Author Topic: LIVE: GSLV D5 (MkII) GSAT-14, January 5, 2014 (1048UTC)  (Read 70501 times)

Offline seshagirib

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Re: GSLV D5 (MkII) GSAT-14, August 19, 2013 (ETD 1100UTC)
« Reply #75 on: 08/18/2013 04:41 PM »
status update ( http://isro.org/ ) : propellant loading of 2nd stage in progress.

 status update:

- 2nd stage propellant loading completed.
- strap on propellant loading in progress.

Offline AJA

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Re: GSLV D5 (MkII) GSAT-14, August 19, 2013 (ETD 1120UTC)
« Reply #76 on: 08/18/2013 07:21 PM »
Regarding the assembly of the launch vehicle in the Vehicle Assembly Building and its subsequent transport to the launchpad on that slow crawler -- is this all necessary?

Why not just mount the building and launchpad on rail tracks to shift them in or out of the way, while leaving the launch vehicle stationary? Seems to me that these large structures are less critical than the launch vehicle itself, and so they could be shifted more rapidly and less gingerly without having to use a slow crawler type of pedestal

They do that for the PSLV don't they? I don't think the pad-roll out is on the critical path. As in shaving time off there probably wouldn't enable faster launch processing. Moreover, I don't think it's less critical than the LV. If you break the VAB while moving it, that's going to cause delays and disrupt the next launch. And possibly even scrub the existing launch, since they don't want to risk further damage.

On the same topic however, SpaceX do highlight the horizontal integration facility they have for the Falcon 9 - pointing out how having everything on the same floor allows concurrent access to all stages within the same facility, and eliminates hoisting operations making stuff safer, and easier to move around. One drawback is increased susceptibility for radial creep (more so for a solid stage perhaps), depending on how long the stage is horizontal. But given that aerodynamic loads during ascent are probably stronger than self-weight, this shouldn't be a show-stopper. Further, it can be countered by a clinostat mount for all the stages. Then, there's the difficulty of erecting a heavy vehicle, without putting too much stress on any one part. But I think they SpaceX learnt from Soyuz, and we can too - given the similar classes of the launch vehicles.

I mention this because a horizontally integrated rocket, would have a higher 'safe' speed limit - although, again, I don't think roll-out is on the critical path.

Online William Graham

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Re: GSLV D5 (MkII) GSAT-14, August 19, 2013 (ETD 1120UTC)
« Reply #77 on: 08/18/2013 10:02 PM »
Regarding the assembly of the launch vehicle in the Vehicle Assembly Building and its subsequent transport to the launchpad on that slow crawler -- is this all necessary?

Why not just mount the building and launchpad on rail tracks to shift them in or out of the way, while leaving the launch vehicle stationary? Seems to me that these large structures are less critical than the launch vehicle itself, and so they could be shifted more rapidly and less gingerly without having to use a slow crawler type of pedestal

They do that for the PSLV don't they? I don't think the pad-roll out is on the critical path. As in shaving time off there probably wouldn't enable faster launch processing. Moreover, I don't think it's less critical than the LV. If you break the VAB while moving it, that's going to cause delays and disrupt the next launch. And possibly even scrub the existing launch, since they don't want to risk further damage.

There are two active orbital launch complexes at SDSC, the PSLV and GSLV can both launch from either, although the GSLV hasn't flown from the First pad since the Second one was completed. This launch is from the Second pad.

Rockets launched from the First pad are assembled on the pad, rockets launched from the Second pad are assembled vertically and then rolled to the pad.

Online sanman

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Re: GSLV D5 (MkII) GSAT-14, August 19, 2013 (ETD 1120UTC)
« Reply #78 on: 08/19/2013 12:16 AM »
But so that sort of makes it sound like the crawler thing is an evolutionary improvement over the pad assembly. Why is doing it the crawler way better than the old way?

Offline antriksh

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Re: GSLV D5 (MkII) GSAT-14, August 19, 2013 (ETD 1120UTC)
« Reply #79 on: 08/19/2013 03:02 AM »
But so that sort of makes it sound like the crawler thing is an evolutionary improvement over the pad assembly. Why is doing it the crawler way better than the old way?

Launch pad occupancy time reduces. Multiple VABs can share a single launch pad. 
Nasadiya Sukta:
Srishti se pehle sat nahin thaa, asat bhi nahin | Antariksh bhi nahin, aakaash bhi nahin thaa | chhipaa thaa kyaa, kahaan, kisne dhakaa thaa | us pal to agam, atal jal bhi kahaan thaa ||

From: 1st verse of 129th Hymn of the 10th Book of Rig Veda

Offline antriksh

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Re: GSLV D5 (MkII) GSAT-14, August 19, 2013 (ETD 1100UTC)
« Reply #80 on: 08/19/2013 03:13 AM »
Regarding the assembly of the launch vehicle in the Vehicle Assembly Building and its subsequent transport to the launchpad on that slow crawler -- is this all necessary?

Why not just mount the building and launchpad on rail tracks to shift them in or out of the way, while leaving the launch vehicle stationary? Seems to me that these large structures are less critical than the launch vehicle itself, and so they could be shifted more rapidly and less gingerly without having to use a slow crawler type of pedestal.



Thats what the FLP is ,i.e., Integration on Pad. This limits the use of pad by one VAB only. SLP is Integrate Transfer and Launch (ITL) and will allow
VAB and SVAB to share the SLP and the upcoming TLP.
Nasadiya Sukta:
Srishti se pehle sat nahin thaa, asat bhi nahin | Antariksh bhi nahin, aakaash bhi nahin thaa | chhipaa thaa kyaa, kahaan, kisne dhakaa thaa | us pal to agam, atal jal bhi kahaan thaa ||

From: 1st verse of 129th Hymn of the 10th Book of Rig Veda

Offline seshagirib

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Re: GSLV D5 (MkII) GSAT-14, August 19, 2013 (ETD 1100UTC)
« Reply #81 on: 08/19/2013 03:49 AM »
status update ( http://isro.org/ ) : propellant loading of 2nd stage in progress.

 status update:

- 2nd stage propellant loading completed.
- strap on propellant loading in progress.

 update:

- 2nd stage propellant loading completed.
- strap on propellant loading completed.

Offline input~2

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Re: GSLV D5 (MkII) GSAT-14, August 19, 2013 (ETD 1120UTC)
« Reply #82 on: 08/19/2013 04:46 AM »
Live webcast from 1045UTC on http://webcast.gov.in/live
(also tentatively on http://216.185.104.74/isro)

Offline seshagirib

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Re: GSLV D5 (MkII) GSAT-14, August 19, 2013 (ETD 1100UTC)
« Reply #83 on: 08/19/2013 08:22 AM »
status update ( http://isro.org/ ) : propellant loading of 2nd stage in progress.

 status update:

- 2nd stage propellant loading completed.
- strap on propellant loading in progress.

 update:

- 2nd stage propellant loading completed.
- strap on propellant loading completed.

update:

cryogenic propellants loading in progress.

Offline vyoma

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Re: GSLV D5 (MkII) GSAT-14, August 19, 2013 (ETD 1100UTC)
« Reply #84 on: 08/19/2013 08:25 AM »
status update ( http://isro.org/ ) : propellant loading of 2nd stage in progress.

 status update:

- 2nd stage propellant loading completed.
- strap on propellant loading in progress.

 update:

- 2nd stage propellant loading completed.
- strap on propellant loading completed.

update:
- Third Stage Cryogenic Propellant filling operation is in progress.
- Propellant filling operation of First Stage Strap-Ons is completed.
-- vyomagaami --

Offline AJA

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Re: LIVE: GSLV D5 (MkII) GSAT-14, August 19, 2013 (ETD 1120UTC)
« Reply #85 on: 08/19/2013 08:46 AM »
In before this becomes an update thread for the day.

The Coolest Hot Engine!!!!!

OK.. so from the video, and the brochure, this is what I've managed to corral about the CUS.

Length: 8.7 m
Diameter: 2.8 m
Prop: LH2/LOX (Typical Isp of combination - 450 s)
Propellant Mass: 12.8 tonnes

Max Thrust: 75 kN

Nominal thrust: 73.55 kN - including thrust from the 2 gimballed steering engines on the stage (Separate engines, or is the gas generator exhaust being used for this a la Merlin? The fact that the brochure says that the Main engine has 200s of test time and the steering has 100s makes me think these are hypergolic verniers. If it was the GG exhaust, the steering would've had ATLEAST the same run time as the main. Having said that, the animation shows a separate off axis gas generator exhaust, so that's probably used too.)

Nominal Burn time: 720 s

Ballpark Cricket-stadium Isp  (assuming uniform mass flow rate for 720s) : 430.2 seconds ...Hmm..

The nozzle has a jacket for cooling, and propellant (LH2/LOX?) pre-heating. The stage also has a bell extension. Pretty standard.

Individual booster pumps for LH2 and LOX, feeding a main turbo-pump running at 40,000 rpm. Thrust control and mixture ratio control possible through two regulators.

I've got a few questions:

1) Thrust control through mixture control? As opposed to throttling both flow rates up/down proportionally to maintain optimum combustion ratio (and conserve propellant)? Does this optimum ratio change through the course of the flight (I'm thinking residual atmospheric oxygen - thinning out with height)

2) The Mahendragiri test video grabs showed a orange/red/yellow flame... Hydrogen burning produces a blue flame doesn't it - regardless of mixture ratio? I mean it's not like there's a partial combustion product for the reaction? The flame was fidgety too.. now I'm not saying they don't have stable combustion - we might have been seeing transients - but it definitely was dancing.

3) What the heck is happening at 7:58 in the video? Something's inflating?

4) Like most modern cryogenic stages, the LH2 tank is physically removed from the LOX tank, with an air-gap present between them. Can someone explain why? I thought the second stage of the Saturn V implemented a great solution in realising a common bulkhead ( - PS: 1:35 is AWESOME :D) The video explicitly mentions it for good measure, but I would've thought anyway - that the steeper thermal gradient would've been between either fluid and the ambient air. Also surprisingly for something that's meant to be kept cool, the tanks are painted black!

5) The video showed the cryo prop-depot enclosure, but the shots of the launch pad don't seem to. How far away is it from the pad? I guess it would be desirable but is it even feasible to have a mobile cryogenic tanker? Related: has anybody here ever been to SDSC? Does ISRO conduct a guided public tour for students/educational institutions atleast? (Or do they share Kanaka's paranoia? :P)
« Last Edit: 08/19/2013 08:50 AM by AJA »


Online Chris Bergin

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L-65 mins. Best webcast link would be appreciated.

Offline seshagirib

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Re: LIVE: GSLV D5 (MkII) GSAT-14, August 19, 2013 (ETD 1120UTC)
« Reply #88 on: 08/19/2013 10:29 AM »
L-65 mins. Best webcast link would be appreciated.

government news channel:

 http://webcast.gov.in/live/

is likely to carry the launch webcast, but cannot say much about the quality.

Offline tehwkd

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