Payload to LEO: 8,000 kgThe powerful cryogenic stage of LVM3 enables it to place heavy payloads into Low Earth Orbits of 600 km altitude.
This is the general discussion (not any mission specific) thread for the launcher. Launcher specs, capabilities, upgrades everything goes here.Let me start with a puzzling spec on ISRO's new webpage for LVM3QuotePayload to LEO: 8,000 kgThe powerful cryogenic stage of LVM3 enables it to place heavy payloads into Low Earth Orbits of 600 km altitude.Seems very less! Even the earlier reports of 10,000 kg to LEO was considered less by some accounts. Or do they mean a sun synchronous 600 km orbit?
Quote from: johnxx9 on 12/20/2014 08:04 pmSeems very less! Even the earlier reports of 10,000 kg to LEO was considered less by some accounts. Or do they mean a sun synchronous 600 km orbit? 10 tonnes is to a 200 km x 45 deg orbit. Since the rocket (whatever it is really called) is supposed to lift 4 tonnes to GTO using a high-energy upper stage, it seems possible that 10 tonnes is about right for LEO. Titan 3C, a similarly sized rocket with "zero stage" solid boosters, but with more efficient core stage engines, could only lift about 12 tonnes to LEO. - Ed Kyle
Seems very less! Even the earlier reports of 10,000 kg to LEO was considered less by some accounts. Or do they mean a sun synchronous 600 km orbit?
It seems glaringly sloppy of ISRO to not keep absolute clarity on the name. Even on their own website, they refer to the same vehicle as both "GSLV Mark III" and "LVM 3" The ambiguity on even something as simple and basic as a name doesn't project ISRO in a positive way, and instead makes them look schizophrenic, or even cavalier and ad-hoc in their thinking. No other country's national space agency exhibits these kinds of eccentricities.
A few pretty basic questions in my mind. Considering that the planned Kerolox stage for LVM3 is ground-lit, what was the reason behind ISRO not making the current L-110 ground-lit too? Does the increase in propellant weight and dead stage weight negate any payload advantages of an additional 1600 kN thrust at lift off? Would the rocket be hauling too much of dead weight when S-200s have burned out? And, if these are indeed the reasons, would these problems be significantly lesser in the planned SC-160 Kerolox core? Due to higher Isp?
One straightforward configuration would have been to upgrade the GSLV, by replacing the solid 1st stage with a liquid one. All they would have needed to do is cluster 3/4 Vikas instead of the current 2 on LVM3 and put it on the first stage (not easy as it sounds, but still at first though sounds better than developing a whole new rocket). Seems pretty straightforward considering they had all the other stages as its from the GSLV.
I admit ISRO isn't alone here, but going by the success that Falcon 9 had so far, has ISRO's design philosophy for LVM3 and ULV already become obsolete? Or is it too early to say?
I'm quite intrigued by the difference in design philosophies of ISRO (and probably many old-school space agencies/enterprises) and SpaceX about what constitutes reliability and cost savings in a rocket design. For LVM3 and its successor ULV designs, ISRO has zeroed on less number of propulsion stages (but of different types - solid, liquid/kerolox, hydrolox) and use of massive solids as the key. While in case of Falcon 9 which has a similar payload capability and objective, SpaceX has chosen a design based on the use of more number of moderately powerful propulsion units of similar types, geared towards lowering costs through mass production and increasing the reliability through redundancy of numbers.
Isn't SpaceX itself moving away from this model? Their next gen methox Raptor engine will generate around 5-6 MN of thrust. I guess they will replace the 9 engine cluster with this single engine.
I'm quite intrigued by the difference in design philosophies of ISRO (and probably many old-school space agencies/enterprises) and SpaceX about what constitutes reliability and cost savings in a rocket design. For LVM3 and its successor ULV designs, ISRO has zeroed on less number of propulsion stages (but of different types - solid, liquid/kerolox, hydrolox) and use of massive solids as the key. While in case of Falcon 9 which has a similar payload capability and objective, SpaceX has chosen a design based on the use of more number of moderately powerful propulsion units of similar types, geared towards lowering costs through mass production and increasing the reliability through redundancy of numbers. Even considering the fact that ISRO is yet to develop a kerolox engine for its use, I feel the major driver in this difference of approach could be that one is a government agency that relies on public funding and is consequently not too worried about costs (as a private company would), while the other is a start-up private enterprise that *has to* aim for reduction in production costs to ensure its success and long term viability. I admit ISRO isn't alone here, but going by the success that Falcon 9 had so far, has ISRO's design philosophy for LVM3 and ULV already become obsolete? Or is it too early to say?Any thoughts?
Hangover @isro.org