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Chandrayaan-3 Soft-landing [video]

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Re: Chandrayaan-3 Soft-landing [video]

#511
post #119

Earlier quoted context omitted.

Goonhilly, Hawaii, but I can't figure out BIK. They're NASA and ESA tracking stations: https://www.eoportal.org/other-space-activities/estrack , https://www.indiatoday.in/science/chandrayaan-3/story/how-is...

It's a station from DLR in Bishkek, Kyrgyzstan: https://www.dlr.de/eoc/en/desktopdefault.aspx/tabid-5287/102...

Confirmed: https://landsat.usgs.gov/historical-international-ground-sta...

Re: Chandrayaan-3 Soft-landing [video]

#512

It will be cool to send a buddy drone with these landers. A minute or so before the touch down, detach from lander and shoot the landing. Then go back and attach with lander for charging and do periodic flights.

Drone on Moon?

How will it fly? There is no atmosphere.

But yes, it’d be cool if it were possible.

Re: Chandrayaan-3 Soft-landing [video]

#513
post #164
post #119

Earlier quoted context omitted.

Goonhilly, Hawaii, but I can't figure out BIK. They're NASA and ESA tracking stations: https://www.eoportal.org/other-space-activities/estrack , https://www.indiatoday.in/science/chandrayaan-3/story/how-is...

If the other 2 are NASA and ESA the other BIK is probably a Russian one.

Likely Biak (Indonesia), from https://www.spacetechasia.com/isro-visits-indonesias-space-a...

“ISRO and LAPAN have had a long history of collaboration, with ISRO owning a ground station on the Indonesian island of Biak, which has supported many of India’s launches.”

Re: Chandrayaan-3 Soft-landing [video]

#514
post #415

Earlier quoted context omitted.

> No, he's just an elected representative of the people, a government servant. Yes. The elected leader is the boss of the executive branch of government. One doesn't negate the other.

PM is not the boss of the executive according to the constitution*. The fact that traditionally and more recently the President follows the whim of the PM does not negate the text that identifies the elected President as the head of the executive. * https://www.mea.gov.in/Images/pdf1/Part5.pdf

> identifies the elected President as the head of the executive.

Wrong. He is a "nominal head", or in other words, "in name only". The powers are vested in the Prime Minister not the President. So it does not make him the head of the executive. Read Article 53 (3)a of Indian Constitution which overrides 53(1) and resolves any ambiguity: https://indiankanoon.org/doc/1597349/

(3) Nothing in this article shall (a) be deemed to transfer to the President any functions conferred by any existing law on the Government of any State or other authority;

So the authority of Prime Minister, as defined by the Constitution, cannot be transferred to the President, even though he is a nominal head. This is as per 53 (3)a.

Article 74(1) further cements this: https://indiankanoon.org/doc/1951021/

"(1) There shall be a Council of Ministers with the Prime Minister at the head to aid and advise the President who shall, in the exercise of his functions, act in accordance with such advice: Provided that the President may require the council of Ministers to reconsider such advice, either generally or otherwise, and the President shall act in accordance with the advice tendered after such reconsideration"

Which means the President can only ask for advice (from PM + Council of Ministers) to be reconsidered, and after reconsideration, he still has to act on the advice. He cannot overrule it. Hence why a Bill can be passed by Parliament and sent back by President to be reconsidered only once. The second time the Bill is sent, the President is duty bound to assent else he can be impeached. The Prime Minister on the other hand cannot be impeached. The ruling Government can be brought down with a no-confidence motion or if enough members from ruling party defect. No other way to impeach a Prime Minister.

Also read Article 77:

77. (1) All executive action of the Government of India shall be expressed to be taken in the name of the President.

It is pretty clear that he has no "real" executive powers and is head in "name" only as the Government is taking actions in his name. The executive power rests with Government of India whose head is the Prime Minister.

It is also even more undermined by the fact that the President is not directly elected by the people (like in US where people vote for the President and representative votes are cast through their electoral college) but through an electoral college consisting of the elected representatives of the People. He has no real executive powers vested in him unlike the President of USA who can pass executive orders.

Tell me one executive order passed by President of India directly and unilaterally. There are none.

Re: Chandrayaan-3 Soft-landing [video]

#516
post #478
post #457

Earlier quoted context omitted.

Is there a TLDW?

IIUC, the salient points are: - target area was very small (500m x 500m) for CY2. With CY3 they've made it bigger at 4km x 4km, allows for larger margin of error. - CY2 lander had limited leeway in fixing issues, by design. CY3 has more and has landed itself, no assistance from base. - CY2 lander had limited time to fix itself, apparently it was just a few seconds short of making it fine

+ Software limited the upper limits of thrust correction/per second to 10% of what was possible.

In other words, it could perhaps correct itself in those many seconds but was allowed only small degrees of change.

Re: Chandrayaan-3 Soft-landing [video]

#517

Earlier quoted context omitted.

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.

That might still be OK if that path literally should never happen in normal operation, but us used, e.g., to handle an error, or at least log it, if the impossible happens because the software is deployed in some unexpected configuration

Re: Chandrayaan-3 Soft-landing [video]

#518
post #359

Earlier quoted context omitted.

Agree. The quicker russians will get rid of putin infestation the sooner this disgrace will end.

[flagged]

Nationalistic flamewar will get you banned here, regardless of which country you have a problem with. No more of this please.

https://news.ycombinator.com/newsguidelines.html

Re: Chandrayaan-3 Soft-landing [video]

#519
post #413

Earlier quoted context omitted.

Though you've no interest in space exploration you qualify to pass judgement on how inflated a space exploration related post, how?

Because what I'm mentioning is a phenomenon that occurs in all Indian-related submissions regardless of content.

Because you're racist, actually.

Re: Chandrayaan-3 Soft-landing [video]

#520
post #86
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…

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.

Possibly the lander had a choice to be more careful/picky if the remaining fuel permitted. (Just as Armstrong did.)
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