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Posted by sohkamyung 4 days ago

India's first privately-developed rocket reaches orbit on dramatic debut launch(arstechnica.com)
377 points | 108 commentspage 2
ColdStream 4 days ago|
Fantastic news! Always good to see others manage achieve great things.
vjsrinivas 7 hours ago||
India's space work often went under the radar. Im glad they're getting the success and attention they deserve.
ghm2199 6 hours ago||
A small but bright light in an economy where manufacturing jobs are hard to come by (https://archive.ph/Haj8n).
dyauspitr 1 hour ago|
It’s a strange place. They’re building out expressways and railways at a breathtaking pace (something like an entire Switzerland’s worth of new track every year), are simultaneously building out multiple nuclear reactors, exports and manufacturing are shooting up, but the cities still look like shit.
adithyareddy 53 minutes ago|||
What you see in Indian cities is a result of multiple factors (like everything):

- Low GDP per-capita, offset by immense scale, which means the central government can mobilize massive resources for national projects, but municipal bodies are financially starved (municipal revenues in India are < 1% of total tax collections, for context it's 6% in South Africa and 10% in Brazil). Cities are completely dependent on the state for money, unlike countries where cities control their own property and commercial taxes, so they raise very little on their own, and states have multiple other priorities so cities never get as much money as they need.

- Leading off the previous point - executive power over cities is very fragmented, most authority rests with state chief ministers and state-appointed bureaucrats rather than empowered local mayors, so city planning is subordinate to state-level political priorities. City management itself is divided among uncoordinated state-level bodies (separate agencies for roads, water, power, and transit). There's a lot of accountability voids where something goes wrong and everybody thinks it's a different body's responsibility. The poor coordination also means you'll have things like a road laid on Monday, and on Wednesday the water authority digs it up to fix pipes underneath.

- The Indian constitution guarantees freedom to move and reside anywhere, so it's not legally possible to control rural to urban migration like China did with its Hukou system. E.g. Bangalore adds anywhere from 350k to 600k people a year almost entirely from internal migration. Much faster than housing, transit, and civic utilities can keep up with.

Things are getting better, although slowly and unevenly:

- Mass transit is expanding rapidly

- Door-to-door solid waste collection now reaches roughly 98% of urban wards (tougher than you would think because the unrestricted migration tends to create a lot of ad-hoc unplanned settlements on the outer parts of cities)

- The central government is working on allowing cities to issue municipal bonds to raise their own funds.

- Bangalore now (as of last year) has a single body called the Greater Bangalore Authority that has statutory oversight over previously uncoordinated agencies that handle water, transport, power, transit etc. Other state governments with major cities are watching to see how it plays out, and will likely copy + adapt it to their own major cities based on how it goes.

blueblisters 1 hour ago|||
India thrives in high tech sectors that are ironically export controlled by the rest of the world. That’s the primary reason the talent in those domains stays back.

As for the rest of India, you can largely find the root causes of problems by tracing adverse selection effects among the elites that do remain, massive, conflicting vested interests and decades of horrible, incompetent policymaking.

ambicapter 7 hours ago||
4 stages feels like a lot of added complexity for your first launch. I assume it gives you more performance margin to drop weight/stages more often?
MobiusHorizons 6 hours ago||
4 stages is certainly a lot more than most rockets, but most rockets don’t use solid rocket stages. Solid rocket motors are generally much more reliable/ simpler than liquid fueled stages, but they can’t be throttled or turned off early which makes it hard to achieve precise orbits. My guess is the extra stages allow for better control by carefully choosing when to light the next stage. The scout family of rockets are also 4 stage solid rockets and probably a good comparison.
ggreer 5 hours ago|||
Solid motors are simpler, but I wouldn't say they're more reliable. It was the solid booster failure that caused the Challenger disaster, and solid booster failures that have caused ULA's Vulcan Centaur rocket to be grounded. As you say, solids can't be throttled or turned off easily. They also can't be test fired. Yes, you can static fire a solid rocket and reuse the housing/nozzle/etc, but solids often fail due to imperfections in the propellant. Pockets of air or fractures in the propellant can cause a sudden increase in propellant surface area, which then generates more pressure, potentially blowing up the booster. With a liquid rocket, the engine can shut down if there's an anomaly. But with a solid, there's no option but to let the reaction continue.

There's also the issue that a solid booster must be "fueled" before it reaches the pad, meaning you have ground crew working around a large quantity of explosive material. A Brazilian solid rocket exploded on the launch pad, killing 21 people.[1] Liquid rockets can be made inert until everyone is far away, then loaded with propellant.

A big advantage of solid rockets is that they can be stored for long periods and quickly launched. This is handy for use cases like ICBMs, but not particularly important for commercial launches.

1. https://en.wikipedia.org/wiki/VLS-1_V03

londons_explore 6 hours ago|||
Don't you need at least a little thrust ~40 mins later to circularize the orbit?

Obviously solid rockets can't be relit.

Could that be the use of the 4th stage?

numpad0 5 hours ago|||
Rockets are usually two-staged + satellites. The booster take it to outside of the atmosphere, then the upper stage puts it into a ballistic trajectory, and the payload does the circularization burn 45 minutes or so after the liftoff at the peak of the parabola.

Above is the basic semantics, and it can be further optimized, such as by extending battery power for the second stage to use it for circularization, inserting a single purpose satellite-like pusher device above the responsibility boundary at the top of second stage and payload satellite and calling it the third stage, or just adding actual third stage above second stage, etc.

Adding more and more stages improve performance per Konstantin Tsiolkovsky's rocket equation, but it'll add risk factors and also obviously add more dead weights in electronics and engines and support equipment, so 2-3 stages is usually the good balance between performance and risk/costs. You can have as many stages as you want if you think you can handle it.

MobiusHorizons 2 hours ago|||
> Rockets are usually two-staged + satellites.

I think that only applies to liquid fueled rockets. At a minimum the Scout family of rockets (USA) and the Lambda 4s (Japan) both use 4 stages. That is what I was trying to say above. The sibling comment also points out that you at least need a third stage to circularize the orbit, since you can't re-light solid rocket motors. I'm not exactly clear on why its 4 and not 3, but that seems to be the standard with solid fueled rockets.

numpad0 2 hours ago||
I think it's for maneuvering. At least L-4S seemed to have had 3rd for the pitchover and 4th for the apogee kick. The first two were spin stabilized and unguided for political reasons. "Payload" stages built more like satellites are better suited for precise guidance.

(ISAS side of Japanese space programs is chock full of political BS, everything from the pencil rocket that continued on from IJN rocket researches to the "unguided" L-4S to the LUNAR-A probe with diameter of approximately 152-155mm to one-man laptop launchable Epsilon LV concept focusing on "civilian low-cost rapid launch demands")

walrus01 4 hours ago|||
One example of a typical liquid fueled small third stage would be:

https://en.wikipedia.org/wiki/Fregat

MobiusHorizons 6 hours ago|||
Good point! The final stage being liquid would also give them more control to fix any errors with the orbit.
walrus01 7 hours ago|||
It's three solid rocket boosters stacked on top of each other and a very tiny liquid fueled engine on the 4th stage. I would be interested in what the delta/v stats/capability of the 4th stage booster are with 350 kg payload.
wat10000 6 hours ago||
A partially empty stage wastes mass on propellant tanks sized for the full load. The mathematical ideal would be an infinite number of infinitesimally small stages.
londons_explore 6 hours ago||
Except you pay the weight for the nozzles on each stage.

That makes there be a mathematically optimal number.

andsoitis 6 hours ago||
Congratulations!
anon291 5 hours ago||
India desperately needs more r&d and advanced manufacturing. Good for them; congrats to the team
Ari_Ugwu 5 hours ago||
I have an AI generated podcast that tries to unearth some of the negative spin that develops around these amazing achievements. No surprise there was a spike in misinformation this week and I’m sure there will be more to come.

It can be hard when you are blindsided by negativity that seems to come out of nowhere. Hopefully this is helpful to us all https://rss.com/podcasts/the-narrative-networks-podcast/3017...

ck2 4 hours ago||
btw recently discovered this neat website that shows ALL upcoming rocket launches

* https://nextspaceflight.com/launches/details/8033/

* https://nextspaceflight.com/launches/

shevy-java 4 hours ago|
It's so sad that the Modi clique controls India. If India could become a real democracy, it could be competitive in the long run against China, because assuming similar quality and costs, people in democracies would much rather support a democracy than sinomarxist China or crazy-oligarch orange king country. But with Modi in charge, none of that is possible. Old men really need to leave politics, they just cause too many problems in general.
throwaway7783 2 hours ago|
I haven't followed Indian politics in a while, but I don't understand the "real democracy" comment. Can you elaborate on this? Or is it because Modi won three elections in a row?
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