Indian Space Programme Discussion - Sept 2016

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Indranil
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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 11 Jul 2018 05:24

prasannasimha wrote:
Indranil wrote:The Indian system uses wireless communication to start with.

I was reading up on pad abort testing and the first pad abort test of tge Apollo crew capsule was placed on a booster. This had 3 wires running and if rwo of 3 wires broke it would initiate the abort automatically. The little joe booster went inro an uncontrollable spin due to some defect and started breaking up and the abort command was initiated automatically. This was a succesful abort test with a an unintentional faikure of the booster !
This highlights the importance of redundancy in these systems.
If you see the crew capsule I think those linear ridges hold interstage connections in addition to wireless coms. ( you can see thise very well in the PSLV and Agni missiles too ).

I am sure that they would have multiple redundancies. But Dr. Sivan marked out wireless trigger mechanism as one of the 6 things tested in this round.
prasannasimha wrote:Looks like once they have all the respective units in place tge formal sanction form human space flight will be given.
Taking crew capsule and service module etc we will need at least 15 Tons to LEO.

ULV in the 2*S200 + SC160 + CE25 config would be able to lift 15 ton to LEO.

The lingering question in my mind is that the SC160 cannot be used as a standalone first stage (stick model). In fact, we won't get to a stick model before we get to TSTO which has a 5 Ton to GTO capacity! What about the lower end? I was hoping that ISRO would be design a SC110 stage powered by SCE200 which can be used as the first stage and boosters.

1. SC110 + CE25 would be the stick model which would be similar in capability to PSLV-CA equivalent: 1 ton to GTO.
2. 2*SC110 (boosters) + SC110 (first stage) + CE25 would be the GSLV Mk2 equivalent: 2.5 tons to GTO
4. 4*SC110 (boosters) + SC110 (first stage) + CE25 would be the GSLV Mk3 equivalent: 4.5 tons to GTO or very similar to TSTO with SC500 + CE25. If the later is ready, then it becomes the stick model for beyond 5 tons to GTO payload.

But this is much lower risk model, and a good fall back option. No clustering of SCE200 involved. SC160 will have a 5 mtr, SC400 closer to 7 mtr, all of which are completely knew developments for India. The SC110 would be similar in structure to the current L110 stage.

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Re: Indian Space Programme Discussion - Sept 2016

Postby jaysimha » 14 Jul 2018 15:26

ISRO to takeover defunct HMT's 109 acre land on July 14
Read more at: https://www.deccanherald.com/state/isro ... 80699.html

Damn sure if it was upavasi govt.,,,,,,,,,, they would have sold the land and pocketed the money.. just like they did for
Hindustan teleprinters land in guindy chennai.............

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Re: Indian Space Programme Discussion - Sept 2016

Postby putnanja » 15 Jul 2018 19:37

ISRO tests higher-thrust Vikas engine, but unfortunately, the press release gives no technical parameters. Not even how much better it is than the current version.


Successful Qualification of High Thrust Vikas Engine

Today (July 15, 2018), a high thrust version of the Vikas Engine was successfully qualified through a ground test for a duration of 195 seconds at ISRO Propulsion Complex (IPRC), Mahendragiri, Tamilnadu. Vikas Engine is the workhorse liquid rocket engine powering the second stage of India’s Polar Satellite Launch Vehicle (PSLV), second stage and the four strap on stages of Geosynchronous Launch Vehicle (GSLV) and the twin engine core liquid stage (L110) of GSLV Mk-III.

All the propulsion parameters during the tests were found satisfactory and closely matched the predictions. This ground test has validated the performance adequacy of the Vikas Engine for its use in the upcoming second developmental flight of GSLV Mk-III. This engine will improve the payload capability of PSLV, GSLV and GSLV Mk-III launch vehicles.

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 15 Jul 2018 20:07

Image

JTull
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Re: Indian Space Programme Discussion - Sept 2016

Postby JTull » 15 Jul 2018 22:06

Chamber pressure increased from 58 bar to 62 bar.

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 16 Jul 2018 00:39

JTull wrote:Chamber pressure increased from 58 bar to 62 bar.


DCan you post the source ?
Can someone estimate the advantage that can be got by increasing the chamber pressure by4 bar ? How much can the payload be increased ?

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Re: Indian Space Programme Discussion - Sept 2016

Postby Ashokk » 16 Jul 2018 01:00

prasannasimha wrote:Can someone estimate the advantage that can be got by increasing the chamber pressure by4 bar ? How much can the payload be increased ?

With eye on lunar mission, ISRO to test high-thrust Vikas engine
LPSC director V Narayanan told Express that the improved engine would give a significant advantage in terms of enhancing payload capability. “Usually, the chamber pressure is 58 bar, but with the use of high-thrust Vikas engine, we will achieve 62 bar, which is a 6% increase in thrust that gives us 70 kgs of additional payload gain in this mission. Right now, we are going to use the high-thrust Vikas engine only in the second stage. Basically, we are validating it. For Chandrayaan-2 mission, we will be using five such engines aiming for a payload gain of around 250 kgs,” Narayanan said.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 16 Jul 2018 04:09

The vacuum-lit version was already flight tested on last GSLV launch. This is the ground lit version.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Varoon Shekhar » 16 Jul 2018 18:37

^
Thanks for pointing that out, I was about to mention that the upgraded Vikas has already been flight tested. Simply put, the second stage Vikas has been developed and successfully flown in a GSLV. This most recent test was of a strap on, correct? Will a 250kg improvement be sufficient for the Chandrayaan-2 which is over 3000kg? There was also an upgraded CUSP engine that was going to be flown soon (C-15), so probably that will cover the increased weight of the Chandrayaan spacecraft.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Varoon Shekhar » 16 Jul 2018 22:05

Is everything on course for the Chandrayaan-2 mission in October? And why no launches in July or August, after earlier talking about one launch each in the two months?
Issues with GSAT and PSLV have cuased issues that delayed things as everything has to be recjhecked and recertified so it is obvious that this will cause delays. Chandrayaan rover is going through various qualifications etc so the final launch date will be still fluid.

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 16 Jul 2018 23:40

ISRO is not being able to keep up with the launch rate. REquired by the nation > ISRO's target > achieved launches.

GSLV Mk2 is not putting Chandrayaan to GTO, but LTO. It can carry larger load to LTO.

They were trying to first get to a reliable GSLV config. Now they will try to increase the payload to 3.2 tons. HTVE on the second stage and full burn of the CUS were the first two improvements. Next is HTVEs on the strap ons. This will not only increase efficiency of the strap on motors, but also decrease the time that the empty weight of the S139 is carried by about 7 seconds. That total improvement in payload will be about 250 kgs. They will also increase the fuel in the CUS and the burn rate. This will also increase the payload by a couple of 100 kgs. For the last few 100 kgs, they will have to decrease the empty weight of the CUS stage.

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 17 Jul 2018 11:44

The lander is being tested etc so the actual launch may get further delayed. There are many things being done for the first time so I dont think a hard schedule will be possible.

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Re: Indian Space Programme Discussion - Sept 2016

Postby prasannasimha » 17 Jul 2018 11:45

Launch window for maximum sunlight will be required too as this does not have an RTG and is solar panel dependent

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Re: Indian Space Programme Discussion - Sept 2016

Postby dinesha » 17 Jul 2018 12:13

Indranil wrote:ISRO is not being able to keep up with the launch rate. REquired by the nation > ISRO's target > achieved launches.

GSLV Mk2 is not putting Chandrayaan to GTO, but LTO. It can carry larger load to LTO.

They were trying to first get to a reliable GSLV config. Now they will try to increase the payload to 3.2 tons. HTVE on the second stage and full burn of the CUS were the first two improvements. Next is HTVEs on the strap ons. This will not only increase efficiency of the strap on motors, but also decrease the time that the empty weight of the S139 is carried by about 7 seconds. That total improvement in payload will be about 250 kgs. They will also increase the fuel in the CUS and the burn rate. This will also increase the payload by a couple of 100 kgs. For the last few 100 kgs, they will have to decrease the empty weight of the CUS stage.


Electro-mechanical actuators using Lithium Ion batteries will also lead to the improvements in payloads.

http://esmats.eu/esmatspapers/pastpaper ... prasad.pdf
The benefits of electromechanical actuators includes,
• Simple configuration and less number of components
• Reduced system weight and cost
• Easy fault detection and isolation scheme
• No life restricting elements
• Reduction in system development and test efforts
• Less lead time for flight readiness
• No launch count down operations

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Re: Indian Space Programme Discussion - Sept 2016

Postby dinesha » 17 Jul 2018 12:27

http://www.newindianexpress.com/states/ ... 93608.html
The next generation Vikas engine developed by the Liquid Propulsion Systems Centre (LPSC) is being flown for the first time. LPSC director V Narayanan told Express that the improved engine would give a significant advantage in terms of enhancing payload capability. “Usually, the chamber pressure is 58 bar, but with the use of high-thrust Vikas engine, we will achieve 62 bar, which is a 6% increase in thrust that gives us 70 kgs of additional payload gain in this mission. Right now, we are going to use the high-thrust Vikas engine only in the second stage. Basically, we are validating it. For Chandrayaan-2 mission, we will be using five such engines aiming for a payload gain of around 250 kgs,” Narayanan said.

Another important experiment that the national space agency is attempting is last depletion mode shutdown. Generally, scientists store extra propellant in the tank and cut off the upper cryogenic stage after reaching desired velocity. However, this time they are attempting to deplete the liquid oxygen, which means using up another 60-70 kgs of propellant in order to achieve 4-5 seconds of additional burn duration.

Narayanan said this would be the best way of mission planning and optimum utilisation of propellants. “All these new things are being done keeping lunar mission in the mind and ISRO’s bigger game plan to increase GSLV payload capability. For Chandrayaan-2, we are formulating a perfect combination. The four strap-ons and second stage will be boosted with high-thrust Vikas engines; cryogenic upper stage will be loaded with enhanced propellants of 15 tonnes instead of current 12.8 tonnes and will be operated with 9.5 tonne thrust compared to the present 7.5.

ISRO chairman K Sivan told Express that the high-thurst Vikas engine has been under development for the past three years and is robust. It has cleared several tests, he said. “It was developed as part of ISRO’s plans to have GSLV launches with heavier payloads. GSLV Mk2 and GSLV Mk 3, when stabilised, will have huge international demand.”On introduction of electromechanical actuation system in place of electrohydraulic actuation in the second stage of the rocket, Sivan said the new system is simpler and more robust, which increases the vehicle’s reliability.

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Re: Indian Space Programme Discussion - Sept 2016

Postby nachiket » 18 Jul 2018 00:32

Indranil wrote:ISRO is not being able to keep up with the launch rate. REquired by the nation > ISRO's target > achieved launches.

GSLV Mk2 is not putting Chandrayaan to GTO, but LTO. It can carry larger load to LTO.

They were trying to first get to a reliable GSLV config. Now they will try to increase the payload to 3.2 tons. HTVE on the second stage and full burn of the CUS were the first two improvements. Next is HTVEs on the strap ons. This will not only increase efficiency of the strap on motors, but also decrease the time that the empty weight of the S139 is carried by about 7 seconds. That total improvement in payload will be about 250 kgs. They will also increase the fuel in the CUS and the burn rate. This will also increase the payload by a couple of 100 kgs. For the last few 100 kgs, they will have to decrease the empty weight of the CUS stage.

Would it have made more sense to use the MkIII for the Chandrayaan II launch considering the number of changes necessary int he MkII due to the higher weight?

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Re: Indian Space Programme Discussion - Sept 2016

Postby Indranil » 18 Jul 2018 02:22

No. The changes on Mk2 are in line with what they wanted to do anyhow. Our mass fractions are not really good. We need to improve significantly from the current 0.5% to 1% (GSLV Mk3 with SC160) and higher. Going higher than that with solids would be very difficult. And that is why I was wondering why ISRO is not studying using SCE200 engine on strapons except for the clustered version on UHLV.

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Re: Indian Space Programme Discussion - Sept 2016

Postby kit » 18 Jul 2018 02:46

Indranil wrote:ISRO is not being able to keep up with the launch rate. REquired by the nation > ISRO's target > achieved launches.
.



instead of incremental improvements, a much heavier payload rocket would be able to carry multiple satellites to orbit.

or build one more launch facility will full private participation and let them build parallel to what ISRO does

both easier said than done .. without government support private players will be quite risk averse.

demand for transponders is just going through the roof

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Re: Indian Space Programme Discussion - Sept 2016

Postby Haridas » 18 Jul 2018 07:26

dinesha wrote:http://www.newindianexpress.com/states/tamil-nadu/2018/mar/28/with-eye-on-lunar-mission-isro-to-test-high-thrust-vikas-engine-1793608.html
.....Narayanan said this would be the best way of mission planning and optimum utilisation of propellants. “All these new things are being done keeping lunar mission in the mind and ISRO’s bigger game plan to increase GSLV payload capability. For Chandrayaan-2, we are formulating a perfect combination. The four strap-ons and second stage will be boosted with high-thrust Vikas engines; cryogenic upper stage will be loaded with enhanced propellants of 15 tonnes instead of current 12.8 tonnes and will be operated with 9.5 tonne thrust compared to the present 7.5.” ..... .

The increase fuel load in CUS necessarily requires using the engine in the uprated thrust mode compared to traditional mode where boosted thrust mode is used only till gravity loss reaches zero (i.e. min altitude insertions, such that trajectory does not drop below 100 km altitude) , there after it is all about increasing orbit and cryo thrust does not matter.
The increased CUS fuel is supported by the higher chamber pressure Vikas. BTW the Chinese earth storable liquid engine's chamber pressure (20 years ago) was always much higher (IIRC ~68 bar) than Vikas. Better late than never.

~ 25 years ago HP-India supplied the data acquisition system for LPSC when it was being established.

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Re: Indian Space Programme Discussion - Sept 2016

Postby jaysimha » 20 Jul 2018 12:54

http://pib.nic.in/newsite/pmreleases.aspx?mincode=14

Department of Space19-July, 2018 16:06 IST
Launching of Replacement Navigation Satellite

Indian Space Research Organisation has launched IRNSS-1I on 12th April, 2018 to replace IRNSS-1A. IRNSS- 1I carried refurbished Atomic clocks.

IRNSS 1A had failure of three Rubidium atomic clocks and IRNSS constellation is functioning with only six satellites. The move to launch the replacement satellite for IRNSS 1A was imperative to complete the seven satellite NavIC constellation. However, IRNSS-1A is still being used for messaging services. The Rubidium clocks were from the same Swiss company. The clocks of NavIC and GALILEO developed problems that were similar in nature.

A thorough analysis and simulation on the failure of the atomic clocks was done. Finally, it was traced to one of the feed through capacitor carrying the DC supply to the physics package, getting in to problem due to excess temperature rise. This was corrected in the IRNSS-1I clocks.

This information was provided by the Union Minister of State (Independent Charge) Development of North-Eastern Region (DoNER), MoS PMO, Personnel, Public Grievances & Pensions, Atomic Energy and Space, Dr Jitendra Singh in written reply to a question in Rajya Sabha today.

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Re: Indian Space Programme Discussion - Sept 2016

Postby AdityaM » 20 Jul 2018 14:21

India's Key Spy Satellite Maker Sacked, Made Advisor To ISRO Chairman

Dr Misra was the architect of India's spy satellite RISAT 1, which died in orbit under mysterious circumstances due to an implosion that was reported and noticed first by NASA and not by ISRO.


The satellite imploded! Any news ever discussed on this here?

ok, so gagan pointed to something here in Jul2017: viewtopic.php?f=3&t=7248&p=2185192&hilit=RISAT+1#p2185192


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