Indian Space Programme Discussion

[maitya]

<snip>
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This not just brings the cost down but also increases launch efficiency.

I think ISRO is hedging its bets., it has the cryo-tech and will scale that up. However scaling up the cryo-tech (to reach US Space Shuttle SSME levels) is not easy and in the meantime the semi-cryo stage provides a stop gap measure and takes care of one risk variable., that is any delay in scaling up the cryo stage does not effect the overall launch programmes.

Also ISRO has demonstrated that it can scale up its solid booster tech. Getting a 5 MN 200 tonne booster is no mean achievement.

Newer variants of solid boosters are in the offing., for example boosters based on CL-20 with carbon fibre and graphene can push the ISP of a solid booster way past a semi-cryogenic one. The current issue here is the cost of such nitramine based compounds like CL-20.
...
<snip>

So Dishaji, from a layman pov, it's basically moving up the "specific impulse" chain while having a eye on the costs as well.

So we are trying to implement a full spectrum of "specific impulse" value chain, with,
Cryo (e.g. CE20, LH-LoX based) - 360-380s > Semi-cryo (e.g. SCE-200, Kerosene/LOX based) - 310-335s > Liquid (e.g. L110) - 293s > Solid (e.g. S200, HTPB based) - 275s.

Which basically means, whilst replacing L110 stages with Semi-cryo offers not too much wrt launch efficiency etc, it does so, if replacing the solid stages. But for that we need 5K kN-class engines while current SCE-200 is at 2K kN-class.

Other alternate option is to continue to pursue the high-energy-but-expensive-and-unproven solid stages (like CL-20 based ones with 320s specific impulse) which provides semi-cryo comparable launch efficiency levels.

So yes, semi-cryo SCE-200 is all about hedging bets - a backup option actually for all stages (maybe except the Cryo Upper stage).

[SSridhar]

The launch of PSLV-C30 carrying India's dedicated multi-wavelength astronomical observation satellite ASTROSAT along with six international customer satellites is scheduled at 10:00 am on Monday, September 28, 2015 from Satish Dhawan Space Centre, SHAR.

And a very detailed write-up in this week's Frontline ( issue also has article on GSLV and interview with ISRO chairman)

http://www.frontline.in/science-and-tec ... epage=true

From that article,

“Also, we had very small teams of skilled people. Such missions abroad have much larger teams and they all would have had some prior experience in similar missions. Even at the TIFR, where three of the five instruments were built, each team had only three to four engineers."

OT here, but the above is bothersome. Generally, that speaks very poorly of the skill base available in scientific & engineering sectors in a massive country like India. ISRO's own institute in T'puram is therefore a good investment for space sciences.

[SSridhar]

‘Safety of crew is the priority for ISRO in manned space missions’ - The Hindu

The Indian Space Research Organisation (ISRO) is focusing on developing a manned space vehicle to carry a crew of two or three members to the low earth orbit and return safely to the earth, said Unnikrishnan Nair, Project Director, Human Space Flight Project, ISRO.

Delivering a lecture after launching an online portal “Direct” of the Electronics and Communications Engineering at the National Institute of Technology-Tiruchi here on Wednesday, he said the ISRO had been working very hard for the launch of manned space vehicles. Various units were working for the successful launch. All aspects, including safe launch, effective ground monitoring, cabin crew safety, living space capsule model, and contingency plans were closely studied. While stating that successful launch was the prime objective of manned space mission programme, ISRO was working out modalities for the safety of the crew members if anything went wrong during the launch. The launch vehicles should be intelligent enough to safeguard the crew members.

The launch vehicle should have a number of support systems. It was a challenge. However, the ISRO would find solutions to all challenges so as to make the mission a success, he said. He said although there was no rating mechanism for the launch vehicles, the ISRO had been systematically working to make launch vehicles as much reliable as possible. The country had demonstrated its brilliance on space mission time and again. Several countries were surprised when Chandrayan and Mangalyaan (Mars Orbiter Mission) were successfully launched.

S. Srinivasan Sundarajan, Director, NIT, said organisations such as ISRO and Defence Research Development Organisations (DRDO) had been working on a number of projects with huge budget. There were many opportunities available for the young students, scientists, and researchers. It should be fully explored.

[Singha]

Imo elegance and efficiency only matter at scale not when countries launch only dozen times a year.

So in that sense china today is far ahead in launching heavy gto payloads and Leo iss type houses.

[Karan M]

The launch of PSLV-C30 carrying India's dedicated multi-wavelength astronomical observation satellite ASTROSAT along with six international customer satellites is scheduled at 10:00 am on Monday, September 28, 2015 from Satish Dhawan Space Centre, SHAR.

And a very detailed write-up in this week's Frontline ( issue also has article on GSLV and interview with ISRO chairman)

http://www.frontline.in/science-and-tec ... epage=true

From that article,

“Also, we had very small teams of skilled people. Such missions abroad have much larger teams and they all would have had some prior experience in similar missions. Even at the TIFR, where three of the five instruments were built, each team had only three to four engineers."

OT here, but the above is bothersome. Generally, that speaks very poorly of the skill base available in scientific & engineering sectors in a massive country like India. ISRO's own institute in T'puram is therefore a good investment for space sciences.

I spoke to someone at DRDO, pre Modi and they said their engineers were wearing multiple hats. Very wary as always of criticizing the MOD/GOI for fear of repurcussion but funding and talent pool (as a result) was a challenge. Many projects were being run on the basis of money siphoned off (for lack of a better term) from closed/complete programs and internally reallocated. But after VKS got censured for liberal funding, even that was being tangled in bureaucratese. Would wager situation at ISRO was similar.

[rsingh]

What does "remote sensing sat " means. To me it is taking high quality pics or live feed. But these sats are placed too high. Is it another jumble of nice words as was the case when we had dhamaka at Pokhran ...................so called "peaceful nuclear explosion" .

[csaurabh]

What does "remote sensing sat " means. To me it is taking high quality pics or live feed. But these sats are placed too high. Is it another jumble of nice words as was the case when we had dhamaka at Pokhran ...................so called "peaceful nuclear explosion" .

Remote sensing is many things. It can mean visual images ofc but also multispectral ( like infrared ), measuring atmospheric moisture, vegetation and so on..

Cartosat is probably the only satellite used by India for military purposes.

[Singha]

risat-1 and risat-2 as well.

[SSSalvi]

What does "remote sensing sat " means. To me it is taking high quality pics or live feed. But these sats are placed too high. Is it another jumble of nice words as was the case when we had dhamaka at Pokhran ...................so called "peaceful nuclear explosion" .

Assuming that you seriously want to know " What is Remote Sensing ? "

It is more than just photoo. Even from the height of 600 to 1000 kms one can have a ground resolution of cms. So if you know what to look for and where then you can find objects as small a motorbike standing in front of a house.

Actual remote sensing study seldom uses 'true colors' ( as seen in Google Earth ) for analysis. They change the image by attributing different colors to the original.

e.g. by a simple manipulation one can bring out vegetation very clearly from its surrounding land/dry features as shown in this example. ( Source: https://shekeine.github.io/visualizatio ... _rgb_in_R/ )

Also notice that the water ( blue/ dark blue ) which gets intermingled with surrounding in the first image comes out clearly in 2nd image.



Of course nowadays this type of 'visual' image processing is used mainly to correlate the accuracy/correctness of digitally processed database.

Another aspect is 'showbaaji' that you are talking of..

Above example is a 'peaceful' application .. in reality major amount of remote sensing usage is not done on the area in own country.....

( complete the sentence yourself )

[member_28108]

Have a look at
http://www.nrsc.gov.in/isprs/pdf/16.pdf

[Singha]

ISRO is going to work with indian railways to do some safety thing for railway crossings. the exact details escape me.

[jayasimha]

I think i got some info
http://www.governancenow.com/gov-next/e ... -crossings

[SSridhar]

ISRO ready for one satellite launch every month: ISAC chief - P.Krishna Kumar, The Hindu

The ISRO is bracing up for one satellite launch every month in the days ahead and has 22 satellite launches lined up for the near future, said M. Annadurai, Director, ISRO Satellite Centre (ISAC).

Speaking to The Hindu on the sidelines of an interaction programme with students of Vidyavardhaka College of Engineering organised by the CII Mysuru chapter here on Saturday, Mr. Annadurai said space assets had limited life and their requirement from ATMs to telemedicine and every conceivable aspect of present day living had made it imperative to keep them functional.

“While 22 satellites have been lined up and are in the pipeline for a launch at the rate of one satellite per month, the actual requirement for the country is reckoned to be around 52 satellites in the next 3 or 4 years,” he said.

On the immediate missions, Mr. Annadurai said ASTROSAT is slated for launch later this month and described it as a multi-wave length observatory capable of studying distant celestial objects and the first dedicated astronomy satellite to be launched by the ISRO.

Underlining the imperatives of harnessing space technology to shore up the quality of life, Mr. Annadurai said using information and communication technology gave the concept of e-governance but harnessing space assets for effective day-to-day governance can usher in the concept of Space Governance.

Earlier, Mr. Annadurai delivered a lecture on science as a way of life which was dedicated to the former President and scientist the late A.P.J. Abdul Kalam.

Interacting with the students, he said ISRO was also contemplating a solar mission to study the Sun and Mission Aditya entailed studying the corona and the solar flares from a low earth orbit.

[member_29172]

Don't they typically send multiple satellite at once? So the ~50 sat. target should be achievable

[SSridhar]

Alka_P, the multiple satellites are all satellites (normally mini & micro) of other countries. In the above, Mr. Annadurai is talking about 52 satellites being "actual requirement for the country".

[SSridhar]

ISRO focussing on low cost access to space: A S Kiran Kumar - PTI

Visakhapatnam, Sept 19:

Indian Space Research Organisation is moving forward with the development of heavy lift launchers and reusable launch vehicles with its main focus being the low cost access to space, its chairman A S Kiran Kumar said here on Saturday.

“ISRO is developing heavy lift launchers, reusable launch vehicles, cryogenic engines and is mainly concentrating on low cost access to space,” Kumar said.

He was addressing as the chief guest the 6th convocation ceremony at Gandhi Institute of Technology and Management, commonly known as GITAM University.

Kumar said the recent success of the Mars Orbiter Mission was a result of a tremendous team effort and innovative use of limited resources to achieve defined goals.

“Advances in satellite remote sensing, global navigation satellite systems and geographic information system are now making it easier to integrate ecological, environmental and other information for developing predictive models that can be used in the surveillance and control of diseases such as malaria and dengue fever,” the space scientist said.

[Gyan]

With ISRO Galloping ahead with Cryogenic and even Semi Cryogenic engines, I think that major challenges for ISRO in engineering & metallurgy in Space Launch capability will be over and from now on, it would be the issue of what design & configuration that they want to launch.

[member_28108]

After launch capability versatality is achieved the enxt thing would be to lower the weight of the launchers.

[Khalsa]

Posted in the wrong thread.

[k prasad]

What does "remote sensing sat " means. To me it is taking high quality pics or live feed. But these sats are placed too high. Is it another jumble of nice words as was the case when we had dhamaka at Pokhran ...................so called "peaceful nuclear explosion" .

Actually sirjee, when it comes to Synthetic Apertures, as long as you're able to get sufficiently strong returns, the actual height of the platform doesn't really change the cross-range resolution much (ie along the flight path). What matters is the so-called dwell time and look angles.

Why, you ask? How can this be? Well, the simple answer is that for SARs to work, they basically coherently add up a number of overlapping images. The larger the number of images they add up, the higher the so-called 'dwell' time on the target point, and the higher the resolution along the flight path. So, as the radar is higher up, it can have a somewhat longer dwell time and so, the larger the number of overlapping images. This is of course counteracted by the beam being so dispersed, and other problems caused by the ground distance changing as look angle changes - so the effective range of angles (and therefore, dwell time) that a Space-based SAR can spend on a target might be smaller than we'd expect.

There are a terrific number of challenges as well, btw. For one, at that height, getting a big enough return from so large an area is extremely difficult. We need to have an extremely precise knowledge of the flight path, and compensate for any extraneous motion. And the processing and data rates are quite huge. But in general, space-based SARs are a pretty mature technology.

However, this doesn't cause the massive degradation in performance that we mgith fear - resolution might be 1-3 m instead of 0.5 m on an airborne SAR.

And there are some really cool advantages too -

1) Space-based SARs have unmatched coverage - something that airborne SARs cannot compete with.

2) Moreover, they can be repositioned in relatively quick time - in comparison, it'd be almost impossible to get an aircraft to fly over most of the areas of interest for hi-res SAR imagery.

3) Coherent Change detection is an extremely useful mode to have on a surveillance SAR. Basically, it uses tiny variations in phase information to pick up even minute changes - like someone walking and causing a small track. (http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA458753 gives some amazing examples of this - scroll straight to the pictures). The changes detected can be so accurate that even when they try to be hidden (like say someone tiptoeing on gravel), it lights up like a christmas tree. This requires repeated passes over the object at almost the same angle, which is something space-borne SARs can do really well.

https://calval.cr.usgs.gov/wordpress/wp ... LTighe.pdf is a great short and sweet resource if anyone is interested.

[edited: Upon further study, I realized that I had ignored some considerations which made my premise somewhat invalid - I've changed my post to reflect this]

[JTull]

Processor for Launch Vehicle Application realised at SCL Wafer Fabrication Facility

...the manufacturing facility has been upgraded from 0.8 μm CMOS 6” Wafer Fabrication to 0.18 μm CMOS 8” Wafer Fabrication.

...Second Lot, out of four Production Lots under processing, has been fabed-out in August 2015. Vikram Processor, one of the key components for Launch Vehicle application, has been successfully realised as part of this Lot...

[prashanth]

Best news I have heard in recent times. Thx JTull Ji. I think 180 nm node must be sufficient to fulfill ISRO's and DRDO's processor requirements. One more tech denial attempt made irrelevant, after cryo-tech.

[Singha]

https://en.wikipedia.org/wiki/180_nanometer

not that it matters in low volume space applications but tells us where SCL is at - 2002 level of pentium3 tech.

around 15 yrs behind the bleeding edge 14nm or whatever it is now.

https://en.wikipedia.org/wiki/800_nanometer

this was 10 years older and 80486 level.

[prashanth]

I think the main objective of realizing this processor was to beat tech denial regime. As reported below, way back in 2013.

http://timesofindia.indiatimes.com/city ... 993653.cms

Vikram Sarabhai Space Centre (VSSC) director (R&D) John P Zacharia, in his keynote address, spoke on the need to indigenize and maintain the quality of every bit of the system. "All our computer systems have a micro-processor developed by us. Just like you see the Intel processor for all MS systems, we have fabricated our own and named it Vikram 1601. So no company in the world can hold our work to ransom by denying us technology. We don't use anything from outside. Every bit and piece is developed by our own R&D," he said.

Since, most space and mil grade applications are fine with 180 nm node (they are more resistant to radiation and environment variations than smaller nodes), ISRO may not even attempt to scale down to smaller nodes.

[Kashi]

I think the main objective of realizing this processor was to beat tech denial regime. As reported below, way back in 2013.
...
Since, most space and mil grade applications are fine with 180 nm node (they are more resistant to radiation and environment variations than smaller nodes), ISRO may not even attempt to scale down to smaller nodes.

I do wonder if DRDO have switched to or are planning to switch to Vikram 1601 for the missile applications atleast.

[JTull]

https://en.wikipedia.org/wiki/180_nanometer

not that it matters in low volume space applications but tells us where SCL is at - 2002 level of pentium3 tech.

around 15 yrs behind the bleeding edge 14nm or whatever it is now.

https://en.wikipedia.org/wiki/800_nanometer

this was 10 years older and 80486 level.

These must by radiation hardened so a bit behind the curve but this is quite far behind. Still, every improvement must be appreciated.

The biggest challenge is that the manufacturing processes that allow thinner wafers require proprietary technologies developed by semiconductor companies and which required huge investments. Some companies invest billions every year to stay ahead of the curve. So, access to these will not be readily available and we must learn ourselves.

[Singha]

Since even our highest volume missiles and bomb would in 1000sss the nm would not matter but for avionics and sensors speed and nm might help with form factor, thermal

[Prasad]

You don't need the latest and greatest for these applications. And there is the thing with diminishing returns. Samsung and Intel can churn out 14nm processors but they're dealing with an entirely different set of conditions. This tech is hideously expensive and unlike these companies, govt run entities can't run behind the bleeding edge continuously, only try to jump across generations.

[Suraj]

https://en.wikipedia.org/wiki/180_nanometer

not that it matters in low volume space applications but tells us where SCL is at - 2002 level of pentium3 tech.

around 15 yrs behind the bleeding edge 14nm or whatever it is now.

https://en.wikipedia.org/wiki/800_nanometer

this was 10 years older and 80486 level.

180nm is what Intel Pentium 4 Willamette was. they then skipped down to 130nm and then 65nm by the time they changed over to the Core architectures that are still being produced since 2006-07. There's no need to focus on the bleeding edge lithography technology. The costs are exponentially greater, and the yields fall. Unless it's feeding a capital intensive commercial supply chain, 180nm isn't bad at all. It's cheap, especially if the output is small. Military and space will emphasize robustness and hardened designs over cutting edge tech . Form factor and power draw is unlikely to be an issue. It depends on several things, including the architecture, clock rate, and implementation of power scaling technologies, all of which can mitigate power draw.

[suryag]

Wtf I thought Suraj ji was a ekhanomist anyway on the fab front there are multiple issues first of all like you said it is economically not viable for small quantities. Having said that memory faults start increasing as you go down the micron race, this is okie for cellphone kind of stuff as ATE screening takes out devices with faults but not for mission critical applications. Investing in ate for such small quantity is again not economically viable as you need to fill forms in triplicate for investing about 20m$

[Neela]

Unless it's feeding a capital intensive commercial supply chain, 180nm isn't bad at all. It's cheap, especially if the output is small. Military and space will emphasize robustness and hardened designs over cutting edge tech . Form factor and power draw is unlikely to be an issue. It depends on several things, including the architecture, clock rate, and implementation of power scaling technologies, all of which can mitigate power draw.

Nice summary.
ISRO is not competing with some Huawei or Samsung to create the latest Snapdragon-like core.
ISRO does not need the volumes as seen in commercial products. Im willing to bet that in 6 months, ISRO could have processor, package, and board etc all ready for several thousand launches.

What kind of number crunching should the processor do? How fast should it do? These will determine clock speed and this in turn would decide the technology node.
Power scaling etc are needed when you have multi-power domains within the chip or SoC.
But why would you need power scaling (or battery saving) when the mission itself lasts for at best 30 mins max.

A 8-inch fab ( for 180nm ) can support some several 1000 wafer starts a month. Depending on die ( several 10s of dies or core silicon chip can be cut from a single wafer, depending on size) . Million-volumes runs can be reached less than a year even by the most laziest of runs in the fab. But what military applications need such high-volume runs?

As the modSaar said, 180nm is a sweet spot that could meet demand and keep it economically viable.

[Singha]

I wuz thinking the could make the fab ops more commercially viable by supplying chips to automotive, electrical and other industries in india.

[Hobbes]

The Vikram 1601 is a 16 bit processor, and hence two generations behind the times. Check http://ijves.com/wp-content/uploads/201 ... -09450.pdf for some info on it. Maybe based on an early MIPS design?

[hnair]

IIRC, three things that caused issues in the 90s for ISRO, due to sanctions. Travelling Wave Tubes, chips and the more famous one, CUS.

Hardened and specialist chips are always a few gens behind, with kinks and gaps entirely shut out. IIRC, F22 is the first architecture that kinda allows a "reasonably recent chipset" anywhere close to the serious parts that control the inflight stuff. MCs are not included, because a manual override is easier.

[member_28108]

This September 24 the MOM will finish one year. It has 30 Kgs of fuel and its functional life is now estimated to be years compared to original plan of 6 months. Dr Kiran Kumar announced the same. MOM has been an unqualified success and has silenced all critics both internal and external.

[member_28108]

http://m.economictimes.com/news/science ... 051138.cms

[srin]

Is there a possibility to do a trade-off ? Use the remaining fuel to make it a less elliptical orbit and get it closer, so it can complete orbits faster and get close up pics ?

[Anujan]

The Vikram 1601 is a 16 bit processor, and hence two generations behind the times. Check http://ijves.com/wp-content/uploads/201 ... -09450.pdf for some info on it. Maybe based on an early MIPS design?

Doesnt matter. Curiosity Mars rover had a 132 Mhz PowerPC 750 (introduced 1997) at 250nm. Curiosity was launched in 2011.

New Horizons mission to pluto uses Mips R3000 (introduced 1988) at 15 Mhz.

Quick: Tell me why you want a 32 bit processor and not a 16 bit?

[JTull]

Just wondering if the cheap PCs being offered by some state govts. to schools and students can be built on Vikram 1601 and version of Linux. This will create a home market and may make further Fab investments commercially viable.

[Neela]

Jtull Sir,

ISRO had hitherto used Motorola's 68000 .
68K are a family of processors tweaked for different uses.
Google uncle tells me it was used in Palm pilots and TI' scientific calculator products.

But when ISRO uses it, this obviously means there were radiation hardened versions. Google also tells me Space shuttle used this. So ISRO sourced this from the US.

So it appears now with Vikram 1601, ISRO has their own CISC Motorola 68000 variant ( My guess is that they duplicated the MC 68000 completely)
These processors have their own instruction sets and would be different from x86 and ARM. Which means you need special compilers which translate high level code to these instruction sets.
I checked if a Linux port is available- it apears there is: www.linux-m68k.org

Maybe this could be a project for making PCs avaiable at school level. I knowm there are Raspberry Pi like stuff flaoting out there. But this one, which could be heavily subsidised by GoI to enable a ecosystem to grow - could be a good idea.