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Chandrayaan-3 Soft-landing [video]

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Re: Chandrayaan-3 Soft-landing [video]

#261

Post by granularity »

pyeri wrote: post #242
dotnet00 wrote: post #188

Earlier quoted context omitted.

Unfortunately all the national space agencies seem to suffer from this. Both NASA and ESA also seem to think that people are tuning in to watch the smarmy politician talk rather than the robot making its way to space/landing on another body. Had the same issue with JWST for example.

On the other hand, political speeches on such occasions go down as most remembered historically. The infamous quote "One small step for man, one giant leap for mankind." was obviously said by some politician! (or at least with non-technical motives)

Here's the actual story about that quote: https://en.wikipedia.org/wiki/Neil_Armstrong#First_Moon_walk

Re: Chandrayaan-3 Soft-landing [video]

#262

Post by goku12 »

Rygian wrote: post #227
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…

That's an example of failing to follow the "Aviate, Navigate, Communicate" rule of thumb.

Could you elaborate how that applies here? Communication is out of the question - there's nothing the people on the ground can correct. And the lander apparently failed because it tried to navigate its way back to the designated landing site.

Re: Chandrayaan-3 Soft-landing [video]

#264

Post by DiggyJohnson »

dotnet00 wrote: post #188
whoknowswhat11 wrote: post #106

Earlier quoted context omitted.

Why such a long political speech and no views from onboard camera?

Unfortunately all the national space agencies seem to suffer from this. Both NASA and ESA also seem to think that people are tuning in to watch the smarmy politician talk rather than the robot making its way to space/landing on another body. Had the same issue with JWST for example.

It's also because these agencies are reliant of politicians and government institutions for funding. So there is a balance between "showing what the public actually cares about" and "keeping this guy happy so we can keep up funding / congressional support / etc."

Re: Chandrayaan-3 Soft-landing [video]

#268

Post by luminati »

veave wrote: post #221
abhayhegde wrote: post #210

Earlier quoted context omitted.

So the mission alone is unimpressive in your opinion? If you were to weed out who did this and only focus on the what, would you not have an inch of wonder and applaud the efforts?

That's not what my comment says. Personally I don't know how impressive or unimpressive the mission is since I am not interested in space exploration and I know almost nothing about it.

You know nothing about space exploration and yet you were compelled to post your earlier drivel?

Re: Chandrayaan-3 Soft-landing [video]

#269

Post by numpad0 »

The_Colonel wrote: post #58
delta_p_delta_x wrote: post #38

Earlier quoted context omitted.

> seems like such a gross omission. Almost all space mission code only ever has the so-called 'happy path'. We rely on extremely tight mechanical and aerospace engineering tolerances to achieve that happy path. The Hubble Space Telescope's primary mirror grinding was off by a matter of micrometres, and resulted in blurry images. Consider all the Mars rovers. Imagine some wind gust threw the descending module off cour…

When saying "we", do you mean you write code for the space missions? Writing only happy path code as a standard practice in the space sector seems quite absurd. You won't ever achieve absolute precision and errors do happen, yet it seems like systems recover most of the time. Recently, the antenna of Voyager 2 got misaligned, but it is expected to recover from that. That was only the last problem it encountered over…

Trying to hand roll a super robust AI software usually backfires. Emergency mode triggers right in the middle of the happy path and ruins your uh, a day if you're lucky. They know that, even I kinda know that.

Re: Chandrayaan-3 Soft-landing [video]

#270

Post by Zigurd »

hoseja wrote: post #126
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.

Also incredibly inefficient.

This is one reason why low cost and efficiency are just a nice-to-have when it comes to to space exploration. Moreso the farther you go. A unique mission like a lunar polar landing should be conservatively engineered, where that is possible, on the first try. Early optimization and space exploration don't mix.
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