Chandrayaan-3: Why did the lander go silent?

On August 23, 2023, India's Chandrayaan-3 mission successfully landed on the Moon. However, shortly after landing, communication with the lander and rover was lost. ISRO, the Indian Space Research Organisation, has been trying to re-establish contact ever since, but so far has been unsuccessful.

The Indian Space Research Organisation (ISRO), which was hoping to awaken the Chandrayaan-3’s Vikram lander and Pragyan rover on September 2, says it has not received any signals from either of the two, despite continuing efforts to establish communications.

What do you think happened to India's best spacecraft? According to Isro Vikram Lander and Rover is made enough for the harsh conditions. Is it true that they really don’t know the temperature at the south pole of the moon? Mean they can’t spectulate it or did they make a blunder by just relying on the data received after landing?

You and I  want the answer to the above question. Let's dig this up and see what happened actually

The mission objectives of Chandrayaan-3 are:

1. To demonstrate a Safe and Soft Landing on the Lunar Surface
2. To demonstrate Rover roving on the moon and
3. To conduct in-situ scientific experiments.

To achieve the mission objectives, several advanced technologies are present in Lander such as,

1. Altimeters: Laser & RF based Altimeters
2. Velocimeters: Laser Doppler Velocimeter & Lander Horizontal Velocity Camera
3. Inertial Measurement: Laser Gyro based Inertial referencing and Accelerometer package
4. Propulsion System: 800N Throttleable Liquid Engines, 58N attitude thrusters & Throttleable Engine Control Electronics
5. Navigation, Guidance & Control (NGC): Powered Descent Trajectory design and associate software elements
6. Hazard Detection and Avoidance: Lander Hazard Detection & Avoidance Camera and Processing Algorithm
7. Landing Leg Mechanism.

You read their objective. I really appreciate ISRO that they stepped out and took a bold step. It is not easy to make the lander land on the south pole of the moon.

The landing was carefully planned to coincide with the start of a lunar day so that Vikram and Pragyaan would have two weeks of sunlight to work with. One day on the Moon equals a little over four weeks on Earth, with the day and night each lasting about 14 days

The Moon's south pole is a region of special interest to scientists because it is one of the coldest and driest places in the solar system. It is also one of the few places on the Moon where water ice has been detected.

Mosaic of approximately 1500 images taken by Clementine of the lunar south polar region (latitude greater than 70°S)

Temperature: The average temperature at the Moon's south pole is -153 degrees Celsius (-243 degrees Fahrenheit). The coldest temperature ever recorded on the Moon was -247 degrees Celsius (-413 degrees Fahrenheit) at the Shackleton Crater.

Pressure: The atmospheric pressure at the Moon's south pole is very low, about 10^-12 atmospheres. This is equivalent to the atmospheric pressure at an altitude of about 100 kilometres (62 miles) on Earth.

Water ice: Water ice has been detected in the polar craters of the Moon, including the Shackleton Crater at the south pole. The ice is thought to be trapped in the permanently shaded craters.

Full Moon with south polar region features marked.

In addition to the above, here are some other notable features of the Moon's south pole:

• It is the highest point on the Moon, with an elevation of about 10 kilometres (6.2 miles).
• It is home to several large craters, including the Shackleton Crater, which is 21 kilometres (13 miles) in diameter                                                                 
• This is the power generation for the lander and the prop module. You can see that the lander needs 738W and the rover needs 50W

Cc: ISRO WEBSITE

It is also worth noting that the Chandrayaan-3 lander and rover are equipped with a hibernation mode, which can be used to conserve power during the lunar night. In hibernation mode, the lander and rover will reduce their power consumption to a minimum.

Chandrayaan-3 – Elements

Here you can clearly see the 3D structure comprising of lander Modulue, Rover and Prop Module.

Pragyan showed that it knew what a crater looked like. It spotted a 4-metre-wide one from 3 metres away and made the smart choice, to change course. It demonstrated another instance of perfect navigation when it avoided a deeper cracker rover that depends on solar panels to charge its battery, for which good visibility and plenty of sunlight are available at the south pole. Also, the south pole does not have a slope of more than 12 degrees as the lander would topple otherwise. There is also a better chance of ice being present.”

What possibly Happened?

The climate on the south pole of the moon is harsh. As explained earlier the temperature is too low for solar cells.

The status of the solar panels on the Chandrayaan-3 rover, Pragyan, is unknown. The rover has not been able to communicate with ISRO since shortly after landing on the Moon on August 23, 2023. It is possible that the solar panels were damaged during the landing. The Moon is a very harsh environment, and the landing process can be very stressful for spacecraft. It is also possible that the solar panels are simply covered in dust, which is common on the Moon the panels are damaged or covered in dust, it is unlikely that the rover will be able to generate enough power to operate. However, ISRO is still trying to re-establish contact with the rover, and there is still a chance that it can be revived.

ISRO has said that it is still too early to say whether the Chandrayaan-3 mission is a success or a failure. The agency is continuing to try to re-establish contact with the rovethereoverping that it may still be able to wake up and begin its mission.