They withdrew it because they re-posted it again under their different account:
https://twitter.com/chandrayaan_3/statu ... 3744214340
They withdrew it because they re-posted it again under their different account:
I understand that since the face of the moon is always facing the earth while it is spinning around the earth, a person on the moon surface will be seeing the earth and the rotation of the earth about its axis 14 times during a lunar day.SSSalvi wrote: ↑25 Aug 2023 07:43It is same why we see only one side of Moon.
This side will always face Earth, although it will see Earth in rotation and all equatorial surface will be seen over about 1 earth day.
Added later: After posting I found that AmberG had already explained it .. but as usual he adds his simple math/numeric masala making it more spicy.
To rejig Modiji's quote - Even the 'Sky' is not the limit with our AmberG!Cain Marko wrote: ↑25 Aug 2023 10:08 Even though I can't understand half of Dishaji and AmberGs posts on math, space and medicine, I propose....
Can we just appoint AmberG as BRs Bill Nye, the Science Guy ( or should it be, gal?).
AmberG, is BR's Scienceji. There. That's proper desi and even rhymes. Screw Bill Nye.
Q. Will the earth 'rise' and 'set' be the equivalent of waxing and waning of the earth, but will always be overhead (for a person on the moon's equator)? Yes, exactly.RCase wrote: ↑25 Aug 2023 12:05
Maybe I should have been a little more specific in my question -
Q. Will the earth 'rise' and 'set' be the equivalent of waxing and waning of the earth, but will always be overhead (for a person on the moon's equator)?
Q. Also during a lunar day, will the person on the moon will be (primarily) seeing places on the earth that are night?
Q. Please correct me if I am wrong in my thought process. The middle of the lunar day would correspond to our full moon, with the beginning and end of the day being the half moon phases on earth?
(I tried to put this as a schematic below).
A two-segment ramp facilitated the roll-down of the rover. A solar panel enabled the rover to generate power.
Here is how the rapid deployment of the ramp and solar panel took place, prior to the rolldown of the rover.
The deployment mechanisms, totalling 26 in the Ch-3 mission, were developed at U R Rao Satellite Centre (URSC)/ISRO, Bengaluru.
RCase wrote: ↑25 Aug 2023 12:05
Q. Will the earth 'rise' and 'set' be the equivalent of waxing and waning of the earth, but will always be overhead (for a person on the moon's equator)?
Q. Also during a lunar day, will the person on the moon will be (primarily) seeing places on the earth that are night?
Q. Please correct me if I am wrong in my thought process. The middle of the lunar day would correspond to our full moon, with the beginning and end of the day being the half moon phases on earth?
Beautifully explained Amber ji!Amber G. wrote: ↑25 Aug 2023 09:46
Mass differs from weight; a 100 kg mass on Earth remains a 100 kg mass on the Moon. (Hint: In orbit, everything is weightless, but that doesn't mean you can carry an unlimited payload.) Newton's laws deal with mass, and for a given change in velocity (delta-V), the energy (fuel) required depends hardly on whether you're on the Moon or not (assuming you're beyond the gravitational "potential well" of local body ).
You have to do work against Sun's gravity to go to Mars..
Whether you're near the Moon or Earth, the delta-V needed to reach Mars (or other outer planets) is approximately 42 km/s. Since Earth (or the Moon) is already moving at around 30 km/s, you might opt to wait for the right orbital alignment. This way, you'd only need about 12 km/s at the optimal time. (For this, you might need to wait for a year or a few, aligning Earth's or the Moon's trajectory with that of Mars.)
Moon's g is 1/6th of earth etc doesn't significantly alter flight time .. Forget about getting faster/slower due to this-- the flight time is mainly dictated by Newton's laws. (assuming you have limited fuel).
While gravity assists, mechanics, and planetary alignments can conserve fuel, apart from the fuel needed to escape Earth's (or the Moon's gravity well - where it has some advantage), the "one-sixth factor" doesn't hold much significance.
Hope this is useful.
Let me add: (Just to be clear):RCase wrote: ↑25 Aug 2023 12:05
I understand that since the face of the moon is always facing the earth while it is spinning around the earth, a person on the moon surface will be seeing the earth and the rotation of the earth about its axis 14 times during a lunar day.
Maybe I should have been a little more specific in my question -
Q. Will the earth 'rise' and 'set' be the equivalent of waxing and waning of the earth, but will always be overhead (for a person on the moon's equator)?
Q. Also during a lunar day, will the person on the moon will be (primarily) seeing places on the earth that are night?
Q. Please correct me if I am wrong in my thought process. The middle of the lunar day would correspond to our full moon, with the beginning and end of the day being the half moon phases on earth?
(I tried to put this as a schematic below).
Q. Please correct me if I am wrong in my thought process. The middle of the lunar day would correspond to our full moon, with the beginning and end of the day being the half moon phases on earth?
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 module, and rover are performing nominally.
Yay!Ashokk wrote: ↑25 Aug 2023 19:18 https://twitter.com/chandrayaan_3/statu ... 7682628884
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 module, and rover are performing nominally.
wow great!Ashokk wrote: ↑25 Aug 2023 19:18 https://twitter.com/chandrayaan_3/statu ... 7682628884
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 module, and rover are performing nominally.
- For those who are curious, if you are on the moon -
All good questions to unpack:Najunamar wrote: ↑24 Aug 2023 10:02 Would we be able to repurpose the SHAPE instrument for analyzing any other planet if all of the habitable planet earth planned experiments are completed as someone else asked? In other words what advantages can be derived from the extended life of the PM? Also if you have both CH-2 and PM in large enough orbits would it be sufficient to communicate with a lander on the far side of course with its PM also kind of like a 3 satellite moon GPS?
Thx for doing the calculations. The engines were cutoff at ~2m and C3 dropped like a stone for a good reason.
Juvva'ji, Please pay attention to above post by Salvi'ji.
The free fall of C3 on Moon from ~2 meters above moon surface was engineered. And for a good reason.
Hey CainJi, thanks. But what about me, that is what desi name you propose?Cain Marko wrote: ↑25 Aug 2023 10:08 Even though I can't understand half of Dishaji and AmberGs posts on math, space and medicine, I propose....
Can we just appoint AmberG as BRs Bill Nye, the Science Guy ( or should it be, gal?).
AmberG, is BR's Scienceji. There. That's proper desi and even rhymes. Screw Bill Nye.
https://www.google.com/amp/s/www.scient ... 3famp=truedisha wrote: ↑25 Aug 2023 20:57Thx for doing the calculations. The engines were cutoff at ~2m and C3 dropped like a stone for a good reason.
Juvva'ji, Please pay attention to above post by Salvi'ji.
The free fall of C3 on Moon from ~2 meters above moon surface was engineered. And for a good reason.
1. On moon there is no atmosphere, so the lunar regolith (or moon dust) does not go through the weathering process that earth's dust goes through. If one goes to deserts of Earth, the rounded weathered silica grains still mess up any system and gets into places where it does not need to be. The lunar regolith is not even nice and well-rounded. It is just sharp with fine edges. Gets into everything and starts cutting up things.
2. The lander's rockets kick up quite a storm of dust. That is why in C2, they added a central motor to kick off the dust to sideways and that created additional algorithm challenges. This time, the mission said, let it free fall from a certain height. That way the dust kicked off has time to get off the way and *no new dust* is kicked off.
---
So all the nanha-mujahids who have not been halal'ed yet, please do not say that we will get moon dust for you to win some brownie points. First of all the moon dust is very sharp and if applied as makeup, will *not* shine the face of your beau but will scratch and cut the skin and make it like a face from one of those horror movies.
the above is from a scientific american article.wrote: Finally, on touchdown, sensors on the lander’s legs triggered the shutdown of its main engines. Chandrayaan-3 now stands tall on the moon.
juvva wrote: ↑25 Aug 2023 22:18
https://www.google.com/amp/s/www.scient ... 3famp=true
the above is from a scientific american article.wrote: Finally, on touchdown, sensors on the lander’s legs triggered the shutdown of its main engines. Chandrayaan-3 now stands tall on the moon.
The drop on moon will be gentler. 1/6th "slower". To perceive from a remote non-high fidelity camera first time & interpreting based on your senses tuned on Earth will lead to errors in perception.
Not exactly --- here are some basics to make everything clear ..
Well, the two velocities shown in the sceenshot are non-zero (-.981 m/s and 0.0053 m/s or something close), clearly the velocity of the lander is not zero. LDV update counter is not velocity- units are not mentioned. This screenshot was taken while the lander was still above the surface of the moon and not landed yet. This squares with the non-zero and non-trivial value of vertical velocity. The lander is moving at 0.983 m/s and still at 3.46 m altitude when the screenshot was taken. I believe the touchdown was not complete at this point.Jayram wrote: ↑25 Aug 2023 08:09Not an expert but we may be overthinking this . two points - LDV (Laser Doppler velocimetry) reads 0.0 - no motion detected ie touch down and the this time is then frozen at 1193.573 -consistent over on the left and right side of the picture. So at that point all the rest of the sensor data is frozen and is what we see in the picture. After all if all the sensor data was reset at touch down the usefulness of that data at that point would be diminished and would not allow for any troubleshooting.SriKumar wrote: ↑25 Aug 2023 06:45 The Laser altimeter is about halfway up the Lander, so about 0.6m above the 'feet' or landing pads of Vikram. That leaves it still 3.46-0.6 = 2.86m above the surface with a velocity of -0.983 ms. If indeed that velocity is -0.983 m/s at 3.46 m altitude, then perhaps the engines cut off at this point but if they do, the free-fall would give it a touch-down velocity of sqrt( 0.983^2 + 2*(9.81/6)*2.86) = 3.21 m/s (going by v^2 = u^2 + 2 *g*s and taking lunar gravity into account). I recall hearing somewhere that the engines would cut off a meter or two above lunar surface.
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.
You could poll multiple sensors (legs, accelerometer, LDV, etc) and get a majority verdict.juvva wrote: ↑25 Aug 2023 23:37 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 safely period.
As I posted before, for Moon, setting up a relay station at L2 as China did works very well.