Chandrayaan 3: Launch and Discussions

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Amber G.
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Re: Chandrayaan 3: Launch and Discussions

Post by Amber G. »

AFAIK: Only outside of Russia tracking of Luna 25, I could see was From @18thSDS just around the launch ..transmission signals too weak to be captured by amature scientists. CY2, CY3 (Both PM & Vikram) can be listened to and dopplered.

As I post - JPL/Horizon has not updated the ephemerides for Vikram yet... so their API could not be used to get the descent and trajectory.
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Re: Chandrayaan 3: Launch and Discussions

Post by Tanaji »

Amber G. wrote: 20 Aug 2023 20:30 AFAIK: Only outside of Russia tracking of Luna 25, I could see was From @18thSDS just around the launch ..transmission signals too weak to be captured by amature scientists. CY2, CY3 (Both PM & Vikram) can be listened to and dopplered.


I am curious as to why that is the case? The spacecraft surely must be transmitting at nearly the same power as other crafts on the same mission profile? Or are they using some fancy coding scheme that allows them to transmit with a smaller EIRP? There is a plethora of amateur astronomers in the world that should be able to get the signal? Was it untraceable even for big radio telescopes?
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Re: Chandrayaan 3: Launch and Discussions

Post by Ashokk »

Landing time updated to 18:04 IST by ISRO.

https://twitter.com/isro/status/1693181653273940240
Chandrayaan-3 is set to land on the moon on August 23, 2023, around 18:04 Hrs. IST.

Thanks for the wishes and positivity!

Let’s continue experiencing the journey together
as the action unfolds LIVE at:
ISRO Website https://isro.gov.in
YouTube https://youtube.com/watch?v=DLA_64yz8Ss
Facebook https://facebook.com/ISRO
and DD National TV
from 17:27 Hrs. IST on Aug 23, 2023.
https://www.isro.gov.in/Chandrayaan3Sof ... ssage.html
Message on Chandrayaan-3 Soft-landing telecast

August 20, 2023

India's pursuit of space exploration reaches a remarkable milestone with the impending Chandrayaan-3 Mission, poised to achieve a soft landing on the lunar surface. This achievement marks a significant step forward for Indian Science, Engineering, Technology, and Industry, symbolising our nation's progress in space exploration.

This eagerly anticipated event will be broadcasted live on August 23, 2023, starting from 17:27 Hrs. IST. The live coverage will be available via multiple platforms, including the ISRO Website , YouTube, ISRO's Facebook page , and DD National TV channel.

The soft landing of Chandrayaan-3 is a monumental moment that not only fuels curiosity but also sparks a passion for exploration within the minds of our youth. It generates a profound sense of pride and unity as we collectively celebrate the prowess of Indian science and technology. It will contribute to fostering an environment of scientific inquiry and innovation.

In light of this, all schools and educational institutions across the nation are invited to play an active role in this historic event. The institutions are invited to actively publicise this event among your students and faculty and organize the LIVE streaming of the Chandrayaan-3 soft landing within the premises.
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Re: Chandrayaan 3: Launch and Discussions

Post by Amber G. »

For reference: (Compiled by Amber G, on August 20, 2023

For those who are not allergic to doing simple math and want to do their calculation to know accurate velocity, position of CY3 and CY2 (till next burn). This is in simple terms (each term explained for those who have basic understanding of orbits):

I have gotten the data from JPL/ISRO figures latest available information. (Will edit any correction)
(Some calculation is my own - I believe mathematically correct but will edit if there is any error/typo)

This is one place to look up the data for CY1, CY2, CY3 to calculate their position at any time. (If you have any orbit calculating software or are handy with slide rule (:) or doing calculation on pen and paper.

It has most uptodate reference data:

It contains:

CY3 - Reference data for both Vikram and PM. (PM data, as I post this message is not available from JP/Horizon system so I put it best I could get from ISRO and math)
CY2 - Ephemerides for both Vikram and Orbiter. (Vikram, of course, we know has crashed, but it's orbit just before crash is here)
CY1 - Is inactive there, but still orbiting. Calculating the position from last known position.

Moon/Sun - so one can understand what the lighting condition would be at the landing site .. where earth would be wrt to lander, and where the landing site would be, if you aim your telescope or try to aim your radio telescope..

Written for non-experts some basic astronomy and math is required.

]For CY3

General Info:


The lander will then touch down in the lunar south polar region, nominally
69.367621 deg. S, 32.348126 deg. E, with a velocity less than 2 m/s vertical
and 0.5 m/s horizontal, slope <= 120 degrees. The prime landing site target
zone is 4 x 2.4 km in dimension.

The propulsion module will remain in lunar orbit to act as a communications
relay between the lander and Earth. The lander and rover are designed to
operate for one lunar daylight period, about 14 Earth days. (CY2 will be the main relay per ISRO/see BRF post by Ashokk)

SPACECRAFT:
Launch mass : 3900 kg
Lunar lander mass: 1752 kg (solar arrays ~ 738 W)
Lander Propulsion : bi-propellant propulsion (MMH + MON3),
4 nos. of 800 N throttleable engines
8 nos. of 58 N
Rover mass 26 kg (solar arrays ~ 50 W)
6 wheels

SCIENCE PAYLOADS
Lander:
Radio Anatomy of Moon Bound Hypersensitive Ionosphere & Atmosphere (RAMBHA)
Chandra's Surface Thermo physical Experiment (ChaSTE)
Instrument for Lunar Seismic Activity (ILSA)
Laser Retroreflector Array (LRA, from NASA)
Propulsion module:
Spectro-polarimetry of HAbitable Planet Earth (SHAPE)
Rover:
Alpha Particle X-Ray Spectrometer (APXS)
Laser Induced Breakdown Spectroscope (LIBS) Propulsion Module:

Chandrayaan 3 Vikram JPL/Horizon id: CH3 - 158 EPOCH: JDN(Julian Day Number)=2460176.5 = August 20, 2023 at 00:00:00 UTC

Brief explanation of Reference system Below and values.

Reference center (origin) : Moon Center
Center radii 1737.4 km (To calculate altitude, subtract this from distance)
Keplerian GM : 4.902.8 km^3/s^2 (µ I used in previous BRF posts .. unit here is converted in km^3/sec^2 for ease of calculation)
Output units : KM-S, deg, Julian Day Number for Tp

Reference frame : Ecliptic of J2000.0 (Which NASA/JPL uses - it is essentially same as ecliptic - plane of earth's orbit around the sun)

So X-Y plane is ecliptic , Z axis pointing to ecliptic north. (This is within 1.5 degrees of Moon's equatorial plane)
X - axis is ICRF - points towards vernal equinox (first point of Aries वसंत विषुव )

e = (eccentricity) = .0294 (roughly circular), Inclination = 89.9 degrees (Nearly polar)
perigee = 1763.66 Km (Altitude 29.3 Km), Apogee = 1870.6 Km, a = (Semimajor axis) = 1817.1 Km
Period = 6950.7 Sec.


Longitude of Ascending Node = 268 deg Argument of Perifocus, = 228 degree
Tp= 2460176.471497831400 (Time in JDN when the spacecraft was at perigee.. so that at any given time you can find its position)
Mean Motion = .0518 degree/sec MA= 127.5 degree TA= 130.2 Degree
(MA is Mean anomaly - angle, if the orbit was circular, TA = True Anomaly - Actual angle at focus, from the major axis of the ellipse)

---
Chandrayaan 2 Orbiter JPL/Horizon id: CH2 - 152 EPOCH: JDN(Julian Day Number)=2460176.5 = August 20, 2023 at 00:00:00 UTC


SPACECRAFT:
Launch mass : 3850 kg
Lunar orbital mass: 2379 kg (solar arrays ~1000 W
Lunar lander mass: 1471 kg (solar arrays ~ 650 W)
Rover mass : 27 kg (solar arrays ~ 50 W)

e = (eccentricity) = .0117 (roughly circular), Inclination =90.5 degrees (Nearly polar)
perigee = 1823.13 Km , Apogee = 1866.17 Km, a = (Semimajor axis) = 1846.6
Period = 7109.4 Sec.

Longitude of Ascending Node = 270.2 deg Argument of Perifocus, = 22.57 degree
Tp= 2460176.462988432497 (Time in JDN when the spacecraft was at perigee.. so that at any given time you can find its position)
Mean Motion = .050635.064 \ degree/sec MA= 161.93 degree TA= 162.34 Degree
(MA is Mean anomaly - angle, if the orbit was circular, TA = True Anomaly - Actual angle at focus, from the major axis of the ellipse)

---
Chandrayaan 2 Lander (Vikram) JPL/Horizon id: CH2 - 153 EPOCH: JDN= 2458733.343750000 = 2019-Sep-06 20:15:00.0000 UTC
(Last Measured position :(

(The orbiter was eventually placed in a 119 x 127 km nearly circular polar
orbit after a series of engine burns.

The lander subsequently separated on 2019-Sep-02 07:45 UTC and was planned to touch
down at predetermined site close to the lunar south pole.

Touchdown is to occur 2019-Sep-07 on a high plain between two craters,
Manzinus C and Simpelius N, about 70 degrees south of the equator.

The orbiter mission covers 1 year, in a 100-km circular polar orbit but is *still* active - Its relay station for CY3)

The six-wheeled Pragyan is resting on the surface.


This is a merge trajectory solutions fit to tracking data
through 2019-Sep-06 ~15:37 UTC, with a planning prediction thereafter
(i.e., does NOT include the descent anomaly & final actual trajectory).

2458733.333333333 = A.D. 2019-Sep-06 20:00:00.0000 TDB
EC= .022 QR= 17679.4 IN= 91.52
OM= 277.3 W = 231.00 Tp= 2458733.339561445639
N = .052 MA= 331.9 TA= 3.30.7
A = 1807.1 AD= 1846.2 PR= 6.893.3 secs

(Yes, with this trajectory, in next 15 minutes it will crash on the moon - easy to see - unless braking is applied..We all know the braking was not sufficient and it hit the surface with greater velocity than expected.


---
Chandrayaan 1 Orbiter JPL/Horizon id: CH1 - 86 EPOCH: JDN= 2459852.500000000 = A.D. 2022-Sep-30 00:00:00.0000 UTC
Chandrayaan-1 was India's first mission to the Moon. It launched October 22,
2008 on a PSLV (Polar Satellite Launch Vehicle, PSLV-C11) from the Satish
Dhawan Space Center (SDSC) in Sriharikota, India.

Launch mass : 1050 kg
Lunar orbital mass: 550 kg
Dimensions : 1.5 meter cube, plus extended solar panel

RESULTS:
The mission studied the Moon's environment and surface processes for a period
of about nine months during 2008-2009, establishing ...

1) A tenuous but active hydrosphere,
2) a volcanically active and geologically dynamic Moon, and
3) global melting of Moon's surface regions and formation of magma
ocean early in the history of Moon.

On Aug. 29, 2009, ISRO abruptly lost contact with the Chandrayaan-1
spacecraft. All attempts to recover the mission failed.

The spacecraft operationally completed 312 days in orbit, making more than
3400 functional orbits of the moon, but the planned mission of two years was
cut in half. About 95% of the mission objectives were completed, including
collection of over 70,000 images.

TRAJECTORY: The inactive spacecraft, still in orbit around the Moon, was
detected by radar echoes seven times over Jul-Sep 2016 using the Goldstone
Solar System Radar. Delay and Doppler measurements were used to estimate
the current trajectory available here.

2459852.500000000 = A.D. 2022-Sep-30 00:00:00.0000 TDB
EC= .0283 QR= 1889.64 IN= 91.01
OM= 159.06 W = 272.8 Tp= 2459852.544464385603
N = .0468 MA= 180.3 TA= 180.3
A = 1944.7 AD= 1999.7 PR= 7695.33

(Work in progress - Will add for CH2, and PM later)
(Let me know if additional detail is desired)

-- To be added: Sun/Moon/Earth positions --

Planetary mean elements for Moon on 2000-01-01.5

a = 384400 Km, e=.0554 , argument of periapsis= 318.15 Mean Anomaly = 135.27
Inclination= 5.16 Degree Ascending Node=125.08 sidereal period =27.322 days
periapsis period =5.997 years node precession period= 18.600 Years.

This means: Using the same coordinate system as we are using for CY3, CY2, etc, to locate earth use:
2460176.500000000 = A.D. 2023-Aug-20 00:00:00.0000
EC= 5.578175491289343E-02 QR= 3.628316980985817E+05 IN= 5.084369946976682E+00
OM= 2.614997325954256E+01 W = 1.284636134449790E+02 Tp= 2460187.527413775679
N = 1.527906903728645E-04 MA= 2.144258354450509E+02 TA= 2.110110607437462E+02
A = 3.842667730542630E+05 AD= 4.057018480099443E+05 PR= 2.356164496157914E+06

So position of the Earth (On days August 20 to September 08 -- One day for CY3) as viewed from the moon ,, (Will explain details later)
******************************************************************************************************************************************************************************
Date__(UT)__HR:MN R.A.___(ICRF)__DEC APmag S-T-O
******************************************************************************************************************************************************************************

2023-Aug-20 00:00 00 23 45.84 +00 37 52.5 -16.540 30.064730
2023-Aug-21 00:00 01 06 38.89 +06 17 00.7 -16.364 30.450113
2023-Aug-22 00:00 01 51 07.05 +11 47 40.0 -16.138 30.976100
2023-Aug-23 00:00 02 38 15.25 +16 57 10.8 -15.857 31.657571
2023-Aug-24 00:00 03 29 05.37 +21 29 59.4 -15.515 32.498406
2023-Aug-25 00:00 04 24 22.93 +25 06 55.6 -15.105 33.483971 .
2023-Aug-26 00:00 05 24 14.64 +27 25 59.4 -14.616 34.573119
2023-Aug-27 00:00 06 27 44.82 +28 05 54.4 -14.040 35.691963
2023-Aug-28 00:00 07 32 53.81 +26 52 28.4 -13.367 36.733643
2023-Aug-29 00:00 08 37 16.25 +23 44 45.2 -12.593 37.569359
2023-Aug-30 00:00 09 38 59.78 +18 56 49.0 -11.721 38.073415
2023-Aug-31 00:00 10 37 19.52 +12 53 58.9 -10.904 38.157325
2023-Sep-01 00:00 11 32 32.69 +06 06 38.2 -11.558 37.798938
2023-Sep-02 00:00 12 25 33.36 -00 55 01.4 -12.423 37.050907
2023-Sep-03 00:00 13 17 28.68 -07 44 03.2 -13.192 36.023455
2023-Sep-04 00:00 14 09 22.64 -13 57 54.1 -13.861 34.851457
2023-Sep-05 00:00 15 02 05.15 -19 18 22.5 -14.436 33.662348
2023-Sep-06 00:00 15 56 02.78 -23 31 15.2 -14.928 32.555993
2023-Sep-07 00:00 16 51 11.51 -26 26 13.4 -15.346 31.598153
2023-Sep-08 00:00 17 46 55.31 -27 57 20.3 -15.701 30.823247
2023-Sep-09 00:00 18 42 15.16 -28 03 39.8 -16.000 30.241169
2023-Sep-10 00:00 19 36 07.72 -26 49 20.9 -16.248 29.844659



'R.A._____(ICRF)_____DEC' =
Astrometric right ascension and declination

Units: RA in hours-minutes-seconds of time, HH MM SS.ff{ffff}
DEC in degrees-minutes-seconds of arc, sDD MN SC.f{ffff}

'APmag ' = The targets' approximate apparent visual magnitude ( brightness) -16 is very bright)
'S-T-O' = The angle between sun and Earth in degrees.





And for sun (wrt to Moon):
Last edited by Amber G. on 21 Aug 2023 03:05, edited 10 times in total.
sanman
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Re: Chandrayaan 3: Launch and Discussions

Post by sanman »

Very sorry to hear about what happened to Luna-25. The Moon has claimed another victim.

Hopefully the Russians will review and re-attempt, as ISRO did after CY-2 landing failure.

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Re: Chandrayaan 3: Launch and Discussions

Post by Amber G. »

Tanaji wrote: 20 Aug 2023 21:23
Amber G. wrote: 20 Aug 2023 20:30 AFAIK: Only outside of Russia tracking of Luna 25, I could see was From @18thSDS just around the launch ..transmission signals too weak to be captured by amature scientists. CY2, CY3 (Both PM & Vikram) can be listened to and dopplered.


I am curious as to why that is the case? The spacecraft surely must be transmitting at nearly the same power as other crafts on the same mission profile? Or are they using some fancy coding scheme that allows them to transmit with a smaller EIRP? There is a plethora of amateur astronomers in the world that should be able to get the signal? Was it untraceable even for big radio telescopes?
CY2, CY3 beacon/RF transmission are on known frequency, strong, active all the time (even when moon is not visible from India)... CY2 has become active recently again too for benefit of us all. Of course, actual important data is encrypted for ISRO's ears only. The frequencies are *not* controlled by atomic oscillators but still quite useful to do measurements.

(Not that many did not try -- but could not get any good signal, just noise -- Moon is a strong emitter of RF noise so unless one knows where to look and has very good directional antenna it is hard ..I am sure, big radio-telescope have seen it but not aam-abdul types)

Luna -25 is/was quiet mostly ..the signals are/were weak (need good antennas and position/time_window) to receive transmission).. frequencies not that well known -- at the time of trouble, some thought that they will switch on more powerful beacon so others (in other locations too) can point to its location etc.. Not surprisingly /unfortunately this time of the month (moon - low on horizon from Russia), time window when it was over russia -- (and can get commands from ground) was small to correct the error.... Also unfortunately , ESA's support (for listening) was causality of Ukraine/politics..
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Re: Chandrayaan 3: Launch and Discussions

Post by Ashokk »

https://ria.ru/20230820/luna-1891116639.html

Translation
Scientist says problems with Luna-25 began before attempt to go into orbit

MOSCOW, August 20 - RIA Novosti. "Disturbing signs" at the station "Luna-25" were noticed even before the attempt to transfer to the preorbit, but the decision to postpone the maneuver was not made, the scientist, Nathan Eismont, a leading researcher of the Institute of Space Research (IKI) of the Russian Academy of Sciences, told RIA Novosti.

"There were problems, they were not that significant, but the signs were, so to speak, alarming, but everyone hoped that it would somehow be dealt with .... The problems were, I'll be careful to say, there are things that are calculated and things that are off par.... If we have a deviation turns out to be slightly higher than we expected, it is a disturbing fact, but apparently it was not disturbing enough to move to a radical solution, "- said Eismont.

The scientist believes that when the problem arose, they should have waited and postponed the transition to the pre-landing orbit. According to him, there would have been "nothing wrong" with it.

"The sad thing is that the time was and apparently the decision on how to proceed was not the best," the scientist added.
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Re: Chandrayaan 3: Launch and Discussions

Post by Amber G. »

^^^ Thanks. As I said, it is unfortunate, that flexibility to correct error becomes quite small as time-window to send/receive commands and monitor the orbit is more limited (relatively speaking) for Russia for Luna-25..
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Re: Chandrayaan 3: Launch and Discussions

Post by Amber G. »

Okay!
JPL has updated the orbit data for landing ! ( updated just a few hours ago)

Image

Yes!
The landing is at 18:04 IST (12:34 UTC) on 23rd August


the excellent animation has been updated.


Enjoy!

You can watch the animation in real time
( The animation plays advancing at 1 second per second or faster if you wish)
Last edited by Amber G. on 21 Aug 2023 06:10, edited 2 times in total.
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Re: Chandrayaan 3: Launch and Discussions

Post by Amber G. »

<Click the image below for excellent video>

Landing time lapse from above the south pole of the moon. As you can see from this angle, Chandrayaan3 is aiming for a lunar day (14 earth days post landing.
Image

HT/Credit Sankara V. Animation.
(displacement/bump map to get shadows from craters is new feature).

LIve streaming could be watched at:
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Re: Chandrayaan 3: Launch and Discussions

Post by SSSalvi »

Ashokk wrote: 20 Aug 2023 22:42 https://ria.ru/20230820/luna-1891116639.html

Translation
Scientist says problems with Luna-25 began before attempt to go into orbit

"Disturbing signs" at the station "Luna-25" were noticed even before the attempt to transfer to the preorbit, but thedecision to postpone the maneuver was not made,


The scientist believes that when the problem arose, they should have waited and postponed the transition to the pre-landing orbit. According to him, there would have been "nothing wrong" with it.

"The sad thing is that the time was and apparently the decision on how to proceed was not the best," the scientist added.
A scientist's thoughts.. discarding the political compulsions.

Very sad.
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Re: Chandrayaan 3: Launch and Discussions

Post by Mort Walker »

Ashokk wrote: 20 Aug 2023 22:42 https://ria.ru/20230820/luna-1891116639.html

Translation
Scientist says problems with Luna-25 began before attempt to go into orbit

MOSCOW, August 20 - RIA Novosti. "Disturbing signs" at the station "Luna-25" were noticed even before the attempt to transfer to the preorbit, but the decision to postpone the maneuver was not made, the scientist, Nathan Eismont, a leading researcher of the Institute of Space Research (IKI) of the Russian Academy of Sciences, told RIA Novosti.

"There were problems, they were not that significant, but the signs were, so to speak, alarming, but everyone hoped that it would somehow be dealt with .... The problems were, I'll be careful to say, there are things that are calculated and things that are off par.... If we have a deviation turns out to be slightly higher than we expected, it is a disturbing fact, but apparently it was not disturbing enough to move to a radical solution, "- said Eismont.

The scientist believes that when the problem arose, they should have waited and postponed the transition to the pre-landing orbit. According to him, there would have been "nothing wrong" with it.

"The sad thing is that the time was and apparently the decision on how to proceed was not the best," the scientist added.
For the Russians every strategic objective has to go through the repetitive meat grinder. They'll get there, but it may be a Luna-26 followed by a Luna-27, Luna-n.
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Re: Chandrayaan 3: Launch and Discussions

Post by Amber G. »

IISU Director Padmakumar ES talks about LIRAP sensor package a bit. It contains four gyros and four accelerometers sensitive down to 2μg, they only need three each, one extra is for redundancy.
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Re: Chandrayaan 3: Launch and Discussions

Post by sanman »

But only thing Propulsion Module has is the SHAPE instrument. It's not clear how much the SHAPE experiment will benefit from this longer operating life. It doesn't even have much of a communications array to supplement other missions.
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Re: Chandrayaan 3: Launch and Discussions

Post by juvva »

sanman wrote: 21 Aug 2023 10:30 But only thing Propulsion Module has is the SHAPE instrument. It's not clear how much the SHAPE experiment will benefit from this longer operating life. It doesn't even have much of a communications array to supplement other missions.
maybe shape could be repurposed to look at other planets like, mars, venus etc. in the extended time.(?)
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Re: Chandrayaan 3: Launch and Discussions

Post by Prem Kumar »

Thanks for the excellent discussion, folks!!

Didn't know that NASA and ESA are helping out ISRO by acting as relays to CY-3. Glad to see the collaboration.

https://www.msn.com/en-in/news/techands ... skbar&ei=6
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Re: Chandrayaan 3: Launch and Discussions

Post by rahulm »

Some useful updates from Richard Stephenson who works at the Canberra DSN and seems to be part of the Canberra team assisting with Chandrayaan 3
Richard Stephenson
@nascom1
·
Aug 20
Chandrayaan 2 hasn't been tracked on the DSN since 2019. Madrid's DSS54 has just conducted a re-validation test in readiness for the attempted CH3 lunar landing in a few days. The DSN will help support both the Chandrayaan 2 orbiter and Chandrayaan 3 lander throughout.
and setting right some concerns raised by Scott Tilley
Richard Stephenson
@nascom1
·
2h
Just for the record everyone. Chandrayaan 3 is a ISRO spacecraft. They have always been very open with information about their missions. Please don't misinterpret a simple observation made by the many people tracking CH3 as an issue with the spacecraft. It's going great.
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Re: Chandrayaan 3: Launch and Discussions

Post by nits »

Thanks for the above post RahulM; after seeing the post from Scott on X - the heart beat was racing up and down...

Good to know all is fine
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Re: Chandrayaan 3: Launch and Discussions

Post by Ashokk »

https://twitter.com/isro/status/1693549487653048418
Chandrayaan-3 Mission:
‘Welcome, buddy!’
Ch-2 orbiter formally welcomed Ch-3 LM.

Two-way communication between the two is established.

MOX has now more routes to reach the LM.

Update: Live telecast of Landing event begins at 17:20 Hrs. IST.
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Re: Chandrayaan 3: Launch and Discussions

Post by nits »

Isro's comms and social media tone and reach has improved drastically... Kudos to the team handling it
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Re: Chandrayaan 3: Launch and Discussions

Post by drnayar »

nits wrote: 21 Aug 2023 17:55 Isro's comms and social media tone and reach has improved drastically... Kudos to the team handling it
The plan to link schools and other educational institutions to witness C 3 s landing is a great idea.. reminds one of the Apollo lunar landing !
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Re: Chandrayaan 3: Launch and Discussions

Post by Ashokk »

S Somnath referred to Prof Padhi during his presentation at IISC, he has been assisting ISRO with the control algorithms for CY2 & CY3.

Chandrayaan-3's Vikram Lander Has An Inbuilt "Salvage Mode" Which Will Help It Land Even If Everything Goes Wrong
Chandrayaan-3's Vikram lander has a built-in "salvage mode" that allows it to land safely even in the event of unexpected issues, according to an aerospace scientist.

Significant improvements have been made following the failure of Chandrayaan-2, and there is complete confidence in the safe landing of Chandrayaan-3.

The failure of Chandrayaan-2 was attributed to the Vikram lander's inability to control its speed, causing it to tumble.

However, this issue has been addressed through the correction of an algorithm failure. The legs of the Vikram lander have also been made more robust, ensuring greater stability during landing.

Professor Radhakant Padhi, an aerospace scientist from the Indian Institute of Science in Bengaluru, has been actively involved in both the Chandrayaan-2 and Chandrayaan-3 missions. The Aerospace department of the institute is also contributing to the moon mission, further enhancing its expertise and capabilities.

Reflecting on the past, Professor Padhi noted that scientists at the Indian space agency (ISRO) were overly confident during the Chandrayaan-2 mission. However, the design philosophy behind Chandrayaan-3 is to ensure a successful landing even in the face of unexpected challenges, leaving no room for complacency, as reported by NDTV.

Radhakant Padhi expressed confidence in the success of the lander, stating that Chandrayaan-3 is designed to be more robust with six "sigma bounds."

Professor Padhi assured that Chandrayaan-3 has undergone rigorous stress testing, with ISRO addressing all known unknowns.

According to Professor Padhi, it is impossible to replicate lunar conditions on Earth. However, the Vikram Lander is equipped with hazard detection capabilities to identify the optimal landing site.

Highlighting an improvement from Chandrayaan-2, Professor Padhi mentioned that the Vikram Lander now features two on-board computers. He expressed a high level of confidence, stating that he is "99.9%" certain that the Vikram Lander will perform as expected.
nits
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Re: Chandrayaan 3: Launch and Discussions

Post by nits »

One side whole India is praying and is with ISRO and at other end is Actor like Prakash Raj mocking ISRO - see his tweet below :evil:

While the actor did not specify the man in the cartoon, many social media users slammed the actor for making fun of former Indian Space Research Organisation chief K Sivan.

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Re: Chandrayaan 3: Launch and Discussions

Post by sanman »

juvva wrote: 21 Aug 2023 11:02 maybe shape could be repurposed to look at other planets like, mars, venus etc. in the extended time.(?)
meh, not while orbiting the Moon
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Re: Chandrayaan 3: Launch and Discussions

Post by Amber G. »

^^^ CH3-PM's shape is being/will be used for studying atmosphere of the earth.
( SHAPE = Spectro-polarimetry of Habitable Planet Earth (SHAPE) - studies the spectral and polarimetric measurements of Earth from the lunar orbit in the near-infrared (NIR) wavelength range (1-1.7 μm))
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Re: Chandrayaan 3: Launch and Discussions

Post by Dilbu »

Chandrayaan 3 will not successfully soft land onlee. :(( :(( :((
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Re: Chandrayaan 3: Launch and Discussions

Post by Amber G. »

Thought I might post the images of Lunar far side area captured by the Lander Hazard Detection and Avoidance Camera (LHDAC).
This camera that assists in locating a safe landing area -- without boulders or deep trenches -- during the descent is developed by ISRO at SA
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Re: Chandrayaan 3: Launch and Discussions

Post by RaviB »

Thank you for your services Dilbuji. I have observed your black magic several times onlee and bow to your superpowers.
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Re: Chandrayaan 3: Launch and Discussions

Post by sanman »

Amber G.
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Re: Chandrayaan 3: Launch and Discussions

Post by Amber G. »

Meanwhile: As usual, WSJ had an article, and somebody from California commented:
While millions live in tin shacks in utter poverty. Sigh.. {yada...yada..}
The following reply became classic!
The housing situation in San Francisco has no bearing on India's space program.
:eek:
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Re: Chandrayaan 3: Launch and Discussions

Post by drnayar »

Amber G. wrote: 21 Aug 2023 20:25 Meanwhile: As usual, WSJ had an article, and somebody from California commented:
While millions live in tin shacks in utter poverty. Sigh.. {yada...yada..}
The following reply became classic!
The housing situation in San Francisco has no bearing on India's space program.
:eek:
Hilarious ..waiting for some gora from UK to comment similarly..their roads now look like the surface of the moon :rotfl: .. could you please post link to above article ?
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Re: Chandrayaan 3: Launch and Discussions

Post by arvin »

nits wrote: 21 Aug 2023 19:14 One side whole India is praying and is with ISRO and at other end is Actor like Prakash Raj mocking ISRO - see his tweet below :evil:

While the actor did not specify the man in the cartoon, many social media users slammed the actor for making fun of former Indian Space Research Organisation chief K Sivan.
OT....He is not mocking Sivan. Thats the mallu don in Jailer movie and using him mocking the Keralite in ISRO.
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Re: Chandrayaan 3: Launch and Discussions

Post by Dilbu »

No sir there is a popular joke about keralite expats that even if you land on the moon you will find a mallu tea shop guy offering you a cup of tea there. This is a cheap attempt to rehash that joke plus slightly mocking the achievement of CY3.
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Re: Chandrayaan 3: Launch and Discussions

Post by sanman »

If for some reason, ISRO cannot go ahead with the landing of Vikram on the surface on Aug 23, then it has Aug 27 as a backup date:

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Re: Chandrayaan 3: Launch and Discussions

Post by SSSalvi »

Reg Prakash Raj cartoon:
Currently we Indians have lost enjoyment and think only "Anti Nationalist "...
Very sad change in our attitude,
We even celebrate Luna25 problem.
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Re: Chandrayaan 3: Launch and Discussions

Post by Pratyush »

Why are we discussing this clown Prakash Raj.
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Re: Chandrayaan 3: Launch and Discussions

Post by Amber G. »

OTOH: Glad to see some Indian news outlets are using scientific, accurate and interactive 3D visualisation for reporting -- like the one we are posting in Brf..
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