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#220
by
abhishek
on 01 Dec, 2014 06:47
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Watch the video-
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#221
by
Lars-J
on 01 Dec, 2014 06:56
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From a report couple of days back
http://www.thehindubusinessline.com/news/science/isro-rushes-to-clarify-on-gslv-mk-iii-launch/article6646542.ece
At 80 km, the atmosphere takes over. From then, the engineers can only check the speed of the falling object, which they do first by firing small rockets on the module in the reverse direction, and later by opening three parachutes one after the other.
I might have missed it. I thought the capsule would be on a free fall with only the parachutes to slow it down in the later phase. Looks like there are small rockets to do the job initially.
It would be interesting to see how its done (Dragon?). For Soyuz and shenzhou, small solid rockets are fired just before the touchdown. For ISRO, it seems liquid thrusters would be used for braking before the parachute deployment. Check out the propulsion module.
Those tanks are likely for the attitude control system, which uses liquid propellant in all capsules. It is unlikely to be an impact braking system like Soyuz.
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#222
by
antriksh
on 01 Dec, 2014 07:19
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From a report couple of days back
http://www.thehindubusinessline.com/news/science/isro-rushes-to-clarify-on-gslv-mk-iii-launch/article6646542.ece
At 80 km, the atmosphere takes over. From then, the engineers can only check the speed of the falling object, which they do first by firing small rockets on the module in the reverse direction, and later by opening three parachutes one after the other.
I might have missed it. I thought the capsule would be on a free fall with only the parachutes to slow it down in the later phase. Looks like there are small rockets to do the job initially.
It would be interesting to see how its done (Dragon?). For Soyuz and shenzhou, small solid rockets are fired just before the touchdown. For ISRO, it seems liquid thrusters would be used for braking before the parachute deployment. Check out the propulsion module.
Those tanks are likely for the attitude control system, which uses liquid propellant in all capsules. It is unlikely to be an impact braking system like Soyuz.
yup they are for attitude control and reorientation. but what the news article mentions is true, I am wondering how they are planning to use it for velocity reduction before parachutes are used ( not for impact braking).
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#223
by
baldusi
on 01 Dec, 2014 11:49
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Why is this crew capsule going to fly up backwards, with the base pointing up?
It does seem a bit strange (would you do strength tests of an automobile upside down?) but presumably this way they can test the heat shield without building the support structure that will ultimately transfer loads through it.
I think it is arranged to omit the turn around procedure, to reduce complexity of the first test flight of the crew capsule.
BTW, I don't see RCS on the capsule, only indications of retro rockets for breaking. The aerodynamic forces should straighten the capsule. So they might have saved that development, too. And this might even simulate a ballistic return. So they qualify for the worst case.
If you look at the structure, it's quite clear that it is a custom structure for launching upside down. The actual capsule will use a pressure vessels, not unlike SpaceX Dragon's.
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#224
by
Ohsin
on 01 Dec, 2014 14:58
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In earlier renderings of crew module with windows there are structures similar to thruster nozzles. But in this test crew module both seems to be absent.
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#225
by
sanman
on 01 Dec, 2014 18:47
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As others have noted, that faring (heat shield) is much larger than the capsule it'll be carrying. Makes me think that they should make the real manned capsule significantly larger, when they do get around to making it.
I wonder how much bigger they could make it, if required?
This capsule we're looking at seems to have been designed for launch on GSLV-Mk2. But as Mk3 becomes available, why not make the most of that, and build as big a crew capsule as can be accommodated?
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#226
by
baldusi
on 01 Dec, 2014 19:17
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That fairing is the stock fairing designed to carry 4+ tonne comm sats to GTO. The aerodynamics of launching a capsule upside down are clearly not easy. For this test is better to launch this way. But when launching in capsule mode I expect no fairing and thus to launch like any other capsule save for Soyuz and Shenzhen, which is the only case of encapsulated capsules I know of. Mercury, Gemini, Apollo, Dragon, CST-100, Dream Chaser and even Hermes launched or proposed to launch without a fairing. Since the GSLV MkIII core is 4m wide, I would actually expect a conical adapter.
But the truth is that we don't know if the crewed capsule will be finished before the new SCE replaces the hypergolic core with an RP-1/LOX SC engine. In fact, the crewed capsule might take long enough for the ULV to actually be commissioned.
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#227
by
Lars-J
on 01 Dec, 2014 21:52
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That fairing is the stock fairing designed to carry 4+ tonne comm sats to GTO. The aerodynamics of launching a capsule upside down are clearly not easy. For this test is better to launch this way. But when launching in capsule mode I expect no fairing and thus to launch like any other capsule save for Soyuz and Shenzhen, which is the only case of encapsulated capsules I know of. Mercury, Gemini, Apollo, Dragon, CST-100, Dream Chaser and even Hermes launched or proposed to launch without a fairing. Since the GSLV MkIII core is 4m wide, I would actually expect a conical adapter.
But the truth is that we don't know if the crewed capsule will be finished before the new SCE replaces the hypergolic core with an RP-1/LOX SC engine. In fact, the crewed capsule might take long enough for the ULV to actually be commissioned.
Yeah, that's the standard fairing, ~5m in diameter. Sanman appears to be confusing what a fairing and heat shield is.
But a nitpick... Apollo launched with a boost protective cover, that served double duty as a fairing and LAS exhaust protection. Orion has the same thing.
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#228
by
sanman
on 01 Dec, 2014 23:20
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I think of heat shield as something that's on the bottom of a space capsule or re-entry vehicle, to shield it from re-entry heating.
But I've noticed a lot of Indians referring to what seems to be the fairing as a "heat shield" (which to me doesn't seem correct), so I was trying to use both terminologies.
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#229
by
vyoma
on 02 Dec, 2014 00:13
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I think of heat shield as something that's on the bottom of a space capsule or re-entry vehicle, to shield it from re-entry heating.
But I've noticed a lot of Indians referring to what seems to be the fairing as a "heat shield" (which to me doesn't seem correct), so I was trying to use both terminologies.
ISRO uses the term "heat shield" for "payload fairing".
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#230
by
abhishek
on 02 Dec, 2014 02:39
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I think of heat shield as something that's on the bottom of a space capsule or re-entry vehicle, to shield it from re-entry heating.
But I've noticed a lot of Indians referring to what seems to be the fairing as a "heat shield" (which to me doesn't seem correct), so I was trying to use both terminologies.
A payload fairing also protects the satellite from atmospheric heating,so you can see a payload fairing as a heat shield.
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#231
by
jcm
on 02 Dec, 2014 02:44
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I think of heat shield as something that's on the bottom of a space capsule or re-entry vehicle, to shield it from re-entry heating.
But I've noticed a lot of Indians referring to what seems to be the fairing as a "heat shield" (which to me doesn't seem correct), so I was trying to use both terminologies.
A payload fairing also protects the satellite from atmospheric heating,so you can see a payload fairing as a heat shield.
Back in the day, the NASA Scout launch vehicle's fairing was called its 'heat shield' in program documents.
That usage has fallen out of common practice over the years, but it's not unprecedented.
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#232
by
vineethgk
on 02 Dec, 2014 06:21
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As others have noted, that faring (heat shield) is much larger than the capsule it'll be carrying. Makes me think that they should make the real manned capsule significantly larger, when they do get around to making it.
I wonder how much bigger they could make it, if required?
This capsule we're looking at seems to have been designed for launch on GSLV-Mk2. But as Mk3 becomes available, why not make the most of that, and build as big a crew capsule as can be accommodated?
The stated LEO capability of GSLV-III (~10 tonnes) is higher than that of CZ-2F (~8.4 tonnes) and Soyuz-FG (~7.8 tonnes). Not to forget that when they get the Kerolox core ready to replace L-110, LEO capability would probably increase to ~12-15 tonnes. That would be much higher than what is needed for the current design, considering a service module and even an additional orbital module. Such a rocket should be capable of accommodating a much larger spacecraft with a carrying capacity of upto 6-7 people (DragonRider/F9 V1.1 comes to mind).
But as mentioned, the current design was probably dictated by the earlier requirement of using a GSLV-II, and ISRO would probably want to leverage the design work that had already gone into it rather than start designing a larger capsule from scratch which would be time-consuming. But it makes me wonder though: since there doesn't appear to be any immediate national requirements to be met through conducting manned spaceflight, would ISRO be better off starting the design works on a larger spacecraft now(with future potential for reusability) and targeting first manned missions in the later half of 2020s,
or continue with the existing smaller design to learn stuff early on? Assuming, of course, that ISRO would not have the resources to pursue both programs in parallel.
Another thing that came to my mind. If the current capsule was indeed designed for GSLV-II, and keeping in mind GSLV-II's LEO capability that was ~5 tonnes, would the rocket have been capable of carrying it? The capsule itself weighs around 3.5 tonnes without a service module, and we would need to take into account the added weight of the launch escape tower. Would all this add up to < 5 tonnes? Or was the original 2-person capsule that ISRO had in mind for GSLV-II smaller than the current one?
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#233
by
abhishek
on 02 Dec, 2014 16:58
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Look what i found
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#234
by
johnxx9
on 02 Dec, 2014 17:22
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^^^
Its an old concept. I remember having seen that design of OV eons ago. Much before the current design emerged.
That launch vehicle seems interesting. It looks like it's powered by a solid first stage and cryogenic 2nd stage.
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#235
by
abhishek
on 02 Dec, 2014 17:40
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^^^
Its an old concept. I remember having seen that design of OV eons ago. Much before the current design emerged.
That launch vehicle seems interesting. It looks like it's powered by a solid first stage and cryogenic 2nd stage.
I know,it's evident from the GSLV 2 rocket.But whats surprised me more was the ISRO logo on the top right end corer of video,was this video made by ISRO ? Because it looks quite professionally made.
Another thing i liked was the docking with the ISS.
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#236
by
johnxx9
on 02 Dec, 2014 17:59
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^^^
Its an old concept. I remember having seen that design of OV eons ago. Much before the current design emerged.
That launch vehicle seems interesting. It looks like it's powered by a solid first stage and cryogenic 2nd stage.
I know,it's evident from the GSLV 2 rocket.But whats surprised me more was the ISRO logo on the top right end corer of video,was this video made by ISRO ? Because it looks quite professionally made.
Another thing i liked was the docking with the ISS.
It's not a GSLV in the video. It's completely different launcher, one which we have never seen or will never see.
Looks like an official ISRO video as part of concept presentation.
And ISS is/was/will never be out of question for India. The other countries only need commitment from India and they would be happy to have us onboard the project. But, from a lay man's perspective it still too early to tell whether that will be ISRO's interests are not.
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#237
by
antriksh
on 03 Dec, 2014 00:46
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^^^
That launch vehicle seems interesting. It looks like it's powered by a solid first stage and cryogenic 2nd stage.
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#238
by
abhishek
on 03 Dec, 2014 02:23
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^^^
thanks a lot.Never knew they had planned a new vehicle whey they conceived the manned mission plan in 2006.
Anyways ,building a LEO travelling Vehicle is not enough.We need a future beyond LEO CM too
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#239
by
antriksh
on 03 Dec, 2014 05:23
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