GSLV D3 Launch Failure

Vikas · Post by **Vikas** » 16 Apr 2010 20:23

nrshah wrote:OT, however could not resist in posting

The next year, in July 1980, we tried again to launch the satellite -- and this time we succeeded. The whole nation was jubilant. Again, there was a press conference. Prof. Dhawan called me aside and told me, "You conduct the press conference today.".....

[/quote]

^^ What a great and wonderful bunch of people.

skganji · Post by **skganji** » 16 Apr 2010 21:42

Indeed it is emplary of Satish Dawan to took the responsibility of the failure. What is the use of these Cry babies who have no idea on how space program works ?. Failure of Cryogenic engine is not a big deal. It is a complex technology and that too it is the first time , India is doing it. Hope the will try to rectify the mistakes associated with Cryogenic Technology.

rahuls · Post by **rahuls** » 16 Apr 2010 23:46

SSridhar wrote: The gas is generated on-board through one of the following means:
In a precombustion chamber
In a separate gas generator
By circulating LH2 through the cooling jacket surrounding the combustion chamber which achieves the twin purpose of cooling the chamber and transferring the heat to LH2 to generate the gas
By bleeding hot gas from the combustion chamber
After flowing through the turbine, the gas can be exhausted through a separate nozzle or through the nozzle of the engine or injected back into the combustion chamber

Thanks SSridhar for a good overview of cryogenic engine. For Point 3 above, am I right in assuming that there is no combustion involved in the turbine and that the high pressure of gaseous H2 is used to run the turbine blades.

karthik · Post by **karthik** » 16 Apr 2010 23:49

I didnt hear the heat shields separated? If the new heat shields was still on then the carbon-fiber heat shield would have with stood reentry(if any) then can the satellite be salvaged or would the Navy be pressed to find the wreckage?

disha · Post by **disha** » 17 Apr 2010 00:11

karthik wrote:I didnt hear the heat shields separated? If the new heat shields was still on then the carbon-fiber heat shield would have with stood reentry(if any) then can the satellite be salvaged or would the Navy be pressed to find the wreckage?

The heat shield separates @160 secs into flight at @70 km of height at @2.6 km/sec flight regime. GSAT cannot be salvaged.

From that height to splash down, GSAT would have broken into many pieces and the debris would have scattered over several hundred square kilometers. No point in searching for the wreckage, and ISRO indicated so.

karthik · Post by **karthik** » 17 Apr 2010 00:25

disha wrote:
karthik wrote:I didnt hear the heat shields separated? If the new heat shields was still on then the carbon-fiber heat shield would have with stood reentry(if any) then can the satellite be salvaged or would the Navy be pressed to find the wreckage?
The heat shield separates @160 secs into flight at @70 km of height at @2.6 km/sec flight regime. GSAT cannot be salvaged.

From that height to splash down, GSAT would have broken into many pieces and the debris would have scattered over several hundred square kilometers. No point in searching for the wreckage, and ISRO indicated so.

Was there a compulsory sequence to follow right after Cryo-Stage separation the heat shields should also compulsorily open?

They could have held it till a few minutes! Not sure i follow this but i hope there was an more valid explanation.

Gagan · Post by **Gagan** » 17 Apr 2010 00:27

The satellite launch heat shield is very different from the missile re-entry heat shield. The satellite nose cone heat shield has explosive blocks in it and it separates at the 70-90 Km altitude as thereafter there is very little protection needed for the satellite. This is a very flimsy heat shield.

The missile warhead re-entry heat shield is usually a part and parcel of the warhead, and is an ablative shield that has to withstand the immense temperatures of re-entry, and the huge G forces involved. This is a very thick and solidly built protective layer.

lakshmikanth · Post by **lakshmikanth** » 17 Apr 2010 01:19

^^^^
Re-entry heat shields are considerably different from Upper atmosphere heat shields. Re-entry heat shields need to be able to withstand much more heat and pressure due to friction compared to upper atmosphere heat shields.

Also when the rocket tumbles out of control a lot of damange can be done to the internal components due to re-entry vibrations. Most likely the craft has been pulverized or damaged beyond usable state. I guess it wont be useful to even study let alone for the US/China to asses the capability of what ISRO has achieved in their engine.

Its a sad loss, but that is the nature of complex technology.

karthik · Post by **karthik** » 17 Apr 2010 01:56

There was spy activity in ISRO about two months ago when we heard of the shooting in front of ISROs gates in Bangalore. How far can we rule out sabotage from this case? Wont getting any wreck show us some meaningful clue?

Some how when something gets tested a thousand times for safety but fizzles out after launch, then it does make one wonder on the nature of the incident.

negi · Post by **negi** » 17 Apr 2010 01:58

rahuls wrote: Thanks SSridhar for a good overview of cryogenic engine. For Point 3 above, am I right in assuming that there is no combustion involved in the turbine and that the high pressure of gaseous H2 is used to run the turbine blades.

Well for both GGE and SCE the hot gases required to drive the turbine are produced outside the turbine itself the difference is , in case of the former gases which drive the turbine are not as fuel rich as in case of a cryogenic SCE because they are to be dumped after turbine has extracted all useful work from the expanding gases , however in case of the latter the only way closed cycle can be achieved is to ensure that turbine runs on a fuel rich mixture so that the spent gases can be re routed into the main combustion chamber (wiki says oxidizer rich designs are avoided due to corrosive effect of Oxygen on plumbing ), however this puts immense stress on the turbine .

kasthuri · Post by **kasthuri** » 17 Apr 2010 03:13

Why didn't the cryogenic engine ignite?

The non-ignition of the cryogenic engine on board the Geo-Synchronous Satellite Launch Vehicle (GSLV-D3) led to the failure of the mission on Thursday (April 15), the Indian Space Research Organisation (ISRO) has more or less concluded. “The cryogenic engine has not ignited, that is for sure. Why it has not ignited, the reasons have to be found out,” said S. Satish, ISRO spokesman, on Friday.

All the telemetry data had come in by 1 p.m. on Friday and the ISRO top-brass was studying them line by line. The GSLV-D3 is a three-stage rocket and it was flying with an indigenous cryogenic engine for the first time.

A cryogenic engine uses liquid hydrogen at minus 253 degrees Celsius as fuel and liquid oxygen at minus 183 degrees as oxidiser. The vehicle lifted off as planned at 4.27 p.m. and its performance was normal up to the end of its second stage till 293 seconds from the lift-off. But the vehicle developed problems when the cryogenic upper stage should have ignited 304 seconds after the lift-off, and it fell into the sea.

An authoritative former ISRO official said: “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.”

The ISRO rocket engineers are puzzled why the cryogenic engine did not fire at all. On April 9, they had repeatedly told reporters at Sriharikota that the GSLV-D3 was “the most reviewed vehicle” because it was flying an indigenous cryogenic engine for the first time.

A national panel consisting of former ISRO chairmen, specialists in cryogenic technology and academicians had reviewed the vehicle several times and signalled the go-ahead. But for these repeated reviews, the flight would have taken place in December 2009, they had said.

Besides, the indigenous cryogenic engine was tested on the ground cumulatively for 7,767 seconds, while it would fire for only 720 seconds in flight.

Post-flight, ISRO Chairman K. Radhakrishnan said the entire cryogenic stage, including its engine, passed the qualification test on November 15, 2007 when it fired for 720 seconds. “In the last three years, we have been working on the flight-engine,” he said. But he pointed to one big difficulty — the ignition of the cryogenic engine taking place in the vacuum of space [which cannot be simulated on the ground].

S. Ramakrishnan, Director (Projects), Vikram Sarabhai Space Centre, Thiruvananthapuram, also noted, “Ignition in vacuum of the cryogenic engine could be done only in flight.”

VikramS · Post by **VikramS** » 17 Apr 2010 04:16

Some experts can add more thought to this, but I have wondered why ISRO went for a full-fledged big kahuna launch for the first ever test flight of the cryogenic engine.

Regardless of how thorough you are, you can never simulate true space conditions on land. From an engineering point of view, developing a smaller version of the engine, which can sit as the second stage of an experimental rocket, and launching that might have helped validate the underlying technologies in the real space environment. Perhaps even a micro version of the engine as the payload of a smaller rocket might have helped validating the basic functionality of the sub-systems.

Your degree of confidence in the success of a full-scale version would be much higher if the micro version is able to demonstrate that key sub-systems operate as expected in the real environment.

My concern is that even the next test of the cryogenic engine will be with a high profile GSLV launch. If the reports of ignition failure are true, then this launch may not have provided any significant data on the performance of the engine which the engineers could use to isolate the problem.

Comments welcome.

Sanjay M · Post by **Sanjay M** » 17 Apr 2010 04:21

I'm curious - ISRO officials have said they intend to develop Semi-Cryogenic propulsion as well, to lower the cost/kg. Presumably, this means RP-1/kerosene with LOX, like the way Russia's RD-170 does it. Why wouldn't it be better to go to Semi-Cryogenic directly, without resorting to the expense of developing cryo/LH2 propulsion? Is cryogenic/LH2 propulsion a necessary stepping-stone to semi-cryogenic propulsion? LH2 is the most extreme fuel to handle, so I wonder why kerosene wouldn't have been preferred from the outset.

I'd even read that DARPA proposed that the US develop its own counterpart to the RD-170, after having imported so many of them from Russia for the Atlas-V. It is after all the most powerful rocket engine in the world.

Is India allowed to buy any RD-170 from Russia, to fly a few and perhaps disassemble and study a few to make its own? Or is that prohibited under MTCR?

Btw, I don't feel that building your own capability from scratch is automatically always the most effective response to any sanctions/denial regime. The most effective response is to cultivate strong enough alliances with the right nations in order to render such denial regimes ineffective. Building your own stuff from scratch can sometimes amount to re-inventing the wheel.

Sanjay M · Post by **Sanjay M** » 17 Apr 2010 04:34

kasthuri wrote:
Why didn't the cryogenic engine ignite?
...
But he pointed to one big difficulty — the ignition of the cryogenic engine taking place in the vacuum of space [which cannot be simulated on the ground].

So how do other nations handle testing of such novel propulsion systems?
Do they also forego vacuum testing until the actual flight-test, or have they developed some way to simulate the vacuum conditions?

Sanjay M · Post by **Sanjay M** » 17 Apr 2010 05:02

Maybe someone should come up with a high-altitude test-bed, for very low pressure conditions.
Perhaps something could be floated up on a balloon and ignited at very high altitude.

kasthuri · Post by **kasthuri** » 17 Apr 2010 05:29

VikramS and Sanjay M raised very pertinent points which I was also thinking along. We don't seem to have any high-altitude testing program in place. I certainly see the point that given the shoe-string budget that ISRO works, having such programs (like piggybacking the cryo engine and testing in high-altitudes) may be difficult. But I don't know if ISRO had approached GoI for such things or any feasibility studies had been carried out. I think such programs are really necessary irrespective of whether the launch happens perfectly (even several times) or not. I view rocket science like any other science - about fundamental human curiosity than sending man to moon or to mars.

Sanjay M · Post by **Sanjay M** » 17 Apr 2010 05:45

Even if we can't build our own vacuum test facility, perhaps we could rent somebody else's:

http://www.nps.gov/history/history/onli ... space7.htm

The Spacecraft Propulsion Research Facility's significance rests in its association with the development of the Centaur Rocket. This facility is the only one in NASA's inventory that can hot fire a large rocket while simulating the vacuum, cryogenic temperatures, and thermal radiation of space. The duplication of this space environment was crucial to the development of the Centaur Rocket which was designed to fire from Earth Orbit to send vehicles to explore the planets and Solar System. The Centaur upper stage rocket has launched some of America's most important space probes including the Pioneer, Viking and Voyager Spacecraft. The successful development and use of the Centaur was due in large measure to data that was collected from successful test firings of Centaur engines in this facility.

http://microgravity.grc.nasa.gov/Launch ... ageEngine/

Upper Stage Engine & Engine/Stage Testing

Thermal/Vacuum Testing of J–2X Engine

As part of the J–2X engine test program for Ares V Earth Departure Stage (EDS) application, Glenn’s Plum Brook Station B–2 facility will be modified to perform thermal/vacuum ignition testing. Engine start and restart in conditions equivalent to the Earth Departure Stage environment will be verified in the test.

Plum Brook’s unique capability to hot fire test an engine at simulated altitude temperatures and pressures will help validate the J–2X engine’s ability to perform in space. The B-2, Spacecraft Propulsion Test Facility was constructed originally to conduct engine and stage testing. It was previously utilized for thermal / vacuum testing of the Centaur RL-10 engine, Centaur Upper Stage and the Delta 3 Upper Stage (shown).

http://www.arnold.af.mil/library/factsh ... p?id=13485

Ambient (sea level) testing of rocket propulsion systems designed for high altitude operations can compromise engine performance data and potentially jeopardize the structural integrity of the nozzle by imposing severe loads from nozzle flow separation. Sea-level testing with truncated nozzles does not properly evaluate nozzle structural integrity. It also requires the test data to be adjusted to calculate full-nozzle and thrust vector control systems performance.

http://www.space-travel.com/reports/ATK ... m_999.html

Alliant Techsystems recently demonstrated a critical capability of its liquid oxygen (LOX)/Methane rocket engine
by igniting it in a vacuum chamber. The successful ignition test was designed to demonstrate the viability of a LOX/Methane rocket engine for a lunar ascent mission.

lakshmikanth · Post by **lakshmikanth** » 17 Apr 2010 06:55

Thanks Sanjay M for the links.

We should absolutely try to achieve atleast some amount of Vacuum testing capability. This is going to be critical for the future endeavors of ISRO.

I am not sure if anyone would let us rent something like this though

Singha · Post by **Singha** » 17 Apr 2010 07:39

we will have to build our own in trivandrum with russian/french assistance and pay the $$$ needed. no other way fwd. we cannot afford much costly misses like GSLV+payload. with cheap ASLV it was much less costly.

vina · Post by **vina** » 17 Apr 2010 08:13

rahuls wrote:Thanks SSridhar for a good overview of cryogenic engine. For Point 3 above, am I right in assuming that there is no combustion involved in the turbine and that the high pressure of gaseous H2 is used to run the turbine blades.

What you have described is called the EXPANDER CYCLE. It is far simpler, many of the American cryogenic engines use that .That cycle however is limited to engine size and beyond that, it wont work.

In staged combustion and gas generator, a small amount of fuel and propellant are burnt and used to the hot gases are used to turn a turbine, which in turn drives the pumps that pump oxidizer and fuel into the combustion chamber.

The difference between staged combustion and gas generator is that in the gas generator, after driving the turbine, the gases are vented out into the atmosphere. In a staged combustion the gases that leave the turbine (usually a fuel rich mixture, though the Russians use a more difficult oxygen rich mixture) and sent into the combustion chamber where they are burnt . That way the staged combustion generates a couple of percentage points more thrust and is more efficeint (coz the gases are used to propel and not wastefully vented out).

vina · Post by **vina** » 17 Apr 2010 08:15

karthik wrote:I didnt hear the heat shields separated? If the new heat shields was still on then the carbon-fiber heat shield would have with stood reentry(if any) then can the satellite be salvaged or would the Navy be pressed to find the wreckage?

Heat shields are discarded at the first opportunity when the vehicle clears the atmosphere. There is no further need for it. If you didn't you are essentially carting empty weight that is of no use .

It is the basic principle of staging. You discard the mass you dont absolutely need to carry.

Re-entry ? For a satellite ?. Whatever for!. It is supposed to go up into space, not come back to earth!.

juvva · Post by **juvva** » 17 Apr 2010 08:44

Ignition failure must be the worst mode of failure, as we get no/minimal data on engine functioning. Hope some useful telemetry can be salvaged, maybe H2/02 tank pressures, volumes, if any pressure was developed at all in the combustion chamber prior to ignition.( these are my novice level guesses).

Can someone more knowledgeable come up with, what useful debug data will be available prior to/at ignition ?

Sanjay M · Post by **Sanjay M** » 17 Apr 2010 08:46

vina wrote:In a staged combustion the gases that leave the turbine (usually a fuel rich mixture, though the Russians use a more difficult oxygen rich mixture) and sent into the combustion chamber where they are burnt . That way the staged combustion generates a couple of percentage points more thrust and is more efficeint (coz the gases are used to propel and not wastefully vented out).

Yes, I've read that the Russian RD-170 uses this hot oxygen-rich mixture to get a more efficient burn and achieve significantly greater thrust, making it the highest thrust rocket engine in the world. I'd read that DARPA had recommended that the US develop its own version of the RD-170.

So this is a semi-cryogenic engine. In which case, why research cryogenic/LH2 engines at all, if the longer-term intent is to go for semi-cryogenic technology at a lower cost/kg?
Yes, we know that LH2 has the highest Isp, but cost/kg is what counts the most in the end.

Could India have a reasonable chance of developing its own version of the RD-170?
I'd read that the rocket recently launched by the SKoreans was powered by a lower-thrust version of the RD-170. So that means there could be an opportunity for us to buy such engines as well. If the US reduces the number of its Atlas-V launches, then the Russian engine fabrication facilities could take some orders from us to fill the gap.

rahuls · Post by **rahuls** » 17 Apr 2010 08:48

Sanjay M wrote: Is India allowed to buy any RD-170 from Russia, to fly a few and perhaps disassemble and study a few to make its own? Or is that prohibited under MTCR?

This puzzles me. How come Russian transfer of cryogenic engines to India violate MTCR whereas transfer of RD-170 to US does not ? The following from MTCR website

End-user Undertakings: MTCR partners have agreed that, in a manner consistent with their national laws and practices and when relevant under the MTCR Guidelines and other existing undertakings, partner countries should obtain the following undertakings before the transfer of a controlled item:

* a statement from the end user specifying the use and end use location of the proposed transfer, if necessary accompanied by documents explaining its business activities and organization;
* an assurance explicitly stating that the proposed transfers will not be used for any activities related to the development or production of delivery systems for WMD; and
* where possible and if deemed necessary, an assurance that a post shipment inspection may be made by the exporter or the exporting government.

Partners have also agreed that partner countries should obtain assurances that their consent will be secured, in a manner consistent with their national law and practices, prior to any re-transfer to a third country of the equipment, material or related technology or any replica thereof.

Inter-partner Trade: MTCR partners have explicitly affirmed the principle that membership in the MTCR does not involve an entitlement to obtain technology from another partner and no obligation to supply it. Partners are expected, just as in such trade between partners and non partners, to exercise appropriate accountability and restraint in inter partner trade.

So is it that we can get cryo engines from Russia, if we want to, if we sign End-User Undertaking. Why isn't Russia-USA transfer against MTCR if Russia-India transfer with End-User Undertaking is against MTCR ?

vina · Post by **vina** » 17 Apr 2010 08:48

we will have to build our own in trivandrum with russian/french assistance and pay the $$$ needed. no other way fwd. we cannot afford much costly misses like GSLV+payload. with cheap ASLV it was much less costly

Those are legacy facilities in places like Unkil Land, Roosi Land and Oireope Land, built largely during cold war /space race years when money was no object.

As skin flint chislin Banias, the Yindoo approach is fine. It probably is going to cost a couple of million dollars, approaching even a $1b and a couple of years to build such a facility.

What was the GSLV+payload combo's cost.. Rs 330 crores ?. ie $70 mil ?. You can do some 10 REAL launches for the cost of the facility.. and mind you , that is absolutely real and no simulation.

It is only that there needs to be 'media management' to make sure that rags like TOI(let) and UndieTV dont go around shooting their mouth off on these things as "failures" , "setbacks" / whatever. Idiots must be made to write a highschool kind of imposition for 1000000000000000000 times that GSLV -D3 is GSLV - Development Flight 3

Sanjay M · Post by **Sanjay M** » 17 Apr 2010 08:58

In which case, we should do developmental flights with less costly payloads than GSAT-4

Ares-1X didn't have any costly payload aboard. It was just treated as an expendable rocket. Perhaps we should have done that.

If we're not loudly advertising our Agni tests, then why do we have to loudly advertise developmental flights that run a high risk of failure?

Also, perhaps India doesn't have to build a full giant-sized vacuum chamber, but could get by with a smaller one by testing scaled down models inside it. Besides, are you going to test everything in flight, including vital new hardware on manned missions? Vacuum chambers aren't just to test rocket engines, they can be used to run tests on all kinds of equipment.

Perhaps India could pool its costs by sharing facilities with Brazil, Israel, and some others.
(Btw, I bet the Israelis are sure glad now that their TAUVEX was bumped from the flight)

vina · Post by **vina** » 17 Apr 2010 09:01

Yes, I've read that the Russian RD-170 uses this hot oxygen-rich mixture to get a more efficient burn and achieve significantly greater thrust, making it the highest thrust rocket engine in the world. I'd read that DARPA had recommended that the US develop its own version of the RD-170.

There is a newer version called RD-180 for which Pratt & Whitney has co production rights which is used in the US Atlas program. In fact the Korean Nara rocket uses the RD-180 as the 1st stage. Yeah. India could get the RD-180 if it so desires, just like we get the CUS from Russia for GSLV. I really dont see a problem if we went that route.

So this is a semi-cryogenic engine. In which case, why research cryogenic/LH2 engines at all, if the longer-term intent is to go for semi-cryogenic technology at a lower cost/kg?

It is "cheap" because Kerosene is cheap and can made in the standard refineries and doesnt require exotic storage and handling beyond normal.

Yes, we know that LH2 has the highest Isp, but cost/kg is what counts the most in the end

Point is, in the lower stages, what you want is brute thrust,more than efficiency (those stages provide the thrust and fall off anyway and dont operate for the longest time). So what you do is to get the cheapest possible solution (solids are another option) and it really isnt worth the trouble to go all cryogenic (like the Japanese H2 for instance).

However for the upper stages you need the efficiency of the full cryogenic. For eg, look at GSLV, the 1st and 2nd stages cumulatively operate for 505 secs or so while the cryogenic upper stage operates for 720 secs, which is more than the previous 2 stages combined . The highly efficient upper stage is where you gain the maximum in terms of overall config and mass fraction. If the upper stage is most efficient, the lower two stages automatically come down in size and you can make do (kaam chalao) with conventional engines and dont need to go fully cryogenic.

Singha · Post by **Singha** » 17 Apr 2010 09:03

10 real launches will take us 10 years given the assembly time and only one launchpad free (the other being kept for more frequent 'workhorse' PSLV)

if we pay $$$ and push hard, we can maybe get the facility going in 4 years and producing
results in 6 years. after that all types of rockets and planetary probe engines can be freely tested on a 24x7 basis.

we need this just as we need better altitude test facilities in line with the legendary Gromov test institute at zhukovsky....every significant aerospace power has at some point
laid out big$ when making the transition from buying/cloning/stealing to making their own stuff. I can bet the PRC has lavish and no-holds-barred facilities for both space and aircraft compared to our shoestring 'cost effective, we are yindu we eat sukhi roti onree' budgets.

we cannot be a big boy on the cheap.

vina · Post by **vina** » 17 Apr 2010 09:08

we cannot be a big boy on the cheap

Oh well. In that case, we can probably hire the facility from the Roosies/Frenchies and maybe Unkil and send the stage for testing there.

South of France will also be a nice R&D (rest and recreation) area for the ISRO folks..

Singha · Post by **Singha** » 17 Apr 2010 09:15

for medium term to work out cryogenic engine issues - yes if possible. but bear in mind these facilities might get blocked for extended periods as the host nations have their own programs to develop. Unkil for one is always looking for vital details which can be used
as strategic chokepoints for tech denial regimes later. the french will probably share such
info in exchange for some other goodies from unkil like nuclear simulation tools.

its better to have own wife than pay a nightly visit through the neighbours window when husband is sleeping

more costly but always available (one hopes).

Sanjay M · Post by **Sanjay M** » 17 Apr 2010 09:23

I'm not sure how developmental this flight will be, if it doesn't tell us why the engines didn't ignite. In the controlled observable conditions of a vacuum chamber, you can get all the data you need.

Anyway, SRB's are considered even more efficient than the liquid-fueled RD-170/180/190, so perhaps that's why the US has gone with SRB's all this time instead of the latter. Since India seems to be doing okay with SRB's, maybe it should just focus on building those bigger and better, rather than going for RD-170/180/190.

Regarding the brute thrust approach for early portion of the trajectory, it makes me wonder why we can't partner with the Russians to develop some kind of MagLev catapult technology, which could be more cost-effective than SRB's or RD-170/180/190. They are good at this type of big engineering, and surely this technology would not be restricted by the MTCR at all. If anything, it could enable us to build bullet-trains for cross-country mass-transit.

Mount your cryo upper stage on some kind of sled on a MagLev track, and use the cryo-fuel to cool the MagLev superconductors to low temp. Accelerate it along a 10-mile track to Mach-3, and have the last half-mile of the track as an upward ramp to hurl it skywards. This should give the lowest cost/kg for unmanned payloads.

lakshmikanth · Post by **lakshmikanth** » 17 Apr 2010 09:49

I guess we cannot rely on scaled down models for testing this technology. From the little bit of research that I have done on opensource info on liquid propellant rocket engines, the design of the turbo-pumps is closely coupled with the size of the engine. I assume this to be even more closely coupled in case of cryo engines because the temperature gradient in the turbo-pumps would be at insanely high levels. So a success in a scaled model would not necessarily translate into success in case of full scale model. Maybe some major problems can be fixed but if the issue was caused by a minor issue like a crack in the pump when the scale is increased for example, or that the startup is jammed due to vacuum, it would be very difficult to predict and solve.

Being an electronics engineer (and an armchair rocket scientist

) what I would suggest as the best thing to do is to instrument this thing do death with telemetry devices strong enough to withstand some re-entry (like a black box) and then hunt for the black box to figure out what went wrong.

This could be interim until we get a vacuum rocket test facility or a high altitude test bed.

vasu_ray · Post by **vasu_ray** » 17 Apr 2010 09:51

ahem...once they fix the cryo stage, would they be willing to put it on top of a PSLV in the payload fairing for flight testing since GSLV currently has a slower rate of production, like they used a sounding rocket for the scramjet

Sanjay M · Post by **Sanjay M** » 17 Apr 2010 09:58

Hmm, well, if you could get enough instrument data from just a few launches, then maybe it outweighs the cost of building a dedicated test facility.

I notice that ISRO still doesn't even mount any cameras aboard the launch vehicle, as is done with NASA, Roskosmos, ESA, and even SpaceX missions. So we landlubbers still never get to see anything.

Couldn't we just float an engine test rig up really high on a big balloon, or something?
At worst, we lose an engine and a balloon, and don't suffer a full $70M loss.
We could use the same method to test all kinds of spacebound equipment. Maybe could even do some astronaut training up there. They say that "Near Space" (upper atmosphere) is also a frontier worth investigating.

vina · Post by **vina** » 17 Apr 2010 10:03

simulation tools

Rather than build the 1960s type facilities, simulation is the way to go. Use Kompooters to do Sim-ooo-lashun. In this day and age, you can decently simulate right from basic physics this kind of stuff like ignition /start in vacuum pretty decently I think.

All you need to do is to throw some sweeteners and toffees to PIGS in the Madrassas and Science Madrassa and they can probably come up with something decent in 6 months .

Much cheaper and faster I think this facility with liquid hydrogen cooled walls and all the rest of it. Heck, they can do faster than the babus can acquire land to even build such a facility.

Sim-ooo-lashun will need no land, no permanent facility to operate, no babus, no clerks, use very little energy and cost a miniscule when compared to a 1960s style facility.

For "confirmation" of sim-ooo-lashun with reality, do one or two launches or go to Unkil or South of France or Freezing Russia to validate stuff and then you are all set to go!

Sanjay M · Post by **Sanjay M** » 17 Apr 2010 10:24

Here is an ESA facility for vacuum testing:

http://www.esa.int/esaCP/ESA5NUZK0TC_Expanding_0.html

I think they have various - another in Netherlands, etc.

If India were to build such ground facilities, then these could be rented out to other aspiring space powers, giving us more leverage against MTCR, etc.

It would be interesting to see how far computing can be taken to simulate real-world conditions like this case.

lakshmikanth · Post by **lakshmikanth** » 17 Apr 2010 10:32

There are many advantages we can gain from building a vacuum test facility. The main advantage would be experience gained in designing and operating a large vacuum chamber. This would be very important if we are going for manned mission (testing the space-walk suits or space stations) and also it would give us experience for building our own nuclear fusion reactors if say for example ITER succeeds.

Singha · Post by **Singha** » 17 Apr 2010 11:12

from Sanjay's link of the P4 test stand used to test upper atmosphere engines, it looks
like a small and compact building, with some part underground no doubt.

http://www.esa.int/esaCP/ESA5NUZK0TC_Ex ... l#subhead1

I doubt this cost $1b or even $500m to setup...my wild guess would be $10 mil for the
physical building and $90mil for the equipment.

there is a ISRO meeting in Triv tomorrow. hope the demand for such kit comes out of it
also and the PMO slaps around a few people to cough up the cash.

Arunkumar · Post by **Arunkumar** » 17 Apr 2010 11:32

Inspired by Gagan-ullah and based on notes posted by SSridhar, Vina, Disha and others in previous posts, this has been my understanding of a staged combustion engine.

SSridhar · Post by **SSridhar** » 17 Apr 2010 11:37

Learning from Failure - Edit in The Hindu