Bharat Rakshak

juvva

Japan's SLIM lander has managed to survive the cold lunar night, even though our lander could not https://www.youtube.com/watch?v=Ac8PKjYWKv4 I'd really like to know what they did better, to make this possible landed at a latitude north of cy3 landing site, night temperature a little more moderate ...

juvva

arvin wrote: ↑06 Dec 2023 19:27

Although orbiting earth, looks like apogee of PM is quite close to Moon's SoI (Sphere of influence).
Interesting they didnt bring it close to earth.

could be due to limited fuel left in pm.

juvva

JTull wrote: ↑19 Oct 2023 15:55 I hope it's a clear day and we get some great videos of the abort test. Recent Russian abort video was amazing.

any link to the video please?

juvva

https://youtu.be/QtsCwdsK0XM?feature=shared

not to be missed , a treasure trove of details explained in simple language, by THE experts.

juvva

are you sure ?, saw some (subsequent?) posts from scott indicating signal is sideband of lro, hence a false alarm.

juvva

what is this trace ? (ground trace ?)

no one was concerned about the deviation during landing or post landing.

juvva

is this real time? if so which orbiter ?

Amber G. wrote: ↑21 Sep 2023 08:03 It is September 21, 2023 (UTC- 00) -- All quiet.

Probably it is programmed so that when it wakes up and gets command from ISRO it may start sending back its radio transmission...

juvva

SriKumar wrote: ↑21 Sep 2023 08:46 They said Pragyan (or Vikram) was tested for cold temperatures. I assume it must have been soaked in liquid nitrogen or something colder. Both have to survive.

not the flight model, for sure.

juvva

same would be the case with L2 , when the moon is on the sunward side of earth ?
am i missing something here ?

added later:

ok i think i got it, it is the L2 point of the earth-moon system, not L2 point of the sun-earth system.

juvva

is it possible to use aditya l1 as a radio relay for any future indian lander missions to the far side of the moon ?

juvva

wouldn't the apparent size of earth be greater than the apparent size of sun as seen from moon?

juvva

^ lunar eclipse at 0:35 s ??

juvva

---- I wonder if the slight repositioning helped with slight inclination/orientation to sun or earth.. The pics look nice ! And @calculating thrust to lift off from the moon - I doubt that this was particularly relevant.. for the actual calculations.. does not look like any significant orientation ...

juvva

did not know that the ramp could be folded back and the science payloads pulled up back in.

what a detailed far sighted design !!!! and a very robust hardware !!!!

juvva

Vikram soft-landed again! https://twitter.com/isro/status/1698570774385205621?t=NahcNIZWvh9syahBc5l6mg&s=19 Did we know this was planned? Wow! What a nice surprise. :D :D :D looks like considerable dust was kicked up, but it seemed to settle down quiet fast. or was it mostly thruster fumes and ...

juvva

Thanks, I got the saddle point analogy. So moving away in certain directions results in a restoring force, but in other directions, it tends to pull the object away. Orbiting a gravitational well like the earth or the moon, I guess one can just keep track of altitude from the surface (or center) of...

juvva

looks like aditya will have quiet a few neighbours, should isro be wary of close encounters?

juvva

phew !!!!! how i wish dd doesn't leave us in the dark on tenterhooks in the middle of a mission, the discussion could have waited...

that to on a day on which dilbu has taken day off.

juvva

cy3 gallery (so far):

https://www.isro.gov.in/chandrayaan3_gallery.html

juvva

https://www.isro.gov.in/media_isro/vide ... scope.webm

APXS in action, as seen by lander.

juvva

assuming depth is measured in positive units ( more deeper greater the positive number ) , any explanation on why temperature increases with depth ?

juvva

^^not sure if some international body like iaea needs to be informed and kept in loop.

juvva

Ye to kaam karna chalu kiya !!! https://twitter.com/isro/status/1695725102166671448/photo/1 Why would the temperature increase above the lunar surface relative to the surface. The heat on moon surface is entirely due to the solar radiation absorbed by the moon surface. I guess the above-the-surface...

juvva

According to people quoting people quoting other people, Team ISRO have tried taking pics using both lander and rover. One of the problems with taking pics from the rover is that the partial shadowing of the rover is causing optical effects. So turning the rover toward better angles is required, bu...

juvva

did isro say explicitly at any time that vikram landed in nominal orientation?

juvva

Obviously this is guesswork based on pictures, but all pictures tell a story. Yes they do. In fact, the lack of an atmosphere on the moon makes it easier to infer more of that story. For example - the shadow of the rover wheel is roughly 2 to 2.5 times longer than the wheel itself. So - assuming le...

juvva

https://www.google.com/amp/s/www.scientificamerican.com/article/chandrayaan-3-makes-historic-touchdown-on-the-moon/%3famp=true the above is from a scientific american article. I think, Scientific American got it wrong . Some of this articles are written prior to the event and they do copy paste fro...

juvva

to me it ( intuitively) feels a safer strategy to shut off engines after confirming physical contact with the surface ,rather than depend on a altimeter to indicate almost there signal. i think isro basically said damn the dust, we dont care , when they removed the central engine - we want to land s...

juvva

disha wrote: ↑25 Aug 2023 23:20

Juvvaji' what will be your take if we prove scientific american wrong?

i will stop reading scientific american

juvva

wiring visible at landing pads maybe related to the sensors.

juvva

i revisited landing video was unable to make out any sudden drop of lander in the animation of lander at touch down, after engine cut off.

same was the case in the footage of lander camera, no definitive sudden drop evident.

juvva

Engines cutoff a meter of two above the surface seems excessive in my opinion especially if there is a possibility of a bounce( in low lunar gravity) with uneven time of touchdown (due to uneven weight distribution of the LM) of the each of the four legs. Thx for doing the calculations. The engines...

juvva

https://twitter.com/chandrayaan_3/status/1695058057682628884 Chandrayaan-3 Mission update: All planned Rover movements have been verified. The Rover has successfully traversed a distance of about 8 meters. Rover payloads LIBS and APXS are turned ON. All payloads on the propulsion module, lander mod...

juvva

amber:

^^i suppose an earth eclipse, would be just a round dot traversing a path on the fully sunlit earth(?).

juvva

how often , will the earth eclipse the sun as seen from the moon ?
will such eclipses come in all the varieties - full, partial, annular - and depend on the location of the observer on the moon?

juvva

SSSalvi wrote: ↑25 Aug 2023 10:46 Curiously ,ISRO Tweeted but withdrew this

Image of CH3 Lander by CH2 Orbiter camera

note the long shadows at dawn.
imagine india ( virtually ) standing on a alien landscape , with the sun low on the horizon.

juvva

The reddit post on this is has a clearer image at touchdown THe altitude in this screenshot reads 3.46m at landing. time is shown as 0.00. The entire lander is only 1.1m high and yet Altitude is 3.46 m and it has 'landed'? Measurement error (unlikely, a 3 meter error is too large) or something else...

juvva

let us enjoy the heart burn of the british ( sorry if you feel i misspellt the last word):

https://youtu.be/lcS8afETDr8?feature=shared

juvva

Gold mine interview with Somnath (even though title says Sivan but Somnath interview in the second half). No redundancies were required or used by VIKRAM, Landing was handled by the inertial unit. The LXXXX cameras were not used is what I understood which is a bit odd because VIKRAM did re-target. ...

juvva

i hope they are not waiting for some vip to release rover pics.

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