramjet Engines, lifted off at 0600 hrs (6:00 am) IST. The important flight events, namely, burn out of booster rocket stage, ignition of second stage solid rocket, functioning of Scramjet engines for 5 seconds followed by burn out of the second stage took place exactly as planned.

After a flight of about 300 seconds, the vehicle touched down in the Bay of Bengal, approximately 320 km from Sriharikota. The vehicle was successfully tracked during its flight from the ground stations at Sriharikota.

Image
Image
More photos in the article.

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Re: Indian Space Programme Discussion

Postby prasannasimha » 28 Aug 2016 14:13

Official statement
http://www.isro.gov.in/update/28-aug-2016/successful-flight-testing-of-isros-scramjet-engine-technology-demonstrator

Aug 28, 2016
Successful Flight Testing of ISRO's Scramjet Engine Technology Demonstrator
The first experimental mission of ISRO’s Scramjet Engine towards the realisation of an Air Breathing Propulsion System was successfully conducted today (August 28, 2016) from Satish Dhawan Space Centre SHAR, Sriharikota.

After a smooth countdown of 12 hours, the solid rocket booster carrying the Scramjet Engines, lifted off at 0600 hrs (6:00 am) IST. The important flight events, namely, burn out of booster rocket stage, ignition of second stage solid rocket, functioning of Scramjet engines for 5 seconds followed by burn out of the second stage took place exactly as planned.

After a flight of about 300 seconds, the vehicle touched down in the Bay of Bengal, approximately 320 km from Sriharikota. The vehicle was successfully tracked during its flight from the ground stations at Sriharikota.

With this flight, critical technologies such as ignition of air breathing engines at supersonic speed, holding the flame at supersonic speed, air intake mechanism and fuel injection systems have been successfully demonstrated.

The Scramjet engine designed by ISRO uses Hydrogen as fuel and the Oxygen from the atmospheric air as the oxidiser. Today’s test was the maiden short duration experimental test of ISRO’s Scramjet engine with a hypersonic flight at Mach 6. ISRO’s Advanced Technology Vehicle (ATV), which is an advanced sounding rocket, was the solid rocket booster used for today’s test of Scramjet engines at supersonic conditions. ATV carrying Scramjet engines weighed 3277 kg at lift-off.

ATV is a two stage spin stabilised launcher with identical solid motors (based on Rohini RH560 sounding rocket) as the first as well as the second stage (booster and sustainer). The twin Scramjet engines were mounted on the back of the second stage. Once the second stage reached the desired conditions for engine “Start-up”, necessary actions were initiated to ignite the Scramjet engines and they functioned for about 5 seconds. Today’s ATV flight operations were based on a pre-programmed sequence.

Some of the technological challenges handled by ISRO during the development of Scramjet engine include the design and development of Hypersonic engine air intake, the supersonic combustor, development of materials withstanding very high temperatures, computational tools to simulate hypersonic flow, ensuring performance and operability of the engine across a wide range of flight speeds, proper thermal management and ground testing of the engines.

India is the fourth country to demonstrate the flight testing of Scramjet Engine. The successful technology demonstration of air-breathing Scramjet engines in flight by ISRO today is a modest yet important milestone in its endeavour to design and develop advanced air breathing engines including engines for ISRO’s future space transportation system.

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Re: Indian Space Programme Discussion

Postby prasannasimha » 28 Aug 2016 14:16

Image

Image

Image

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Re: Indian Space Programme Discussion

Postby JayS » 28 Aug 2016 17:45

Kudos to ISRO for another success. DO we have any close up pics of the SCRAMJET??

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Re: Indian Space Programme Discussion

Postby thammu » 28 Aug 2016 18:06

Why Isro's scramjet flight demonstration is significant
http://www.business-standard.com/article/current-affairs/why-isro-s-scramjet-flight-demonstration-is-significant-116082800279_1.html
The flight demonstration of the hypersonic air-breathing dual mode ramjet engine, which uses atmospheric oxygen in a portion of its journey, is a major step for Indian Space Research Organisation (Isro) in its pursuit for a future space transportation system.

An experimental mission to demonstrate supersonic combustion using atmospheric oxygen was conducted on Sunday. It was the maiden experiment of Isro's Dual Mode Ramjet (DMRJ) engine, which uses hydrogen as fuel and air from the atmosphere as the oxidiser, at hypersonic conditions.

The programme, along with another ongoing programme for developing a re-usable launch vehicle, would position the organisation as a major space fairing agency with technological competence to offer services for low-cost access to space in the long term.


The programme will help the organisation to reduce the number of stages in the current multi-staged expendable launch vehicles to two stages. Most of the current launch vehicles are designed for one time use and are expensive. Further, their efficiency in terms of payload to lift-off mass is low, of the order of 2-4 per cent. Current rocket technology offers little opportunity in this regard given that nearly 85 per cent of the lift-off mass is propellant.

Technologies to reduce weight and cost of space craft

There are ongoing worldwide efforts to reduce launch cost. In order to achieve low-cost access to space, the strategy has been to try and reduce propellant mass, reduce the rocket size to have a higher payload to lift-off mass ratio, and make the rocket re-usable.

When it comes to reducing propellant mass, nearly 70 per cent of the propellant mass is oxidiser. The next generation of launch vehicles will have to use propulsion systems which can utilise atmospheric oxygen during the atmospheric flight regime. This will reduce the total propellant required to place a satellite in orbit for lower stages.

While the ultimate goal is the development of a single-stage-to-orbit (SSTO) launch vehicle configuration, to finally make access to space a routine affair at comparatively lower cost than conventional expendable rockets, a fully rocket-powered SSTO is not feasible with existing material and propulsion technology. However, air breathing propulsion can largely improve the feasibility of a SSTO if the air breathing mode can be efficiently used on a very large flight Mach number range, for example from Mach 1.5 to Mach 12.

There are uncertainties related to air breathing mode performance and the existing material technology puts a question mark on the real feasibility of such a SSTO launcher in the near future. It could be relatively easy to develop a two-stages-to-orbit (TSTO) launcher with an air breathing first stage. The key technology to enable the operation of two stage and finally the SSTO launch vehicle is air breathing propulsion which can operate over a wide Mach number regime. Besides, if the first stage of the TSTO is made re-usable, the cost of launching satellites will come down by a magnitude two. The future combination of re-usable launch vehicles along with air-breathing propulsion, thus, would lead towards routine space missions at far lower cost.

Concepts of air breathing technology

One of the concepts for air breathing technology being studied worldwide is a ramjet. A ramjet is a form of air breathing jet engine that uses the vehicle's forward motion to compress incoming air for combustion without an axial compressor. Fuel is injected in the combustion chamber where it mixes with the hot compressed air and ignites. Ramjets cannot produce thrust at zero airspeed; they cannot move an aircraft from a standstill. A ramjet-powered vehicle, therefore, requires an assisted take-off like a rocket assist to accelerate it to a speed where it begins to produce thrust. The ramjet works best at supersonic speeds and as the speed enters the hypersonic range, its efficiency starts to drop.

Another concept is the scramjet. A scramjet engine is an improvement over the ramjet engine as it operates at hypersonic speeds and allows supersonic combustion, which gives it its name — supersonic combustion ramjet, or scramjet. The exhaust gases are then accelerated to hypersonic speeds using a divergent nozzle.

The scramjet is composed of three basic components — a converging inlet where incoming air is compressed, a combustor where gaseous fuel is burned with atmospheric oxygen to produce heat, and a diverging nozzle where the heated air is accelerated to produce thrust. Unlike a typical jet engine, a scramjet does not use rotating, fan-like components to compress the air. Instead, the speed at which the vehicle moves through the atmosphere causes the air to compress within the inlet. As such, no moving parts are needed in a scramjet, which reduces the weight and the number of failure points in the engine.

While scramjets are conceptually simple, actual implementation is limited by extreme technical challenges, including that when the vehicle is within the atmosphere, it will be at a higher temperature than the surrounding air and it would be similar to lighting a candle in a hurricane, as the fuel must be injected, mixed, ignited, and burned within milliseconds. Worldwide efforts are on to achieve powered flight using scramjet engines.

The third concept is a mix of ramjet and scramjet, which is called DMRJ. There is a need for an engine which can operate at both supersonic and hypersonic speeds. A DMRJ is an engine design where a ramjet transforms into a scramjet over Mach 4-8 range, which means, it can operate in both the subsonic and supersonic combustor mode.

Most of the research on air breathing engines is classified. Computational fluid dynamics (CFD) tools also have recently reached maturity levels to make reasonable computations in solving scramjet operation problems possible. However, it is yet to be perfected and as such, flight testing is the only tool available to master all the key technologies of scramjet propulsion and have an assessment of the integrated engine performance.

Isro's mission

The mission objectives of the ATV-D02/DMRJ mission are to demonstrate supersonic ignition, sustain the flame for combustion, and evaluate integrated DMRJ engine performance at hypersonic flight conditions. The flying test bed for Isro's DMRJ engine at supersonic conditions is provided by a sounding rocket platform — the ATV D02.

Dual mode engine systems and subsystems has undergone an extensive qualification and testing programme, which includes wind tunnel testing, CFD runs, structural tests, material characterisation, static test of solid motor, supersonic ignition and combustion experiments.

The space organisation says that the technological challenges for the mission include hypersonic air intake geometry with high pressure recovery and better shock wave-boundary layer management; design of supersonic combustor, which includes fuel injection and flame holding device; performance and operability across wide range of flight speeds, which is the transition from ramjet to scramjet; thermal management of engines; computational tools to simulate hypersonic flow and arrive at optimum Mach number-dynamic pressure window; thermo-structural tests of scramjet engines and ground test at higher Mach number conditions; among others.

For Isro, the technology demonstration of hypersonic air breathing dual ramjet engines would lead to the design and development capability of advanced air breathing engines, including engines with variable geometry air intake for its future space transportation system.

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Re: Indian Space Programme Discussion

Postby Ashokk » 28 Aug 2016 18:40

Image
Image

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Re: Indian Space Programme Discussion

Postby SriKumar » 28 Aug 2016 19:14

Interesting. Nice pictures. The two scramjets on the rocket would have had to ignite absolutely simultaneously and function identically for the rocket to stay stable during the test. This was a test of 2 engines in one shot.

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Re: Indian Space Programme Discussion

Postby JayS » 28 Aug 2016 19:52

Been thinking the same. I have never seen two scramjets tested like this. But I would put my money n this - the two engine were to maximize the chance of success or two were of different configuration to gather more data in one shot. ISRO being ISRO, we know they always try to combines things and extract maximum out of it. I am not sure of the thrust of each of those engines. But for me to leave the fate of the test on possibility of both the engines starting bang on the same time is too much risk. Either the un-start of one one engine was not of big consequence or it was taken into account with the guidance system of the rocket itself so it would stay on the course.

Anyhow I am feeling very happy to finally see ISRO Scramjet engine flying. I have worked on this one -specifically the air inlet - for my thesis work under ISRO funding.

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Re: Indian Space Programme Discussion

Postby Varoon Shekhar » 28 Aug 2016 19:57

A dumb layman may ask "Wonderful, but why only a 5 second test? Why not 30 seconds? Is it because that's the prototype they've designed, and are confident in testing it only for that duration?"

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Re: Indian Space Programme Discussion

Postby JayS » 28 Aug 2016 20:20

If ISRO has achieved 5sec of sustained scramjet operation thats a huge achievement. I think the longest ever flight achieved is some 200-300sec by X51. But that's after a large amount of tests. Important point is 5sec is more than sufficient to collect the data, since at M6.5 flow reaches steady state within milliseconds. Typically hypersonic tunnels have runs times of <1sec only, that too for a small test section areas.

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Re: Indian Space Programme Discussion

Postby prasannasimha » 28 Aug 2016 21:12

5 second ignition is indeed a huge success because it allows validation of initiation and maintenance of the function of the scramjet that allows further validation with all the data collected. The next test with data obtained will be of a longer duration.

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Re: Indian Space Programme Discussion

Postby disha » 29 Aug 2016 01:02

Varoon Shekhar wrote:A dumb layman may ask "Wonderful, but why only a 5 second test? Why not 30 seconds? Is it because that's the prototype they've designed, and are confident in testing it only for that duration?"


Because:

1. If both the scramjet engines worked., it is total 10 seconds of test data. Even if both are not ignited simultaneously!
2. The amount of hydrogen needed for 5-10 seconds of burn time and amount needed for say 300s and the need to cram avionics to gather data vs. the need to extend the test time.
3. If any failure happens, it happens in the first <1 second of ignition initiation. What is the point of planning for 300s when you can characterize the entire flight test data requirements in 5 seconds of flight?
---

Important information:

1. Per Hindu, it was 6s of scramjet ignition
2. Real time data to qualify the data obtained from on-ground experiments.

Dual mode engine systems and subsystems has undergone an extensive qualification and testing programme, which includes wind tunnel testing, CFD runs, structural tests, material characterisation, static test of solid motor, supersonic ignition and combustion experiments.


3. Design and validation of supersonic combustion (including its associated paraphernalia), transition from supersonic to hypersonic and ensuring that the entire package stays together.

... the technological challenges for the mission include hypersonic air intake geometry with high pressure recovery and better shock wave-boundary layer management; design of supersonic combustor, which includes fuel injection and flame holding device; performance and operability across wide range of flight speeds, which is the transition from ramjet to scramjet; thermal management of engines; computational tools to simulate hypersonic flow and arrive at optimum Mach number-dynamic pressure window; thermo-structural tests of scramjet engines and ground test at higher Mach number conditions; among others.


4. Mach 6.( that is @2 Km per second *)

*PS: Last time I touched any physics related was >2.5 decades back. Everything is from memory only and a need to simplify it for the 'masses'.
------

I loved the way two engines strung together. Here is my wish list:

1. ISRO should immediately start a family of 'scramjet sounding rockets' for university students to research their probes. Basically operationalize the scramjet engines and gather more data.

2. A next test on variable inlet design and managing transitions from supersonic to hypersonic (mach 1.5 to Mach 12). Particularly the variable inlet design. Now imagine two scramjet engines, with a variable inlet design - one can do turns by increasing (or decreasing) thrust in one or the other engine. Of course one needs data on the dynamic pressure to arrive at various max-Qs (hence the tests!)

All in all a major leap for India. Congrats!

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Re: Indian Space Programme Discussion

Postby SriKumar » 29 Aug 2016 04:07

JayS wrote:Been thinking the same. I have never seen two scramjets tested like this. But I would put my money n this - the two engine were to maximize the chance of success or two were of different configuration to gather more data in one shot. ISRO being ISRO, we know they always try to combines things and extract maximum out of it. I am not sure of the thrust of each of those engines. But for me to leave the fate of the test on possibility of both the engines starting bang on the same time is too much risk. Either the un-start of one one engine was not of big consequence or it was taken into account with the guidance system of the rocket itself so it would stay on the course.

I think I agree with you. I had not considered the effect of the airflow (supersonic or hypersonic) on the rocket itself to stabilize it from any perturbations arising from a difference in the thrusts of the 2 scramjets. It will surely have some stabilizing effect (correct me if I am wrong). And yes, they could have accounted for it by including it in the overall control system of the rocket. As long as the rocket itself did not disintegrate from the imbalance of forces, the test would have yielded useful data for any start sequence. In fact, it would yield more interesting data if one started before the other.
In a way, this test reminds me of the RLV test where the mission control kept calling out 'yaw normal' every 1-2 seconds during launch given that the payload was exposed to the atmosphere.

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Re: Indian Space Programme Discussion

Postby prasannasimha » 29 Aug 2016 07:47

It is not so simple (that 6 seconds is enough) this relates to the initiation of the scramjet but remember that sustenance of the scramjet has also been a problem and the X51 indeed did not maintain its full flight duration fo 300 seconds and caused all sort of problems till they could achieve full flight. . One problem is the limitations of the sounding rocket to carry more fuel given its size as we still need to have enough fuel plus we have not used the DMRJ truly in "dual mode" (though the RAM jet part would ahve been tested on ground) and the transition from RAM to SCRAM JET may or may not have been tested. So solid rocket fuel plus hydrogen would have been carried and so automatically we are limited by the payload capacioty of the sounding rocket that limits the duration of the current test.

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Re: Indian Space Programme Discussion

Postby vina » 29 Aug 2016 08:00

though the RAM jet part would ahve been tested on ground

No it cannot , unless you test it in a trans sonic wind tunnel. And even if you did, it would be very sub scale, given the "Paki gulping down Baksheesh" kind of quantities of air a full scale test would require and if continuous flow wind tunnel (unlike the blow down type that the NAL), half of south Bangalore would be without power for the duration of the test.

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Re: Indian Space Programme Discussion

Postby SSSalvi » 29 Aug 2016 11:59

Here is an update with more detailed numbers .. Thanks to my old colleague Shri V K Srivastav who provided these details.

Rohini second stage achieve a height of 70 km and sustain Mach 6+.05 and dynamic pressure 80+35kPa for seven seconds.

Scramjet successfully operated with 6 s of its ignition in specified Mach window with 0.594g acceleration against 0.4g .

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Re: Indian Space Programme Discussion

Postby PratikDas » 29 Aug 2016 12:05

SSSalvi wrote:Here is an update with more detailed numbers .. Thanks to my old colleague Shri V K Srivastav who provide these details.

Rohini second stage achieve a height of 70 km and sustain Mach 6+.05 and dynamic pressure 80+35kPa for seven seconds.

Scramjet successfully operated with 6 s of its ignition in specified Mach window with .594g acceleration against.4g.

SSSalvi ji, does that last line mean that natural deceleration after seven seconds of Rohini second stage is 4g and the two scramjets effected an incremental acceleration of 0.594g?

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Re: Indian Space Programme Discussion

Postby SSSalvi » 29 Aug 2016 12:25

You have a very fast finger Pratikji.

Before I read the post after posting and correcting by addition of a 0 in .4 too 0.4 you found the likely pitfall. :D

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Re: Indian Space Programme Discussion

Postby PratikDas » 29 Aug 2016 12:42

SSSalvi wrote:You have a very fast finger Pratikji.

Before I read the post after posting and correcting by addition of a 0 in .4 too 0.4 you found the likely pitfall. :D

Please, Sir - You cannot use the honorific Ji with me. I have read your posts on this thread and fully appreciate the ΔG (Gyan) between us.

Thanks for the correction. The jingo feels better!

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Re: Indian Space Programme Discussion

Postby JayS » 29 Aug 2016 12:50

^^Awesome SSS ji. Thanks for the data. If I am correct in understanding it means 0.4G acceleration was expected but 0.594G was achieved in practice.

Another Q: Was this scramjet with open cowl right from Launch or its cowl was closed until it reached M6??

We will have to wait for some hardcore technical data until ISRO publishes few research papers on this one. I can't imagine how valuable the data gathered is. All our desi high speed Aero and propulsion codes could/would be benchmarked with this (and some more from future missions) data for decades to come. So far we would use data available from NASA publications. Gemini re-entry capsule data is still used for benchmarking.

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Re: Indian Space Programme Discussion

Postby SaiK » 29 Aug 2016 17:34

would it be possible to attain the same result with heavier rocket specs?

don't we have a small window for ballistics: [assuming our data is mostly not for ballistic use]
Image

how many seconds we need to test say for our GSLV payloads/weight?

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Re: Indian Space Programme Discussion

Postby disha » 29 Aug 2016 22:02

SaiK'ji., If I understand your question., what you are asking is how come scramjet will be useful if the time spent in atmosphere is few seconds. Trajectory of a scramjet is not the same for a rocket.

A rocket booster puts the core above the atmosphere and the core kicks the satellite into orbit. So it is important for the booster+core to spend least time in atmosphere where of course the most friction is. Here rocket core will carry both the H2+O2 with it and that extra O2 is the weight one can potentially take from the atmosphere itself.

A scramjet on the other hand spends most of the time in atmosphere, gaining velocity using atmospheric oxygen. Only issue is heat management. That is scramjet is a depressed trajectory compared to traditional rockets.

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Re: Indian Space Programme Discussion

Postby durvasa » 30 Aug 2016 01:33

Scramjet may be more useful in hypersonic missiles where speed is of strategic value and vehicle will be in air for a longer period. Most studies in the last 30-40 years conclude tht unless technologies improve substantially, Scramjet is not practical for space applications. Probably this ISRO dual-scramjet tests provided minimal thrust (most initial US tests too had low thrust).

Despite not carrying oxidizer, weight-thrust ratio is not better compared to regular rockets. Does not mean it can't happen but I am no rocket scientist, no pun intended.

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Re: Indian Space Programme Discussion

Postby Bheeshma » 30 Aug 2016 02:10

Is there some use in Brahmos-2 or Shaurya missile?

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Re: Indian Space Programme Discussion

Postby disha » 30 Aug 2016 03:28

Not in Brahmos as such., but Brahmos-like missiles.

Durvasa'san., there was a study that came out in early 2000s on electric cars that unless technologies improve substantially there is no practical use for electric cars. Guess what., present day any car company which primarily has only integral combustion engine based product is considered obsolete.

Same is happening in aerospace/space technologies. In mid-90s I was at an group of techies in Australia and I said that within a generation Indians will be sending probes to Mars, there was laughter all around and people were almost ROFL. Now that is history.

What is the use of X-37B? Imagine a RLV with scramjet engines (heck no need to imagine, ISRO is already planning that) which can change orbits., say enter into atmosphere and use aerodynamic maneuvers to launch into a different orbit. What use will that be?

Or RLV with scramjet can launch only 10 Kgs of payload., but at $100/kg instead of $10000/kg. What use will that be? :-)

Indranil
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Re: Indian Space Programme Discussion

Postby Indranil » 30 Aug 2016 03:35

SaiK wrote:would it be possible to attain the same result with heavier rocket specs?

don't we have a small window for ballistics: [assuming our data is mostly not for ballistic use]
Image

how many seconds we need to test say for our GSLV payloads/weight?
disha wrote:SaiK'ji., If I understand your question., what you are asking is how come scramjet will be useful if the time spent in atmosphere is few seconds. Trajectory of a scramjet is not the same for a rocket.

A rocket booster puts the core above the atmosphere and the core kicks the satellite into orbit. So it is important for the booster+core to spend least time in atmosphere where of course the most friction is. Here rocket core will carry both the H2+O2 with it and that extra O2 is the weight one can potentially take from the atmosphere itself.

A scramjet on the other hand spends most of the time in atmosphere, gaining velocity using atmospheric oxygen. Only issue is heat management. That is scramjet is a depressed trajectory compared to traditional rockets.

Another aspect of it is that human body starts dying above 25,000 feet (about 7.5 km). But this is not true about air breathing machines. Advanced turbojets have an extreme operational ceiling of about 40 km (check out the SR-71/Mig 25/Mig 31), while ramjets have a ceiling of about 55 km. Scramjets can operate up to 75 km high without fear of stalling.

Interestingly, the SR-72 proposal is also based on a Dual Ramjet Scramjet propulsion, and Lockheed feels it can do it.

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Re: Indian Space Programme Discussion

Postby Indranil » 30 Aug 2016 04:03

There were a few questions. What about asymmetric thrust by the two engines:
1. One theory is that the two engines tested on this flight were designed to produce zero thrust as in the Hyshot experiments.
2. As Jay says, the engines create very little thrust compared to the second stage and are placed very close to the axis. Hence they create a very small moment which can be taken care of by the fins.

Why was the duration of ignition only 5 seconds.
1. As correctly pointed out, 5 seconds of sustained ignition is enough to prove the engine.
2. Another aspect comes from the flight profile of the carrier rocket. This from ATV-D01 test (from 2010)
During the flight, the vehicle successfully dwelled for 7 seconds in the desired conditions of Mach number (6 + 0.5) and dynamic pressure (80 + 35 kPa). These conditions are required for a stable ignition of active scramjet engine combustor module planned in the next flight of ATV.


My only complaint: 6 years between ATV01 and ATV02?!! :-?

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Re: Indian Space Programme Discussion

Postby Indranil » 30 Aug 2016 04:48

Some other interesting differences between ATV-D01 flight and ATV-D02 flight.

ATV-D01's flight profile: The rocket reached an altitude of 46km in 120 seconds (two minutes) and the entire flight duration was 240 seconds (four minutes)
Image

Notice that for ATV-D01 the scramjets were supposed to be ignited after the burnout of the second stage. However, according to the ISRO's report on the ATV-D02, the scramjets functioned in unison with Stage 2. Also, the flight duration of ATV-D02 was about 300 seconds.

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Re: Indian Space Programme Discussion

Postby prasannasimha » 30 Aug 2016 07:34

http://www.isro.gov.in/remembering-irs-1b-which-was-launched-exactly-25-years-back

Remembering IRS-1B which was launched exactly 25 years back
Aug 29, 2016

IRS-1B, the second of the series of indigenously developed remote sensing satellites of India, was successfully launched into a polar sun-synchronous orbit on August 29, 1991 from the Soviet Cosmodrome at Baikonur. It carried a trio of Linear Imaging Self-Scanning (LISS) remote sensing instruments working in four spectral bands: 0.45-0.52 μm, 0.52-0.59 μm, 0.62-0.68 μm, and 0.77-0.86 μm. The 38.5 kg LISS-I images a swath of 148 km with a resolution of 72.5 mtr while the 80.5 kg LISS-IIA and LISS-IIB exhibited a narrower field-of-view (74 km swath) but were aligned to provide a composite 145 km swath with a 3 km overlap and a resolution of 36.25 mtr.

IRS-1B had improved features compared to IRS-1A like gyro referencing for better orientation sensing, time tagged commanding facility for more flexibility in camera operation and line count information for better data product generation.

IRS-1B, similar to IRS-1A with improved performance provided regular data to user community. The data from the satellite was used for various applications in the areas of integrated mission for sustainable development, agriculture, forestry, flood mapping, snow melts and run-off studies, urban sprawl studies, wheat production estimation, locating water source etc.

IRS-1B Mission was completed on December 20, 2003 after serving for 12 years and 4 months.

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Re: Indian Space Programme Discussion

Postby SaiK » 30 Aug 2016 07:49

while we celebrate the scramjet happiness, here is some sad news

https://www.pgurus.com/cbi-closure-repo ... cientists/
CBI closure report on ISRO Spy case blames IB officials for spoiling the career of top scientists
In a Spy case that never was, IB was taken to task for a shoddy job by the CBI report


https://www.scribd.com/document/3224861 ... from_embed
Full report

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Re: Indian Space Programme Discussion

Postby hnair » 30 Aug 2016 09:42

indranilroy wrote:My only complaint: 6 years between ATV01 and ATV02?!! :-?


From whatever one hears, funding is very low (sustenance) for what is considered as non-standard launches. A successful launch of a new tech (shuttle, scram etc) will cause a flurry of excitement in Dilli. There is a tiny window before this excitement subsides. The team leads better catch the next flight, jump on to the back of bean counters and squeeze money for the next few launches. Or a long wait before the next launch happens. Because once the window closes, they cant escalate up the chain and hope the politicians remember their exploit.

This trickle funding affects everything from making teams bigger to building bespoke test rigs

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Re: Indian Space Programme Discussion

Postby Bharath » 30 Aug 2016 22:42

Scramjet! Congrats ISRO on achieving this milestone.

Gurus, does this mean the SPEX (Scramjet Propulsion Experiment) component of the RLV TD programme is complete?

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Re: Indian Space Programme Discussion

Postby disha » 31 Aug 2016 06:20

No Bharath'ji - this is just a start. It has many milestones to go., for example wider dynamic range (from supersonic to hypersonic transitions)., longer duration, scale up, heat management and then integration with RLV and further tests.

Good part is that the simulation and design by desi engineers is A++., but as Nair'ji pointed out - the Bean Counters (BCs) are at it again. We do need scale up in tests and out of box ideas on scaling up the tests!

For example, even if it is a 1Kg - sub-orbital - sounding experiment., ISRO must open it up to the universities., I am sure if 10 engineering colleges with a budget of 1 Cr and a staff student of 10 with a professor at helm each can come up with several experimental payloads on scramjet to try for Masters/PhDs can be done. UGC/Min. of Science and Tech/DOS can also match up 1-to-1 creating a scale up of 2x-3x and a sustained funding of 20-30 Crores per year can be had. Over 5 years that in itself is 100-150 Crores. Budget is shoe-string, but sometimes better than running to BCs. Long term network effect should also not be discounted.

Such out of box thinking is required. This is similar to what Univ. of Queensland did.

What we need is a quick turn around., not 6 years between ATV01 and ATV02., but should be more like 6 months. Even RLV needs a scale up. Also all this forays is actually helping the industry., anything and everything here must be taken up by CII. For example - the process to make carbon composites - it can go in your cycles, rickshaws, autos. Thermal management of batteries - it can go in your electric scooters. The boundaries are unlimited ...

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Re: Indian Space Programme Discussion

Postby Varoon Shekhar » 01 Sep 2016 22:04

The isro site now has a detailed preview of the GSLV Insat 3dr mission

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Re: Indian Space Programme Discussion

Postby SSSalvi » 02 Sep 2016 11:18

@ Indranilroy,

Is the source data ( on which your figure above pertaining to ATV-02 is based ) available anywhere in open source?


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