🚀 Chandrayaan-3 Dashboard: Vikram Lander, Pragyan Rover Not Responding To ISRO's Calls Just Yet

🚀 Chandrayaan-3 Dashboard: Vikram Lander, Pragyan Rover Not Responding To ISRO's Calls Just Yet

by Swarajya Staff - Friday, September 22, 2023 07:25 PM IST
🚀 Chandrayaan-3 Dashboard: Vikram Lander, Pragyan Rover Not Responding To ISRO's Calls Just YetChandrayaan-3 lander on the Moon as an anaglyph
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🗓️ Friday, 22 September

7.25 pm: No signals incoming from Vikram, Pragyan

ISRO has made attempts to make contact with the Vikram lander and Pragyan rover after the lunar night passed and the day arrived — they've had no luck so far.

However, the space agency said they will keep trying.

The next attempt will take place tomorrow, according to Nilesh M Desai, the director of the Space Applications Centre. Read our report.

🗓️ Thursday, 21 September

11.14 am: Hope on the horizon

With a new daybreak at the Moon's south pole, ISRO is preparing to awaken the lander and rover modules of the Chandrayaan-3 mission from their slumber in the freezing lunar conditions.

According to an ISRO official, the ground stations will attempt to revive the lander and rover modules and onboard instruments on Thursday or Friday (21 or 22 September), taking advantage of optimal sunlight.

While the chances of revival are not high, it is not a hopeless situation, either. There is a possibility that the lander or rover module may awaken but not fully regain functionality. Read our report.

🗓️ Saturday, 9 September

6.22 pm: Vikram lander imaged by radar on Chandrayaan-2 orbiter

ISRO shares an image of the Chandrayaan-3 lander as captured by the dual-frequency synthetic aperture radar (DFSAR) instrument on board the Chandrayaan-2 orbiter on Wednesday, 6 September. Read the Swarajya report.

🗓️ Tuesday, 5 September

7.40 pm: Chandrayaan-3 lander in 3D

ISRO has shared a special composite picture of the Vikram lander on the Moon that feels like 3D — but you'll need the right lenses for it.

Chandrayaan-3 lander on the Moon as an anaglyph, shared by ISRO on X
Chandrayaan-3 lander on the Moon as an anaglyph, shared by ISRO on X

The space agency has shared what's called an "anaglyph."

It's a technique that tricks the brain into thinking that a two-dimensional picture is actually three-dimensional.

The idea is to present each eye with a slightly different version of the picture. So, a 3D visual is created by laying two images over one another, each with a different filter, typically red and cyan.

The overlapping images are put together but offset to an extent, creating a perception of depth.

With the use of the lenses corresponding to the filters used, the two images magically combine (thanks, brain) to produce a 3D effect.

"At the most basic level, anaglyphs work by superimposing images taken from two angles," The NASA Earth Observatory explains, with the two images "printed in different colors, usually red and cyan."

To appreciate the picture, the viewer needs glasses with lenses in the same colours. The lenses filter out the unwanted image for each eye.

"The brain, seeing two different pictures through each eye, interprets this as a three-dimensional scene," the Observatory says.

ISRO seems to have taken this route in the creation of its anaglyph image.

"The Anaglyph presented here is created using NavCam Stereo Images, which consist of both a left and right image captured onboard the Pragyan Rover," the space agency said on X.

"In this 3-channel image, the left image is positioned in the red channel, while the right image is placed in the blue and green channels (creating cyan)," it added.

"The difference in perspective between these two images results in the stereo effect, which gives the visual impression of three dimensions."

You'll need to use red and cyan glasses for viewing in 3D.

Now, here's LG UK demonstrating an anaglyph with a touch of humour in a video from 2010:

🗓️ Monday, 4 September

2.54 pm: Lander readies for lunar night

After rover Pragyan on Saturday (2 September), the Vikram lander was set to sleep mode in the morning today, around 8 am.

The lander was moved to a new location yesterday after it had hopped on the lunar surface as part of an experiment. It moved about 30-40 cm away from its original landing site, Shiv Shakti point.

At its new location, the lander's on-board payloads ChaSTE, RAMBHA-LP, and ILSA were put to work on scientific experiments. The data picked up by the instruments were successfully transferred back to Earth.

Just as with Pragyan, Vikram's payloads have been switched off and receivers left on.

"Vikram will fall asleep next to Pragyan once the solar power is depleted and the battery is drained," ISRO said on X, hoping that they both rise and shine around Friday, 22 September.

The space agency has also shared two sets of pre- and post-hop images captured by the lander imager 1 camera.

🚀 Chandrayaan-3 Dashboard: Vikram Lander, Pragyan Rover Not Responding To ISRO's Calls Just Yet
🚀 Chandrayaan-3 Dashboard: Vikram Lander, Pragyan Rover Not Responding To ISRO's Calls Just Yet

11.38 am: Vikram soft-lands again

With all three objectives of the Chandrayaan-3 mission met, and the lunar night fast descending, the Vikram lander has gone ahead and re-done objective one: demonstration of safe and soft landing on the lunar surface.

The Vikram lander remarkably underwent a "hop experiment" with implications for future sample return and human missions.

The lander fired its engines after it was commanded to do so, lifted up off the lunar surface by about 40 cm, and then landed safely at a distance of about 30-40 cm away.

On a tiny but definitive scale, Vikram achieved a 'hop' or 'kick-start' which can be seen as equivalent to a lunar launch and landing.

Whether to bring lunar samples back to Earth or ferry humans to the Moon and back, a lunar launch and landing is essential.

The lander deployed the ramp once again after the second touchdown. The payloads ChaSTE and ILSA were folded back and redeployed successfully, ISRO said.

The experiment was conducted yesterday (3 September).

Watch the video of the experiment on ISRO's X post:

🗓️ Sunday, 3 September

10.49 am: Rover enters sleep before lunar night

ISRO said last night that the Pragyan rover, having completed its assignments, has been safely parked and set in sleep mode.

Its two payloads, which have both yielded scientific results, primarily to do with the detection of sulphur and other elements in the south pole region, have been turned off.

Since the rover can only communicate with the lander, the data from the APXS and LIBS payloads has been transmitted back to Earth via the lander.

ISRO noted that the rover's battery is fully charged and its receiver is kept switched on.

The agency has oriented the rover's solar panel in such a way that it receives light at the next lunar sunrise, expected on Friday, 22 September.

"Hoping for a successful awakening for another set of assignments! Else, it will forever stay there as India's lunar ambassador," ISRO said.

Do not go gentle into that good night,
Old age should burn and rave at close of day;
Rage, rage against the dying of the light.

— Dylan Thomas

🗓️ Sunday, 3 September

10.49 am: Rover enters sleep before lunar night

ISRO said last night that the Pragyan rover, having completed its assignments, has been safely parked and set in sleep mode.

Its two payloads, which have both yielded scientific results, primarily to do with the detection of sulphur and other elements in the south pole region, have been turned off.

Since the rover can only communicate with the lander, the data from the APXS and LIBS payloads has been transmitted back to Earth via the lander.

ISRO noted that the rover's battery is fully charged and its receiver is kept switched on.

The agency has oriented the rover's solar panel in such a way that it receives light at the next lunar sunrise, expected on Friday, 22 September.

"Hoping for a successful awakening for another set of assignments! Else, it will forever stay there as India's lunar ambassador," ISRO said.

🗓️ Saturday, 2 September

4.07 pm: Pragyan is 100 not out

In a landmark development, the Chandrayaan-3 rover has traversed more than 100 metres across the surface of the Moon.

ISRO made the announcement in an X post, but also ISRO Chairman S Somanath provided the update a little earlier during his address at the Satish Dhawan Space Centre, Sriharikota, after India's solar probe Aditya-L1 was successfully injected into Earth orbit.

"Good news is that the rover has moved almost 100 metres from the lander," said Somanath.

The graphic shared by ISRO on X states a total traverse of 101.4 metres.

"We are going to start the process of making the both of them (Vikram lander and Pragyan rover) sleep in the coming one or two days because it has to withstand the night," the ISRO chief added.

The Sun is set to descend on the Moon within about the next four days. The lunar night lasts about 14 Earth days. The lander and rover, which rely on solar power, will be unable to function, receiving no help also from the crazy cold of -200 degrees Celsius, during this period.

🚀 Chandrayaan-3 Dashboard: Vikram Lander, Pragyan Rover Not Responding To ISRO's Calls Just Yet

🗓️ Thursday, 31 August

7.47 pm: New data from ILSA on board Vikram lander

The Instrument for Lunar Seismic Activity (ILSA), a probe on board the Vikram lander, has been recording the movements of Pragyan and its payloads as the rover navigates the lunar surface.

Sometime ago, ISRO shared data of the vibrations recorded during the rover's movements on 25 August.

"Additionally, it (ILSA) has recorded an event, appearing to be a natural one, on August 26, 2023. The source of this event is under investigation," ISRO said in an X post.

ILSA data — I
ILSA data — I
ILSA data — II
ILSA data — II

ILSA is tasked with measuring ground vibrations generated by natural quakes, impacts, and artificial events.

It is the first micro-electro-mechanical systems (MEMS) technology-based instrument on the Moon.

ILSA comprises a cluster of six high-sensitivity accelerometres.

As for how it works, ISRO explains: "The core sensing element consists of a spring-mass system with comb-structured electrodes. External vibrations lead to a deflection of the spring, resulting in a change in capacitance which is converted into voltage."

ILSA was developed by the Laboratory for Electro-Optics Systems (LEOS), with the deployment mechanism built by U R Rao Satellite Centre (URSC). Both the LEOS and URSC centres are based in Bengaluru.

6.59 pm: Langmuir probe measures near-surface plasma content

The plasma near the surface of the Moon is relatively sparse, ISRO finds after an initial assessment of data from the RAMBHA-LP payload on board the Chandrayaan-3 lander.

RAMBHA-LP is short for the Radio Anatomy of Moon Bound Hypersensitive Ionosphere and Atmosphere–Langmuir Probe. It estimates plasma density and its variations.

Plasma consists of freely moving ions and free electrons. Regarded as the "fourth state of matter," it comprises over 99 per cent of the visible universe.

The lander probe has made the first-ever measurements of the near-surface lunar plasma environment over the south polar region.

"The initial assessment indicates that the plasma encompassing the lunar surface is relatively sparse, characterized by a number density ranging from approximately 5 to 30 million electrons per cubic meter," ISRO said.

RAMBHA-LP initial data
RAMBHA-LP initial data

This characterisation is from early in the lunar daytime. However, the probe is operating without interruption, exploring the changes occurring in the near-surface plasma environment throughout the lunar day.

"These quantitative measurements potentially assist in mitigating the noise that Lunar plasma introduces into radio wave communication," ISRO said, adding that the data "could contribute to the enhanced designs for upcoming lunar visitors."

The space agency has provided some details about the workings and deployment of the Langmuir Probe, named after the Nobel-prize-winning chemist Irving Langmuir.

Langmuir had proposed the term 'plasma' in a paper in 1928 to describe a "region containing balanced charges of ions and electrons."

He invented the Langmuir probe, which measures the temperature and density of electrons in a plasma.

RAMBHA-LP was developed by the Space Physics Laboratory (SPL), Vikram Sarabhai Space Centre (VSSC), Thiruvananthapuram.

2.37 pm: ISRO again confirms presence of sulphur

After previously using the Laser-Induced Breakdown Spectroscope (LIBS), ISRO has employed the other rover payload, the Alpha Particle X-ray Spectroscope (APXS), to once again confirm the presence of sulphur in the south pole region of the Moon.

"This finding by Ch-3 compels scientists to develop fresh explanations for the source of Sulphur (S) in the area: intrinsic?, volcanic?, meteoritic?,......?," ISRO said.

In a paper from 1992 titled 'Uses of Lunar Sulfur', Los Alamos National Laboratory scientists had said, "Sulfur deserves serious consideration as a lunar resource."

Besides sulphur, the APXS on board Pragyan rover detected other elements like aluminium, silicon, calcium, and iron.

"Detailed scientific analysis of these observations are in progress," ISRO said.

APXS, the Indian space agency says, is well-suited to carry out an analysis of the elemental composition of soil and rocks on the surface of planetary bodies with little atmosphere, such as the Moon.

The scientific instrument emits alpha particles and X-rays on to the surface. The soil and rocks in the targeted area in turn emit X-ray lines corresponding to various elements.

"By measuring the energies and intensities of these characteristic X-rays, researchers can find the elements present and their abundances," ISRO explains.

The Vikram lander has filmed the operation of APXS. Watch it here.

ISRO's explanation: "The video shows an automated hinge mechanism rotating the 18 cm tall APXS, aligning the detector head to be approximately 5 cm in proximity to the lunar surface."

APXS was developed by the Physical Research Laboratory (PRL) with support from the Space Applications Centre (SAC), both based in Ahmedabad, while Bengaluru-based U R Rao Satellite Centre (URSC) built the deployment mechanism.

'Playful' Pragyan captured by Vikram

In another video shared by ISRO, the Vikram lander captures the Pragyan rover turning around in search of a safe route to take on the lunar surface.

This video, taken by the Lander Imager Camera, is from 29 August.

10.31 am: "Iconic snap" of Vikram lander

ISRO shared a second picture — an "iconic snap" — of the Vikram lander taken by the Pragyan rover.

Pragyan photographs Vikram again
Pragyan photographs Vikram again

This picture is from around 11 am yesterday, with the lander and rover separated by a distance of about 15 m.

🗓️ Wednesday, 30 August

4.43 pm: 'Image of the mission'

Going anywhere exotic demands of the visitor to take pictures, no? Pragyan is no different.

The rover took a picture of Vikram lander this morning and ISRO was kind enough to draw from its photo gallery to share that one picture with us.

The "image of the mission," as ISRO has described it, was taken by the navigation camera (NavCam) on board the rover.

The rover NavCams were developed by the Laboratory for Electro-Optics Systems (LEOS), the developer also of the rover payload LIBS.

Vikram lander as seen by Pragyan rover
Vikram lander as seen by Pragyan rover

A close-up image of the lander shows where two of its payloads, ChaSTE and ILSA, are positioned.

ChaSTE, short for Chandra's Surface Thermophysical Experiment, will help uncover the thermal behaviour — relating to heat — of the Moon's surface.

The Instrument for Lunar Seismic Activity (ILSA) will measure the seismicity around the landing site ('moonquakes').

00.06 am: Sulphur, other elements detected in 'first-ever' measurements

In only the second science result shared by ISRO, a scientific instrument on board Pragyan rover, called the Laser-Induced Breakdown Spectroscope (LIBS), "unambiguously" confirmed "the presence of Sulphur (S) in the lunar surface near the south pole..."

This unambiguous confirmation was "something that was not feasible by the instruments onboard the orbiters," ISRO said.

Additionally, the rover also detected, as expected, aluminium, calcium, iron, chromium, titanium, manganese, silicon, and oxygen.

"Search for Hydrogen (H) is underway," ISRO said.

These findings are part of the first-ever in-situ measurements made on the elemental composition of the lunar surface near the south pole.

How LIBS works: The instrument shoots a high-energy laser pulse on to the lunar surface. The laser pulse generates searing hot, localised plasma.

"The collected plasma light," explains ISRO, "is spectrally resolved and detected by detectors such as Charge Coupled Devices."

In the plasma state, each element emits radiation in its own signature set of wavelength. In this way, it becomes easy to tell which elements are present.

LIBS emission spectrum of the lunar surface
LIBS emission spectrum of the lunar surface

The rover payload LIBS was developed at a Bengaluru-based ISRO centre called The Laboratory for Electro-Optics Systems (LEOS).

🗓️ Monday, 28 August

5.08 pm: Pragyan evades a large crater

The lunar terrain is making things interesting for our rover, as also for the team stationed here on Earth.

Pragyan is said to have retraced its path yesterday, following a command from the Bengaluru mission control, after encountering a crater 4 metres in diameter lying just 3 metres ahead.

The crater was captured by the navigation camera on board Pragyan.

After taking evasive action, the rover was set off on a different route. "It's now safely heading on a new path," ISRO said.

Good job, Pragyan and the control room.

Here are the pictures shared by ISRO:

Pragyan rover evades crater - 1
Pragyan rover evades crater - 1
Pragyan rover evades crater - 2
Pragyan rover evades crater - 2

12.57 pm: Rover negotiates first major crater

In recent good news, the rover reportedly (TOI) overcame the first major obstacle on its path — a lunar crater that is 100 mm (10 cm) deep. Read our report to know more, especially about the challenges faced when directing the rover's movements on the lunar surface.

🗓️ Sunday, 27 August

3.34 pm: Already a lunar profile like never before

After the lander and rover have done their landing and roving jobs, now it's time for some science.

Even with the science, the lander and rover will be the ones to do the job.

Luckily for us, the first science is in!

ISRO has shared the first observations from the 'ChaSTE' payload on board the Vikram lander.

This payload measures the temperature profile of the lunar topsoil.

ChaSTE is short for Chandra's Surface Thermophysical Experiment. It will help us understand the thermal behaviour — which relates to heat — of the Moon's surface.

ISRO has represented the first data picked up by this instrument as a graph. The two parameters plotted are temperature and depth.

The graph tells us how temperature varies with depth on the lunar surface or "near-surface," since measurements are made even up to a small distance beneath the lunar surface, in the south pole region.

For measurements below the surface, a temperature probe drills down into the lunar surface and records the temperature.

According to ISRO, ChaSTE "has a temperature probe equipped with a controlled penetration mechanism capable of reaching a depth of 10 cm beneath the surface." This probe has 10 individual temperature sensors attached to it.

From the graph, we see that just above the lunar surface, the temperature is as high as 50 degrees Celsius. Go beneath the surface by a little over 8 cm and it's a totally different story — the temperature there is about -10 degrees Celsius.

That's a difference of about 60 degrees Celsius over a roughly 9-10 cm distance in the lunar topsoil.

Temperature vs depth on the lunar surface/near-surface
Temperature vs depth on the lunar surface/near-surface

"This is the first such profile for the lunar south pole," ISRO says. Detailed observations are said to be underway.

ChaSTE was developed by a team led by the Space Physics Laboratory (SPL), a premier laboratory of the Vikram Sarabhai Space Centre (VSSC), in collaboration with Physical Research Laboratory (PRL), Ahmedabad.

🗓️ Saturday, 26 August

10.36 pm: Two of three Chandrayaan-3 objectives met

With the lander having landed ('safe and soft landing on the lunar surface') and the rover having roved ('rover roving on the Moon'), ISRO has knocked off two of the three objectives set for the Chandrayaan-3 mission.

Now, over to the third objective: carrying out scientific experiments on the surface of the Moon.

ISRO says that's currently underway and all payloads are performing nominally.

4.11 pm: Rover moves further along

ISRO is slowly but surely revealing Pragyan rover's tiny but definitive advances across the lunar surface.

In the latest video shared by the space agency, the rover is seen moving some distance away from the Shiv Shakti Point, the name of the Vikram lander's landing spot on the Moon, and then turn in place. It almost gives the impression of the rover looking back at the Vikram lander.

In the morning today, ISRO Chairman S Somanath revealed that the rover had already covered a distance of 12 metres across the lunar surface. That is about eight average human strides.

What lunar secrets will the rover uncover in the days to come?

For now, see the video shared by ISRO:

10.53 am: Rover updates, unreleased picture, names for landing sites, and more

Pragyan rover updates

– "Now the rover has already moved 12 metres," ISRO Chairman S Somanath told Prime Minister Narendra Modi while taking him through animated renderings of various deployments undertaken thus far.

– "The rover is almost out of the field of view, it will turn in the day today and look at the lander and take more pictures," he added.

New rover picture

This framed picture presented to PM Modi by Somanath shows the rover some distance away — further than we've seen in all the released images so far — from the lander and making a turn in place.

Quite a milestone for the rover! And there's more to come today.

Framed picture presented to PM Narendra Modi at ISTRAC, Bengaluru
Framed picture presented to PM Narendra Modi at ISTRAC, Bengaluru

Release of images

"These images take a lot of time to come to Earth because data rate and processing," Somanath explained.

India leaves mark on the Moon

– The Chandrayaan-3 touchdown site has been named 'Shiva-Shakti'.

– The day of the Chandrayaan-3 Moon landing, 23 August, will be commemorated as National Space Day every year.

– The Chandrayaan-2 impact site has been named 'Tiranga'.

India's burgeoning space sector

– Citing experts, PM Modi said the Indian space industry will grow from $8 billion to $16 billion over the next few years.

– Over the last four years, the Prime Minister said, the number of startups engaged in the space sector has grown from four to nearly 150 today.

🗓️ Friday, 25 August

6.39 pm: Rover covers good lunar ground

Today's been a good day for anyone worried about the lack of updates about the Pragyan rover.

ISRO reports that the Pragyan rover has traversed a distance of about 8 metres on the surface of the Moon.

For a reference, that would be around the distance covered by two average-sized cars parked back to back.

Further, the space agency said that all planned rover movements have been verified and the rover payloads are turned on.

Referencing our detailed article about the rover, here's the bit about the two rover payloads:

"It is equipped with two payloads for carrying out scientific experiments, namely the Alpha Particle X-ray Spectrometer (APXS) and the Laser Induced Breakdown Spectroscope (LIBS).

Whereas the APXS will try to determine the elemental composition of the lunar soil and rocks around the landing site, the LIBS will be responsible for qualitative and quantitative elemental analysis, deriving the chemical composition, and inferring the mineralogical composition.

The LIBS will come into play through the spectroscopic study of gases emitted from the surface of the Moon after it is melted using lasers.

The work with the APXS, on the other hand, will involve shooting alpha particles on to the lunar surface and creating emissions, and then studying the chemical composition.

The rover will specifically look for the elements magnesium, aluminium, silicon, potassium, calcium, titanium, and iron."

Finally, ISRO has said all payloads on the propulsion module, lander module, and rover are performing nominally.

Phew! Keep on keeping on, little rover.

5.05 pm: What enabled the rover to step on to the lunar soil

For the Pragyan rover to reach the surface of the Moon, one side of the Vikram lander had to pop open and act as a ramp down which the rover had to roll.

Additionally, the rover required powering up, for which a solar panel had to be deployed.

These deployments are seen in a video of the crucial operations shared by ISRO, set to a surprisingly ominous tone. (It's okay, we don't mind the drama :))

"A two-segment ramp facilitated the roll-down of the rover. A solar panel enabled the rover to generate power," ISRO said.

These are among the 26 deployment mechanisms developed at the U R Rao Satellite Centre, Bengaluru, specifically for the Chandrayaan-3 mission.

Watch the mechanisms play out:

11.13 am: Rover's roll-out on to the Moon

Probably what everyone was waiting for — ISRO has shared footage of the Chandrayaan-3 rover exiting the lander module using a ramp and rolling out on to the lunar surface. It was captured by the lander imager camera.

10.35 am: Chandrayaan-3 landing spot

Shanmuga Subramanian, who had discovered the debris from the Chandrayaan-2 Vikram lander in 2019, says his predicted landing location for the Chandrayaan-3 Vikram lander tallies with the spot pinpointed by ISRO through an image captured by the Chandrayaan-2 orbiter.

9.57 am: ISRO has deleted its post on X which shared a picture of the Chandrayaan-3 lander from Chandrayaan-2 in orbit

The contents of the now-deleted post were shared in this update:

9.41 am: Chandrayaan-3 snapped by its predecessor in orbit

ISRO has shared a picture from its orbiter high-resolution camera (OHRC) on board Chandrayaan-2 of the area where the Chandrayaan-3 lander now resides on the Moon.

The space agency has put two pictures from 23 August side by side — one taken in the afternoon, hours before the spacecraft landed, and one taken at night, by which time the Vikram lander had settled in.

Pictures from Chandrayaan-2 in orbit
Pictures from Chandrayaan-2 in orbit

In its post on X, ISRO described the Chandrayaan-2's famed photographer OHRC as "the camera with the best resolution anyone currently has around the moon."

ISRO is flexing, as it must after a historic Moon landing. The OHRC provides the highest-resolution optical images ever from a lunar orbiter platform.

At its best, OHRC images at a resolution of 0.25 metres per pixel, which happens to be twice the best resolution of 0.5 metres per pixel offered by NASA's Lunar Reconnaissance Orbiter (LRO), explains Jatan Mehta, a space writer with a Moon focus.

The camera has a resolution of 0.32 m with a field-of-view of 12 km x 3 km from 100 km altitude.

Not to miss, ISRO has typed out the date of the historic Chandrayaan-3 landing in an interesting way! See their post.

🗓️ Thursday, 24 August

7.54 pm: Lander camera's capture during the powered descent phase

7.16 pm: Lander payloads, rover ops begin

Three payloads on the lander module and the sole payload on the propulsion module were turned on Thursday (24 August) and Sunday (20 August), respectively, ISRO said.

Notably, rover mobility operations have commenced, as well.

Further, all activities are on schedule and all systems normal, the space agency said.

Lander module payloads switched on:

> The Instrument for Lunar Seismic Activity (ILSA) will measure the seismicity around the landing site ('moonquakes')

> Radio Anatomy of Moon Bound Hypersensitive Ionosphere and Atmosphere (RAMBHA) — or the Langmuir Probe (LP) — will estimate the plasma density and its variations

> Chandra’s Surface Thermophysical Experiment (ChaSTE) will measure thermal conductivity and temperature

Propulsion module payload switched on:

> Spectro-polarimetry of Habitable Planet Earth, or SHAPE

It will do two things from its home in lunar orbit, as ISRO outlined recently on X:

– Perform spectroscopic study of the Earth’s atmosphere, and

– Measure the variations in polarisation from the clouds on Earth – to accumulate signatures of exoplanets that would qualify for our habitability

Meanwhile, the wait is on for images of the rover.

10.06 am: India's 'walk' on the Moon

After the historic soft-landing yesterday evening, ISRO today confirmed that the Chandrayaan-3 rover "ramped down from the Lander and India took a walk on the moon !"

The space agency is presumably referring to the imprint of the Indian state emblem, an adaptation of the Lion Capital of Asoka at Sarnath, and ISRO logo that the rover is designed to leave on the lunar surface as it moves about and must have done so as it went for a 'walk'.

"More updates soon," ISRO said.

The space agency referred to the rover as 'Made in India, Made for the Moon.'

In an X post, the President of India Droupadi Murmu congratulated ISRO for having deployed the rover successfully.

With the successful deployment of the rover, ISRO will have executed two of the three objectives identified for the Chandrayaan-3 mission. The third is the carrying out of scientific experiments on the Moon.

🗓️ Wednesday, 23 August

11.51 pm: Congratulatory messages from a likely future Moon mission partner

Lupex, short for the lunar polar exploration mission, is likely to be India's next Moon mission. India on that occasion won't go it alone. The Japan Aerospace Exploration Agency (JAXA) is in discussions with India's ISRO for:

"...an international collaborative mission to obtain the data on the quantity and forms of the water resources present on the Moon, in order to determine the feasibility of utilizing such resources for sustainable space exploration activities in the future," as explained by JAXA.

After the successful landing of Chandrayaan-3, JAXA's Lupex project members sent in their congratulatory messages. They compiled the various sweet messages into a nice graphic and shared it on X. Take a look:

9.51 pm: Pragyan rover process initiated?

And... here's the first image of the Pragyan rover rolling out of the lander on the ramp:

9.38 pm: Image of the Chandrayaan-3 landing site

ISRO has just now shared an image captured by the landing imager camera after the lander set foot on the Moon.

Pictured is Chandrayaan-3's landing site, and you can even see the shadow of a lander leg.

The landing site appears relatively flat, something that ISRO alluded to in a comment with the interesting emoji "🙂".

Chandrayaan-3 landing site imaged by the Vikram lander
Chandrayaan-3 landing site imaged by the Vikram lander

8.24 pm: Lander linked up, plus descent images!

The communication link has been established between the Chandrayaan-3 lander and the Mission Operations Complex (ISTRAC), Bengaluru, ISRO reports.

Plus, the space agency has shared the pictures captured during the lander module's descent using the lander horizontal velocity camera.

Here they are, on ISRO's X feed:

7.07 pm: NASA chief congratulates ISRO

6.53 pm: Nailed the landing phase

The same phase that in 2019 delivered a heartbreak was a source of joy this time around, close to four years later, in 2023.

The powered descent phase involved a cut back of velocity from about 6,000 kilometres per hour to next to nothing.

And the Chandrayaan-3 lander module couldn't count on any assistance from the extraordinarily thin lunar atmosphere.

Let's review the powered descent phase briefly.

The powered descent was carried out by the onboard autonomous landing sequencer or ALS, which is a series of instructions pre-loaded to the lander module.

"These instructions include," as explained on ISRO's soft-landing telecast, "the commands to be executed, data to be collected and analysed, and decisions to be made and executed autonomously throughout the powered descent."

The powered descent is divided into four phases:

Rough braking, to bring the lander altitude down from 30 km to 7.4 km, and the velocity from 1,680 metres per second to 358 metres per second, over a period of roughly 11.5 minutes

Attitude hold, in which two lander sensors make an estimate of the distance in this 10-second phase

Fine braking, in which the lander, only about 800 m from the landing site, turns vertical, the entire phase taking about 3 minutes, after which the lander velocity drops to near-zero

Local navigation or terminal descent, in which two lander engines are shut off; this is the final phase leading to the touchdown

6.20 pm: 'Reached my destination'

6.10 pm: This success is for humanity, says PM Narendra Modi

"India's successful Moon mission is not India's alone.

This is a year when India is witnessing the G20 presidency. Our approach of One Earth, One Family, One Future is resonating across the globe. This human-centric approach that we present and that we represent has been welcomed universally.

Our Moon mission is also based on the same human-centric approach. Therefore, this success belongs to all of humanity. And it will help Moon missions by other countries in the future.

I am confident that all countries in the world, including those from the Global South, are capable of achieving such feats.

We can all aspire to the Moon and beyond."

6.07 pm: Prime Minister Narendra Modi speaks

"We took a promise on Earth and we have fulfilled it on the Moon," he says.


6.02 pm: Vikram lander nearly at zero velocity

Currently only two engines are being fired. Vikram is approaching the Moon's surface.

6.00 pm: Fine braking phase concludes.

We are now in the vertical descent phase.

5.56 pm: Fine braking begins

This phase will last three minutes.

Meanwhile, Prime Minister Narendra Modi has joined virtually from Johannesberg, South Africa.

5.54 pm: Next phase is the attitude hold phase. The fine braking phase will then follow.

5.52 pm: Nominal conditions so far as Vikram descends

5.50 pm: The lander module is propelling towards the Moon.

Vikram is currently in what's called the rough braking phase. This is the first phase of the powered descent.

3.53 pm: Voyager 1 & Chandrayaan-3

Tracking spacecraft, super old and super new, super far and super close:

1.13 pm: We are ready for you, Vikram

In its latest update, ISRO says it's all set to initiate the automatic landing sequence (ALS).

Simply put, the ALS is a sequence of events that's programmed into the lander module so that it can carry out the last phase until touchdown by itself.

The space agency says it's waiting for 5.44 pm. That is when the lander module will arrive where ISRO wants it, and the command from ISRO will follow right after.

"Upon receiving the ALS command, the LM activates the throttleable engines for powered descent," ISRO said, adding, "The mission operations team will keep confirming the sequential execution of commands."

Just a reminder that the live telecast of operations at the Mission Operations Complex (MOX) begins at 5:20 pm today.

See pictures from MOX, as shared by ISRO just a short while earlier:

MOX, Bengaluru
MOX, Bengaluru
MOX, Bengaluru
MOX, Bengaluru

12.40 pm: Sign of good things today?

The CanberraDSN, which is part of NASA's Deep Space Network, shared a sweet morning update today involving a small flock of birds and... Chandrayaan-3's chances? Take a look:

The CanberraDSN will be supporting Chandrayaan-3 all the way.

Its two 34-metre-wide antennas in the Deep Space Network, DSS34 and DSS36, along with the DSS65 antenna of the MadridDSN, will be supporting the powered descent and landing attempt by Chandrayaan 3 today at 6.04 pm, or roughly 12.35 pm UTC.

Follow the tracking on Deep Space Network Now.

Note: "On Deep Space Network Now, you may see intermittently that there are no communications. No cause for concern. That may just be due to the spacecraft passing behind the Moon from our point of view," the CanberraDSN said in an X post.

At its core, the Deep Space Network or DSN is a space messaging service. But it does more than that.

The DSN is NASA’s international array of giant radio antennas that supports interplanetary spacecraft missions, plus a few that orbit Earth.

Operated by the Jet Propulsion Laboratory, the DSN also provides radar and radio astronomy observations that improve our understanding of the solar system and the larger universe.

Obviously, ISRO itself is tracking the spacecraft from Bengaluru, Karnataka, in addition to the European Space Agency (ESA)’s 35-metre deep space antenna in New Norcia, Australia.

New Norcia only now wrapped up its first session of tracking Chandrayaan-3. The session lasted around three hours. Their second session will cover the landing attempt.

🗓️ Tuesday, 22 August

12.38 pm: "Smooth sailing is continuing"

In an update on X, ISRO said the Chandrayaan-3 mission is on schedule, that systems are being subject to regular checks, and that it's all "smooth sailing" thus far.

"The Mission Operations Complex (MOX) is buzzed with energy & excitement!" the space agency said. We can imagine!

As part of this update, ISRO shared more images of the Moon from Saturday, 19 August.

These images were captured by the lander position detection camera (LPDC) from an altitude of about 70 km.

"The LPDC images," ISRO explained, "assist the Lander Module in determining its position (latitude and longitude) by matching them against an onboard moon reference map."

Just like with all the previous images, this set identifies many lunar features which help us become more familiar with Earth's natural satellite.

Watch the video on ISRO's X post:

3.26 pm: And here's another one —

The Moon, as viewed by the lander imager camera 4 on Sunday, 20 August.

It's quite exhilarating to see the surface of the Moon zipping past!

9.50 am: Alternative landing date for Chandrayaan-3

During his meeting with Dr Jitendra Singh, the Union Minister of State (Independent Charge) for Science and Technology, in New Delhi yesterday, ISRO Chairman S Somanath said all systems are working perfectly and no contingencies are expected on launch day.

But what if issues arise?

Speaking to ANI, Nilesh M Desai, Director of ISRO's Space Applications Centre, said should any factor appear unfavourable two hours before the scheduled landing time of around 6.04 pm, Chandrayaan-3 Moon landing will be pushed to Sunday, 27 August.

He added, "No problem should occur and we will be able to land the module on 23 August."

On August 23, two hours before Chandrayaan-3 lands on the Moon, we will take a decision on whether or not it will be appropriate to land it at that time based on the health of the lander module and the conditions on the Moon. In case, if any factor appears to be not favourable, then we will land the module on the Moon on August 27. No problem should occur and we will be able to land the module on August 23.
Nilesh M Desai, Director, Space Applications Centre, to news agency ANI

🗓️ Monday, 21 August

11.34 pm: Chandrayaan-3 status update

ISRO Chairman S Somanath met with Dr Jitendra Singh, the Union Minister of State (Independent Charge) for Science and Technology, in New Delhi today.

During the meeting, Somanath provided an update on the status and preparedness of Chandrayaan-3 for its scheduled Moon landing on the evening of Wednesday, 23 August.

Somanath informed the minister about the health condition of Chandrayaan-3, stating that all systems are working perfectly and no contingencies are expected on launch day.

Over Tuesday and Wednesday, the health of Chandrayaan-3 will be continuously monitored. Additionally, the final landing sequence will be loaded two days in advance and thoroughly tested.

Dr Jitendra Singh expressed his confidence in Chandrayaan-3 successfully achieving a soft landing this time.

He expressed hope that Chandrayaan-3 will script a new history of planetary exploration, according to a Department of Space note.

3.03 pm: "Ch-2 orbiter formally welcomed Ch-3 LM"

A two-way communication has been established between the Chandrayaan-2 orbiter and the Chandrayaan-3 lander module, ISRO said.

According to the space agency, this gives the Mission Operations Complex (MOX) at the ISRO Telemetry, Tracking, and Command Network (ISTRAC) in Bengaluru "more routes to reach" the lander module.

Further, ISRO provided a revised time for the start of the live telecast of the soft-landing event. The new time is 5.20 pm, India time, on Wednesday, 23 August. Earlier, they had stated 5.27 pm as the time. (Refer to the Sunday, 2.53 pm update for more information.)

9.57 am: Fresh images of the Moon

ISRO today shared images of the area on the far side of the Moon.

The pictures were taken on Saturday, 19 August, by a camera on the lander called the Lander Hazard Detection and Avoidance Camera (LHDAC).

This camera has a crucial role to play: it will assist the Vikram lander in locating a safe landing area — one without boulders or deep trenches — as it descends to the surface of the Moon in the all-important south pole region.

The LHDAC was developed at the Space Applications Centre, Ahmedabad, a major research and development centre of ISRO.

Check out the images:

Each of the images identifies a feature on the Moon, for reference.

  • Hayn

  • Boss L

  • Mare Humboldtianum

  • Bel'kovich

🗓️ Sunday, 20 August

4.01 pm: Russia's Luna-25 suffers a crash

In a disheartening development, Russia's Luna-25 spacecraft has crashed into the Moon after it had moved into an uncalculated orbit. Read our report.

2.53 pm: ISRO states landing date & time, shares special message

Chandrayaan-3 is set to land on the surface of the Moon this Wednesday, 23 August, around 6.04 pm, India time, ISRO said in an X post.

Penning a special message, ISRO said India is approaching a "remarkable milestone" in the country's pursuit of space exploration with Chandrayaan-3 "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," the space agency said.

In its note, ISRO described the upcoming soft landing of Chandrayaan-3 as 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," ISRO said.

The space agency has invited all educational institutions, including schools, across the country "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," ISRO said.

The live broadcast will begin on Wednesday (23 August) at 5.27 pm.

The live coverage of the soft-landing will be available, among other platforms, on:

Read ISRO's message.

3.56 am: Russia's lunar mission dealing with a situation

An "emergency situation" occurred with Russia's Luna-25 spacecraft on Saturday (19 August) while it was preparing for its transfer to the pre-landing orbit, according to Roscosmos, Russia's national space agency.

"During the operation, an emergency situation occurred on board the automatic station, which did not allow the maneuver to be performed with the specified parameters," Roscosmos said in a statement posted on Telegram, adding that "the management team is currently analyzing the situation." (The original statement is in Russian.)

The Russian lunar spacecraft is scheduled to land on the Moon's south pole, which is also Chandrayaan-3's destination, on Monday (21 August).

3.13 am: Final deboosting done

ISRO performed the second and final deboosting operation successfully earlier today, just before clock struck 2 am, reducing the lander orbit to 25 km x 134 km.

At its closest point to the Moon in orbit, the Chandrayaan-3 lander is now only 25 km away!

For perspective, over a month ago, as Chandrayaan-3 stood on the launch pad eager to fly, the Moon was about 384,000 km away for our dear moon craft. How far it has come!

"The module would undergo internal checks and await the sun-rise at the designated landing site," ISRO said.

The lander module's powered descent to the surface of the Moon will take place around 5.45 pm, India time, on Wednesday, 23 August.

🗓️ Friday, 18 August

4.11 pm: Lander orbit reduced

ISRO reports a successful deboosting operation that has taken the lander module's orbit down to 113 km x 157 km.

The health of the lander module is declared normal.

The next deboosting operation to further lower the orbit will take place at around 2 am on Sunday (20 August), India time.

Will you be awake for it? 😊

First deboosting operation for the lander module
First deboosting operation for the lander module

3.41 pm: Chandrayaan-3's new 'Chandra' captures

We've received new visual treats of the Moon from on board Chandrayaan-3 just before the weekend.

ISRO has shared not one but two views of the Moon, taken on different days.

One is the Moon as captured by the lander position detection camera on India's Independence Day (15 August).

Watch it here:

Next up... the Moon as captured by the lander imager camera 1 yesterday (17 August), soon after the separation of the lander module from the propulsion module.

🗓️ Thursday, 17 August

1.54 pm: "'Thanks for the ride, mate!'"

ISRO has confirmed the successful separation of the lander module from the propulsion module.

"'Thanks for the ride, mate!👋'" says Chandrayaan-3 lander in ISRO's cool take.

The plan next is for the lander to descend to a slightly lower orbit. That will be accomplished with a deboosting manoeuvre that ISRO has planned for around 4 pm tomorrow (18 August), India time.

As for the propulsion module, it now joins India's two existing orbiters around Moon to become the third satellite to Earth's natural satellite.

The propulsion module will remain in its orbit around the Moon for at least a few months and hopefully for many years.

Kudos to the propulsion module! It took the lander-rover module all the way to lunar orbit and then bid it goodbye for the business end of the Chandrayaan-3 journey.

Besides, the propulsion module is not an empty vessel. It hosts the SHAPE payload.

SHAPE is short for "Spectro-polarimetry of Habitable Planet Earth."

This scientific payload was developed by ISRO's U R Rao Satellite Centre, Bengaluru.

It will do two things, as ISRO has clearly stated in an X post:

– Perform spectroscopic study of the Earth’s atmosphere, and

– Measure the variations in polarisation from the clouds on Earth – to accumulate signatures of Exoplanets that would qualify for our habitability!

Cool, isn't it?

The 2,148 kg, 758 W propulsion module communicates with the Indian Deep Space Network (IDSN).

The IDSN, commissioned in 2008 at Byalalu village near Bengaluru, forms the ground segment for providing deep space support for India’s space science missions.

The IDSN complex comprises deep space antennas of 18 m and 32 m, capable of supporting interplanetary missions. It also houses a 11 m antenna facility to support Earth-bound scientific missions.

Lander separates from the propulsion module
Lander separates from the propulsion module

🗓️ Wednesday, 16 August

10.12 am: ✅ Final lunar-bound manoeuvre done

ISRO today successfully placed the Chandrayaan-3 into an orbit of 153 km x 163 km, as intended.

With this latest firing, it's a wrap on the lunar-bound manoeuvres.

"It’s time for preparations as the Propulsion Module and the Lander Module gear up for their separate journeys," ISRO said in an X post.

What next: The lander module will separate from the propulsion module tomorrow; that is, Thursday, 17 August. Isn't that exciting?

The lander module comprises the Vikram lander and Pragyan rover.

We are now only a week away from the soft-landing attempt on the Moon.

🗓️ Monday, 14 August

12.56 pm: Spacecraft only 177 km away from the Moon

ISRO confirmed just after noon that a precise manoeuvre performed today has achieved a near-circular orbit of 150 km x 177 km for Chandrayaan-3.

Previously, the spacecraft was in an elliptical orbit of 174 km x 1437 km.

"Orbit circularisation phase commences," the space agency said.

Chandrayaan-3 will ultimately be guided to a 100 km circular orbit before the crucial final phase, beginning with lander separation, is initiated.

Watch out for ISRO's next move, planned for around 8.30 am on Wednesday, 16 August, India time.

Just for perspective, Chandrayaan-3 is now only 177 km away from the Moon at the farthest point in the lunar orbit. There was a time around mid-July, just before launch, when the Moon was about 384,000 km away from it. Way to go!

🗓️ Friday, 11 August

4.10 pm: Russia off to the Moon

The Russian Moon mission took off earlier today. This is the country's first lunar mission since 1976, and they are targeting a soft landing in the south pole region, just like Chandrayaan-3.

We have written about it all here.

According to Yuri Borisov, the head of the Russian space agency Roscosmos, the Luna-25 lander is expected to touch down on the Moon on 21 August, as reported by news agency Interfax.

Roscosmos had previously announced 23 August as the landing date.

Chandrayaan-3, as you know, is likely to arrive at the Moon's surface on 23 August.

The Russian lander, therefore, could potentially reach the Moon's surface before or around the same time as its Indian counterpart, the Vikram lander of Chandrayaan-3.

Although this development might get billed as a "race" to the lunar surface, it's better to see the bigger picture and wish both lunar missions the best, just as ISRO graciously did in a tweet today morning.

🗓️ Thursday, 10 August

11.41 am: Earth and Moon, as viewed from Chandrayaan-3

For a Thursday morning treat, ISRO shared images of the Earth and Moon as captured by the cameras on board the Chandrayaan-3 lander.

The Earth image was taken by the lander imager camera on Friday, 14 July, the day of the Chandrayaan-3 launch.

Earth from Chandrayaan-3
Earth from Chandrayaan-3

The Moon image was taken by the lander horizontal velocity camera on Sunday, 6 August, a day after Chandrayaan-3 was inserted into lunar orbit.

Moon from Chandrayaan-3
Moon from Chandrayaan-3

The lander imager camera and lander horizontal velocity camera were developed by the Space Applications Centre (SAC), Ahmedabad, and the Laboratory for Electro-Optics Systems (LEOS), Bengaluru, respectively.

Fun fact: The LEOS, situated in Bengaluru's Peenya Industrial Estate, was where the first Indian satellite was fabricated, in 1975.

Moon features marked by ISRO

> Pythagoras: Lunar crater, 129 km in diameter and 4.8 km deep, located near the Moon’s northwest limb; the crater is from the Eratosthenian period — one of the five periods on the lunar geological time scale — spanning 3,200 million years ago to 1,100 million years ago.

> Aristarchus: Impact lunar crater, about 40 km in diameter and 2.7 km deep, and plateau; it is one of the most geologically complex areas on the Moon, NASA says.

> Raman: Small impact lunar crater, previously called Herodotus D, a satellite crater of Herodotus, before being renamed by the International Astronomical Union (IAU); it is named after the Nobel-prize-winning Indian physicist Sir Chandrasekhara Venkata Raman.

> Eddington: Lava-flooded remnant of a lunar impact crater, located on the western part of Oceanus Procellarum; it is named in honour of English astronomer, physicist, and mathematician Sir Arthur Stanley Eddington.

> Oceanus Procellarum: Latin for 'Ocean of Storms', it's the largest of lunar maria or seas and, therefore, gets the name ocean; it's situated on the western edge of the visible side of the Moon and extends over 2500 km along its north-south axis and covers an area of about 4 million sq m.

🗓️ Wednesday, 9 August

2.19 pm: ✅ Second orbit reduction

ISRO has reported success with its second orbit reduction manoeuvre, bringing Chandrayaan-3 "even closer to the moon’s surface."

The spacecraft's orbit is now reduced to 174 km x 1437 km.

The next Moon-bound manoeuvre will take place between 11.30 am and 12.30 pm on Monday, 14 August 2023.

Meanwhile, ISRO Chairman S Somanath recently made a strong statement about Chandrayaan-3's chances of soft-landing on the Moon, a key objective.

He said essentially that as long as the propulsion system works well, we are good for a landing.

If everything fails, if all the sensors fail, nothing works, still it (Vikram) will make a landing. That's how it has been designed — provided that the propulsion system works well.
S Somanath, 'Chandrayaan-3: Bharat's Pride Space Mission'

Plus, have you heard of Russia's lunar lander mission yet? They are taking off soon. They have planned to clear a village in the country's far east in the early morning on launch day, 11 August.

🗓️ Sunday, 6 August

11.58 pm: Chandrayaan-3 orbit around Moon

ISRO successfully carried out a planned orbit reduction manoeuvre at about 11 pm today to bring the Chandrayaan-3 closer to its destination.

"The retrofiring of engines brought it closer to the Moon's surface, now to 170 km x 4313 km," ISRO said in its customary Twitter update.

That's excellent, no?

Check this ISRO graphic accompanying their Twitter update:

Chandrayaan-3 orbit reduced
Chandrayaan-3 orbit reduced

Of course, more moves are planned to accomplish further reduction of orbit. The next operation is scheduled for Wednesday, 9 August, between 1 pm and 2 pm, India time.

11.31 pm: The Moon, as viewed from Chandrayaan-3

ISRO has given us a fantastic up-close view of the Moon, as seen by Chandrayaan-3 during its insertion into the lunar orbit just yesterday.

Looking up at the night sky, the Moon is there for us to see on most days — near enough to appreciate it fondly but far enough never to take it for granted.

With such footage as that shared by ISRO, a whole different world from ours, about 384,000 kilometres away, immediately feels like it's within our humble reach.

Watch the video here.

In a Twitter post, businessman Anand Mahindra thanked ISRO for "igniting our dreams."

🗓️ Saturday, 5 August

10.14 pm: ✅ Lunar orbit insertion

Chandrayaan-3 has been successfully inserted into the lunar orbit, ISRO said just sometime back.

The spacecraft was commanded from the Mission Operations Complex (MOX) at the ISRO Telemetry, Tracking, and Command Network (ISTRAC) in Bengaluru for "a retro-burning at the Perilune."

Perilune refers to the point in an orbit closest to the Moon.

The operation began at 7.12 pm and lasted 1,835 seconds, or about 30 and a half minutes. It resulted in an orbit of 164 km x 18,074 km for Chandrayaan-3, as was the plan.

This marks the third ocassion in a row that "ISRO has successfully inserted its spacecraft into the lunar orbit, apart from doing so once into the Martian orbit," the space agency said in a one-page brief about the operation today.

The next operation, ISRO said, is a reduction of orbit, scheduled for 6 August 2023, between 10.30 pm and 11.30 pm, India time.

This move will be part of a series of orbit reduction manoeuvres that will also position Chandrayaan-3 over the lunar poles.

There will then come a point when the lander will separate from the propulsion module in orbit.

"Following that," says ISRO, "a series of complex braking maneuvers will be executed to facilitate a soft landing in the South Polar region of the Moon on August 23, 2023."

The space agency has reported normal health for the Chandrayaan-3 spacecraft.

Its health is being monitored from ISTRAC, the Indian Deep Space Network antenna at Byalalu, near Bengaluru, with the support of the European Space Agency (ESA) and the Jet Propulsion Laboratory (JPL) Deep Space Network.

🚀 Chandrayaan-3 Dashboard: Vikram Lander, Pragyan Rover Not Responding To ISRO's Calls Just Yet

🗓️ Friday, 4 August

2.46 pm: How far is Chandrayaan-3 now?

ISRO reveals the spacecraft has covered about two-thirds of the distance to the Moon.

FYI: The Earth-Moon distance, on average, is 384,400 km.

Next up is the lunar orbit injection (LOI), set to take place tomorrow around 7 pm, India time.

Then, just like we had the Earth-bound manoeuvres before, some Moon-bound manouevres are lined up next.

Over the course of these moves, the spacecraft will be brought down to a 100 km x 100 km circular orbit, after which the lander will separate from the propulsion module.

Chandrayaan-3 getting there (Photo: ISRO/Twitter)
Chandrayaan-3 getting there (Photo: ISRO/Twitter)

🗓️ Tuesday, 1 August

5.31 pm: Chandrayaan-3 in new orbit

ISRO reports that the midnight perigee burn has raised the Chandrayaan-3 orbit up to 288 km x 369,328 km.

"In this orbit, the spacecraft enters the moon’s sphere of influence," the space agency said, adding, "A crucial maneuvre at perilune would achieve the Lunar Orbit Injection (LOI)."

Perilune refers to the point in an orbit closest to the Moon. Apolune, on the other hand, is the point in an orbit farthest from the Moon.

Going by the plan, ISRO will perform perilune manoeuvres to finally bring the Chandrayaan-3 down to a 100 km x 100 km circular orbit, after which the lander will separate from the propulsion module.

But that's all for later.

For now, the spacecraft’s health is confirmed to be normal.

Let's await Chandrayaan-3‘s orbits around the Moon.

12.59 am: Off it goes to the Moon!

ISRO's update is in. After completing its orbits around Earth, Chandrayaan-3 is now headed towards the Moon.

ISRO has injected Chandrayaan-3 into the translunar orbit after a successful perigee firing, performed at ISTRAC, Bengaluru.

"Next stop: the Moon 🌖," the space agency said in a tweet.

Four days later, ISRO will carry out the lunar orbit insertion. Mark the date: 5 August. It will be a Saturday.

Next stop: the Moon 🌖
Next stop: the Moon 🌖

🗓️ Monday, 31 July

12.11 pm: Road to the Moon

Soon, ISRO will slingshot the Chandrayaan-3 spacecraft towards the Moon.

The 'translunar injection' manoeuvre is fast approaching. It will take place on Tuesday, 1 August, between 12 midnight and 1 am, India time.

The move is expected to last between 28 minutes and 31 minutes, as per journalist Chethan Kumar's report in The Times of India.

The thrusters on board Chandrayaan-3 will fire when the spacecraft is at the perigee, the closest point to Earth, where its velocity will be the highest in its elliptical orbit around Earth, the report explains.

The spacecraft will then exit the Earth's influence and head definitively towards the Moon before it gets captured, days later, in a lunar orbit. A set of Moon-bound manoeuvres will then follow, leading up to the grand landing event.

In the run up to this major move, watch the 3D animation of the Chandrayaan-2 journey published by ISRO in June 2019. It shows the Earth-bound manoeuvres as well as the slingshot towards the Moon, and all the rest of it. By watching it you'll know what to expect.

In addition, take a look at this ISRO graphic indicating the various manoeuvres, first around Earth, then to the Moon, and then around the Moon, for an idea of the journey.

Chandrayaan-3 will soon head towards the Moon
Chandrayaan-3 will soon head towards the Moon

🗓️ Thursday, 27 July

10.36 am: Chandrayaan-3 in new orbit

ISRO confirmed last night in a tweet that the Moon craft has achieved an orbit of 127,603 km x 236 km, just as was planned after the fifth orbit-raising manoeuvre.

🗓️ Tuesday, 25 July

3.06 pm: ✅ Earth-bound firing 5

ISRO performs another Earth-bound firing successfully from ISTRAC. This is the fifth one.

The space agency said the spacecraft will attain an orbit of 127,609 km x 236 km, adding, "The achieved orbit will be confirmed after the observations."

This concludes Chandrayaan-3's five Earth-bound maneouvres.

The next move will be the translunar injection, planned for 1 August 2023 between 12 midnight and 1 am, India time.

Fifth orbit-raising manoeuvre done
Fifth orbit-raising manoeuvre done

🗓️ Thursday, 20 July

9.50 pm: Orbit after fourth burn

According to ISRO's latest update, Chandrayaan-3 has attained a 71,351 km x 233 km orbit, as planned.

4.12 pm: ✅ Earth-bound firing 4

ISRO reports the successful completion of the fourth orbit-raising manoeuvre.

As always, the move was performed at ISTRAC/ISRO, Bengaluru.

The next firing is planned for Tuesday, 25 July, between 2 pm and 3 pm IST, ISRO said in a tweet.

It's a special day today as far as the Earth's natural satellite goes. Today is International Moon Day. ISRO made a reference to it in its tweet update.

The International Moon Day is a United Nations-designated international day to be observed annually on 20 July.

The resolution to the effect, under the banner of "International cooperation in the peaceful uses of outer space," was adopted by the General Assembly on 9 December 2021.

The International Moon Day, or 20 July, marks the anniversary of the first landing by humans on the Moon as part of the Apollo 11 lunar mission.

On this day in 1969, US commander Neil Armstrong and lunar module pilot Buzz Aldrin landed the Apollo lunar module “Eagle” on the surface of the Moon and kicked open the door to human lunar exploration.

A little over five decades later, India is making moves to advance the lunar exploration journey initiated by the US in 1969.

Not a bad day for ISRO's Earth-bound perigee firing to propel Chandrayaan-3 a little closer to the Moon, eh?

🗓️ Tuesday, 18 July

8.59 pm: Chandrayaan-3 in new orbit

ISRO tweeted the Moon craft's new orbital parameters hours after confirming the completion of the third orbit-raising manoeuvre.

As planned, the spacecraft is now in a 51,400 km x 228 km orbit.

The major change is to the apogee, which was previously 41,603 km.

Meanwhile, check out this very cool Chandrayaan-3 orbit animation created by Sankaranarayanan Viswanathan.

Sankar describes himself as a "software craftsman" who is passionate about computing, astronomy, science, and photography.

He has previously developed spacecraft orbit animations for Chandrayaan-2 (ISRO), Mars Orbiter Mission (ISRO), and New Horizons (NASA) for educational purposes.

And, while you're at it, see this timelapse created by the Virtual Telescope Project using 15 July data.

It's a thrill to see the Chandrayaan-3 zipping through space against a background of celestial bodies.

3.22 pm: ✅ Earth-bound firing 3

ISRO has successfully carried out the third orbit-raising manoeuvre from ISTRAC, Bengaluru.

The mission is on schedule, the space agency said.

The next firing is planned for Thursday, 20 July, between 2 pm and 3 pm IST.

🗓️ Monday, 17 July

1.35 pm: ✅ Earth-bound firing 2

ISRO has confirmed the successful completion of the second orbit-raising manoeuvre.

According to journalist Chethan Kumar, the "firing lasted only for 42-odd seconds."

This second Earth-bound firing has lifted the spacecraft up to a 41,603 km x 226 km orbit.

The major change is to the perigee (term defined in the previous update), which has gone up from 173 km to 226 km.

The space agency has revealed that the next firing is planned for Tuesday, 18 July, between 2 pm and 3 pm IST.

Three more Earth-bound firings are planned including the one on Tuesday.

🗓️ Sunday, 16 July

10.37 am: ✅ Earth-bound firing 1

ISRO tweeted last night that they successfully performed the first orbit-raising manoeuvre at ISTRAC, Bengaluru. ISTRAC is short for ISRO Telemetry Tracking and Command Network.

The spacecraft was placed in a 41,762 km x 173 km orbit.

After the launch on Friday, the LVM-3 rocket had placed Chandrayaan-3 in an elliptic parking orbit of roughly 36,500 km x 170 km.

The two numbers representing the orbit specify the apogee (the number on the left) and perigee (the number on the right). The apogee and perigee tell us the farthest and closest points from Earth in an orbit, respectively.

The first orbit-raising manoeuvre, therefore, made a major change to the spacecraft's apogee. The next move will see the perigee rise significantly.

Four more orbit-raising manoeuvres (after the one performed now) are planned before Chandrayaan-3 is sent decisively towards the Moon.

The Chandrayaan-3 orbital journey
The Chandrayaan-3 orbital journey

The health of the spacecraft is reported to be normal.

ISTRAC: It provides tracking support for all the satellite and launch vehicle missions of ISRO. Additionally, it provides space operations support for India's deep space missions.

The ISTRAC network comprises ground stations in Bengaluru, Lucknow, Mauritius, Sriharikota, Port Blair, Thiruvananthapuram, Brunei, Biak (Indonesia), and the Deep Space Network Stations.

And... Never a bad time to watch the majestic Chandrayaan-3 launch another time — especially if it includes 33 seconds of onboard camera views.

🗓️ Friday, 14 July

6.25 pm: Speaking to the media after the successful launch of Chandrayaan-3, ISRO Chairman S Somanath revealed many significant details. Highlights:

The schedule, if all goes according to plan:

– Translunar injection, which is when Chandrayaan-3 will leave Earth orbit for the Moon, will take place on 1 August.

– The separation of the propulsion and lander modules will take place on 17 August.

– The final powered descent and landing will take place on 23 August at 5.47 pm IST.

Importance of the Moon landing

"Chandrayaan3 is a very important step. First, we did an orbital mission around Moon, we did an orbital mission around Mars, and we tried for a landing mission on the Moon. But we couldn't do it the last time. So, landing this time is very important.

"Unless you land, you cannot actually take samples, you cannot land human beings, you cannot create Moon bases. So, landing is one important step for further exploration."

Two areas of interest with Chandrayaan-3

"We are focusing on specifically two areas — to find out the geophysical or thermophysical and chemical characteristic of the regolith, the surface of the Moon.

"Second is, we are trying to study the very close atmosphere near to the surface of the Moon.

And we want to study this only towards the (unexplored) south pole."

Cost of the project

The cost of the Chandrayaan-3 project is over Rs 600 crore.


– "Let us all pray for Chandrayaan-4. If this will happen, very good. We will have Chandrayaan-4."

How the industry is playing its part

– Industry contribution to the LVM3 rocket is phenomenal. As much as "85 per cent of the money spent on the LVM3 rocket is in industry." Only 15 per cent of the work was done within ISRO.

– "The entire materials, the entire manufacturing of everything that you are seeing outside the rocket, also inside the rocket, is... coming from industry. Only the final processing part, quality control, the mission design, the final operations only done by ISRO."

– Many industry players are working within ISRO's facilities via the GOCO mode — Government-owned company operated mode. They are producing critical systems, such as nearly all of the RF systems in the LVM3 rocket, within ISRO presently and will be able to do so by themselves in the future.

– In comparison, the industry contribution to satellites is lower.

3.28 pm: The Prime Minister tweets after a successful launch

2.51 pm: "Congratulations India," says ISRO Chairman S Somanath, speaking at SDSC-SHAR (Sriharikota) after Chandrayaan-3 was placed into intended orbit successfully.

Chandrayaan-3 has begun its journey to the Moon. The health of the spacecraft is normal, ISRO reports.

2.45 pm: 'Stage performance normal'

Chandrayaan-3 is knocking off one stage after another successfully. It's on its way to Earth orbit.

2.36 pm: We have lift-off!

The LVM3-M4 rocket has lifted off with Chandrayaan-3.

Lift off🚀 (Photo: LVM3-M4/CHANDRAYAAN-3 MISSION/Twitter)
Lift off🚀 (Photo: LVM3-M4/CHANDRAYAAN-3 MISSION/Twitter)

2.29 pm: Take a quick look at the Chandrayaan-3 journey:

India's journey to the Moon, as shared by ISRO
India's journey to the Moon, as shared by ISRO

2.18 pm: Chandrayaan-3 launch authorised

Mission Director S Mohana Kumar has cleared the start of the Chandrayaan-3 automatic launch sequence after receiving confirmation of all the clearances.

The launch sequence begins at T-14 minutes and 30 seconds. It is in progress right now.

2.07 pm: ISRO live from mission control

Follow the live stream here:

12.28 pm: "14th July 2023 will always be etched in golden letters..."

Prime Minister Narendra Modi has shared a special Twitter thread ahead of the Chandrayaan-3 launch. Highlights:

> "This remarkable mission will carry the hopes and dreams of our nation."

> "Chandrayaan-1 is considered to be a path breaker among global lunar missions as it confirmed the presence of water molecules on the moon. It featured in over 200 scientific publications around the world."

> "Maybe in the future, it (the Moon) can be potentially inhabited!"

> "The key scientific outcomes from Chandrayaan 2 include the first ever global map for lunar sodium, enhancing knowledge on crater size distribution, unambiguous detection of lunar surface water ice with IIRS instrument and more."

Read the Prime Minister's thread in full:

11.54 am: Where Chandrayaan-3 will land

Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, has tweeted an image of the targeted landing site for Chandrayaan-3.

11.12 am: Global ground station support for Chandrayaan-3

ISRO has a 32-metre deep space tracking station near Bengaluru, Karnataka, which enables it to locate, track, command, and receive data from a spacecraft.

But when the spacecraft goes outside the field of view of its antenna, ISRO operators need external assistance to track or command the spacecraft.

So, for Chandrayaan-3, in addition to ISRO’s own deep space communication antenna, the mission will receive support from ground stations around the world, coordinated by ESA and NASA.

Ground stations send data to and receive data from spacecraft. They use big satellite dishes to do so.

It really helps to communicate with whatever it is that we are sending out there in the vastness of space, you know?

"Without ground station support, it’s impossible to get any data from a spacecraft, to know how it’s doing, to know if it is safe or even to know where it is," says ESA.

The ESA has shared a graphic that notes the ground stations supporting Chandrayaan-3. Take a look:

Ground station support for Chandrayaan-3
Ground station support for Chandrayaan-3

"ESA’s 15 m antenna in Kourou, French Guiana, will be used to track Chandrayaan-3 during the days after launch to help ensure that the spacecraft survived the rigours of lift off and is in good health as it begins its journey to the Moon," the space agency explained.

As the spacecraft moves away from Earth, it will be over to the 32-metre antenna operated by Goonhilly Earth Station Ltd in the UK.

According to ESA, "Goonhilly will support Chandrayaan-3’s propulsion and lander modules. Crucially, it will support the lander during the entire phase of lunar surface operations, helping to ensure that science data acquired by the rover arrives safely with ISRO in India."

European support to the Chandrayaan-3 mission will last from launch day until the end of the Pragyan rover’s lunar surface operations.

Read all about the Pragyan rover.

9.59 am: We are at launch day.

Just as a reminder, the launch time is 2.35 pm.

The countdown is progressing at Sriharikota, ISRO has said, providing a couple more updates:

– Propellant filling in the L110 stage is completed.

– Propellant filling in the C25 stage is commencing.

Meanwhile, read about how ISRO developed the cryogenic engine that will install Chandrayaan-3 in orbit around Earth, written by Swarajya's Prakhar Gupta.

🗓️ Thursday, 13 July

1.18 pm: Countdown commences

The countdown to the Chandrayaan-3 launch has begun.

The precise time of launch tomorrow is 14:35:17 IST. The livestream proceedings will begin earlier, at 2 pm, on ISRO's YouTube channel.

Along with this update, ISRO tweeted the link to the Chandrayaan-3 curtain-raiser video, which we shared with you in an update earlier today.

11.53 am: Prayers offered at Tirupati temple

With the Chandrayaan-3 launch a day away, a team of ISRO scientists offered prayers at the Tirupati temple early morning today.

The scientists also carried with them a miniature model of Chandrayaan-3.

ISRO Scientific Secretary Shantanu Bhatawdekar was among the scientists who visited the Tirupati Venkatachalapathy Temple in Andhra Pradesh.

ANI has tweeted out the video.

Besides, have you seen ISRO's Chandrayaan-3 curtain raiser video? The points covered in the video:

– Importance of studying the Moon

– A review of the Chandrayaan programme and its achievements

– From Earth to Moon, the journey that Chandrayaan-3 will undertake

– The importance of the landing site

– Scientific instruments on Chandrayaan-3 and their purpose

Watch the video here.

🗓️ Wednesday, 12 July

7.41 pm: Countdown just a day away

The mission readiness review was completed today, ISRO confirmed.

"The board has authorised the launch," the space agency said in a tweet.

The countdown begins tomorrow; that is, Thursday.

Save the link to watch the launch live on 14 July. Proceedings begin at 2 pm, with the launch slated for 2.35 pm.

🗓️ Tuesday, 11 July

4.14 pm: Launch rehearsal done

ISRO has reported concluding the Chandrayaan-3 launch rehearsal.

The space agency simulated the entire launch preparation and process taking all of 24 hours.

As they say, practice makes perfect.

🗓️ Monday, 10 July

7.10 pm: 'Failure-based design in Chandrayaan-3'

Speaking on the sidelines of India Space Congress 2023 earlier today, here's what ISRO Chairman S Somanath said about what went wrong with Chandrayaan-2 and how it's rectified now in the third mission:

"We were trying to target a landing in a particular spot, closer to the South Pole, that is 70 degrees to the South Pole, and in doing so, we faced certain challenges."

The five engines responsible for the retardation, or reduction of the velocity, of the Chandrayaan-2 lander "developed a little higher thrust than that was expected," Somanath said.

This was coupled with the lander's desperation to land at its designated spot even when it was still far away, thereby increasing its velocity, which was already very high, even if still within the specifications.

"So, there was a contradictory requirement of reaching to the exact spot and, at the same time, achieve a low velocity. It became mathematically difficult for it to do it in the available time. So, finally, when it actually did it, it was (sic) fell short of almost half a kilometre and the velocity of touch was higher," the ISRO chief said.

As to what needed to be rectified in Chandrayaan-3, Somanath said, "We found that... we must give more flexibility to the craft to handle dispersions, essentially."

"So, instead of success-based design in Chandrayaan-2, we are doing a failure-based design in Chandrayaan-3. What all can fail, and how to protect it — this is the approach that we have taken...," he said.

As for a concrete change, ISRO has expanded the area of landing for the Chandrayaan-3 lander, from 0.5 km x 0.5 km in Chandrayaan-2 to 4 km x 2.5 km in the next instalment.

Watch the ISRO chief explain all this and more in a video clip tweeted by news agency ANI:

3 pm: We are just under four days out from the launch of Chandrayaan-3.

It's an exciting time as India will soon lift off once again for the Earth's neighbour, the Moon, committed to sticking the landing this time and completing the mission as planned.

ISRO revealed launch details via Twitter on Thursday, 6 July. Have you marked your calendar yet?

Although the launch is slated for 14 July, the launch window is open from 12 July to 19 July.

Just a day before the launch announcement, on 5 July, the Chandrayaan-3 assembly was mated with the rocket chosen for the mission — the Launch Vehicle Mark 3, or simply LVM3 — at the Satish Dhawan Space Centre, Sriharikota.

The LVM3 is the operational heavy-lift launch vehicle of ISRO that has turned over six successful missions in a row. It was previously known as the Geosynchronous Launch Vehicle Mark 3 (GSLV Mk III).

The specific LVM3 rocket that will launch Chandrayaan-3 is called LVM3-M4. The "M4" in the rocket name signifies that the Chandrayaan-3 will be this launch vehicle's fourth operational mission.

LVM3-M4 will lift off from the Second Launch Pad at the Sriharikota spaceport.

On the day after the assembly, the LVM3-M4 launch vehicle–Chandrayaan-3 integrated assembly began moving gingerly towards the launch pad in the early hours of 6 July.

Later that afternoon, the journey to the launch pad was completed, opening up the final stage of preparations for the launch. Take a look at the pictures shared by ISRO:

ISRO also shared a video of the launch vehicle's movement towards the launch pad. Check it out:

ISRO had offered Indian citizens the opportunity to witness the Chandrayaan-3 launch directly from the Launch View Gallery at Sriharikota. Unfortunately, the registration is closed by now.

Chandrayaan-3, the Basics

Coming nearly four years after the partially successful Chandrayaan-2 mission, Chandrayaan-3 aims to demonstrate end-to-end capability in safe landing and roving on the lunar surface with the lander and rover.

The landing has to be a "soft landing" — which, roughly speaking, is the opposite of a hard landing or crash landing. So, the idea is to have to a controlled descent of the Chandrayaan-3 lander, called Vikram, with it ultimately landing intact.

Roving refers to the movement of the Pragyan rover on the lunar surface after the lander has touched down. The rover will carry out in-situ chemical analysis of the lunar surface as it moves about on the Moon.

The lander will touch down with the rover in the south polar region of the Moon, near 69.37 S, 32.35 E.

The mission life for the lander-rover unit is one lunar day, which approximately amounts to 14 Earth days.

The lander and rover make up the Chandrayaan-3 integrated assembly along with the propulsion module.

The job of the propulsion module is to ferry the lander-rover configuration all the way up to a 100-km circular polar orbit around the Moon.

But, of course, it comes into play only after the LVM3 rocket has placed the integrated spacecraft in an elliptic parking orbit (EPO) of size approximately 170 x 36,500 km.

The lander, rover, and propulsion modules have payloads.

Lander payloads

  • Chandra’s Surface Thermophysical Experiment (ChaSTE) will measure thermal conductivity and temperature.

  • The Instrument for Lunar Seismic Activity (ILSA) will measure the seismicity around the landing site.

  • The Langmuir Probe (LP) will estimate the plasma density and its variations.

  • A Laser Retroreflector Array from NASA will be a passive experiment to understand the dynamics of the Moon system.

ISRO has also listed several advanced technologies present in the lander.

Rover payloads

The Alpha Particle X-ray Spectrometer (APXS) and Laser-induced Breakdown Spectroscope (LIBS) for deriving the elemental composition in the vicinity of the landing site.

Propulsion module payload

It's called the Spectro-polarimetry of Habitable Planet Earth (SHAPE) and will study the spectral and polarimetric measurements of Earth from the lunar orbit. It will begin its operation after separation from the lander-rover unit.

Chandrayaan-3, the three major elements (Image: ISRO)
Chandrayaan-3, the three major elements (Image: ISRO)

Check out ISRO's dedicated Chandrayaan-3 webpage for more details, but also for pictures. And for even more details, read the Chandrayaan-3 brochure.

Let's not forget: The Chandrayaan-3 mission is expected to be a stepping stone for future interplanetary missions by ISRO.

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