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Chandrayaan-3 Soft-landing [video]

isro.gov.in

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Re: Chandrayaan-3 Soft-landing [video]

#451

Post by yencabulator »

itissid wrote: post #343

Congrats to all of the team at ISRO. Assuming the software development for these is non trivial; Its interesting that with the last mission(per Scott Manly) was designed to always select a spot(or more precisely a trajectory) and try hit it. What made them make that decision? Was it like "lets be as precise as we can because we want to get to the spot X because X is special" and thus "Lets let the software always com…

Complete wild-ass guess: safe landing spots are hard to find, they knew X to be a larger region safe to land in (so small errors wouldn't matter), and didn't at the time have the more complex subsystem to find safe landing spots (!= X) on the fly based on where the lander happens to go.

Re: Chandrayaan-3 Soft-landing [video]

#452

Post by nrb »

steno132 wrote: post #443

An embarrassing day for America. The country that first visited the Moon should have explored the lunar south pole decades ago. Then the dark side of the moon. Then a manned colony. Instead we are beaten by a foreign nation to the south pole. And our next project is a manned landing on the moon, which we already accomplished in the 1960s.

Great to see other countries making accomplishments in space, I don’t see a cause for embarrassment when we’re driving rovers and helicopters around on Mars.

Re: Chandrayaan-3 Soft-landing [video]

#453

Post by rst »

ansible wrote: post #152
m0llusk wrote: post #86

Earlier quoted context omitted.

If anything they seem to have overcorrected for this. This landing path stopped with a near hover at around 800m, then a prolonged hover at 150m while the lander scoped the situation, then an extremely slow descent that allowed for corrections the whole way down. Very impressive.

Yes, it was a very conservative landing trajectory. But it is very, very difficult to get a hoverslam right the first time, or the second, or the third... I did like seeing the live images captured during descent, I also hope those get made into a video and posted online. Looking forward to the rover deployment too.

This doesn't seem to have been a hoverslam, though -- the probe was hovering at, I think, 150 meters for quite some time, and then maintained a steady and slow rate of descent while still under power.

Re: Chandrayaan-3 Soft-landing [video]

#454

Post by nrb »

steno132 wrote: post #450
kpandit wrote: post #446

Earlier quoted context omitted.

We are doing now what you did half a century ago. How exactly is that embarrassing for you?

The US should have been to the first to the lunar south pole, not a foreign country.

“Here men from the planet Earth first set foot upon the Moon July 1969, A.D. We came in peace for all mankind”

To the moon, we’re all foreigners.

Re: Chandrayaan-3 Soft-landing [video]

#455

Post by steno132 »

nrb wrote: post #454
steno132 wrote: post #450

Earlier quoted context omitted.

The US should have been to the first to the lunar south pole, not a foreign country.

“Here men from the planet Earth first set foot upon the Moon July 1969, A.D. We came in peace for all mankind” To the moon, we’re all foreigners.

Humans don't view things from a moon perspective, they view things from a human perspective.

Space races are real, it's each country for itself, and it's a zero sum game. And today's not a good day.

Re: Chandrayaan-3 Soft-landing [video]

#456

Post by oaktowner »

raverbashing wrote: post #17
jvm___ wrote: post #12

Scott Manly has a video on why he thinks the last one failed. It sounds like their landing software didn't have "oh crap, we're way off course, just land wherever". It only had the happy path of "fly to here and land", so when it switched to the landing phase it tried valiently (including flying upside down) to try to fly back to the landing zone, but the landing zone was much further than fuel supplies allowed. Hope…

This applies to general software development but is especially true in this case While we think "this cannot ever happen" in a lot of cases it can, in ways you did not consider. Both for good and bad

While I worked at Google I once searched for "//this should never happen" in the code base.

It was in there.

A lot.

Re: Chandrayaan-3 Soft-landing [video]

#457

Post by itake »

gourabmi wrote: post #429
itissid wrote: post #343

Congrats to all of the team at ISRO. Assuming the software development for these is non trivial; Its interesting that with the last mission(per Scott Manly) was designed to always select a spot(or more precisely a trajectory) and try hit it. What made them make that decision? Was it like "lets be as precise as we can because we want to get to the spot X because X is special" and thus "Lets let the software always com…

If you understand Hindi, Gareeb Scientist has an amazing video about the landing algorithm issues of Chandrayaan-2 https://youtu.be/4oUdD_QSgRs

Is there a TLDW?

Re: Chandrayaan-3 Soft-landing [video]

#458

Post by alephnerd »

yumraj wrote: post #363
darkclouds wrote: post #322

Earlier quoted context omitted.

Here Here. It also ironic that a country and population seen as backwards by the British Empire have overtaken the British in landing on the moon. Would be nice to see the African and South American continent achieve a moon landing as well.

> It also ironic that a country and population seen as backwards by the British Empire have overtaken the British in landing on the moon. This is not the moment to go there, but still since we're on the topic, current leaders of Britain (Prime Minister), Ireland (Taoiseach) and Scotland (First Minister) are all of Indian-Subcontinent origin. Britain and Ireland have leaders of Indian origin, while Scotland has of Pak…

Sunak and Yousaf are both Punjabi, Sunak's family was from Gujranwala region in Pakistani Punjab before partition and Yousaf's is from Khanewal in Pakistani Punjab as well, plus both are the children of East African Indians who moved to the UK during the mass expulsion of South Asians in the 1960s and 70s (Freddie Mercury is also part of that community as well, though ethnically Parsi Gujarati). Also, they both attended elite Grammar Schools, so they were within the same Old Boys network.

They're much closer culturally than Varadkar who's dad's side of the family is from Konkan region (the coastal region stretching from Goa to Mumbai/Bombay)

Re: Chandrayaan-3 Soft-landing [video]

#459

Post by cpursley »

goku12 wrote: post #236
The_Colonel wrote: post #71

Earlier quoted context omitted.

Besides what others said, it gets extra spice from the fact Russia failed to do the same just days ago.

Russian space program is a shadow of what it once was. Their history is full of daring missions and extraordinary achievements. I wish they would engage in a space race than in a war.

American space program is a shadow of what it once was. Their history is full of daring missions and extraordinary achievements. I wish they would engage in a space race rather than constant illegal, brutal, destructive and absolutely unnecessary war.

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

Re: Chandrayaan-3 Soft-landing [video]

#460

Post by cpursley »

ironyman wrote: post #337
tjpnz wrote: post #297

Earlier quoted context omitted.

Might be time for China to reconsider its role with Russia in future manned moon missions. Any prestige the Russian program once had has long since faded, even ground operations at Baikonur are now at risk with equipment being impounded by bailiffs from Kazakhstan to service billions in debt.

Russia retains an (rapidly diminishing) edge in certain areas of space. One of them is engine design. China is still keen on buying the best Soviet engines, namely Energia's RD-170 and its variants but of course Russia is less than keen on parting ways with them. Even CALT, the major launch vehicle provider in China, admits it will be well into the late 2020s/early 2030s before they can get an engine as good as the R…

Not as "cool" as the SpaceX stuff, but Angara, Amur, Soyuz-5, Soyuz-7 are all in the works.
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