India fails to re-establish communication with its Moon probe | Hacker News Reader

India fails to re-establish communication with its Moon probe

efe.com

170 pointsthunderbong89 comments

If I understand correctly, this was the expected and most likely outcome. The planned lifespan of the lander and rover was only 14 days.

Yes, probability of it surviving 14 days in Lunar Night at -200C was extremely low. India doesn't have Radioisotope batteries that work at this temp. It will also increase the payload size and will require larger launch infra. Not to mention all the material and chemical challenges faced at these temp.

That seems like an obvious opportunity for diplomatic and scientific outreach and partnership. Did India want this project to be entirely homegrown?

"Did India want this project to be entirely homegrown?"

I suspect so and I also think that if you are going to test your skills, then being realistic in the first place is good idea. The mission was always sold as unlikely to survive the night but that would be a nice to have if it did.

For me the mission seems to have worked rather well and performed exactly as billed.

Not entirely. There were plans for international cooperation for the missions (with Russia IIRC). However, it didn't go through. Anyway, future collaborations are planned - probably with Japan first.

Has any country exported an RTG to be shot into space by someone else?

Vertically-integrating it yourself is one thing, but I'd expect NASA exporting a chunk of plutonium to India, even if they're both are nuclear states, would be challenging.

the US supplies nuclear weapons to partner countries and keeps them in US custody and guard while on foreign soil. I suspect the same kind of agreement would be in place with an RTG until launched.

Yep, everyone knew that making it through the lunar night was pretty unlikely. A successful landing was always the main goal.

Russia attempted something similar with Luna-25. When they failed, their top rocket scientist suddenly died. The ISRO deserved more recognition for their success, IMO.

Agreed, it's an impressive accomplishment, especially on the very limited budget they had to work with.

Russia sent the first man to space as an underdog. A country with a population of 1.5 billion only now sent something to the moon.

You cannot compare these.

Coincidentally, Russia also sent the first dog into space, as an Untermensch, if you will.

Did they say it beforehand? That's the only way one gets credit. Saying afterward, 'we planned it that way', is too easy.

The Mission Life was stated as one lunar daylight period (14 earth days) well before the launch. You can see this in the Wikipedia article [1] and in the citation for it. So yes, it was stated beforehand.

[1]: https://en.m.wikipedia.org/wiki/Chandrayaan-3

Wikipedia definitely doesn't count! :D But I'll trust you on the citation.

"However, there was uncertainty about the possibility of these to resume functioning after facing extremely low temperatures of the lunar night which can go as low as -200 degrees Celsius.

Moreover, its battery needed to remain at a certain level to be able to recharge again with the solar dawn."

Naive guy would think that alone can and would be extensively tested on earth?

> Naive guy would think that alone can and would be extensively tested on earth?

The article says the probe achieved its objectives in the first active period. This attempted wakeup was for bonus time.

And it would have been designed to achieve all those objectives in the 14-day lunar sunshine period.

You could design a car that runs for a billion miles, but no-one could afford it. You pick a reasonable lifespan for a project and target your specifications around that.

Ya, and the Indian mission was already one of the lowest budget successful missions there has been. The US is one of the few countries that can spend billions on missions where the lander may last months/years longer than expected.

We probably found it cheaper to build it, send it, test it than build a lab to get to -200°c :)

I too like to live dangerously and test in production

Hopefully you never get to peek behind the scenes of much of the world's running infrastructure.

You have to build the thing and test every possible problem before you build it again and do it for real

We all know everyone is perfectly willing to pay and wait for thorough testing so it works perfectly

Nobody would ever underfund something and then complain about how the final product didn't produce 150% of what was promised

Everyone tests in production. Some people also have additional environments to test in.

And yet the lunar lander and the astronauts on the moon did just fine. Did the lunar lander and the body suits have heaters?

They did, but they also left before the lunar night.

The humans inside the suits and lander also provided some useful heat. For most spacecraft, once you put humans into them the problem changes from conserving heat to getting rid of it.

Ok so at 120 degrees C got it

Kinda crazy what effect different albedos have, isn’t it? :)

If you haven't already, I would highly recommend watching 'Apollo 13'[1]. On a technical basis it is really accurate to the real-life events. The astronauts having to shut down the lunar lander's (LEM) heating system comes into the story about half way through. It's one of my all-time favourite films!

[1]: https://www.imdb.com/title/tt0112384/

Or, if you want to be a purist, there's this. [0](thank you whoever submitted this to HN a while back!)

[0] - https://apolloinrealtime.org/13/

Wow, that's amazing. I'm know what I'm going to be doing on Sunday!

They didn't last 14 days or try to survive the lunar night, and we spent a rather large % of our GDP on the project, while India's landing was an order of magnitude cheaper than any previous moon lander.

At least they've sucessfully got a probe onto the Moon, as opposed to Russia who poisoned their lead scientist with mushrooms after it failed to do so.

Interesting. Is there a source for this claim?

Yes, plenty. This one has the tone of The Onion.

"Professor Vitaly Melnikov, 77, who had headed the Department of Rocket and Space Systems at RSC Energia, Moscow's leading spacecraft manufacturer, had been battling a sudden and grave illness before his death. The source of his poisoning was inedible mushrooms, Moskovsky Komsomolets, a Moscow newspaper reported."

It's strange to me that the only footage released has been low res/low frame rate. It seems like a significant oversight to neglect to include cameras that can take, store, and transmit high quality video. Anyone have any links to footage I might have missed?

I'm pretty sure that camera isn't the problem. It's the bandwidth of the radio uplink. That's limited primarily by the power budget.

There has been other probes that continued to operate over multiple lunar cycles, how did they manage?

JPL and whoever's behind engineering for the ESA have decades of experience on the Indian space program.

I believe the approach is to shut down all nonessentials and run a heater to keep the battery above failure level during the night. This sounds simple but I'm pretty sure it's an absolute nightmare to design autonomous systems for, especially when you've only encountered those situations theoretically or in a controlled lab environment.

Space is hard. It hates us. It hates life. It hates any form of order and will actively attempt to destroy it. Trying to make things that survive in space is Difficult. It would have been easy to go "Lol india amirite", but the fact is, this is one of the hardest things humanity can do.

> This sounds simple

Especially for someone who never experienced anything lower than -5°C. Most cars wouldn't even start at -20°C if not equipped with a more powerful generator and battery from the factory. This is measly 20° difference.

It got below 0F a couple years ago and my garage door wouldn't open.

-200C in a vacuum is an entirely-different engineering paradigm as I understand it. Materials just don't behave the way we expect at regular temp/pressure.

There was a whole writeup (on here, IIRC) about the engineering behind the only (or one of less than a handful) types of planes that can transit Antarctica during the cold, dark months.

The fuel freezes, the oil freezes, the rubber in the tires and gaskets becomes brittle, and basically nothing normal works. I recall it being similar-but-different to the SR71 modifications, where the parts are loose and continuously leaks fluids because the materials all change shapes so much in the environment they're designed for. And of course it all has to return to the initial state for (a safe) landing.

The Concorde would get something like a foot longer at speed due to the expansion of the fuselage.

Stupid question, and maybe I should have web searched for it, but why did the fuselage expend? Something to do with the heat generated by the high speed and hence by the high friction?

https://www.flickr.com/photos/anachrocomputer/1829622910/

https://duckduckgo.com/?q=site%253Areddit.com+concorde+pilot...

I made the mistake of going splitboarding in the backcountry a few years back in -20°C with -40°C windchill.

Going up the mountain was surprisingly fine. I even had taken off both my jackets and was just wearing thermals as the heat I was generating working to go uphill was enough to keep me comfortable.

Unfortunately when we reached the top, we also ended up directly in the wind with no available cover. Within the ten minutes it took to put my jackets back on and transition to go downhill, I was nearly hypothermic. I couldn’t even operate my fingers enough to bring the idiot-proof magnetic clasp on my helmet together. The whole group was on the verge of panic to get off the top of that ridge. If we’d stayed there five more minutes, I’m not confident we would have made it back home that day.

I can’t fully express how obscenely, unconscionably, and incomparably cold that was. I have never felt anything like it and I hope never to again.

I once encountered -30°F one winter in Fairbanks. I visited a hot spring where, for some cruel and unusual reason, the facility was designed so you needed to walk about 10 meters out of the (well heated) building to get to the water. And of course, you would do this walk in nothing but just your bathing suit. That was the longest 10m walk of my life.

The cherry on the cake of the experience was that you get into water that is 70+°F but every part of your body above the water line is exposed to -30°F winds. Fun!

Where I grew up, each winter there were a few days that started at -30-40°C. Walking is not too bad (in the squeaky snow) because usually there's NO wind. Cars usually had (plug-in engine-coolant) 'tank heaters' and battery trickle-chargers to keep engines startable.

But there were plenty of snowmobile riders in the area. Some of them who bundled up and attempted to ride at these temperatures learned that their lungs did not work well after a short time.

Living in Ulaanbaatar Mongolia for some time I experienced temperatures of -20 -30 -40 Celsius. Every ten degrees lower I thought it was going to be the same, but was I wrong.

My most notable discovery was when I wanted to jump start my car, because the battery died due to the cold. I was about to bring out my jumper cables when my local friend told me to bring the cables inside first.

I didn't understand why and naively ignored what he said only for the rubber jumper cables to literally crumble in my hand, breaking as I tried to straighten them.

Mongolians are so resilient and have so much knowledge on how to survive in extreme weathers with a simple yurt and a livestock of 100 sheep goats and horses.

Most modern cars will happily start at -20°C and many will start at -30°C without any special additions (don't ask me how I know, you just need to know what you are doing). Of course it's not -200°C, but one thing to remember is that there is no temperature in the vacuum. The temperature of the Lunar surface is not it. An object without heating can easily reach lower temperatures there, yet it may not be that hard to keep that object warm as e.g. somewhere in the Arctic as there is no conductivity, only the radiation heat transfer.

> Most modern cars will happily start at -20°C and many will start at -30°C without any special additions

A couple years ago temps here went below -25° and there were a lot of cars which didn't go nowhere. Sure, some of them just had a battery too low from the usual urban minimal distance travel, but I heard enough rants from and about people who was forced to abandon their car and use the public transport or taxi. Diesels without an engine heater were among them.

> don't ask me how I know, you just need to know what you are doing

Ye, have an 'offline' (lol) charger for your car battery or have a 'kick-starter' kit. The thing is what the cars sold here are prepared for the winter conditions, yet many of them failed at a slightly lower temps - which again shows how a mere 5° difference can be way too much even for things what work otherwise just fine.

People just don't care about their vehicles, that's why. There are multiple examples of even diesels starting at -25°C without heating. All my cars have been gas and while starting them at -30°C required some magical actions (like turning on headlights briefly to warm the battery up or depressing the clutch if you have a manual transmission) they all started most of the time. No extra tools or devices were necessary.

> or depressing the clutch if you have a manual transmission

What exactly does depressing the clutch do as compared to not doing it and starting the vehicle in neutral? Is it to reduce the engine load further? Or something else?

Standard gear box oil is 80W90, which at -30C (even at -20C) turns into a thick jelly. Even in neutral starter has to move gears in that jelly. So normally you don't want to release the clutch until engine is warm enough and stable, and even when you do release it (in neutral) you do it slowly, sometimes in multiple attempts to avoid engine stalling, like starting on a steep hill. I haven't tried automatic at those temperatures, but ATF is much less viscous, so it should be much easier on the starter at low RPM.

> It hates any form of order and will actively attempt to destroy it.

If you are talking about ever increasing entropy, it applies to any environment. But keep in mind that the Moon itself is a manifestation of order. If it hadn't been the case we would have been observing a cloud of dust and gas where our Solar system is.

Oil and water separating into layers when mixed also looks orderly, but is in fact the higher entropy state https://physics.stackexchange.com/questions/111955/homemade-...

Yes, entropy increases in the salad dressing, but only when it's insulated (in reality we can't consider salad dressing outside of the Earth gravitational field, but let's say the Earth is insulated too). Now imagine that the extra energy (i.e. generated heat) has dissipated (either out of a window or, if we consider the Earth too, into the space). Is it still an increase of entropy? Our Solar system is not a closed system, the extra heat that was generated by creation of planets has dissipated (and is continuing to do so). So in the end the entropy of the Solar system is lower, i.e. we have more order, at least in our vicinity. Possibly in the whole universe since it's (presumably) expanding. Anyway, I wouldn't apply 2nd law of thermodynamics to the whole universe, we have no idea what happens at that scale.

Cosmic radiation hates electronics. Vacuum is inexorable.

By having some source of heat, for example, while the Chinese rover from a few years ago was solar powered, it had a radioisotope heater which used the heat produced by some plutonium-238 to keep the electronics warm enough to survive the night.

They use RTGs[1] as the power and heat source, I think CY3 was just solar powered and did not have thermal protection you get from RTGs for electronics.

[1]https://en.m.wikipedia.org/wiki/Radioisotope_thermoelectric_...

They are still working on RTGs. https://www.thehindubusinessline.com/economy/isro-barc-join-...

Above was paywalled, check this https://www.reddit.com/r/ISRO/comments/151j6zw/isro_barc_joi...

By spending massive amounts of money.

Few factors -

1. Design goals. The program had a budget, and with that budget their goal was a 14 day target. Anything extra is icing on the cake. They could have used an RTG to ensure long term survival, but it would have exploded their budget.

2. If I remember correctly the probe is in the south pole of the moon. Most probes are closer to the equator. The poles get colder and I think in some circumstances have more night time

3. Experience. This is their first successful moon probe. Now they understand the parameters better, so maybe next one will do better?

I mean Reliance Jio (India's most popular cell phone plan) is great for how cheap it is, but it has its limits!

Kind of off-topic: first time I see a efe.com link, looked it up in Wikipedia and surprisingly it's "the world's fourth largest wire service after the Associated Press, Reuters, and Agence France-Presse ... created in 1939"

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

Just four posts were submitted to HN: https://news.ycombinator.com/from?site=efe.com

> the major multimedia news agency in the Spanish language

That's probably why.

Seems about right, two English speaking, one French, one Spanish.

The legacy of empire.

Blame Canada.

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