Indian Space Programme Discussion

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Re: Indian Space Programme Discussion

Post by member_28108 »

Versatility in all the available technologies is ideal.
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Re: Indian Space Programme Discussion

Post by member_28502 »

Semi Cryogenic is relatively easy to manufacture, as it only has Liquid Oxygen as Cryogenic fuel instead of both Oxygen and Hydrogen being Cryogenic.

The Russians and US who copied V2 rockets had semi route using Liquid Oxygen and Kerosene.

The R7 family here
http://www.russianspaceweb.com/r7.html
the Chinese copied it and have help from Ukraine as well
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Re: Indian Space Programme Discussion

Post by merlin »

Sridhar wrote:Hypergolic liquid engines have their own place in ISRO's future (besides the PSLV and LVM3, they are and will continue to be used for the on-board engines on satellites and for interplanetary spaceships), but the semi-cryo will involve easier handling and lower costs besides providing an ISP boost for the core stage. That is ISRO's stated logic behind the SC development program.
Hypergolics are not used on satellites and spaceships, monopropellants are used there (MMH mostly). Hypergolics only have a future in the PSLV, not anywhere else once SC is developed. But as you said ISP boost is the main reason for going the SC route, besides ease of use compared to full cryogenic except for the upper stage where it is very useful.
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Re: Indian Space Programme Discussion

Post by Sridhar »

merlin wrote:Hypergolics are not used on satellites and spaceships, monopropellants are used there (MMH mostly). Hypergolics only have a future in the PSLV, not anywhere else once SC is developed. But as you said ISP boost is the main reason for going the SC route, besides ease of use compared to full cryogenic except for the upper stage where it is very useful.
MMH is hypergolic! The INSAT and GSAT series use MMH as propellant and MON-3 (mixed oxides of nitrogen) as oxidizer, for instance. Chandrayaan and the Mars Orbiter Mission both use bipropellant engines.

See page 7 of this brochure for the latest GSLV-D5/GSAT-14 mission.
http://www.isro.org/gslv-d5/pdf/brochure.pdf

It clearly mentions that GSAT-14 has a bipropellant engine using MMH as fuel and MON-3 as oxidizer.


Here are the Chandrayaan onboard propulsion specs from an ISRO FAQ on the mission.
8. What type of propulsion system will Chandrayaan-1 use? How much propellant will it carry?
Chandrayaan-1 will use bipropellant integrated propulsion system for orbit raising and attitude control. It consists of one 440N engine and eight numbers of 22N thrusters, mounted on the negative roll face of the spacecraft. Two tanks each with a capacity of 390 litres are used for storing fuel and oxidizer.
http://www.isro.gov.in/Chandrayaan/htmls/faqs.htm

And here's the specs of the Mars orbiter mission (with almost identical propulsion system specs as on Chandrayaan but with greater propellant loading).
Proplusion System consists of one 440N Liquid Engine and 8 numbers of 22N thrusters. The propellant tanks have combined storage capacity up to 852 kg propellant. The 22N thrusters are used for attitude control during the various activities of the mission like, orbit raising using liquid engine, attitude maintenance, Martian orbit maintenance (if any) and momentum dumping.

As the critical operation of Martian Orbit Insertion with Liquid Engine burn occurs after 10 months of launch, suitable isolation techniques are adopted to prevent fuel/ oxidiser migration issues.
http://www.isro.org/mars/challenges.aspx
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Re: Indian Space Programme Discussion

Post by disha »

Nijalingappa wrote:Semi Cryogenic is relatively easy to manufacture, as it only has Liquid Oxygen as Cryogenic fuel instead of both Oxygen and Hydrogen being Cryogenic.
:eek: Saar it is *not* about temperature!!!!!
merlin wrote:Hypergolics are not used on satellites and spaceships, monopropellants are used there (MMH mostly). Hypergolics only have a future in the PSLV, not anywhere else once SC is developed.
:eek: Saar, what is used on Mangalyan? And honestly, SC is useless there!!!

Sridhar saar, yes., I owe a very long paper on this subject.
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Re: Indian Space Programme Discussion

Post by member_28108 »

With a semicryogenic engine we can get a greater mass lift with a lighter vehicle.That in itself is an advantage.As far as temperature not being an issue - indeed it is one of the issues- storing LH2 and pumping it is one of the difficult issues in a cryogenic engine so the design of a semicryogenic engine is relatively "simpler" even with the cooled fuel systems. The current systems have their uses but if we want to move on we do need cryogenic and semicryogenic systems for the simple reason that they have a better lsp and mass flow rate.
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Re: Indian Space Programme Discussion

Post by member_28502 »

disha wrote:
Nijalingappa wrote:Semi Cryogenic is relatively easy to manufacture, as it only has Liquid Oxygen as Cryogenic fuel instead of both Oxygen and Hydrogen being Cryogenic.
:eek: Saar it is *not* about temperature!!!!!

Understanding this paper will help a lot

https://webfiles.uci.edu/dbeerer/rocket ... ective.pdf
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Re: Indian Space Programme Discussion

Post by member_28468 »

Please enligten me if i am wrong why not india try for somrthing new like orion or magnetic capatulate or space elevator some thing like that.
I know some will say it will be expansive like hell but if you can make industry out of it or ifwe can make industries in space we will and can be no. 1 .

Please give your views becuse this idea :idea: is floating in my head since i read about Orion i know it is banned but you can see the potentiol of a space ship with million ton lifting capacity. :mrgreen:
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Re: Indian Space Programme Discussion

Post by raj.devan »

vishant chaudhary wrote:Please enligten me if i am wrong why not india try for somrthing new like orion or magnetic capatulate or space elevator some thing like that.
I know some will say it will be expansive like hell but if you can make industry out of it or ifwe can make industries in space we will and can be no. 1 .

Please give your views becuse this idea :idea: is floating in my head since i read about Orion i know it is banned but you can see the potentiol of a space ship with million ton lifting capacity. :mrgreen:
It's not so much an issue of the expense involved, as much as it is an issue of the time it takes to research and develop such technologies. To successfully R&D something like nuclear pulse technology would take at least a couple of decades before viable launch vehicles are operational.

So ISRO has to focus on technologies that can potentially reap dividends in the near future - especially considering that even these have taken years to develop to their current level.

But you're right in the sense that we have to initiate and persevere with R&D in nascent technologies keeping an eye on a longterm future. 20 years from now when the world has started to use nuclear pulse rockets, we should not be left behind.
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Re: Indian Space Programme Discussion

Post by merlin »

Sridhar wrote:
merlin wrote:Hypergolics are not used on satellites and spaceships, monopropellants are used there (MMH mostly). Hypergolics only have a future in the PSLV, not anywhere else once SC is developed. But as you said ISP boost is the main reason for going the SC route, besides ease of use compared to full cryogenic except for the upper stage where it is very useful.
MMH is hypergolic!
You are right, of course. My brain freeze moment :((
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Re: Indian Space Programme Discussion

Post by SSridhar »

GAGAN being launched at Chennai Airport - ToI
Flying over Chennai skies will soon become cost effective for airlines. The GPS-aided geo-augmented navigation system (Gagan) will see to that.

Chennai has been chosen for pre-launch trials of the satellite-based system, through which crucial navigational data is transmitted to pilots during the flight as well as during landing and take-off, a senior official at the Airports Authority of India headquarters in Delhi said. "It will cut short flying time by optimising routes. It will also help avoid 20-30 minutes of holding time for flights during peak hours at busy airports," he said. It will take one year before the system is fully operationalised.

Ensuring safety will be a significant part of the system, said to be the first of its kind in South East Asia. It provides information about the terrain as well as about traffic to Air Traffic Controllers and pilots.

A senior navigation officer said a flight is kept on hold for 20-25 minutes before landing at the country's major airports, including Mumbai and Delhi. "With the help of Gagan, this holding time can be avoided by rescheduling take-off from the origin airport. This helps airlines save a minimum 600kg of Aviation Turbine Fuel (worth around Rs 55,000)," he said.

Currently, a plane cannot fly straight from one city to another, for instance from Chennai to Mumbai or Delhi, due to several factors, including dense clouds, traffic and sterile sky zones above military establishments. "Gagan will help optimise the routes, making them shorter and straighter, by transmitting real time traffic and weather data to ATCs and pilots. This would help save a minimum 300kg of ATF or avoid 10-15minutes delay in journey," he said.

The question is whether airlines will be ready to install satellite-based antennae, each costing around Rs 75 lakh, for Gagan. "When a single flight can save nearly Rs 80,000 worth of ATF with the help of optimised routes and less holding time at the destination, spending Rs 75 lakh for each aircraft should not be a problem," said an AAI official. For an airline with at least four flights a day, he said, Gagan would help save at least Rs 3 lakh a day in fuel cost.

Ground-based GPS receivers have already been installed at Chennai airport. "The system may also be provided to civilian flights in neighbouring countries for a fee," said the official.
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Re: Indian Space Programme Discussion

Post by Varoon Shekhar »

IRNSS-1B launch on Friday April 4th, brochure and pictures are out.

http://isro.org/pslv-c24/pdf/pslv-c24-brochure.pdf
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Re: Indian Space Programme Discussion

Post by Sridhar »

LVM3-X1 update. L110 stage being transported from LPSC to SHAR. (the title of the article is misleading, BTW, so not posting it)

http://www.thehindu.com/news/gslv-mark- ... epage=true
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Re: Indian Space Programme Discussion

Post by krishnan »

lets wait and watch how some dorks say that we are wasting money on this
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Re: Indian Space Programme Discussion

Post by srin »

Is that graphic accurate ? The satellites in GSO will keep moving north and south of Equator - so they would provide coverage over a wider area. Or will then keep changing their orientation to focus on India all the time ?
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Re: Indian Space Programme Discussion

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http://www.thehindu.com/news/national/p ... sliderNews


PSLV-C24 launch rehearsal goes without hitch
T. S. SUBRAMANIAN

The IRNSS-1B will be useful in terrestrial, aerial and sea navigation

The campaign for the lift-off of the Polar Satellite Launch Vehicle (PSLV-C24) is gathering momentum. The rocket will blast off at 5.14 p.m. on April 4 from Sriharikota and put into orbit a 1,432-kg navigation satellite, called the Indian Regional Navigation Satellite System (IRNSS-1B).

Engineers of the Indian Space Research Organisation (ISRO) have stacked up the vehicle’s four stages in the first launch pad. The satellite, sheathed in the heat-shield, has been mated with the vehicle. The launch rehearsal was completed without hitch on Saturday.

“Everything is ready,” said ISRO Chairman K. Radhakrishnan. “On Thursday, we completed the final checks on the vehicle… The countdown, lasting 58 hours and a half, will begin at 6.44 a.m. on April 2.”

M.C. Dathan, Director of Liquid Propulsion Systems Centre at Mahendragiri in Tamil Nadu, said the launch rehearsal “went off without any issues.” ISRO engineers checked the vehicle’s telemetry, tele-command and power systems.

The IRNSS-1B is the second in a series of seven satellites. The IRNSS-1A was put into orbit on July 1, 2013. The PSLV will launch two more such satellites before the end of 2014.

The IRNSS-1B will be useful in terrestrial, aerial and sea navigation. It will beam back accurate information on the position of trucks, cars, battle tanks, aircraft, missiles, ships and submarines with precise timing reference. Truck and car drivers, pilots of civilian or combat aircraft and ship captains can properly plan their route using the IRNSS satellites which will guide them towards their destination with the help of a receiver. The satellites will way-point the missiles to their targets.
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Re: Indian Space Programme Discussion

Post by SSridhar »

srin wrote:Is that graphic accurate ? The satellites in GSO will keep moving north and south of Equator - so they would provide coverage over a wider area. Or will then keep changing their orientation to focus on India all the time ?
The IRNSS geosyncrhonous (GSO) satellites are in pairs at each location and it conserves slots and provides coverage over the region as well. Their attitude will be maintained just like those in GEO . That's why we see a figure of 8 (analemma) on earth. It is cost effective to manouevere the ground station rather than continuously adjusting the attitude of the GSO satellite.
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Re: Indian Space Programme Discussion

Post by symontk »

SSridhar wrote:
srin wrote:Is that graphic accurate ? The satellites in GSO will keep moving north and south of Equator - so they would provide coverage over a wider area. Or will then keep changing their orientation to focus on India all the time ?
The IRNSS geosyncrhonous (GSO) satellites are in pairs at each location and it conserves slots and provides coverage over the region as well. Their attitude will be maintained just like those in GEO . That's why we see a figure of 8 (analemma) on earth. It is cost effective to manouevere the ground station rather than continuously adjusting the attitude of the GSO satellite.
Actually that is the difference between GSO and GEO. The GSO satellites will move over equator south and north. The GEO will be seen as stationary over a spot over earth
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Re: Indian Space Programme Discussion

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http://isro.org/pslv-c24/c24-status.aspx

Apr 01, 2014
The 58 hrs and 30 minutes countdown is expected to start at 6:44 hrs (IST) on Apr 02, 2014
Pre countdown activities are in progress
Launch rehearsal completed successfully
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Re: Indian Space Programme Discussion

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Image
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Re: Indian Space Programme Discussion

Post by Anurag »

So a quick question for the more learned. After IRNSS-1B, the other two launches before year end will complete the four satellites in GSO. Are they using the 3 GEO sats for the system from the existing ones already up there? I take it those would have been the ones launched from Arianne launch some time back?
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Re: Indian Space Programme Discussion

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I thought a system of 7 satellites will make up the complete system.

http://www.isro.gov.in/newsletters/cont ... ticle5.htm

http://en.wikipedia.org/wiki/Indian_Reg ... ite_System
gives the launch schedules. With minimum of 4 satellites you can triangulate and get altitude. There is also a ground based network in addition to augment the system.
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Re: Indian Space Programme Discussion

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Apr 02, 2014
The 58 hrs and 30 minutes countdown of PSLV-C24/IRNSS-1B mission commenced at 06:44 hrs (IST)
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Re: Indian Space Programme Discussion

Post by SSridhar »

After 10 years in orbit, Insat 3E goes out of service - Madhumitha D.S. The Hindu
Communications satellite INSAT-3E has completed its life and gone out of service. Built to last 15 years, it has completed ten-and-a-half years in orbit.

The third-generation satellite was launched in September 2003 with 36 transponders — 24 C-band and 12 extended C-band transponders — but only 25 of them have been working since 2009.

K. Radhakrishnan, Chairman of the Indian Space Research Organisation, which builds and operates Indian satellites, told The Hindu , “The satellite has been decommissioned.”

A few days ago, it ran out of the on-board oxidiser, which, along with fuel, keeps it Earth-locked (or fixed over India) and runs its daily functions.

The ISRO had apparently expected that the satellite, positioned at 55 degrees E longitude, would last a few more months and that it would be smoothly replaced with GSAT-16.

Now the space agency is getting set to launch IRNSS-1B, second of its seven regional navigation satellites, on April 4.

Dr. Radhakrishnan said, “We started shifting users of INSAT-3E on to standby capacities on some of our other satellites. The migration process began on March 22 and is going on.” The spare capacity includes the three-month-old GSAT-14.

INSAT-3E’s 10 extended C-band transponders supported VSAT operators; its C-band supported BSNL and captive communication networks of the National Thermal Power Corporation and the Oil and Natural Gas Corporation, among others.

The ISRO is now left with 189 transponders on its INSAT/GSAT fleet and 91 additional transponders leased on foreign satellites. Dr. Radhakrishnan said, “No one is suffering for want of capacity.”

Service disruption

INSAT-3E had briefly blinked and disrupted services for almost a day in September 2012 and was restored.

Meanwhile, the Master Control Facility at Hassan is due to move the expired satellite into a higher ‘graveyard’ orbit and keep it out of the way of many working spacecraft of other countries.
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Re: Indian Space Programme Discussion

Post by Austin »

How did the satellite ran out of fuel so early , considering it has a designed life of 15 years the fuel capacity would have included the designed period plus some extra reserves ?
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Re: Indian Space Programme Discussion

Post by SSridhar »

Austin, it had a power problem and several transponders were lost and later it lost attitude control as well. I expect that a lot of on-board fuel was expended to overcome technical issues.
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Re: Indian Space Programme Discussion

Post by vic »

It gave ten year service, what do you what? Bacche ki jaan lega kayaa?
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Re: Indian Space Programme Discussion

Post by Austin »

SSridhar Thanks for the clarification ...vic yes 10.5 years is good but had it continued till its designed life then the problem of need for additional transponder would have been less of an urgency for ISRO
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Re: Indian Space Programme Discussion

Post by rsingh »

SSridhar wrote:After 10 years in orbit, Insat 3E goes out of service - Madhumitha D.S. The Hindu
Communications satellite INSAT-3E has completed its life and gone out of service. Built to last 15 years, it has completed ten-and-a-half years in orbit.

The third-generation satellite was launched in September 2003 with 36 transponders — 24 C-band and 12 extended C-band transponders — but only 25 of them have been working since 2009.

K. Radhakrishnan, Chairman of the Indian Space Research Organisation, which builds and operates Indian satellites, told The Hindu , “The satellite has been decommissioned.”

A few days ago, it ran out of the on-board oxidiser, which, along with fuel, keeps it Earth-locked (or fixed over India) and runs its daily functions.

The ISRO had apparently expected that the satellite, positioned at 55 degrees E longitude, would last a few more months and that it would be smoothly replaced with GSAT-16.

Now the space agency is getting set to launch IRNSS-1B, second of its seven regional navigation satellites, on April 4.

Dr. Radhakrishnan said, “We started shifting users of INSAT-3E on to standby capacities on some of our other satellites. The migration process began on March 22 and is going on.” The spare capacity includes the three-month-old GSAT-14.

INSAT-3E’s 10 extended C-band transponders supported VSAT operators; its C-band supported BSNL and captive communication networks of the National Thermal Power Corporation and the Oil and Natural Gas Corporation, among others.

The ISRO is now left with 189 transponders on its INSAT/GSAT fleet and 91 additional transponders leased on foreign satellites. Dr. Radhakrishnan said, “No one is suffering for want of capacity.”

Service disruption

INSAT-3E had briefly blinked and disrupted services for almost a day in September 2012 and was restored.

Meanwhile, the Master Control Facility at Hassan is due to move the expired satellite into a higher ‘graveyard’ orbit and keep it out of the way of many working spacecraft of other countries.
Any chance of bringing it down by using "Integrated De-orbiting Technology Demonstrator Quick Launch Vehicle"
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Re: Indian Space Programme Discussion

Post by sanjaykumar »

Help. Toxic hydrazine on board.
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Re: Indian Space Programme Discussion

Post by fanne »

Ws it deoribated, so that that slot be taken by another Indian satellite
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Re: Indian Space Programme Discussion

Post by Cybaru »

Is it not possible to put some sort of monitoring equipment on board (during design and construction) and send it out on a journey into outer space when these satellites finish their life.
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Re: Indian Space Programme Discussion

Post by NRao »

I just rolled off a project working with sat junkies, will ask them some time. Long time back, some had suggested to send them into the sun. But:

Pentagon's DARPA reveals plans to reuse old satellites

Also, there are a ton of billionaires that are investing is a bunch of new techs - some in space, SpaceX being a great example and there are at least 4 companies that I know of that fall under this category. IF they find they can make money out of anything out there they will. There is one that uses laptop batteries and cell phone techs to build a sat and with 130 of them they will compete with Digital Globe to photograph the earth.
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Re: Indian Space Programme Discussion

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Filling of Oxidiser (Mixed Oxides of Nitrogen) into the fourth stage of PSLV C24 has been completed successfully.
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Re: Indian Space Programme Discussion

Post by vic »

Austin wrote:SSridhar Thanks for the clarification ...vic yes 10.5 years is good but had it continued till its designed life then the problem of need for additional transponder would have been less of an urgency for ISRO
Sirji, it was attempt at humor only, don't be so serious! :D
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Re: Indian Space Programme Discussion

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Deleted duplicate post
Last edited by member_25400 on 03 Apr 2014 13:59, edited 1 time in total.
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Re: Indian Space Programme Discussion

Post by member_25400 »

Re: Insat :
NRao/Cybaru :

If it had that amount of delta vee onboard, it's life would not be over. The amount of delta vee required to send a satellite wandering off into space (presumably interstellar) or into the sun is quite substantial (and may not be available even when new).

It will be cheaper to de-orbit it. However, this one has been parked in a higher orbit. (cheaper still in terms of delta vee)
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