Indian Space Program Discussion

[Yugandhar]

More of ISRO’s eyes in the sky
http://www.hindu.com/2008/04/28/stories/2008042851471000.htm

Twenty years ago, the Indian Space Research Organisation (ISRO) launched the country’s first operational earth-observation satellite, the IRS-1A. In the years since then, ISRO has sent up 10 more remote-sensing satellites. (Six of these satellites are currently operational, including the ageing IRS-1D, which was launched more than 10 years ago with a design life of three years and is reportedly used sparingly these days.)

somehow most of our satellites if not all have exceeded their designed lifetimes..

In 2011-12, Cartosat-3 could go into the orbit. The panchromatic camera on this satellite is expected to provide images with a resolution of 30 cm. Currently, the American WorldView-1 satellite launched in September last year offers the highest resolution imageries that are commercially available and the resolution of those images is 50 cm. WorldView-2, which will be launched next year, will provide images with a resolution of 46 cm.

the pakis and their goats will be fully visible

[Vivek K]

Good work ISRO! Congratulations to all! Look forward to GSLV's success!

[Vidyarthi]

Congratulations to ISRO, a job well done!

In the future could people in this thread please place links to where a launch can be watched live? Its going to be a busy year for launches and its a significant event to watch. Thanks in advance.

I watched it live today, just like the previous several ones on DD National Channel. The telecast commences about 20 minutes before the scheduled lift-off and continues till the injection of the satellites into their desired orbits. There is a running commentary by two senior specialists of ISRO, alternately in Hindi and English. Some time they also include a ten minute capsule, showing vehicle integration. The telecast shows the Mission Control Center and Plot boards displaying the predicted trajectory along with the actual trajectory.

As compared to the all too-brief video reports, the telecast gave a front seat view of the entire count down activities, the lift-off and the complete flight trajectory till the completion of the mission of the launch vehicle. Commentary pointed out that hundreds of health parameters of the launch vehicle were monitored by computers, for their staying within prescribed limits, during the count down. Implying that if any parameter wanders away, computer will impose a hold, to be cleared by human intervention to correct the abnormality. During the flight, when the plot boards indicated that the flight path has deviated slightly from the predicted trace in the initial phase of the flight, I felt concerned. But was soon reassured, when the commentators pointed out that it is due to over performance of the first stage and the closed loop guidance had not commenced. Sure enough, when the operation of the closed loop guidance commenced, the deviations were corrected and the orbital injection parameters did not suffer inaccuracy and were within specs.
In brief, watching the telecast was not just thrilling beyond description, but was also very educative. It showed the meticulous work and set up behind the superlative performance.

Afraid, I do not know of any Internet link, giving lift-off live

[Gerard]

Remote-sensing satellites usually circle the Earth at a height of a few hundred kilometres. ISRO plans to put a Cartosat-type camera on a satellite that will be placed in geostationary orbit at a distance of about 36,000 km. In this orbit, the satellite matches the Earth’s rotation and therefore appears stationary from the ground. Stationed over India, the ‘Geo-HR Imager’ (as the satellite has been named) would be able to take images of the country and neighbouring regions whenever needed. .

Paki missile launches?

[Pulikeshi]

Remote-sensing satellites usually circle the Earth at a height of a few hundred kilometres. ISRO plans to put a Cartosat-type camera on a satellite that will be placed in geostationary orbit at a distance of about 36,000 km. In this orbit, the satellite matches the Earth’s rotation and therefore appears stationary from the ground. Stationed over India, the ‘Geo-HR Imager’ (as the satellite has been named) would be able to take images of the country and neighbouring regions whenever needed. .

Paki missile launches?

neighboring regions means more than that

[pradeepe]

Way to go ISRO. Way to go. Congratulations!!

[Kakarat]

Annual Report 2007-2008

[satyarthi]

Remote-sensing satellites usually circle the Earth at a height of a few hundred kilometres. ISRO plans to put a Cartosat-type camera on a satellite that will be placed in geostationary orbit at a distance of about 36,000 km. In this orbit, the satellite matches the Earth’s rotation and therefore appears stationary from the ground. Stationed over India, the ‘Geo-HR Imager’ (as the satellite has been named) would be able to take images of the country and neighbouring regions whenever needed. .

Paki missile launches?

Resolution will drop in the same proportion as the height incresases given the same imaging camera. So a factor of 50 increase in height means a 1m resolution camera will have a resolution of 50m. That would be fine for "normal" map making. IR imaging capability should be able to pick up strong thermal anomalies like missile launches, even if blurred.

[svinayak]

Remote-sensing satellites usually circle the Earth at a height of a few hundred kilometres. ISRO plans to put a Cartosat-type camera on a satellite that will be placed in geostationary orbit at a distance of about 36,000 km. In this orbit, the satellite matches the Earth’s rotation and therefore appears stationary from the ground. Stationed over India, the ‘Geo-HR Imager’ (as the satellite has been named) would be able to take images of the country and neighbouring regions whenever needed. .

Paki missile launches?

Resolution will drop in the same proportion as the height given the same imaging camera. So a factor of 50 increase in height means a 1m resolution camera will have a resolution of 50m. That would be fine for "normal" map making. IR imaging capability should be able to pick up strong thermal anomalies like missile launches, even if blurred.

If multiple leo orbit Satellites are orbiting it is possible to monitor a region continuously without break and with high resolution

[Dilbu]

Congratulations ISRO. You guys have brought tears of joy in my eyes. Keep up the good work. May god bless our beloved motherland.

[hnair]

Annual Report 2007-2008

From this report, some info on RLV-TD





Wow, they are serious about blunt bodies!!

Also Arun_S saar, the earlier report spoke of a closed-loop pre-burner for the turbo-pumps, but this pic clearly shows two jets on the sides. Any clues what they are?

[/img]

[satyarthi]

Remote-sensing satellites usually circle the Earth at a height of a few hundred kilometres. ISRO plans to put a Cartosat-type camera on a satellite that will be placed in geostationary orbit at a distance of about 36,000 km. In this orbit, the satellite matches the Earth’s rotation and therefore appears stationary from the ground. Stationed over India, the ‘Geo-HR Imager’ (as the satellite has been named) would be able to take images of the country and neighbouring regions whenever needed. .

Paki missile launches?

Resolution will drop in the same proportion as the height given the same imaging camera. So a factor of 50 increase in height means a 1m resolution camera will have a resolution of 50m. That would be fine for "normal" map making. IR imaging capability should be able to pick up strong thermal anomalies like missile launches, even if blurred.

If multiple leo orbit Satellites are orbiting it is possible to monitor a region continuously without break and with high resolution

Since we won't know in advance which region to watch for, we will need to cover whole of Pakistan and China. To cover whole of Pakistan and China continuously from LEO is not possible. It will take a huge number of sats.

http://www.isro.org/pslv-c9/cartosat2a.htm
Above link shows that for cartosat 2A the resolution is 1m, with a swath of about 10 km at 635 km height . So in LEO we will need a huge number of sats to cover Pakistan and China since each will have a swath only of 10km at a time.

At geostationary orbit, approximating it to be about 50 times higher, we get 50m resolution with 500 km swath.

Even with a 500 km swath it is not possible to cover all of pakistan or china at any given time.

Either the swath is increased while keeping the resolution same or better, or we need multiple sats even in Geostationary orbit.

[hnair]

For Pak, all it needs is one of Gerard's pot-bellied havildar standing on a machan@mango tree at the border and peering through a pair of binoculars. He can see upto Kandahar on a good day (if he doesnt spit out the paan, has adequate stealth too - round peon at top, flat machan at bottom etc). They might have retired the Mig25, thinking it is an overkill because of this. The utility of photoing Kahuta etc lost its value, once unkil released the google hounds.

No, all these stuff are not for Pakis for sure

[SaiK]

Naah.. I think we need to have more dedicated mil type systems for feedbacks into anti-missile batteries. Carto-X series could be a staging tech for such system.

We not only need constant vigilant, and logic to determine missile launch, especially those un-notified ones, and quickly scramble, scan while lock on from sat, and then feed direct to missiles, and their homing devices for course corrections, finally dispatch the mission completion pics, videos to mission control at some defence HQ.

[svinayak]

Even with a 500 km swath it is not possible to cover all of pakistan or china at any given time.

Either the swath is increased while keeping the resolution same or better, or we need multiple sats even in Geostationary orbit.

Only the region of importance is targetted for high resolution. Mil assets and imp locations are identified for targetting and the orbits can be programmed for monitoring only those locations

[Vipul]

Bigger rockets to help ISRO tap $3-b global launch biz.

The perfect launch of 10 satellites, two Indian and eight foreign, simultaneously by the Polar Satellite Launch Vehicle C-9 has catapulted the Indian Space Research Organisation (ISRO) into a new orbit. The world record mission not only demonstrates capability to launch small satellites but also puts ISRO’s commercial arm, Rs 660-crore Antrix Corporation, in a competitive position to capture a portion of the over $3-billion global satellite launch business. But if ISRO seeks to tap this market aggressively, it will have to shift focus to launch bigger rockets and heavier satellites.

Satellite launch for applications spanning direct-to-home (DTH) services, global positioning systems (GPS), education, telecom, weather monitoring and others is increasing worldwide. But the launch costs are prohibitively-high. Here, ISRO’s satellite launch services at about 60-70% cheaper costs could provide a boost to India’s space programme. “Today, PSLV is one of the proven vehicles to carry satellites. We will offer more launch products in the global market,â€

[Rahul Shukla]

Allah ho Akbar!

Those dirty yindoos can never let the pious rest in peace and pray 5 times a day. Now they have gone and launched 10 tin-dabbas into space polluting the future orbits of Paksat-2, 3, 4, ... ,5055 with unnecessary space debris. What was the need for that, I ask?

Now it is time for Paa'stan to waste i.e. launch another gadha/godhi which is henceforth declared to be capable of intercepting a yindoo prithvi mizzile in boost face, surviving and continuing ascent without damage, putting 11 tin-dabbas into space, releasing 10,000 pious MIRV's, and re-entering the atmosphere to take out and arjun tank in top attack mode.

Gadha/Godhi = ABM+Satellite launcher+ICBM+ATGM.

H&D restored!!! Beat that yindoos...

--------------------

Hail ISRO!!!

[ranganathan]

DAmn it!! don't spoil the thread by bringing in porkis into it. Heck before them iran, Sk and Brazil will put something in space.

[Arun_S]

Congratulations to ISRO, a job well done!

In the future could people in this thread please place links to where a launch can be watched live? Its going to be a busy year for launches and its a significant event to watch. Thanks in advance.

I watched it live today, just like the previous several ones on DD National Channel. The telecast commences about 20 minutes before the scheduled lift-off. There is a running commentary by two senior specialists of ISRO, alternately in Hindi and English. Some time they also include a ten minute capsule, showing vehicle integration. The telecast shows the Mission Control Center and Plot boards displaying the predicted trajectory along with the actual trajectory.

Afraid, I do not know of any Internet link, giving lift-off live

Sir,
I think you might have watched PSLV launches up close too.
Wondering if you could share some thoughts on where ISRO/SAC is poised now and the progress made from the humbler days?

Thanks

[Arun_S]

Also Arun_S saar, the earlier report spoke of a closed-loop pre-burner for the turbo-pumps, but this pic clearly shows two jets on the sides. Any clues what they are?

My recollection is that preburner for turbo pump is for the new C25 developed for GSLV-Mk3 upper stage and not CUS that is for GSLV-Mk-2

Also this image is apparently of the larger C25 Cryo stage of GSLV-Mk3.

[ramdas]

The C-25 engine is supposed to be an open cycle engine. The CUSP on the other hand comprises of a main engine with staged combustion cycle (fuel rich preburner) and a 2 chamber vernier engine powered by gas generator cycle. This is similar to the KVD-1 engine in Russia. However, the CUSP has the ability to function in a heavily uprated mode generating 93.5kn vs 75kn nominal. The image shown is that of CUSP. The large pipe with a U- turn feeding the combustion chamber from above clearly indicates a staged combustion cycle.

Most engines that powered soviet SLBMs has a main engine supplemented by multiple chambered vernier engines. These engines ran on UDMH/N2O4. The main engines used an oxidizer rich staged combustion cycle. The RD-0244 powering the RSM-54 has a chamber pressure between 275kg/cm^2 and 325kg/cm^2 according to the book on "History of LPRE's" by G. Sutton. The higher figure maybe during ground testing in a mode uprated from the nominal. By far the highest chamber pressure in an operational LPRE. Even the associated vernier engine uses staged combustion. Of course, the main engine in soviet SLBMs was "submerged" in the fuel tank.

Wonder what cycle our Semi-cryogenic engine will use.

[sunilUpa]

Good job ISRO. Yesterday I spoke to the man who once headed ISRO . May meet him this weekend, if I can fly to Bangalore. I will post if I learn any new things and allowed to share the same.

[Anujan]

Kudos to ISRO. Onward to a successful Chandraayan, two GSLV Mk-II flights and GSLV-Mk III development flight D1 ! Good luck to ISRO for that. Two missions Rakshaks would be interested in following

(*) RISAT - Launch date in 2008, not confirmed yet. From hereand here

Considering that the major crop (Khariff) season is largely covered with clouds, thus debilitating data acquisition from electro-optical cameras on board IRS satellites, a Radar Imaging Satellite (RISAT) has been taken up for development. The satellite equipped with a capability of imaging under day and night as well as cloudy conditions will become an important complementary system to the band of electro-optical sensors launched hitherto. The satellite will involve the development of a multi-mode, multi polarisation, agile Synthetic Aperture Radar (SAR) operating in C-band and providing 3-50 metre spatial resolution.

The RISAT spacecraft is configured around the payload to minimize the spacecraft weight, suitable for launching by ISRO's PSLV launcher. RISAT will be placed on dawn to dusk sunsynchronous polar orbit to ensure maximum solar power availability. All the basic building blocks have already crossed design stage and have undergone rigorous space qualification program. Presently a complete SAR with one tile has been integrated as design verification model and is under rigorous testing.


Synthetic Aperture Radar being tested using an aircraft

(*) INSAT 4E from here and here

Capacity to deliver over ten video channels and over ten audio channels in each beam (which will grow over time through better digital transmission, encoding and compression technologies) through downlink component of the system, including interactive services such as text messaging, weather information, disaster warning, etc.

[Anujan]

How it started

Humble beginings indeed ! But not devoid of magnificient vision. From President Kalam's "Wings of Fire"

The leader of the India space program, Prof Vikram Sarabhai, had comprehended the full implications of the challenge and had not balked at taking it on. Right from the day INCOSPAR was formed, he was aware of the need to organize an integrated national space program, with the equipment for the manufacture of rockets and launch facilities developed and produced indegenously. With this view, a wide-ranging programme for scientific and technological development in rocket fuels, propulsion systems, aeronautics, aerospace materials, advanced fabrication techniques, rocket motor instrumentation, control and guidance systems, telemetry, tracking systems and scientific instruments for experimentation in space were launched at the space science and technology center and physical research laboratory at ahmedabad.

[arun]

PSLV-XL configuration.

Propellant loading of the strap-on motors increased from 9 tonnes to 12 tonnes.

Six strap-on motors as now.

ISRO Chairman G Madhavan Nair :

Moon mission in 3rd quarter of '08: ISRO

…… “A special vehicle of the Polar Satellite Launch Vehicle (PSLV) called the PSLV-XL is being prepared for it. The weight of the strap-on thrust will increase from nine to 12 tonnes. All the six motors are ready," …….

[Arun_S]

The C-25 engine is supposed to be an open cycle engine. The CUSP on the other hand comprises of a main engine with staged combustion cycle (fuel rich preburner) and a 2 chamber vernier engine powered by gas generator cycle. This is similar to the KVD-1 engine in Russia. However, the CUSP has the ability to function in a heavily uprated mode generating 93.5kn vs 75kn nominal. The image shown is that of CUSP. The large pipe with a U- turn feeding the combustion chamber from above clearly indicates a staged combustion cycle.

Most engines that powered soviet SLBMs has a main engine supplemented by multiple chambered vernier engines. These engines ran on UDMH/N2O4. The main engines used an oxidizer rich staged combustion cycle. The RD-0244 powering the RSM-54 has a chamber pressure between 275kg/cm^2 and 325kg/cm^2 according to the book on "History of LPRE's" by G. Sutton. The higher figure maybe during ground testing in a mode uprated from the nominal. By far the highest chamber pressure in an operational LPRE. Even the associated vernier engine uses staged combustion. Of course, the main engine in soviet SLBMs was "submerged" in the fuel tank.

Wonder what cycle our Semi-cryogenic engine will use.

Thanks boss.

[Arun_S]

PSLV-XL configuration.

Propellant loading of the strap-on motors increased from 9 tonnes to 12 tonnes.

Six strap-on motors as now.

ISRO Chairman G Madhavan Nair :

Moon mission in 3rd quarter of '08: ISRO

…… “A special vehicle of the Polar Satellite Launch Vehicle (PSLV) called the PSLV-XL is being prepared for it. The weight of the strap-on thrust will increase from nine to 12 tonnes. All the six motors are ready," …….

Check the last 2 ISRO annual reports for picture of the 1.2m dia motor on ground test jig.

Surprisingly DRDO is also making 1.2 m dia. See BR Agni article for the pic of the motor w/Natrajan.

[nkumar]

Scientists in joy: ‘Baby is healthy’

By OUR SPECIAL CORRESPONDENT

Chennai, April 28: Within seconds of Cartosat-2A was placed into orbit by the PSLV-C9 mission, the Spacecraft Control Centre in Bangalore, set up exclusively to monitor its signals, started receiving feedback. According to a senior Isro scientist, the signals were amazing. "The ‘baby’ is healthy and vibrant," said the scientist who did not want to be named. A team of senior scientists led by Dr V. Jayaram, director, earth observation system, Isro, were closely following each and every movement associated with the Cartosat-2A at the SCC. The next couple of days will see the satellite getting positioned in the predetermined orbit and sending pictures. The mission control room, the nerve centre Crowds jubilant, scientists emotional:of the Satish Dhawan Space Centre, Sriharikota, reverberated with thunderous applause from more than 250 veteran launch specialists as the PSLV-C9 rose majestically from the second launch pad.

"It was a launch with computer precision. I feel the ideal term should be ‘laptop liftoff’," said C. Venugopal, vehicle director, PSLV-C9 mission. Mr Venugopal, a PSLV specialist, told this newspaper that the mission was a total success.

"This is yet another proof that PSLV has graduated into the major league. It is the most efficient and cost–effective launch vehicle in its class," said Mr Venugopal, who is also associate project director, PSLV. While Mr Venugopal, a mechanical engineer turned scientist, donned the role of vehicle director for the second time, Mr George Koshy, project director, PSLV, was mission director for Monday’s launch. It was the Koshy-Venugopal team which led the previous PSLV mission which put an Israeli satellite into space.

All the engineers assembled at the Satish Dhawan Space Centre are returning to their respective headquarters for strategic meetings and brainstorming sessions. "We will be back in SDSC shortly because our hands are full with launch missions," said one of the space scientists.

[vina]

The C-25 engine is supposed to be an open cycle engine. The CUSP on the other hand comprises of a main engine with staged combustion cycle (fuel rich preburner) .

Doesn't make sense does it ? . When you have the more efficient staged combustion cycle with the CUS for MkII, why would you go for the less efficient open cycle design for the C-25 for the MKIII . Makes sense to scale the more efficient MKII design to MK III!

[vina]

Check the last 2 ISRO annual reports for picture of the 1.2m dia motor on ground test jig. ;)

Surprisingly DRDO is also making 1.2 m dia. See BR Agni article for the pic of the motor w/Natrajan.

Isn't the strap on boosters of the PSLV derived from the 1st stage of the SLV-3 , which was also used as the 1st stage of the Agni I, II and III series by DRDO ? .

[arun]

PSLV-XL configuration.

Propellant loading of the strap-on motors increased from 9 tonnes to 12 tonnes.

Six strap-on motors as now.

ISRO Chairman G Madhavan Nair :

Moon mission in 3rd quarter of '08: ISRO

…… “A special vehicle of the Polar Satellite Launch Vehicle (PSLV) called the PSLV-XL is being prepared for it. The weight of the strap-on thrust will increase from nine to 12 tonnes. All the six motors are ready," …….

Check the last 2 ISRO annual reports for picture of the 1.2m dia motor on ground test jig.

Surprisingly DRDO is also making 1.2 m dia. See BR Agni article for the pic of the motor w/Natrajan.

If the " " is meant to suggest that you beleive that the increased propellant loading of the PSOM-XL is being met by an increase in the diameter to 1.2 meters, you are incorrect.

The increased propellant loading of the PSOM-XL is being met by an increase in the length to 13.5 meters and not by an increase in diameter to 1.2 meters.

[amar_g]

...i only wish the cryo engine scientists at ISRO were somehow able to help the ones at DRDO with kaveri..

[SSridhar]

The C-25 engine is supposed to be an open cycle engine. The CUSP on the other hand comprises of a main engine with staged combustion cycle (fuel rich preburner) .

Doesn't make sense does it ? . When you have the more efficient staged combustion cycle with the CUS for MkII, why would you go for the less efficient open cycle design for the C-25 for the MKIII . Makes sense to scale the more efficient MKII design to MK III!

Vina, while it is true that the staged-combustion or the closed-loop cycle will give higher specific impulse, the high pressure pre combustor will generate a lot more pressure making the gas generator, turbine and the associated piping heavy and complex. Relatively speaking, an open cycle is easier to build as the turbine exhaust is directly injected into the nozzle beyond the throat. There is a small advantage also in the latter as it can protect the nozzle around the place where the gas is discharged.

This shows that C-25 will only get better as ISRO masters the complex technology and the manufacturing process and incorporated the staged-combustion cycle into the next version.

[Vipul]

More of ISRO’s eyes in the sky.

Twenty years ago, the Indian Space Research Organisation (ISRO) launched the country’s first operational earth-observation satellite, the IRS-1A. In the years since then, ISRO has sent up 10 more remote-sensing satellites. (Six of these satellites are currently operational, including the ageing IRS-1D, which was launched more than 10 years ago with a design life of three years and is reportedly used sparingly these days.)

“Today, India is one of the major providers of earth observation data in the world in a variety of spatial, spectral and temporal resolutions, meeting the needs of many applications of relevance to national development,â€

[Vipul]

More of ISRO’s eyes in the sky.

Twenty years ago, the Indian Space Research Organisation (ISRO) launched the country’s first operational earth-observation satellite, the IRS-1A. In the years since then, ISRO has sent up 10 more remote-sensing satellites. (Six of these satellites are currently operational, including the ageing IRS-1D, which was launched more than 10 years ago with a design life of three years and is reportedly used sparingly these days.)

“Today, India is one of the major providers of earth observation data in the world in a variety of spatial, spectral and temporal resolutions, meeting the needs of many applications of relevance to national development,â€

[Arun_S]

PSLV-XL configuration.

Propellant loading of the strap-on motors increased from 9 tonnes to 12 tonnes.

Six strap-on motors as now.

ISRO Chairman G Madhavan Nair :

Moon mission in 3rd quarter of '08: ISRO

…… “A special vehicle of the Polar Satellite Launch Vehicle (PSLV) called the PSLV-XL is being prepared for it. The weight of the strap-on thrust will increase from nine to 12 tonnes. All the six motors are ready," …….

Check the last 2 ISRO annual reports for picture of the 1.2m dia motor on ground test jig.

Surprisingly DRDO is also making 1.2 m dia. See BR Agni article for the pic of the motor w/Natrajan.

If the " " is meant to suggest that you beleive that the increased propellant loading of the PSOM-XL is being met by an increase in the diameter to 1.2 meters, you are incorrect.

The increased propellant loading of the PSOM-XL is being met by an increase in the length to 13.5 meters and not by an increase in diameter to 1.2 meters.

":wink: " is to think about what is coming down the pipe.
Of course the 1.2m dia baby is ~20 tonne mass (see stage confign on BR Agni--IIAT) and not the -XL 12 tonne puppy used here.

[ramana]

In above post

[quote]
The Indian Mini Satellite-1 (IMS-1), which was earlier called the Third World Satellite (TWSAT), will be a co-passenger with the Cartosat-2A on the PSLV. While the latter weighs 690 kg, the IMS-1, a small satellite, weighs slightly over 80 kg at lift-off.

“The IMS-1 should be seen as a technology demonstrator for miniaturising both space and ground segments,â€

[Kakarat]

4 m Dia Payload Fairng for GSLV-D3

[satyarthi]

In 2011-12, Cartosat-3 could go into the orbit. The panchromatic camera on this satellite is expected to provide images with a resolution of 30 cm.

Cartosat 2A has resolution of about 1m. To get 30 cm resolution, the telescope collector diameter will have to become 3 times bigger. I was wondering PSLV could accomodate 3 times bigger telescope. It seems it can.

http://isro.org/pslv-c9/photo/10.jpg
http://www.bharat-rakshak.com/SPACE/Ima ... c4-big.jpg
http://isro.org/pslv-c9/cartosat2a.htm

The telescope mirror containing cylinder is seen at the top. And diameter of PSLV payload area is 3.2m. From relative sizes, the telescope dia is about 0.8m. For diffraction limited imaging at 0.85 micron wavelength about 0.66m dia of the mirror is needed. To increase the resolution to 30cm, the telscope of diameter of between 2.1m and 2.4m would be needed. Since the payload area dia is about 3.2m, it should still fit there comfortably.

[Mort Walker]

Cartosat 2A has resolution of about 1m. To get 30 cm resolution, the telescope collector diameter will have to become 3 times bigger. I was wondering PSLV could accomodate 3 times bigger telescope. It seems it can.

Unless ISRO has developed some sort of folding-unfolding mirror. The Cartosat2A, IIRC is suppose to have a resolution [/]better[/i] than 1m according to the ISRO web-site.