Indian Space Program Discussion

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SuKan
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Re: Indian Space Program Discussion

Postby SuKan » 27 Dec 2008 14:40

Wind tunnel model Of RLV- TD

Image

http://www.nal.res.in/picts/ntaf221208.jpg

Abhijit N
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Re: Indian Space Program Discussion

Postby Abhijit N » 27 Dec 2008 15:12

Wind tunnel model Of RLV- TD


That looks so cool...so what are the challenges to making it manned after the demo flight? I guess they will have to design it on the lines of fighter plane cockpits and the experience with the Soyuz redesign for the manned mission should help(apologies for my ignorance on these areas :oops: )

I also came across this interesting article from Science@NASA:-
http://science.nasa.gov/headlines/y2008/24dec_sport.htm?list128625

A company called WorldWinds, Inc. uses NASA's SPoRT program to reveal sea surface temperatures, lightning fronts ,windspeed and of course cloud buildup.

http://science.nasa.gov/headlines/y2008/images/sport/sst.jpg

Not only can these help prevent storms, but sea temperatures can point to a prize catch!!...this is an amazing use to which we can put our satellite data as well !.

I wonder how they are able to detect lightning fronts as well !
http://science.nasa.gov/headlines/y2008/images/sport/ss_fronts_clouds_lightning.jpg

Here is the software they use in action:-
http://science.nasa.gov/headlines/y2008/images/sport/GarminWeb.mov

Gerard
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Re: Indian Space Program Discussion

Postby Gerard » 28 Dec 2008 21:38


Abhijit N
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Re: Indian Space Program Discussion

Postby Abhijit N » 29 Dec 2008 20:24

..also pave way for an Indian colony on moon, a few decades down.

:wink:
That'll be something!!

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Re: Indian Space Program Discussion

Postby Arun_S » 30 Dec 2008 00:39

Abhijit N wrote:
Wind tunnel model Of RLV- TD


That looks so cool...so what are the challenges to making it manned after the demo flight? I guess they will have to design it on the lines of fighter plane cockpits and the experience with the Soyuz redesign for the manned mission should help(apologies for my ignorance on these areas :oops: )


What you see here is the reuseable strap on booster (solid or liquid fueled, the latter is more useful because it only need simple checkout and a gas nozzle to fuel it up for next mission) as a first step that will land back intact after it is expended and jettisoned by the rocket.

The RLV concept will then be extended to core and upper stages. The problem for upper stages is the impact on mass fraction due to winglets and larger mass fraction required for re-entry stress abatement.

Imagine what will happen if GSLV-I's four strap-on Vikas motors and the second stage Vikas can fly back and be re-used 10 times?

Image Image

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Re: Indian Space Program Discussion

Postby Daedalus » 30 Dec 2008 01:32

p_saggu wrote:
AERODYNAMIC CHARACTERISATION OF RLV-TD

Any pictures / concept drawings around?


Check this link out.

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Re: Indian Space Program Discussion

Postby Kailash » 30 Dec 2008 03:37

Abhijit N wrote:That looks so cool...so what are the challenges to making it manned after the demo flight?


I believe this is a predominantly a launch platform for putting satellites into space. If India is modifying Soyuz, then our manned space program would use a capsule very similar to Soyuz. Gurus please correct me if I am wrong.

May be this RLV will be modified to a manned version slowly over next 2 decades - first from two stage to single stage (TSTO to SSTO), make it horizontal take off and landing with the scramjet/dual mode scram/ram jet or Kaveri core. Lot of things are unclear here. I remember seeing the ISRO roadmap around this somewhere. Will post it if I can find it.

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Re: Indian Space Program Discussion

Postby disha » 30 Dec 2008 05:19

Daedalus wrote:
p_saggu wrote:
AERODYNAMIC CHARACTERISATION OF RLV-TD

Any pictures / concept drawings around?


Check this link out.


Thanks for the link. Do you have the complete paper?

The above looks just like X-37. http://en.wikipedia.org/wiki/Boeing_X-37. And it is to be flight tested in 2009. If we can beat them, cool! 8)

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Re: Indian Space Program Discussion

Postby nash » 30 Dec 2008 11:21

Would you please post the content of link ....

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Re: Indian Space Program Discussion

Postby rakall » 30 Dec 2008 11:51

Arun_S wrote:
Abhijit N wrote:
Wind tunnel model Of RLV- TD


That looks so cool...so what are the challenges to making it manned after the demo flight? I guess they will have to design it on the lines of fighter plane cockpits and the experience with the Soyuz redesign for the manned mission should help(apologies for my ignorance on these areas :oops: )


What you see here is the reuseable strap on booster (solid or liquid fueled, the latter is more useful because it only need simple checkout and a gas nozzle to fuel it up for next mission) as a first step that will land back intact after it is expended and jettisoned by the rocket.

The RLV concept will then be extended to core and upper stages. The problem for upper stages is the impact on mass fraction due to winglets and larger mass fraction required for re-entry stress abatement.

Imagine what will happen if GSLV-I's four strap-on Vikas motors and the second stage Vikas can fly back and be re-used 10 times?

Image Image



I seriously doubt if the windtunnel model is a re-usable strap-on booster.. It could be a model of a true-RLV envisioned for 10-15years from now..

it could be launched atop a modified GSLV-MKIII or it could be launched as part of a launcher that would depend on environmental Oxygen collection and liquifacition..

1. Especially if you see the wings at the bottom of the body of the model -- I dont think there is enough space to accomodate the wings on the launcher to assemble the strap-on boosters with the wings..
2. The similarity in body-shape of the RLVmodel to the strapon boosters is due to the angle in which the artist's rendering of GSLV is being viewed..
3. If you campare the actual picture of strap-on with the W/T model of RLV - one can notice big differences.. the cylindrical portion of strap-on (before the conical portion starts) is much much longer in the strap-on as compared to the RLV model..
4. The clinching difference is the number of aft tail/fin surfaces... the artist rendering creates an illusion as if there are two tail surfaces on each strap-on, similar to RLV model.. But actually there is one tail-surface per strap-on, but two in RLV model..

I guess if one looks at the strap-on in the lauch pictures it becomes easy to compare and notice that RLV model may not be a re-usable model of the GSLV strap-on.. The W/T model is most probably of a futuristic true-RLV...

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Re: Indian Space Program Discussion

Postby K Mehta » 30 Dec 2008 12:40

Daedalus wrote:
p_saggu wrote:
AERODYNAMIC CHARACTERISATION OF RLV-TD

Any pictures / concept drawings around?


Check this link out.

Daedelus thanks for the link

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Re: Indian Space Program Discussion

Postby neeraj » 30 Dec 2008 14:51

http://www.ndtv.com/convergence/ndtv/story.aspx?id=NEWEN20080078163
Scientists to announce findings of moon data next month: ISRO

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Re: Indian Space Program Discussion

Postby nash » 30 Dec 2008 15:25

BANGALORE: Indian Space Research Organisation (ISRO) chairman G. Madhavan Nair has said that after the success of Chandrayaan 1, India's Space
Research Organisation (ISRO) is going to launch an exclusive weather satellite jointly with the French space agency CNES (Centre National d'Etudes Spatiales) in 2009.

The satellite, named 'Mehga Tropiques' will study the tropical atmosphere and its associated phenomena and would help India and France to study the cyclones, monsoon and other changes.

The Indian Remote Sensing Satellite (IRS) would be built and launched by ISRO and two instruments called SCARAB and SAPHIR would be built by the CNES.

The other critical instrument called MADRAS will be jointly engineered by ISRO and CNES.

Talking to reporters here on the sidelights of a programme on Monday, Nair said that the satellite would be launched by the end of 2009.

"It is a joint agreement between France and ISRO. Some instruments are made by French people and some we are doing it. By the end of the 2009, it would be launched. This satellite will provide lot of inputs for weather modulates and near time weather forecast and so on," said Nair.

The satellite would be operated by ISRO and both the countries (India and France) would share data.

India hopes to send an astronaut into space by 2012 and a manned mission to the moon by 2020.

India's Chandrayaan-1, the first unmanned spacecraft mission to moon and the country's first space vehicle to venture beyond Earth's orbit successfully entered lunar orbit on November 8.

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Re: Indian Space Program Discussion

Postby vishal » 30 Dec 2008 15:30

How many satellites does India currently have in orbit? TIA.

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Re: Indian Space Program Discussion

Postby p_saggu » 30 Dec 2008 15:53

Daedelus, thanks!

Image

Image

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Re: Indian Space Program Discussion

Postby Abhijit N » 30 Dec 2008 22:49

...larger mass fraction required for re-entry stress abatement.

Are we talking tiles here like the ceramic ones in the X37 that disha mentioned...that will add quite a bit of weight combined with lots of maintenance to prevent Columbia like disaster...or are there better options like maybe silica with low density & insulation as used in shuttle.....wikipedia image of Silica at 1260C:
Image
Then there is the question of how to glue the tiles or is it better to use ablative shielding as in Apollo
http://depts.washington.edu/matseed/mse_resources/Webpage/Space%20Shuttle%20Tiles/Space%20Shuttle%20Tiles.htm

..which would again make the RLV into non-RLV etc etc.....seems easier to just let go of the booster. The end section of the paper mentioned above also points to bigger things..

The dream of making a vehicle which can take off from a runway like an aircraft, and to return to the runway after deploying the spacecraft in the desired orbit (or Single Stage To Orbit or SSTO) can be fulfilled only by the availability of more advanced high strength but low density materials so that the structural mass of the vehicle could be reduced considerably from the present levels. The advent of nanotechnology could play a deciding factor in developing such exotic materials. However, the materials
Proceedings of the International Conference on Aerospace Science and Technology
26 - 28 June 2008, Bangalore, India technology available today can realize a Two Stage To Orbit (TSTO) vehicle only and the configuration of the vehicle which is being considered is shown in Fig.1. However, the before realizing the RLV-TSTO it is important to perfect many critical technologies pertaining to hypersonic reentry vehicles. Hence a technology demonstrator vehicle (RLV-TD) is being developed. Fig.2 shows RLV-TD.

Re-entry is going to be a challenge.

This satellite will provide lot of inputs for weather modulates and near time weather forecast and so on," said Nair.

...and I hope we have more accurate models in place too for this. Just satellite data doesn't help...supercomputers I guess isn't a problem for solving the models :)

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Re: Indian Space Program Discussion

Postby Gerard » 30 Dec 2008 23:53

Didn't SRE-1 use silica tiles?

Image

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Re: Indian Space Program Discussion

Postby Daedalus » 30 Dec 2008 23:59

disha wrote:Thanks for the link. Do you have the complete paper?

The above looks just like X-37. http://en.wikipedia.org/wiki/Boeing_X-37. And it is to be flight tested in 2009. If we can beat them, cool! 8)

Unfortunately I don't. Wish ISRO had some thing on their website about new techs/developments they are working on, like in automobile websites showing future/concept models. I would really like that. :twisted:

p_saggu wrote:Daedelus, thanks!
.
K Mehta wrote:Daedelus thanks for the link

No problem.

nash wrote:Would you please post the content of link ....

Its a PDF document, to be exact a paper presented at an IIT conference.

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Re: Indian Space Program Discussion

Postby Abhijit N » 31 Dec 2008 00:10

Yeah Gerard ...you are right :oops: ..just read up on that.. silica tiles and carbon-phenolic composite ablative nose cap. And planning on full carbon composites for RLV..seems they have the problems licked more or less.

By the way I was wondering how the RLV manages to liquify oxygen onboard...
And any idea of the kind of propulsion system ...like is it a combined propulsion system as mentioned here in ISRO newletter archives:-
http://www.isro.org/newsletters/spaceindia/oct2005mar2006/ISROachieves.htm

Air breathing propulsion for launch vehicles envisages a combination of propulsion cycles: turbojet engine (widely used in aircraft), ramjet engine (currently being used in missiles), SCRAMJET engine (being developed around the globe) and rocket engine (the workhorse of today’s launch vehicles). They could either function as separate propulsion systems co-located or as a “combined” propulsion cycle engine by synergistically integrating them. A variant, rocket based combined cycle engine, which avoids the complex (rotating) turbojet component where the rocket engine in its air augmented mode is used for the low speed flight, is also gaining popularity.


In RAMJET, combustion chamber speeds are higher than that in turbojet but are still subsonic. As the flight speed increases, decelerating air from supersonic flight speeds to subsonic speeds becomes more and more inefficient, both in terms of pressure recovery and combustion processes. For flight Mach numbers of about six and above, there is a need to restrain the level of air deceleration and to retain its lower supersonic speed as it enters the combustion chamber. This necessitates Supersonic Combustion RAMJET or SCRAMJET.

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Re: Indian Space Program Discussion

Postby Arun_S » 31 Dec 2008 01:31

Chandrayaan's moon impact photos to be released soon

New Delhi (IANS): It is a set of pictures that is among the most anticipated in India - around 3,200 frames tracking the descent of the first-ever Indian-built device to the moon's surface.

But the Indian public may have to wait for some more time to take a peek at that journey.

The images were taken by the 35-kg Moon Impact Probe (MIP) as it hurtled down for nearly 25 minutes after detaching from India's maiden lunar probe Chandrayaan-I and landed on the lunar surface at 8.31 p.m. Nov 14.

That day, the Indian Space Research Organisation (ISRO) had released two photos of the pockmarked surface taken from MIP. Nothing after that.

According to a key Chandrayaan scientist, it is now a matter of waiting a bit more - though he still could not specify the date.

"While we have released some sample images already, the full set of 3,200 pictures will also be made public after some more time," A.S. Kiran Kumar, deputy director, sensor development area in ISRO's Ahmedabad-based Space Applications Centre, told IANS.

Kumar headed the team which built the Terrain Mapping Camera (TMC), one of India's key payloads on Chandrayaan.

The pictures are currently being analysed at ISRO's Physical Research Laboratory. "We could be releasing it in a couple of months," Kumar said, adding that the last photograph on the set was from a height of two to three kilometres from the surface.

One of the several activities involved in getting the pictures ready for public release is to identify the surface features. "Since the pictures are of very high resolution, the features are not listed on any current moon atlas," he said.

The TMC has meanwhile been mapping the South Pole at a resolution of five metres, through lens capable of capturing images at three angles simultaneously.

Recently, China unveiled a three-dimensional map of the lunar surface with data from its Chang'e-1 mission, while Japan has been frequently releasing imagery from its lunar orbiter, Kaguya, including that of the landing site of the Apollo 17 spacecraft.

But, Kumar insisted, photographs collected by the Indian orbiter would be better due to higher resolution and lower orbit height at 100 km.

"The Chinese camera is three-dimensional but only has a resolution of 200 metres compared to our five-metre resolution. The Japanese one has 10-metre resolution, but they have only stereo doublet - we have a stereo triplet," he said.

By stereo triplet, the senior ISRO scientist referred to TMC's capability to take images from three angles - frontal, nadir and rear views. "The advantage is that no portion (of the surface) will be blocked. Occlusion will not be a problem," he said.

In optics, 'occlusion' refers to the method in which a close object masks or covers an object that is further away.

While Chandrayaan goes around the moon approximately 12 times each day - the camera is operational for two to three orbits.

"We have to balance every activity on the satellite, take note of the operating condition and find the optimal time to transmit to the ground station," Kumar said.

The time slot also gets limited as the camera has to factor in the solar illumination angle, which changes with the orbit of the moon. The scientists have decided to limit the solar angle to 30 degrees on both sides of the equator to take consistently well-lit images.

During the 20-minute photographing in each orbit, TMC captures images over an area 1,700 km long and 20 km wide, which translates into 1.4 km per second.

"Every second of data recorded takes about two and a half seconds to be transmitted to the ground station," said Kumar. The latest photograph released is of a lunar impact crater on the far side of the moon.

The senior ISRO scientist said several images have also been provided to academic institutions for analyses.

NASA's Moon Mineralogy Mapper payload team has also sought information from TMC. "They are interested in particularly looking at the terrain data," Kumar added.

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Re: Indian Space Program Discussion

Postby Arun_S » 31 Dec 2008 01:43

This the long delayed satellite. The delay was due to French dragging their feet. The project was almost canned.

India to launch exclusive satellite for climate: 'Mehga Tropiques'
30 Dec 2008, 1344 hrs IST, ANI
BANGALORE: Indian Space Research Organisation (ISRO) chairman G. Madhavan Nair has said that after the success of Chandrayaan 1, India's Space Research Organisation (ISRO) is going to launch an exclusive weather satellite jointly with the French space agency CNES (Centre National d'Etudes Spatiales) in 2009.

The satellite, named 'Mehga Tropiques' will study the tropical atmosphere and its associated phenomena and would help India and France to study the cyclones, monsoon and other changes.

The Indian Remote Sensing Satellite (IRS) would be built and launched by ISRO and two instruments called SCARAB and SAPHIR would be built by the CNES.

The other critical instrument called MADRAS will be jointly engineered by ISRO and CNES.

Talking to reporters here on the sidelights of a programme on Monday, Nair said that the satellite would be launched by the end of 2009.

"It is a joint agreement between France and ISRO. Some instruments are made by French people and some we are doing it. By the end of the 2009, it would be launched. This satellite will provide lot of inputs for weather modulates and near time weather forecast and so on," said Nair.

The satellite would be operated by ISRO and both the countries (India and France) would share data.

India hopes to send an astronaut into space by 2012 and a manned mission to the moon by 2020.

India's Chandrayaan-1, the first unmanned spacecraft mission to moon and the country's first space vehicle to venture beyond Earth's orbit successfully entered lunar orbit on November 8.

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Re: Indian Space Program Discussion

Postby Gerard » 31 Dec 2008 04:57


disha
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Re: Indian Space Program Discussion

Postby disha » 31 Dec 2008 07:37

Abhijit N wrote:By the way I was wondering how the RLV manages to liquify oxygen onboard...
And any idea of the kind of propulsion system ...like is it a combined propulsion system as mentioned here in ISRO newletter archives:-
http://www.isro.org/newsletters/spaceindia/oct2005mar2006/ISROachieves.htm



Check this link out -> http://en.wikipedia.org/wiki/SABRE#cite_note-aau-1. Unrelated to RLV, but an indicator on how Oxygen may be liquefied.

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Re: Indian Space Program Discussion

Postby SuKan » 31 Dec 2008 11:30

Arun_S wrote:This the long delayed satellite. The delay was due to French dragging their feet. The project was almost canned.


Sir, when was it originally scheduled to be launched , how many months it has been delayed.

The below link says, the launch will be during 2009 and it is still 2009 in the new report.

http://www.thaindian.com/newsportal/sci ... 68797.html
http://www.topnews.in/india-france-laun ... ear-251555

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Re: Indian Space Program Discussion

Postby ss_roy » 31 Dec 2008 17:04

A quick question/idea..

Since ISRO is already developing the S200 solid stage and an upgraded Vikas engine for the GSLV-3, what about creating a 0.5 GSLV-3

1st stage (S200 Solid) 110 seconds burn
2nd stage (55 ton fuel vikas) 240 second burn.
3rd stage hypergolic (LEO payload) or cryogenic (GTO missions).

Such a launcher could easily put about 8 tons (upgraded Soyuz) in LEO or about 3 tons in GTO. It would be about 100 tons heavier than the PSLV..

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Re: Indian Space Program Discussion

Postby Gerard » 31 Dec 2008 18:31

The "unified modular launch vehicle" mentioned in ISRO's outcome budget (semi-cryo core) is the next launcher in the pipeline

http://www.isro.org/Accounts/OutcomeBudget2008-2009.pdf
Semi-cryogenic Engine / Stage

Development Developing a higher thrust semicryogenic core stage for the unified modular launch vehicle.
(Project not yet approved)
Finalisation of the project report.
Initiation of the design and development efforts.

The proposal is in initial stages. The final outcome, in terms of availability of higher thrust semi-cryogenic stage is expected after six years.

The approval of the project is targetted during the FY 2008-09

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Re: Indian Space Program Discussion

Postby Abhijit N » 31 Dec 2008 20:52

Thanks disha....I got this:
In an operational setting with LACE, the system was to be placed behind a supersonic air intake which would compress the air through ram compression, then a heat exchanger would rapidly cool it using some of the liquid hydrogen fuel stored on board. The resulting liquid air was then processed to separate out the liquid oxygen for burning in the engine. The amount of warmed hydrogen was too great to burn with the oxygen, so most was to be simply dumped overboard (nevertheless giving useful thrust.)

Seems to be a bit of a waste dumping all that expensive hydrogen though....
and about the RLV taking off from a conventional runway & not like a rocket..we can always use a combined turbo jet & ram jet where a turbo jet is housed inside a ram jet. Air is allowed into the turbojet at lower speeds & at higher speeds flaps close the turbojet intakes to prevent the turbine blades from melting, allowing air to pass into the ram jet
Image

SR-71 Blackbird
http://www.aerospaceweb.org/question/propulsion/q0175.shtml

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Re: Indian Space Program Discussion

Postby lakshmikanth » 01 Jan 2009 07:23

Abhijit N wrote:Seems to be a bit of a waste dumping all that expensive hydrogen though....


It is because of the compromises to be made in order for the O2 collection and this is one of the compromises in that case.

The issue is a tradeoff between several factors.
If all the hydrogen has to be burned we need oxygen to burn it, which can come from
  • LOX collected so far
  • Oxygen present in the atmosphere

If the rate of O2 needed to burn H2 (that is used to cool the air)is more than the rate that is collected and liquefied, then you cannot do but go with the next option i.e. use oxygen present in the atmosphere which brings us to the next issue.

i.e. can we design a scramjet engine which can grab enough air to burn the hydrogen that is used for liquifying O2? If we can then we should do a study on whether the extra "drag" and the extra weight that would be created by this scramjet when its not working worth or not. Since H2 is low density its very difficult to design a compact scramjet which will have very low weight and very low hypersonic drag (when its not in use).

One thing we can do is release H2 along the Hypersonic shock wave, which compresses the air/H2 mixture and pushes it into the ram intake (this sort of thing is done by Concorde and XB-70 Valkyrie Bomber) and is burned in. It should be kept on all the time and would need a little bit more H2 that is needed. The drag and weight factor for this can be reduced by using compression lift:- again used by Valkyrie XB-70

It would be so interesting to study the underlying design issues :)

This is a good read for H2 Scramjets: http://www.aerospaceweb.org/question/propulsion/q0170.shtml

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Re: Indian Space Program Discussion

Postby SuKan » 02 Jan 2009 12:08

ISRO to test high-end launch vehicle GSLV Mark III in 2009
01 January 2009

Following the launch of Chandrayaan last year, ISRO will roll out several ambitious initiatives to consolidate the gains and build on its last year's achievements over the coming years. According to ISRO calendar the new year will mark a crucial testing phase in its development of Geosynchronous Satellite Launch Vehicle (GSLV) Mark III, which is slated for space flight in 2010-11.

GSLV Mark III is a next generation launch vehicle designed to put four tonne satellites into orbit. But more importantly, it is expected to cut the costs of launching satellites by half, to enable Antrix Corporation, ISRO's commercial arm offer the cheapest space launches in the niche market. The current GSLV can put 2.2 tone satellites in orbit.

According to K Radhakrishnan, director, Vikram Sarabhai Space Centre, the new year will see solid booster testing for Mark III. This will be followed by the liquid stage and finally the cryogenic engine stage will be tested, he added.

He said that the flight testing will be carried out duirng the 2010-11 period.

He said that with GSLV III, ISRO will be able to pack more transponders per space flight which would make for cost effective solutions, giving India an edge in the category of four tonne satellite launches.

He added that the GSLV Mark III will also help ISRO put more Indians in the manned space flight program which will be undertaken in 2015. He said that as per current plans, the agency will send two Indians on a week long space sojourn in that year.

However, instead of the regualr GSLV if GSLV Mark III is used, it will be possible to send three persons instead of two he said.

The Geosynchronous Satellite Launch Vehicle, GSLV, is an expendable launch system developed by the Indian Space Research Organisation(ISRO). Expendable launch systems derive their name from the expendable launch vehicle (ELV) they use to carry a payload into space.

Vehicles in expendable launch systems are expended during a single flight; they can, therefore, be used only once. The vehicles comprise several rocket stages, that are discarded one by one with the vehicle gaining altitude and speed.

The GSLV was developed by ISRO for launching INSAT type satellites into geostationary orbit and to lessen India's dependence on foreign rockets.

http://www.domainb.com/aero/space/satel ... ark-3.html

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Re: Indian Space Program Discussion

Postby putnanja » 03 Jan 2009 07:57

ISRO arm plays favourites

ISRO arm plays favourites


Express News Service
First Published : 02 Jan 2009 08:18:00 AM IST
Last Updated :

BANGALORE: A performance audit of the Antrix Corporation Limited (ACL), the commercial arm of Indian Space Research Organisation (ISRO), has revealed many irregularities in the functioning of the company, including undue benefits to private companies.

The Express has a copy of the report of the Comptroller & Auditor General of India on the performance of Antrix Corporation Limited, which was tabled in the Lok Sabha in October.

The report highlights the following points: n ACL extended undue benefit to Space TV (Tata Sky) by reducing the rates originally accepted by the customer while entering into a longterm agreement. Due to a reduction in lease charge, there was a recurring loss of revenue of Rs 4.8 crore per annum, whereas revenue of another Rs 5 crore was foregone due to increase in free period by a month.

n The company allowed Reliance Communications Limited to bill for the bandwidth utilised by them instead of the bandwidth allocated to them.

Absence of a deemed supply clause in 16 contracts led to a loss of Rs 27.45 crore in revenue.

n The service charge on foreign transponders was voluntarily reduced by the company, resulting in a recurring loss of Rs 8.3 crore in seven cases. There were delays in recovery of quarterly recurring charges and service.

n Service Tax was not being collected from foreign hired transponders resulting in a likely liability of Rs 16.77 crore to the exchequer. However, service tax was collected from INSAT operations.

n Though the company was set up as the commercial arm of the Department of Space (DOS), several commercial contracts like with Prasar Bharati, New Sky Satellite, Netherlands and INTELSAT were not entrusted to the company.

n ACL’s non-operational revenue (interest earned from deposits in banks) averaged around 50 per cent of the profit after tax during 2002-03 to 2006-07, which suggests that the company was used as a special purpose vehicle for unutilised funds by the DOS.

n Despite having substantial cash balances, ACL had not developed proper procedures to increase its yield from the surplus cash retained by it.

n There were delays in revenue recognition or raising bills and important contractual provisions in respect of performance bank guarantee, surrender or termination of leased capacity were not followed.

n Company-specific guidelines and procedures for investments, personnel and accounts had not been developed even 15 years after the company’s creation in 1992 and despite Government’s clear directive.

n The functional distinction between the company and the DOS was ambiguous since the department’s officers were also executives of the company. Proper delegation of powers consistent with good governance, structure and growth of the company had not been drawn.

n ACL credited the DOS share of revenue to ISRO instead of the Consolidated Fund of India. Remittances were also prompt even though the relevant money was shown as accrued to the DOS in the Accounts. Periodical reconciliation of amounts due and payable to the DOS had not been carried out.

Abhijit N
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Re: Indian Space Program Discussion

Postby Abhijit N » 04 Jan 2009 00:05

....The drag and weight factor for this can be reduced by using compression lift


I was reading about compression lift here:
http://www.aerospaceweb.org/design/wave ... sign.shtml

The author gives a layman's explanation of how a vehicle shape can be derived to harness compression lift. Here is the gist of it:
Any shape will cause Lift and Drag (L & D), since if we want maximum lift, L/D ratio has to be maximized. So if take a simple cone moving through air, it will generate upward(positive) & downward(negative) lift, as it pushes air out of its way and the air in turn reacts with its own force on the body.
Image

So he has suggested removing the upper part of the cone.
Next he has gone for the wing:-
Image
If we attach our "half cone" above to any arbitrary wing shape, then we notice that as the body passes through a high-speed flow field it generates a shock wave, and the body can only impart downward momentum on the fluid between its surface and the shock wave. Thus, the wing should extend to the shock wave to capture this change in momentum but not beyond it since this extra area will only create more skin friction drag and structural weight(unnecessary L/D increase). So now we got the wing.
Finally to harness compression lift we simply trap the air being pushed out of the vehicle's way(compressed) in between wing flaps, forcing it to lift our vehicle
Image

So finally!!...a basic shape may be as follows:-
Image

The author mentions that the above principle has been used to make a successful Mach 3 aircraft. However our RLV seems to have exactly the opposite features :D
Image

I guess there are sound principles at work here...but the initial design seems to be incapable of compression lift. There is more info at these 3 links :-
http://www.aerospaceweb.org/design/waverider/examples.shtml#x30
http://www.aerospaceweb.org/design/waverider/waverider.shtml

I guess there are no blunt edges so as to disperse heat fluxes.
http://www.aerospaceweb.org/design/waverider/flow.shtml#layer

Some of the other similar examples are:-
National Aerospace Plane (NASP) and X-30
Image

X-43 Hyper-X:
Image

and concept planes:-
Aurora Mach 5 Recon aircraft
Image

cruise missile with similar design
Image

There is also a marked absence of an underside wedge as in the XB-70
Image

Under the center of the wing, the Valkyrie featured a prominent wedge at the center of the engine inlets, designed to produce a strong shock wave. By acting upwards upon the wings, this shock wave would allow the aircraft to recover energy from its own wake. At high speeds, compression lift increased the lift of the wings by thirty percent, with no increase in drag


Lets see if I get the hang of these...

By the way lakshmikanth can you give me any links which discusses the
... release of H2 along the Hypersonic shock wave, which compresses the air/H2 mixture and pushes it into the ram intake .....

Seems to be a very interesting concept....I have heard of air being bled from the shock wave in Su-7 by moving the inlet cone in, during flight to "bleed" air from lip of the shock wave...
http://en.wikipedia.org/wiki/Inlet_cone
..this seems to be different.

Vipul
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Re: Indian Space Program Discussion

Postby Vipul » 04 Jan 2009 01:41

India plans future space missions.

Shillong: India has planned its future space mission systematically in phases up to the year 2025 with the proposed next unmanned mission to Moon in 2012 to be followed by a similar mission to Mars in 2013 and would sent a man on a space voyage in 2015.

The Chairman of Indian Space Organisation (ISRO), G Madhavan Nair speaking at the 96th Indian Science Congress said that the unmanned Chandrayan-I mission sent to moon on October 22, 2008 had generated enormous data for the global scientific community.

These data would be reviewed in January 2009. The satellite took images of the moon's surface close to a distance of 4 km and captured 35,000 images. Moon impact probe was conducted in November 14, 2008 and the wealth of data generated through the mission would be reviewed in January, 2009.

Though no traces of water, ice or oxygen was found, there were places were traces of iron was detected, he said and added that next mission to moon would pick up more materials and process more data.

Nair said finest of the instruments were deployed in taking the imagery, five of which were indigenous and five other sourced from other countries. Peaks of 2 km height was noticed on moon's surface. He admitted that India's moon mission could be successful due to global cooperation.

He said that ISRO has worked with a small budget of $ one billion as against NASA's budget of 20 billion.

Within a span of four decades ISRO has developed infrastructure for deep space network, payload operations and for processing scientific data.

"We will send a second unmanned mission to moon in 2012 followed by a similar mission to Mars in 2013 and sent a man on space voyage in 2015. ISRO has also drafted Indian Space Mission-2025," said Nair and added that in future space tourism would be a reality.

According to Nair ISRO with improved technology would aim at reducing the cost of its operations. Resuseable launch vehicles (RLV) would be developed in next 10 to 15 years and also heavy left launcher would be developed

ISRO has also developed applications for broadcast, meteorology, communication and for development programmes in the country.

Kailash
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Re: Indian Space Program Discussion

Postby Kailash » 04 Jan 2009 07:42

Abhijit N wrote:The author mentions that the above principle has been used to make a successful Mach 3 aircraft. However our RLV seems to have exactly the opposite features :D


Something to think about. But for initial testing the RLV is going to be using Rocket assisted take off. Again lift can be generated due to the angle of the craft with respect to air flow too. I do not know at what altitude the scramjet engines would kickoff or the amount of aerodynamic lift at those altitudes - may be some guru can comment on this. For the return journey, drag is more important than the lift. Currently the space shuttle also is inclined at a certain angle and exposing only the protected underside during descent.

lakshmikanth
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Re: Indian Space Program Discussion

Postby lakshmikanth » 04 Jan 2009 07:45

Abhijit N wrote:
The author mentions that the above principle has been used to make a successful Mach 3 aircraft. However our RLV seems to have exactly the opposite features :D

I guess there are sound principles at work here...but the initial design seems to be incapable of compression lift.


From my "internal" sources at ISRO (who themselves have very limited information) RLV-TD would more likely be having a vertical launch profile on an S9 solid booster engine. By the time the trajectory becomes horizontal it would have cleared the lower atmosphere. The S9 booster would be later redesigned to be recoverable.

Another thing that intrigues me is that there are no ramjet pods to be seen in the RLV-TD. I wonder where the air breathing pods are as well?
My guess is RLV-TD first version (that we have seen here) wont be air breathing. It would have a cryo stage that might take it to orbit (with no payload) and then bring it back to earth safely). Once this has been mastered there might be changes to include the ramjet pods or the air breathing engine pods. Not sure about it.

Also compression lift was a suggestion from my side. I dont know if the ISRO guys are onto it. However I certainly did see some of the hypersonic vehicle characteristics in the DRDOs HSTDV (Hypersonic Technology Demonstration vehicle).

The release of H2 along the hypersonic compression wave was something that I heard being discussed (dont remember where) while i was at a conf. Here is why it would work:- Shockwaves are caused by vehicles moving more than the speed of sound, because the air particles viscosity makes them not adapt around the vehicle as in the case of a subsonic flight. This causes the vehicle to "push" the air infront of it into a narrow compressed region which causes adiabatic compression of the air around the shockwave and also compresses it due to the "push". The temperature reaches nearly 1000 deg in case of mach 5(my guess) and nearly 2000 (my guess) in case of mach 7 leading to chemically reactive flows.

Now lets say you have a cylindrical object in a supersonic medium its very easy to see that the center of the cylinder will have HOT compressed air because of shockwaves from its edges release H2 along the edges and you would see that it would burn inside the cylinder causing the air to expand even more. This is a very technically "hot" and promising area in hypersonic reasearch and hope our ISRO babus are aware of it.

Here is DRDO's concept of Hypersonic air breathers (which i must say is very similiar to what RLV-TD aims to be :) )
http://www.aeroindiaseminar.com/Feedback-pdf_Speakers.aspx?cid=20

Here is a paper describing one experiment:
http://pdf.aiaa.org/preview/CDReadyMHYP06_1276/PV2006_7981.pdf

More result from google search term:
hypersonic + external + fuel + injection

ss_roy
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Re: Indian Space Program Discussion

Postby ss_roy » 04 Jan 2009 08:48

I have still not understood the fascination with an RLV. The reality is that while an RLV can be built, its real operating costs are going to be much more than using a disposable rocket launcher.

The biggest and unappreciated cost of an RLV arises from two factors-

1] A reusable spacecraft has to be much more durable and stronger than an equivalent disposable launcher+ payload as most of the spacecraft returns to earth for refurbishment. But chemical fuels have a limited Isp, and the best cryogenic engines top out at around 460 secs thrust. Therefore there is a limit to reducing fuel weight as a % of total weight. All spacecraft (reusable/ expendable) designs are a compromise of these two requirements (strength and fuel capacity). Moreover the weight savings possible by collecting oxygen from the air , in an RLV, are substantially negated by the extra weight and complexity necessary to achieve that. Add in the requirements (and weight penalty) for some glider like characteristics and many of the purported advantages of an RLV are gone.

The net result of these factors is that RLVs are always significantly more expensive (manufacturing costs) and complex (systems/ subsystems) than equivalent one-shot crafts.

2] The second problem is a consequence of the first, namely that the added complexity and compromises resulting from the design process result in higher operational costs. Since each system has a certain risk of failure, putting more systems in a vehicle increases the risk of something going wrong at any given time. Moreover because of the linkages of various sub-systems, the effects of individual part failure can be far more catastrophic than expected.

To rectify these problems, one has to spend much more money on quality control and inspections. Even then an RLV is unlikely to exceed the safety inherent in disposable designs.

So why are we doing this? just to show whites that we can do it? who cares?... Screw them..

Let us do things because they make sense, are profitable, practical, efficient and useful to US as a people.

If you really want a useful (as opposed to a usable) RLV, try designing high output (say 1 MN) engines with an Isp of over 1,000 secs. However I doubt that indians will try to design such engines because they will almost certainly use some form of nuclear energy and we all know that indian scientists and administrators are very sensitive to criticism from whites and their brown/ yellow chamchas.

Stop pleasing others! Let them go to hell ! Look out for your interests.. not theirs!

PS- Here is a link to a fairly good idea for a cheap disposable laucher. If we used an 1 chamber/ 4 nozzle RD-170 engine instead of their 9 engine cluster we might actually have a cheaper and more reliable launcher.

http://www.spacex.com/falcon9.php

ss_roy
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Re: Indian Space Program Discussion

Postby ss_roy » 04 Jan 2009 11:08

I think India should build a better falcon-9 type expendable launcher. It would be cheap to build and could put a decent amount in LEO and GTO orbits.

http://www.theregister.co.uk/2009/01/02/falcon_9/

http://en.wikipedia.org/wiki/Falcon_9

I think a falcon-9 heavy could put a soyuz size space vehicle on a roundabout trip to the moon- without the lander of course.

http://www.spacex.com/falcon9_heavy.php

A falcon-9 with 4 boosters instead of the 2 in the current heavy version you could launch an apollo style mission in 2 shots. I bet that 2 extra heavy falcon-9 types built in india for a lunar mission would cost less than 200 million dollars. The astronaut training+ spaceship+ infrastructure + research might cost a couple of billion dollars though.

vavinash
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Re: Indian Space Program Discussion

Postby vavinash » 04 Jan 2009 11:38

ISRO has never done anything to please others. So stop the crap about doing it to show off bit. IF ISRO did not think TSTO is practical then they would not pursue it. RLV-TD is only a TD to test the systems for the TSTO.

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Re: Indian Space Program Discussion

Postby lakshmikanth » 04 Jan 2009 13:40

ss_roy wrote:I think India should build a better falcon-9 type expendable launcher. It would be cheap to build and could put a decent amount in LEO and GTO orbits.


This is the other direction future space tech is going to be in. A large vehicle with multiple engine assembly. Again.. I hope ISRO pursues this, its not too difficult to do. Even amateurs like us would be able to get considerable progress in this area ;) . The benefit here is that mass production can be ensured instead of batch production for the engines, which will bring down the cost drastically.

Also the use of Rp1 instead of LH2 brings down the cost again( a tech that India does not have :) ). Its amazing that Pay-Pal founder can start a company (SpaceX) who start building LOX-Rp1 engine from the get go. Dude must be real smart :)

Kailash
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Re: Indian Space Program Discussion

Postby Kailash » 04 Jan 2009 19:02

ss_roy wrote:A reusable spacecraft has to be much more durable and stronger than an equivalent disposable launcher+ payload as most of the spacecraft returns to earth for refurbishment. But chemical fuels have a limited Isp, and the best cryogenic engines top out at around 460 secs thrust. Therefore there is a limit to reducing fuel weight as a % of total weight. All spacecraft (reusable/ expendable) designs are a compromise of these two requirements (strength and fuel capacity). Moreover the weight savings possible by collecting oxygen from the air , in an RLV, are substantially negated by the extra weight and complexity necessary to achieve that


Agreed that it is going to be much more complicated than what ISRO has achieved till date. But as Mr.Nair put it, it is more about retaining talent by keeping them challenged intellectually. More problems to solve, more cutting edge research would attract and keep the best talented people in ISRO.

Till the RLV converts to a horizontal takeoff, single stage to orbit vehicle, the mass fraction would look absurd, unnecessary. It would look like an extremely complication venture with not much returns. But long term would prove it to be wrong..

ss_roy wrote:So why are we doing this? just to show whites that we can do it? who cares?... Screw them..

Let us do things because they make sense, are profitable, practical, efficient and useful to US as a people.


Well then India should stop its space program. With GSLV-Mk3 we should be able to launch our heaviest satellites - after 2009, we would not need any more improvements to our space vehicles atleast (our satellites are already world class). Regarding cost, we Indians are quite efficient with the allotted funds and used to working on shoestring budgets. Regarding practicality, it depends on what all other countries think is practical - there was no reason in 1960s to go to the moon or send a man there, there has been no activity for almost 4 decades, now suddenly it started picking up in Asia (all this helium stories are humbug - would never be economical to mine stuff from moon, and we still havent perfected N-fusion yet). The latest fad is hypersonic flight and affordable space transport. But dont forget that due to their spending in the 60s, Russia and America are the top scientific superpowers when it comes to space today. Also you can only spend money in all this when your economy is doing good - but the knowledge/experience would stay for a long time to come.

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Re: Indian Space Program Discussion

Postby Raj Malhotra » 04 Jan 2009 20:01

GSLV-III will lob around 3.5 tons in space but now Communication satellites are growing in weight upto 6-7 tons, so its lift capacity would be low. There is no official indication of GSLV-IV, which in any case won't be commercially available before 2020


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