Author Topic: GSLV MkII & cryo stage discussion thread  (Read 38104 times)

Offline vyoma

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Re: GSLV MkII & cryo stage discussion thread
« Reply #80 on: 09/09/2016 05:43 AM »
http://www.business-standard.com/article/pti-stories/isro-plans-to-make-two-three-gslv-mkii-launches-every-year-116090801275_1.html
Quote
"...Our intent is to launch two-three GSLV-MkII missions every year in the coming years," ISRO Chairman A S Kiran Kumar told reporters here.


http://www.deccanchronicle.com/business/economy/090916/isro-eyeing-330-billion-market.html
Quote
Isro officials said they were also planning to enhance the GSLV’s [GTO] payload capacity — from 2,600 kg to 2,800 kilos.

Offline vineethgk

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Re: GSLV MkII & cryo stage discussion thread
« Reply #81 on: 09/09/2016 05:57 AM »
http://www.deccanchronicle.com/business/economy/090916/isro-eyeing-330-billion-market.html
Quote
Isro officials said they were also planning to enhance the GSLV’s [GTO] payload capacity — from 2,600 kg to 2,800 kilos.

That's news for me. Would that imply that ISRO does intend to keep GSLV-II running for a considerable period even after LVM3 is ready for operational flights?

EDIT: It brings another question to my mind. Are there many payloads in the 2-2.5 tonne range in the international GTO launch market that GSLV-II could tap into?
« Last Edit: 09/09/2016 06:02 AM by vineethgk »

Offline sanman

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Re: GSLV MkII & cryo stage discussion thread
« Reply #82 on: 09/09/2016 02:04 PM »
http://www.deccanchronicle.com/business/economy/090916/isro-eyeing-330-billion-market.html
Quote
Isro officials said they were also planning to enhance the GSLV’s [GTO] payload capacity — from 2,600 kg to 2,800 kilos.

That's news for me. Would that imply that ISRO does intend to keep GSLV-II running for a considerable period even after LVM3 is ready for operational flights?

EDIT: It brings another question to my mind. Are there many payloads in the 2-2.5 tonne range in the international GTO launch market that GSLV-II could tap into?

If you check ISRO's launch roster, you'll see there are plenty of flights slated for Mk-II, even after LMV3 comes into service. Maybe it's an easier/cheaper vehicle for them to fabricate, since Mk-II is similar to the PSLV architecture.
« Last Edit: 09/09/2016 02:05 PM by sanman »

Offline Stan Black

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Re: GSLV MkII & cryo stage discussion thread
« Reply #83 on: 09/11/2016 01:52 PM »
So, I went through the available documentation and tried to figure out what payload was assigned to each GSLV. I used the outcome budget and the five-year plans.

Some documents here:-
http://forum.nasaspaceflight.com/index.php?topic=32023.msg1569474#msg1569474



Period 2001-2002

GSLV-D1   GSAT-1
GSLV-D2   GSAT-2
GSLV-D3   GSAT-3
GSLV-C1   INSAT-3D
GSLV-C2   GSAT-4
GSLV-C3



Period 2005-2006

GSLV-D1   GSAT-1
GSLV-D2   GSAT-2
GSLV-D3   GSAT-4
GSLV-F01  GSAT-3
GSLV-F02  INSAT-4C
GSLV-F03  INSAT-3D
GSLV-F04  INSAT-4D (GSAT-5)
GSLV-F05  INSAT-4E (GSAT-6)
GSLV-F06



11th Five Year Plan 2007-2012

Rocket    Payload                         Upper Stage
GSLV-D1   GSAT-1     launched 20.04.2001  Mk. I
GSLV-D2   GSAT-2     launched 08.05.2003  Mk. I
GSLV-D3   GSAT-4                          Mk. II

GSLV F01-F10 ten launch vehicles

Rocket    Payload                         Upper Stage
GSLV-F01  GSAT-3     launched 20.09.2004
GSLV-F02  INSAT-4C   launched 10.07.2006
GSLV-F03  INSAT-3D
GSLV-F04  INSAT-4CR
GSLV-F05  GSAT-5
GSLV-F06  GSAT-9
GSLV-F07  GSAT-6
GSLV-F08  Chandrayaan-2
GSLV-F09  GSAT-12
GSLV-F10  GSAT-13

Notes:-
GSLV-F04 launched September 2007.



Period 2008-2009

Rocket    Payload                         Upper Stage
GSLV-D1   GSAT-1     launched 20.04.2001
GSLV-D2   GSAT-2     launched 08.05.2003
GSLV-D3   GSAT-4                          CUS-03 (A6)

GSLV F01-F10 ten launch vehicles

Rocket    Payload                         Upper Stage
GSLV-F01  GSAT-3     launched 20.09.2004
GSLV-F02  INSAT-4C   launched 10.07.2006
GSLV-F03  INSAT-3D
GSLV-F04  INSAT-4CR  launched 02.09.2007
GSLV-F05  GSAT-5
GSLV-F06  GSAT-9 (identical to INSAT-4C)



Period 2009-2010

Rocket    Payload                         Upper Stage
GSLV-D1   GSAT-1     launched 20.04.2001
GSLV-D2   GSAT-2     launched 08.05.2003
                                          CUS-02
GSLV-D3   GSAT-4                          CUS-03 (A6)
                                          CUS-04 (A7)
                                          CUS-05

GSLV F01-F16 sixteen launch vehicles

Rocket    Payload                         Upper Stage
GSLV-F01  GSAT-3     launched 20.09.2004
GSLV-F02  INSAT-4C   launched 10.07.2006
GSLV-F03  GLONASS
GSLV-F04  INSAT-4CR  launched 02.09.2007
GSLV-F05  GSAT-5
GSLV-F06  INSAT-3D
GSLV-F07  GSAT-6

Notes:-
Reference to GSLV-F16.



Period 2010-2011

Rocket    Payload                         Upper Stage
GSLV-D1   GSAT-1     launched 20.04.2001
GSLV-D2   GSAT-2     launched 08.05.2003
GSLV-D3   GSAT-4                          CUS-03 (A6)
                                          CUS-04 (A7)
                                          CUS-05

GSLV F01-F16 sixteen launch vehicles

Rocket    Payload                         Upper Stage
GSLV-F01  GSAT-3     launched 20.09.2004
GSLV-F02  INSAT-4C   launched 10.07.2006
GSLV-F03
GSLV-F04  INSAT-4CR  launched 02.09.2007
GSLV-F05  GSAT-6
GSLV-F06  GSAT-5P
GSLV-F07  INSAT-3D
GSLV-F08  GSAT-7

Notes:-
No reference to GSLV-F03.
GSLV-D3 with GSAT-4 launched April 2010.
GSLV-F06 with GSAT-5P launched December 2010.



Period 2011-2012

Rocket    Payload                         Upper Stage
GSLV-D1   GSAT-1     launched 20.04.2001
GSLV-D2   GSAT-2     launched 08.05.2003
GSLV-D3   GSAT-4     launched 25.04.2010  CUS-03 (A6)
GSLV-D4   GSAT-4R                         CUS-05 (A8)
GSLV-D5   GSAT-6

GSLV F01-F16 sixteen launch vehicles

Rocket    Payload                         Upper Stage
GSLV-F01  GSAT-3     launched 20.09.2004
GSLV-F02  INSAT-4C   launched 10.07.2006
GSLV-F03
GSLV-F04  INSAT-4CR  launched 02.09.2007
GSLV-F05  GSAT-7
GSLV-F06  GSAT-5P    launched 25.12.2010

Notes:-
Only year with reference to a GSLV-D4.



12th Five Year Plan 2012-2017

GSLV-D1   GSAT-1     launched 20.04.2001
GSLV-D2   GSAT-2     launched 08.05.2003
GSLV-D3   GSAT-4     launched 25.04.2010  CUS-03 (A6)
GSLV-D4
GSLV-D5   GSAT-14
GSLV-D6   GSAT-6

GSLV F01-F16 sixteen launch vehicles

Rocket    Payload                         Upper Stage
GSLV-F01  GSAT-3     launched 20.09.2004
GSLV-F02  INSAT-4C   launched 10.07.2006
GSLV-F03
GSLV-F04  INSAT-4CR  launched 02.09.2007
GSLV-F05
GSLV-F06  GSAT-5P    launched 25.12.2010
GSLV-F07
GSLV-F08  Chandrayaan-2
GSLV-F09  GSAT-9
GSLV-F10  GISAT
GSLV-F11  GSAT-6A
GSLV-F12  GSAT-7A
GSLV-F13  INSAT-3DR

Notes:-
No reference to GSLV-D4, GSLV-F05 or GSLV-F07 (GSLV-F03 already dropped).



Period 2012-2013

Rocket    Payload                         Upper Stage
GSLV-D1   GSAT-1     launched 20.04.2001
GSLV-D2   GSAT-2     launched 08.05.2003
GSLV-D3   GSAT-4     launched 25.04.2010  CUS-03 (A6)
GSLV-D4
GSLV-D5   GSAT-14                         CUS-05 (A8)
GSLV-D6   GSAT-6                          CUS-06 (A9)

GSLV F01-F16 sixteen launch vehicles

Rocket    Payload                         Upper Stage
GSLV-F01  GSAT-3     launched 20.09.2004
GSLV-F02  INSAT-4C   launched 10.07.2006
GSLV-F03
GSLV-F04  INSAT-4CR  launched 02.09.2007
GSLV-F05
GSLV-F06  GSAT-5P    launched 25.12.2010
GSLV-F07
GSLV-F08  Chandrayaan-2                   CUS-07 (A10)

Notes:-
Launch of GSAT-7 using procured launch services.



Period 2013-2014

Rocket    Payload                         Upper Stage
GSLV-D1   GSAT-1     launched 20.04.2001
GSLV-D2   GSAT-2     launched 08.05.2003
GSLV-D3   GSAT-4     launched 25.04.2010  CUS-03 (A6)
GSLV-D4
GSLV-D5   GSAT-14                         CUS-05 (A8)
GSLV-D6   GSAT-6                          CUS-06 (A9)

GSLV F01-F16 sixteen launch vehicles

Rocket    Payload                         Upper Stage
GSLV-F01  GSAT-3     launched 20.09.2004
GSLV-F02  INSAT-4C   launched 10.07.2006
GSLV-F03
GSLV-F04  INSAT-4CR  launched 02.09.2007
GSLV-F05
GSLV-F06  GSAT-5P    launched 25.12.2010
GSLV-F07
GSLV-F08  Chandrayaan-2                   CUS-07 (A10)

Notes:-
Launch of INSAT-3D using procured launch services.
GSLV-D5 with GSAT-14 launched January 2014.



Period 2014-2015

Rocket    Payload                         Upper Stage
GSLV-D1   GSAT-1     launched 20.04.2001
GSLV-D2   GSAT-2     launched 08.05.2003
GSLV-D3   GSAT-4     launched 25.04.2010  CUS-03 (A6)
GSLV-D4
GSLV-D5   GSAT-14    launched 05.01.2014  CUS-05 (A8)
GSLV-D6   GSAT-6                          CUS-06 (A9)

GSLV F01-F16 sixteen launch vehicles

Rocket    Payload                         Upper Stage
GSLV-F01  GSAT-3     launched 20.09.2004
GSLV-F02  INSAT-4C   launched 10.07.2006
GSLV-F03
GSLV-F04  INSAT-4CR  launched 02.09.2007
GSLV-F05
GSLV-F06  GSAT-5P    launched 25.12.2010
GSLV-F07
GSLV-F08

Notes:-
Reference to GSLV-F07.



Period 2015-2016

Notes:-
GSLV-D6 with GSAT-6 launched August 2015.



Period 2016-2017

Rocket    Payload                         Upper Stage
GSLV-D1   GSAT-1     launched 20.04.2001
GSLV-D2   GSAT-2     launched 08.05.2003
GSLV-D3   GSAT-4     launched 25.04.2010  CUS-03 (A6)
GSLV-D4
GSLV-D5   GSAT-14    launched 05.01.2014  CUS-05 (A8)
GSLV-D6   GSAT-6     launched 27.08.2015  CUS-06 (A9)

GSLV F01-F16 sixteen launch vehicles

Rocket    Payload                         Upper Stage
GSLV-F01  GSAT-3     launched 20.09.2004
GSLV-F02  INSAT-4C   launched 10.07.2006
GSLV-F03
GSLV-F04  INSAT-4CR  launched 02.09.2007
GSLV-F05  INSAT-3DR  launch      07.2016  CUS-07 (A10)
GSLV-F06  GSAT-5P    launched 25.12.2010
GSLV-F07
GSLV-F08
GSLV-F09  GSAT-9     launch      03.2017  CUS-08

Notes:-
GSLV-F05 with INSAT-3DR launched September 2016.



See also:-
https://web.archive.org/web/*/http://www.isro.org
http://forum.nasaspaceflight.com/index.php?topic=1173.msg727300#msg727300
http://forum.nasaspaceflight.com/index.php?topic=1173.msg567502#msg567502
« Last Edit: 09/12/2016 03:35 PM by Stan Black »

Offline vineethgk

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Re: GSLV MkII & cryo stage discussion thread
« Reply #84 on: 09/11/2016 02:16 PM »
Thanks!

So the future launches that are planned for GSLV appear to be :

SouthAsiaSat
GSAT-9
Chandrayaan-2
GISAT-1
GSAT-7A
GSAT-6A
NISAR
Mars-2(?)

Anything I missed?

Offline vineethgk

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Re: GSLV MkII & cryo stage discussion thread
« Reply #85 on: 09/26/2016 09:00 AM »
Now that ISRO could demonstrate multiple engine restarts in its hypergolic upper stage, what would be the key challenges it would face in replicating the same in its cryogenic upper stages? I guess having an ignition system that works for multiple burns is one challenge, as it does not use hypergols. Also, would the engineering difficulties be different in CE-7.5 (SCC) compared to CE-20 (GGC)? Any insights are appreciated.

« Last Edit: 09/26/2016 09:04 AM by vineethgk »

Offline cave_dweller

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Re: GSLV MkII & cryo stage discussion thread
« Reply #86 on: 09/27/2016 11:05 PM »
Now that ISRO could demonstrate multiple engine restarts in its hypergolic upper stage, what would be the key challenges it would face in replicating the same in its cryogenic upper stages? I guess having an ignition system that works for multiple burns is one challenge, as it does not use hypergols. Also, would the engineering difficulties be different in CE-7.5 (SCC) compared to CE-20 (GGC)? Any insights are appreciated.



Would have to use hypergols or battery to ignite LH2/LOX. Which raises the question, what is the current ignition mechanism in CE 7.5? And what will it be in CE 20 engine?

Alternately, (I don't believe this has been attempted before) could also let the stage coast in the orbit and use solar power to spark the fuel. But this would require either co-incidental orientation of the stage with sunlight OR specifically re-orienting the stage to receive sunlight -- which means it would require some extraneous thrust.

Another trade-off to consider is where to put the fuel. In the launch vehicle or on the satellite?

In the case of Mangalyaan, being that PSLV didn't have the thrust to develop the velocity to deliver the craft directly into an earth escape orbit (similarly in the case of Chandrayaan-1), the choice was made to store the fuel in the satellite/craft and use a combination of thruster burns + Earth gravity to develop velocity and ultimately escape.

This brings forth another question, could a larger satellite be used as a launch vehicle for a cluster of nano satellites that don't have self sufficient orientation/navigation thruster/booster engines?

Offline worldtimedate

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Re: GSLV MkII & cryo stage discussion thread
« Reply #87 on: 09/28/2016 08:34 PM »
As I expected, since GSLV MK-II's Cryogenic Upper Stage does NOT have multiple restartable capability, it will launch the Chandrayaan-2 into a parking orbit similar to GTO.

Here is the report from Frontline Magazine Science Section

Quote
G. Nagesh, Project Director, Chandrayaan-2, said the orbiter, the lander and the rover were together called the composite module. The GSLV-Mk II will first place this composite module in an orbit of 170 km by 19,500 km, called earth-parking orbit. From there, with the help of the liquid engines in the orbiter, we will take Chandrayaan-2 to the moon’s orbit of 100 km, he said. It is exactly the same as Chandrayaan-1's orbit. Once Chandrayaan-2 (that is, the composite module) is in the lunar orbit, ISRO will beam commands to it for the lander to fly out of the orbiter.


Source : Cryogenic gains for GSLV

worldtimedate [ http://www.world-timedate.com/ ]

Offline sanman

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Re: GSLV MkII & cryo stage discussion thread
« Reply #88 on: 09/28/2016 10:44 PM »
As I expected, since GSLV MK-II's Cryogenic Upper Stage does NOT have multiple restartable capability, it will launch the Chandrayaan-2 into a parking orbit similar to GTO.

Here is the report from Frontline Magazine Science Section

Quote
G. Nagesh, Project Director, Chandrayaan-2, said the orbiter, the lander and the rover were together called the composite module. The GSLV-Mk II will first place this composite module in an orbit of 170 km by 19,500 km, called earth-parking orbit. From there, with the help of the liquid engines in the orbiter, we will take Chandrayaan-2 to the moon’s orbit of 100 km, he said. It is exactly the same as Chandrayaan-1's orbit. Once Chandrayaan-2 (that is, the composite module) is in the lunar orbit, ISRO will beam commands to it for the lander to fly out of the orbiter.


Source : Cryogenic gains for GSLV

worldtimedate [ http://www.world-timedate.com/ ]


I've always heard everyone say that the CUS was designed to have restart capability, but that it's just that ISRO hasn't tried to flight test it yet - maybe they don't want to risk trying it out on a politically sensitive prestige mission like Chandrayaan-2?

http://space.stackexchange.com/questions/3505/does-isros-cryogenic-upper-stage-have-restart-capability


Offline K210

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Re: GSLV MkII & cryo stage discussion thread
« Reply #89 on: 09/29/2016 05:35 AM »
According to previous annual reports the CE-7.5 is designed to be restartable

Offline worldtimedate

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Re: GSLV MkII & cryo stage discussion thread
« Reply #90 on: 09/29/2016 05:43 AM »
I agree with Sanman that GSLV MK-II CUS might have multiple restart capability like all the CUS of other space fairing nations such as USA, Japan, ESA and China. But ISRO has yet to test and master it. Going by the recent PSLV C35 launch of 8 Satellits into different orbits, I am sure ISRO is capable of emulating that feat in GSLV MK-II CUS. Just as PSLV tested the multiple restart feature of upper stage twice before launching satellites, GSLV MK-II has to do the same thing. As for the Chandrayaan II mission, it would be unwise of ISRO to take such risk in doing the multiple restart feature to inject it to Lunar Orbit.


worldtimedate [ http://www.world-timedate.com/ ]

Offline baldusi

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Re: GSLV MkII & cryo stage discussion thread
« Reply #91 on: 09/29/2016 06:46 PM »
According to previous annual reports the CE-7.5 is designed to be restartable
I didn't knew that the KVD-1 was ever restartable. In fact, I don't think that any non hypergolic Russian staged combustion engine is restartable. Start-up is particularly delicate issue for staged combustion engines, the hypergolic gas generator Vikas is trivial to restart in comparison.

Offline sanman

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Re: GSLV MkII & cryo stage discussion thread
« Reply #92 on: 09/30/2016 05:32 PM »
So I want to apologize and correct:

CUS is not restartable at present.

(That answer came right from the horse's mouth)

Offline worldtimedate

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Re: GSLV MkII & cryo stage discussion thread
« Reply #93 on: 01/31/2017 06:06 PM »
Recently in the Indian Science Congress in a speech Mr. Somnath of LPSC Director has mentioned that GSLV MK-II payload cababily would be incrementally increased to 3 Ton or even more.

Umamaheshwaran, the GSLV MK-II project director already said last year that GSLV MK-II payload capability would be increased to 2.8 Ton.

Source : Cryogenic gains for GSLV

If that happens, that would be a monumental achievement for the naughty boy GSLV MK-II that gave the ISRO Launch Vehicle Team lot of headache until it was successfully launched for 3 consecutive times with the Indigenous Cryogenic Engine CE-7.5. Please check the Following Video.

Indian science congress 2017 Live Stream 4  : ( Speech by Mr. S. Somnath, LPSC Director )


worldtimedate [ http://www.world-timedate.com/ ]

Offline vineethgk

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Re: GSLV MkII & cryo stage discussion thread
« Reply #94 on: 05/19/2017 07:46 PM »
Late bloomer GSLV is small cheer
Quote
The late bloomer may even be a short-lived intermediate rocket instead of being ISRO’s primary satellite vehicle as it was planned, as a few ISRO old-timers and industry watchers privately suggest.

The GSLV is caught in a glaring mismatch: it cannot lift India’s bigger satellites; and the size that it can lift is out of fashion and does not make economic sense.

While ISRO was perfecting the GSLV and falling behind schedule with the rocket’s crucial cryogenic stage, it progressed on the spacecraft side and upgraded the communication satellites to 3,000-plus kg in 2005. This was done to pack more punch (or transponders) per spacecraft. It would be roughly 24 regular transponders for 2,000 kg; 36 transponders for 3,000 kg and 48 transponders in a four-tonner.

Replying to a query from The Hindu, Gagan Agrawal, analyst with the U.S.-based space industry consulting firm Northern Sky Research, said: “The communications satellite market is consistently looking at payload sizes greater than four tonnes and the question remains whether the GSLV or [the bigger] MKIII can cater to the market [yet.] ”

As painted in the report, I would have been equally skeptical of GSLV Mk2's long-term career prospects until a few months back. But the recent reports of ISRO looking at building 2-tonne class all-electric satellites, and issuing tenders for the supply of EPS towards that goal, might save the GSLV after all. That possibility doesn't appear to have been taken into account in this news item. Moreover, rather than the prospect of ISRO throwing in the towel on Mk2, recent news reports have quoted ISRO sources hinting that they plan to increase the GTO payload capability of the launcher to 3 tonnes by incremental upgrades as well.

Incidentally, after reading reports of the all-electric, 2300kg SES-15 that was launched by Soyuz from CSG yesterday, I'm quite hopeful that we might see the 'naughty boy of ISRO' flying for some time. An EPS-enabled satellite of similar class can pack a decent number of transponders and can change the fortunes of GSLV Mk2 in the coming years, at least in the domestic market. There might be many requirements for which launching a smaller EPS comsat on a cheaper GSLV Mk2 rocket makes better sense than doing a heavier one on LVM3/GSLV Mk3. And then there is the advantage of a higher flight rate as well owing to it's PSLV heritage.

Offline seshagirib

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Re: GSLV MkII & cryo stage discussion thread
« Reply #95 on: 06/10/2017 04:42 PM »
So I want to apologize and correct:

CUS is not restartable at present.

(That answer came right from the horse's mouth)

On the contrary:

See this youtube video

"AIS 2017 A2 Dr V Narayanan LPSC 14 Feb 17"
 


Dr. Narayanan has confirmed the built in restart capability for both CUS-7 and C20. (question and answer session from 25:55 onwards ). He also said that the  capability will be tested after the MK-3 flight.


Offline sanman

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Re: GSLV MkII & cryo stage discussion thread
« Reply #96 on: 06/11/2017 12:14 AM »
So I want to apologize and correct:

CUS is not restartable at present.

(That answer came right from the horse's mouth)

On the contrary:

See this youtube video

"AIS 2017 A2 Dr V Narayanan LPSC 14 Feb 17"
 
...

Dr. Narayanan has confirmed the built in restart capability for both CUS-7 and C20. (question and answer session from 25:55 onwards ). He also said that the  capability will be tested after the MK-3 flight.

I hate to push back, but the source I asked was just as authoritative as Dr Narayanan. So, maybe this then sounds like some threshold must have been crossed between Sep-30-2016 and Feb-14-2017 in order for both statements to be true? Maybe it achieved certification for restartability during those 5 months? ???

Prior to asking, I too had always heard people on the net saying that the CE-7.5 was restartable, but I then asked anyway, just to be sure.

Re: GSLV MkII & cryo stage discussion thread
« Reply #97 on: 07/01/2017 05:48 PM »
So I want to apologize and correct:

CUS is not restartable at present.

(That answer came right from the horse's mouth)

On the contrary:

See this youtube video

"AIS 2017 A2 Dr V Narayanan LPSC 14 Feb 17"
 
...

Dr. Narayanan has confirmed the built in restart capability for both CUS-7 and C20. (question and answer session from 25:55 onwards ). He also said that the  capability will be tested after the MK-3 flight.

I hate to push back, but the source I asked was just as authoritative as Dr Narayanan. So, maybe this then sounds like some threshold must have been crossed between Sep-30-2016 and Feb-14-2017 in order for both statements to be true? Maybe it achieved certification for restartability during those 5 months? ???

Prior to asking, I too had always heard people on the net saying that the CE-7.5 was restartable, but I then asked anyway, just to be sure.
It's written in the book From fishing Hamlet to red planet that the kvd-1 was meant to be restartable. Since they didn't want to take the two-burn risk, they decided to run it uprated first and then later at normal thrust to sort of simulate a two burn.

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Offline sanman

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Re: GSLV MkII & cryo stage discussion thread
« Reply #98 on: 07/02/2017 09:46 AM »

It's written in the book From fishing Hamlet to red planet that the kvd-1 was meant to be restartable. Since they didn't want to take the two-burn risk, they decided to run it uprated first and then later at normal thrust to sort of simulate a two burn.

But a real re-start means re-lighting the stage , which hasn't yet been tested in flight, correct? I wonder how much they've tested it on the ground.

Re: GSLV MkII & cryo stage discussion thread
« Reply #99 on: 07/04/2017 06:17 AM »

It's written in the book From fishing Hamlet to red planet that the kvd-1 was meant to be restartable. Since they didn't want to take the two-burn risk, they decided to run it uprated first and then later at normal thrust to sort of simulate a two burn.

But a real re-start means re-lighting the stage , which hasn't yet been tested in flight, correct? I wonder how much they've tested it on the ground.
No the restart hasn't been tested on the ground. Restart capability not only requires re-ignition ability but also the gas bottles need to be at an adequate pressure level in order to ensure the required propellant flow into the preburner. Not to mention the propellant loss due to boil off.

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« Last Edit: 07/04/2017 06:18 AM by demonslayer »

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