
India Loses Contact with Probe Just as It Prepares to Land on Moon - Anon84
https://www.wsj.com/articles/india-loses-contact-with-probe-just-as-it-prepares-to-land-on-moon-11567805330?mod=rsswn
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dang
All: please don't take this thread, or any other HN thread, into nationalistic
flamewar. It breaks the site guidelines and is off topic here.

If your comment might contain flamebait, please edit it until it clearly
doesn't.

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abhiminator
Here's [1] a data graph of the Doppler curve from Dwingeloo Radio Telescope
(based in Netherlands) showing the exact moment the probe crashed into the
surface of the moon.

[https://twitter.com/cgbassa/status/1170072672266592256](https://twitter.com/cgbassa/status/1170072672266592256)

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mkagenius
I am confused, the contact with ISRO was lost at 2.1 km height (as per ISRO's
last night statement). So, not at 0 km height (crash) ?

Edit: I meant contact with ISRO..

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penagwin
This isn't contact per-say, the telescope wasn't in communication with the
probe, it was just watching it r.

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kappi
Latest update.. DSN did a carrier lock on lander

[https://twitter.com/dsn_status/status/1170391223040954368](https://twitter.com/dsn_status/status/1170391223040954368)

DSS 54 carrier lock on Chandrayaan-2 Lander Frequency: 2.2846GHz Signal
strength: -143dBm IDLE OFF 1 TURBO

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adt2bt
Can you explain in layman’s terms what this might mean?

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sandworm101
It means they are _trying to contact it_ using the most powerful antennas
available. It hasn't phoned home yet.

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JulianMorrison
Space is hard. I wish India all success in their next try.

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raverbashing
It seems it was supposed to be a polar landing, which should be harder (I
think) than landing from an equatorial arrival

Nonetheless, this is rocket science and failures are very common and not
unexpected. Too bad, but it happens.

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egdod
Why would landing from a polar orbit be harder?

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seer
I’m no expert but doing polar landing would involve a plane change maneuver
after you arrive in moon orbit (or some clever orbital mechanics to minimize
delta-v losses and somehow do it in a single burn (both capture and plane
change).

Apart from that, I’d presume theres also complexity of the landing site not
being directly visible from earth, necessitating re-transmissions from the
orbiter.

Not something that hasn’t been done before by any chance, but still harder
than say USSR’s lunokhod missions.

Though this is mostly coming from my Kerbal Space Program experience.

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kraetzin
In terms of orbital mechanics the polar orbit around the moon isn't
significantly more complicated than an equatorial one. A small midcourse
correction after entering a flight path towards the moon is all that's needed
to ensure capture into orbit around the poles (and a capture burn), without
the need for a plane change (note that this is also based on experience from
KSP).

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raverbashing
I see what you mean, though I'm not sure of all the details, you might want to
get into an equatorial orbit (there is an orbiter, though I'm not sure about
its orbit) just because the error margin is smaller (?) or for some other
reason.

(But then of course the moon is neither too far nor too big so I might just be
barking at the wrong tree here)

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kraetzin
As far as I can tell, the lunar orbiter itself is in a polar orbit, so it
would make sense that it entered orbit as such. In terms of complexity the
main part of the journey to the moon is the midcourse correction and ensuring
that the engines fire at the correct time, in the correct direction, and for a
certain duration. Depending on the engines used - ie. engines that can be used
mutliple times - more than one midcourse adjustement may have been possible.
It seems that all of these things worked out fine, since the Chandrayaan-2
orbiter has been there in a polar orbit since 20th of August [0]. The lander
seperated since then, and the loss of contact a few seconds before the
expected landing time implies that the lander reached the surface with a
velocity higher than expected.

[0][https://timesofindia.indiatimes.com/city/mangaluru/ISRO-
chie...](https://timesofindia.indiatimes.com/city/mangaluru/ISRO-chief-
signals-Indias-readiness-for-Chandrayaan-II-mission/articleshow/51178528.cms)

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happy-go-lucky
Latest update... looks like they've found the location of the lander on the
lunar surface, the orbiter has clicked a thermal image of the lander, and
they're trying to establish a contact with it.

Don't know how reliable this source is:

[https://twitter.com/ANI/status/1170610654232731648](https://twitter.com/ANI/status/1170610654232731648)

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plibither8
Edit: This is a fake account. My apologies.

From the ISRO Chief himself:
[https://twitter.com/KailasavadivooS/status/11706129755828879...](https://twitter.com/KailasavadivooS/status/1170612975582887937)

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happy-go-lucky
>
> [https://twitter.com/KailasavadivooS/status/11706129755828879...](https://twitter.com/KailasavadivooS/status/1170612975582887937)

It's a fake account :)

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plibither8
Thanks for pointing it out!

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brij0102
What do we think went wrong? I expect maths to be right but there was a
comment somewhere about the regolith with fine particles whose specific
composition could have caused unexpected dust clouds as the lander sped to the
ground ... how was this tech different from the other 3 successes?

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sandworm101
Those dust clouds, depending on particle size/composition, could start
reflecting radar. Lander then gets confused about its altitude and crashes.
This sort of thing makes some areas, the dusty flat ones, potentially more
dangerous than others. But they are also flatter and so you don't worry about
landing on a rock and tipping over. It's a judgement call.

~~~
brij0102
That would always be a problem though, right? So for unmanned moon landings,
do we instead need those inflated bouncy balls? Or did the previous successes
just got it right?

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meesterdude
This is a great thing for the people of India - I mean, hopefully.

The science we expel is a reflection of the cultures that created it. In
space, everyone has had failures. And I hope this failure offers reflection
and improvement and that they can grow from it.

But even still, this is otherwise part of a narrative change for the people of
india, and something "so simple" can have a huge impact on future generations
and what people tell themselves on an individual level.

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imtringued
This is a boring comment section. Only the top 40 comments are actually about
the space mission. 130 comments respond to the same parent about a world
government and the rest of the comments are flagged...

I personally am sad that this mission has failed. Exploring the permanently
shadowed craters of the moon is necessary to find whatever sliver of ice
remains on it. The satellite industry is growing but there is still no
economic case for going to the moon and this mission could have changed that.

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brentis
Unexpected condition.

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dragonsh
It's a good effort by ISRO and it's scientist. Just can't understand why so
many countries reinventing the wheels. Space missions should be multi-country
efforts continuously as it belongs to all. We should not extend our tribal
nationalistic thinking to space.

Best scientist can be in any nation and more diverse the group and experience
the better chances of success.

I know I am just dreaming, but hopefully we can come to consensus and try
challenges of space as a new frontier as a single human race, originating from
Africa.

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rayiner
No. We’re different groups of people with different interests, different
values, different ideas principles cultures histories views of the world. It’s
good for us to be competing to explore space (and in trying to develop
technological advantages in general). For countries like India it’s critical
to develop their own technologies on this front. Otherwise they’ll remain
eternally dependent on America, etc., for access to space.

A “single human race” would be a deeply dysfunctional, unworkable mega-
society. Our societies are already too big to be governable. (Ever notice how
in Star Trek, aside from token, curated, differences, trillions of people are
somehow almost completely culturally homogenous? That’s what makes the
federation governable. But it would never work that way in real life. There
would be intense conflict. The idea of a society that big being governable is
part of the science fiction.)

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nafey
Well let's revisit this statement in 500 years. Every decade has brought the
world closer. Even the recent developments (brexit, trump) are reactions to
increased pace of integration. You can find kfc, coca cola in socities as
diverse as Mongolia and Madagascar. It will be extremely difficult to turn the
clock back on this and this will only keep on intensifying in my opinion.

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coldtea
> _Every decade has brought the world closer._

Well,

(1) there are more sovereign nations now than ever,

(2) all the big empires (from Babylonian, to Alexander's, to Roman, to
Byzantium, to Persian, to Incas, all the way to the Ottoman, Austro-Hungarian,
British and French colonial empires, USSR, and more) -aside from the Chinese
and Indian who are more homogenous racially/culturally - have collapsed

(3) there is way more infighting that on any time in the previous 40 years

(4) nations that were held together for half a century as a single country
have nonetheless split at the first chance, often under fierce wars (e.g.
Yugoslavia), and even centuries old countries like Canada, Belgium, UK, Spain,
etc, still have infighting, and even votes to break up...

(5) a worsening of climate change and economy will more than likely see every-
nation-for-itself than some unity, even if there's a coordinated effort to
reduce emissions and so on, there will also be huge pressure to ascertain
certain resources, safety, etc at a country by country level (sharing is only
good for those that need it. For those that have the power to avoid it, or
even grab from others, it just gives you moral points)

> _You can find kfc, coca cola in societies as diverse as Mongolia and
> Madagascar._

Yeah, that's a huge cultural (and dietary) destruction...

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Razengan
> _aside from the Chinese and India_

Do you know how many different empires, rulers, internal wars and government
systems China and India have gone through in 2000 years, and how many "races"
and "cultures" they have?

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coldtea
> _Do you know how many different empires, rulers, internal wars and
> government systems China and India have gone through in 2000 years, and how
> many "races" and "cultures" they have?_

Yes. Still more homogeneous and stable than most other empires...

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Der_Einzige
Oh you mean like that time when the Mongol conquered and ruled china for like,
100+ years, ushering in the largest case of minority rule the world had ever
seen to that point.

[https://en.m.wikipedia.org/wiki/Yuan_dynasty](https://en.m.wikipedia.org/wiki/Yuan_dynasty)

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coldtea
I mean like that time when this was just an episode in millennia of history...

I also mean like that time when the eventual demise of most empires and huge
nations was my point, which China and India managed to avoid, and not China
and India themselves (which are totally orthogonal to the point I was making,
and in fact an exception to the rule I posited)

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agrippanux
Kudos to India for even trying. While they are trying to put a probe on the
moon, we have a President going through dementia arguing about a 2 week old
weather forecast.

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Mountain_Skies
What value do you think your comment added to the discussion?

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PeterStuer
Perspectives on evolution vs. devolution? But agreed, we are digressing.

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mieseratte
It’s a bit of a false dichotomy, really. It isn’t as if the US is behind on
accessing the moon or space in general.

Nothing more than distracting partisan virtue signaling.

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PeterStuer
I was commenting in the context of the original remark. fwiw, personally I'd
say the emperors are wearing no clothes on either side of the US polarized
partisan divide, but then again I don't think the rest of the world is far
behind and catching up fast in the race to the 'post truth' society.

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mieseratte
And I'm commenting in response to your remark on "devolution." There is none,
insofar as I can see. It's a pointless partisan jab not rooted in reality.

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PeterStuer
Well, we are talking forging weather maps with a sharpie, but I'll leave
everyone to draw their own conclusions (pun intended).

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nikhil5
I have spent many years in India, and I know that the poorest of its people do
not support these kinds of financial adventures (or in this case disasters)

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sbmthakur
Do all homeless people in developed countries support their respective
nation's space program?

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wtdata
Homeless people in developed countries, are in almost every case (perhaps with
the exception of the USA, I'm not sure) homeless due to mental issues and
because they don't want to go into community housing. They aren't homeless due
to a general lack of resources.

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newsgremlin
It's not always a lack of resources but access to resources. They need an
address, along with a long waiting list the accommodation they have access to
is shared, often with other homeless with said mental health issues. That
itself is a scary and a dangerous place to be, they are also targeted by drug
dealers that prey on any addictions, trying to get them addicted.

