Has the cryogenic stage been integrated into the launch vehicle?
uh oh.....\
telemetry on screen does not look good....
From what I know, the GSLV "stage 0" boosters burn longer than the "stage 1" core. How's that handled? Is it not a parallel-burn (like the Titan III/IV, not the Delta/Atlas)?
It just is an unusual way of doing things, I guess.From what I know, the GSLV "stage 0" boosters burn longer than the "stage 1" core. How's that handled? Is it not a parallel-burn (like the Titan III/IV, not the Delta/Atlas)?
Why would that pose a problem if the liquids have control authority?
In watching the velocity numbers from the video, I didn't see the expected velocity increase that should have occurred following cryo engine ignition. So in my own humble opinion, I don't think that the cryo engine ignited.
Anyway, just my personal opinion.
In watching the velocity numbers from the video, I didn't see the expected velocity increase that should have occurred following cryo engine ignition. So in my own humble opinion, I don't think that the cryo engine ignited.
Anyway, just my personal opinion.
Makes sense. Why would a failure of two verniers cause anything but a roll issue? I assume the engine gimbals in pitch and yaw. Anyway a shocking development for modern spaceflight.
In watching the velocity numbers from the video, I didn't see the expected velocity increase that should have occurred following cryo engine ignition. So in my own humble opinion, I don't think that the cryo engine ignited.I tend to agree, as supported by these telemetry data (extracted from various live broadcasts):
| Time (s) velocity (km/s) altitude (km) event 262.8 4.113 127.5 263.8 4.138 127.8 290.4 GS2 Shutoff 293.0 GS2 Separation 297.0 4.898 134.7 298.0 4.898 134.9 299.0 4.898 135.1 300.0 4.898 135.3 301.0 4.897 135.5 304.9 CUS Ignition 308.0 4.895 136.5 309.0 4.895 136.7 310.0 4.895 136.8 316.0 4.893 137.5 317.0 4.893 137.6 318.0 4.893 137.7 319.0 4.893 137.8 320.0 4.893 137.8 321.0 4.893 137.9 322.0 4.893 138.0 323.0 4.893 138.0 324.0 4.892 138.1 325.0 4.892 138.2 326.0 4.892 138.2 327.0 4.892 138.3 328.0 4.892 138.3 329.0 4.892 138.3 373.0 4.899 134.9 379.0 4.901 133.7 446.5 4.951 107.4 505.0 5.023 65.9 |
I wouldn't assume that the verniers were for roll only. Zenit and Soyuz both, I believe, use fixed engines with verniers (Zenit 2nd stage) for pitch, roll, and yaw.In watching the velocity numbers from the video, I didn't see the expected velocity increase that should have occurred following cryo engine ignition. So in my own humble opinion, I don't think that the cryo engine ignited.
Anyway, just my personal opinion.
Makes sense. Why would a failure of two verniers cause anything but a roll issue? I assume the engine gimbals in pitch and yaw. Anyway a shocking development for modern spaceflight.
I wouldn't assume that the verniers were for roll only. Zenit and Soyuz both, I believe, use fixed engines with verniers (Zenit 2nd stage) for pitch, roll, and yaw.In watching the velocity numbers from the video, I didn't see the expected velocity increase that should have occurred following cryo engine ignition. So in my own humble opinion, I don't think that the cryo engine ignited.
Anyway, just my personal opinion.
Makes sense. Why would a failure of two verniers cause anything but a roll issue? I assume the engine gimbals in pitch and yaw. Anyway a shocking development for modern spaceflight.
--N
I wouldn't assume that the verniers were for roll only. Zenit and Soyuz both, I believe, use fixed engines with verniers (Zenit 2nd stage) for pitch, roll, and yaw.In watching the velocity numbers from the video, I didn't see the expected velocity increase that should have occurred following cryo engine ignition. So in my own humble opinion, I don't think that the cryo engine ignited.
Anyway, just my personal opinion.
Makes sense. Why would a failure of two verniers cause anything but a roll issue? I assume the engine gimbals in pitch and yaw. Anyway a shocking development for modern spaceflight.
--N
The cryogenic engine has not ignited, that is for sure.
It is very clear that the cryogenic engine did not ignite when you look at the curve [of the vehicle's trajectory], everything was normal up to the GS2 [second stage] shutdown. Then you can see clearly that there is no increment in the vehicle's velocity. The velocity is the same. It started losing its altitude also.
I wonder if India's going to have to build a dedicated vacuum test facility now, or if they can rent someone else's.
As I mused in another thread, I wonder if it's possible to just float an engine test rig up on a balloon to some high altitude, in order to test-fire it. Otherwise, there would seem to be a huge amount of engineering involved in building a ground-based vacuum test facility.
How big will the balloon need to be to support the weight of the engine, propellant supply and instrumentation, and support structure?
How will this flying arrangement compensate for thousands of pounds of thrust, in whatever direction?
I suspect the real problem with the Indian engine will be something other than the vacuum condition. If ISRO doesn't have a altitude compensating test chamber, it's time they build one. Do you know how it works? It's surprisingly simple in principle.
QuoteI suspect the real problem with the Indian engine will be something other than the vacuum condition. If ISRO doesn't have a altitude compensating test chamber, it's time they build one. Do you know how it works? It's surprisingly simple in principle.
India does not have a macro-scale vacuum test chamber, and vacuum conditions were not simulated in ground testing of the engine. I think they may have tried to simulate this merely through numerical methods, and not through an actual test-firing under these conditions.
From what I've read, these vacuum chambers work through "steam ejectors" which not only have to produce a vacuum, but have to maintain it in the face of the huge exhaust put out by the engine being tested.
Perhaps it would be easier just to rent somebody else's in the near term, and consider building one for the long haul.
The steam ejector works initially to pump down the chamber; the high speed exhaust of the engine being tested does the rest of the work.
Russia has a couple of dandy facilities, and India has traditionally worked closely with them.
But let's wait for a failure analysis to point to the real problem. Quite a number of things could have caused this. Liquid hydrogen has an annoying tendency to freeze anything that's not helium, for example.
Interesting - where is the data for engine chamber pressure, pump speeds, propellant flow and pressures and other information? New vehicle would have lots of detailed telemetry? Maybe the information will come out later.
Since this was still a high velocity flight why do you need to settle fully loaded cryogenic propellants with ullage pressures in place?What has velocity to do with it? It's about acceleration and the lack of it (or gravity) means that there is a possibility of gaseous H2/O2 at the turbopump inlet rather than LH2/LOX.. which could result in the 'burp'.
My point is that tanks are pressurized when fully loaded which helps to seat the propellants gravity or not.
Screenshot from televised video at T0+505s when telemetry link was lost (curves and scales have been colored for better readability)
- Nominal altitude vs time in green
- Nominal relative velocity vs time in magenta
- Observed deviations in red
GS2 IGN = second stage ignition
CUS IGN = third stage ignition
CUS OFF = third stage cut-off
(http://img684.imageshack.us/img684/9048/datam.jpg)
So.. even if the cryo ignited it did not impart any force towards increasing the velocity of the rocket.I tend to agree. This is illustrated below when zooming in from my earlier graph (http://forum.nasaspaceflight.com/index.php?topic=18858.msg576689#msg576689) on the period around CUS IGN.
Indian launches are never insured(source (http://economictimes.indiatimes.com/news/news-by-industry/et-cetera/High-premium-deters-ISRO-from-insuring-projects/articleshow/5862418.cms))
ISRO should have gone with a dummy satellite (rocks even !!! :)) of equal weight instead of trying with original satellite while doing experiemnts. This saves cost in case of failuare.