Chandrayaan 4: Mission, Launch and Discussions

[SSridhar]

Please use this thread to track all developments on the Chandrayaan 4 Mission.

Recent historic space achievements of Bharat;

1) Chandrayaan 3: viewtopic.php?t=7922

2) Gaganyaan: viewtopic.php?t=7954

2) Aditya-L1: viewtopic.php?t=7930

3) Mangalyaan: viewtopic.php?t=6678

[SSridhar]

In a first, Isro to launch 2 vehicles for Chandrayaan-4 mission; spacecraft to bring lunar rocks to India - ToI

For the first time in the history of Isro, India will launch two rockets to complete a single mission — the country’s fourth moon mission Chandrayaan-4 that will bring moon rocks and soil (regolith) back to Earth.

Two separate rockets — heavy-lifter LVM-3 and Isro’s workhorse PSLV — will carry different payloads for the same moon mission and will be launched on different days.

If successful, Chandrayaan-4, which is slated to be launched not before 2028, will make India the fourth nation with capability to bring back samples from the lunar surface. “The aim of the mission is to collect samples from the lunar surface and return the samples safely to Earth for scientific studies,” according to a recent presentation by Isro chairman S Somanath at National Space Science Symposium.

Unlike previous Moon missions, which involved 2-3 modules, the Chandrayaan-4 mission will consist of a total of five spacecraft modules. These are the propulsion module, descender module, ascender module, transfer module and re-entry module, the presentation said.
PSLV

While the four-tonne payload lifter LVM-3 will carry three modules —propulsion, descender and ascender modules, PSLV will launch the transfer and re-entry modules. The two rockets will be launched at different interval of time — one set of modules is likely to take the longer Earth-orbit manoeuvre route and use moon's gravity to travel to the lunar orbit in around 40 days to lessen fuel expense, the other set of modules is likely to travel straight to the lunar orbit like Russia's Luna-25 did by burning fuel. However, the exact sequence of these launches and finer details have not been disclosed by Isro.

The propulsion module will guide Chandrayaan-4 to the lunar orbit after performing Earth-bound orbit manoeuvers like Chandrayaan-3 module did. It will later get separated in the lunar orbit. The descender module will make the lunar landing, similar to Vikram lander of Chandrayaan-3. The ascender module, introduced for the first time in India's noon mission, will collect and store rock and regolith samples from the lunar surface and will lift off from the moon and reach the lunar orbit where it will dock with the transfer orbit, The transfer module will be responsible for grabbing the ascender module, collecting lunar samples from it and then carrying the samples back to Earth’s orbit; and the re-entry module will safely land with the moon samples on Earth.

Chandrayaan-4 will carry five payloads:

1. Propulsion Module (PM) -- guide spacecraft to lunar orbit
2. Descender Module (DM) -- make lunar landing
3. Ascender Module (AM) -- will collect lunar samples and lift off from Moon to lunar orbit
4. Transfer module (TM) -- will dock with ascender, get samples and return to Earth’s orbit
5. Re-entry module (RM) -- land on Earth with lunar samples

Two launch vehicles involved:
1. Isro's workhorse PSLV rocket
2 Heavy-lifter LVM rocket

Launch date: Around 2028

Mission objectives:
1. To perform safe and softlanding on lunar surface
2. To demonstrate lunar sample collection and containersiation
3. Demonstrate ascend from Moon's surface
4.Demonstrate docking and undocking in lunar orbit
5. Demonstrate transfer of samples from one module to other
6. To demonstrate return and re-entry to Earth for sample delivery

[sanman]

From one of these knockoff imitation not-really-ISRO accounts, but still a nice graphic:

[Amber G.]

India's Chandrayaan-4 mission aims to bring back lunar rocks and soil to Earth, with a planned landing site near Shiv Shakti Point on the Moon's surface. This location is of significant scientific interest due to its proximity to the Moon's south pole and potential water ice deposits in permanently shadowed regions. The mission will have an operational life of approximately 14 Earth days, with the goal of studying and retrieving samples from these valuable regions.

Chandrayaan-4 will be a complex mission involving multiple launches and spacecraft modules, including a propulsion module, descender module, ascender module, transfer module, and re-entry module. If successful, India will become the fourth nation to achieve lunar sample return, following the United States, Russia, and China. The mission will contribute to the global scientific understanding of the Moon's composition, formation, and potential resources, furthering India's lunar exploration program.

For more details see:

Chandrayaan-4 to land close to Shiva Shakti Point on the MoonChandrayaan-4 to land close to Shiva Shakti Point on the Moon

A Readable article: (Nice details)
India plans Chandrayaan-4 moon sample return, will involve private sector

Nilesh Desai, Director of the Space Applications Centre (SAC), revealed the details in a presentation marking National Technology Day at SAC in Ahmedabad. “We are working on that and hopefully in the next four or five years or so. This also opens up many new technologies. The private sector also is going to be involved in a big way...

[sanman]

[Amber G.]

Meanwhile .. Athena Moon lander set to land near the South Pole today!

(NASA's Athena Moon lander is scheduled to land near the Moon's South Pole, marking a significant milestone in lunar exploration. The lander, designed by Intuitive Machines, aims to conduct scientific research and provide crucial data on lunar resources, including water ice.)

My take - Learnings for Chandrayaan 4:
- Like Chandrayaan-3, Athena is targeting the Moon's South Pole, highlighting the region's significance for lunar exploration.
- Both missions aim to detect and study water ice, which is crucial for future human exploration and sustainability on the Moon.
- Athena's sophisticated instruments and cutting-edge technology can provide valuable insights for Chandrayaan 4's design and development.
- NASA's collaboration with private companies like Intuitive Machines and SpaceX can serve as a model for future international collaborations, involving ISRO.

[Mort Walker]

The Athena Moon Lander is a being done by a private company Intuit Machines. It's been declared dead after landing sideways. Right now it is only India's CY3 that has been successful on the south pole of the moon. Just wish it had nuclear batteries - the potential was great.

https://www.space.com/the-universe/moon ... to-reveals

[Amber G.]

To add to above and another post by SSridhar (in other dhaga):

How difficult moon landing has been proven by the second successive failure of a NASA-backed Intuitive Machine lander.

Few comments:

As said, the challenges of moon landing have indeed been highlighted by the recent experiences of Intuitive Machines' landers. Their second lander also faced difficulties, but it's essential to acknowledge that the first lander, Odysseus, did successfully touch down on the moon's surface, making history as the first private spacecraft to do so .

Although Odysseus landed on its side, which affected its solar panels' positioning and ultimately led to a premature end to the mission, the achievement demonstrated significant progress in private lunar exploration . The lander's ability to transmit data and images from the lunar surface, despite the challenges, showcases the remarkable engineering and resilience of the spacecraft.

BTW .. NASA has declared the IM-1 mission an "unqualified success" despite the hard landing, emphasizing the importance of learning from these experiences to improve future missions .. ityadi ...

Some details and news articles of related matter:

Intuitive Machines faces early end to moon mission after lander tips over
Intuitive Machines and NASA call IM-1 lunar lander a success as mission winds down

[Amber G.]

The Centre has recently accorded approval for the ambitious Chandrayaan-5 mission to study the Moon, ISRO Chairman V Narayanan said on Sunday (March 16, 2025).

Centre has approved Chandrayaan-5 mission: ISRO chief

[RCase]

Seems like these landers tend to tip over on their side. All of them have struts with landing pads.
Question to any of the experts:
Could it be possible to make the lander like a Thanjavur doll with a circular base and low CG so that it automatically bounces back to be right side up upon landing on the lunar surface. Maybe extend the legs out if stability is required post landing.

[EswarPrakash]

Seems like these landers tend to tip over on their side. All of them have struts with landing pads.
Question to any of the experts:
Could it be possible to make the lander like a Thanjavur doll with a circular base and low CG so that it automatically bounces back to be right side up upon landing on the lunar surface. Maybe extend the legs out if stability is required post landing.

Wouldn't that require a smoother, non pot-holed surface for it to tip over correctly? We don't know the lunar surface enough to guarantee we will land on a smooth surface though?

[arvin]

Landers tipping over seems like a design \ algorithm issue where they either failed to reduce the horizontal velocity to zero before touch down or the landing area had a steep slope.

Chandrayaan 3 \ Vikram took care of it by way of a hover mode at 150 meters above surface to assess the risk and then proceed.

[Amber G.]

India Plans Chandrayaan-4 Mission with Advanced Docking, Lunar Sample Collection: Dr. Jitendra Singh in Lok Sabh

[Amber G.]

Just for perspective sharing a friend's thought..‘Chandyaan-2’ travelled 3,84,00 0KM as planned and only the last 2.1 km while landing on moon was not as expected,We have topped with 99.9% score in this mission, though were expecting 100% but incredible and we salute ISRO!

Data is still being analysed. Orbiter is still active to keep sending signals from Moon’s Orbit!