After the failure of Chandrayaan-2 landing, India will make a second attempt to land on the moon.
Bengaluru
The Indian Space Research Organization (ISRO), after a series of experiments in terms of corrections and overcoming possible errors, is all set to launch Chandrayaan-3 at 2.30 pm on 14 July. After the failure of Chandrayaan-2 landing, India will make a second attempt to land on the moon.
Preparations for the launch are underway at the second launchpad of the Satish Dhawan Space Centre in Sriharikota. Testing of the electronic systems of the 640-tonne state-of-the-art launch vehicle, LVM-3 (GSLV Mark-III) at the launchpad has been completed. Scientists are working day and night to make the mission successful.
Talking to The Sunday Guardian, ISRO Chairman S. Somnath said that he was confident this time to land safely on the moon. “We have learned a lot from the failure of Chandrayaan-2 and have made a lot of improvements in Chandrayaan-3. In the Chandrayaan-2 mission, the orbiter was successfully placed in the lunar orbit. However, there was a problem in the final stage while landing on the lunar surface. We could not make a soft landing. That problem was well understood as to why this happened. Many improvements have been made in Chandrayaan-3 to correct all those anomalies.”
There are a lot of improvements on the lander. “Among the deficiencies we were trying to overcome was the lander legs, which we expected could have withstood a higher velocity [during Chandrayaan-2]. So we have factored how much we could increase the velocity tolerance in the available structure. We have enhanced the landing velocity to 3m/second from 2m/second. That means even at 3m/sec, the lander will not crash or break. More propellant (fuel) has also been kept in the lander this time to handle more disruptions and have the ‘ability to come back’; so there’s more cushion to handle the mission. Additional sensors have been installed on the lander to measure its speed. A new sensor called the Laser Doppler Velocity Meter has been added, which will continuously monitor the Moon during the landing.”
“The solar panel of the lander has also been improved which will now generate more power. Compared to Chandrayaan-2, more solar panels have been installed all around in Chandrayaan-3 so even if the sun is in the opposite direction, energy production will not be hindered. Software has also improved to have more tolerance to failures like engine disruptions, thrust disruptions, sensor failures.”
Somnath added: “There were 5 engines in Chandrayaan-2 but only four engines in Chandrayaan-3. In the last phase of the mission, 2 engines will be fired while landing the lander. Multiple tests of each equipment and systems have been carried out. Another important change is that a limited area of only 500 meters was designated for Chandrayaan-2’s landing. This time the landing site is at 70 degrees from the South Pole and the landing radius has been kept at about 4 km. We are not going to the South Pole because the Sun is not visible from there. Due to this, the lander and rover will not get energy. If the mission is launched on 14 July and all goes well, then on 23 or 24 August, there will be the first attempt to land the lander Vikram on the lunar surface. Since there are 15 Earth days of day, and 15 Earth days of night on the moon, we will land on the moon on the day when the day is beginning there. If there is a successful landing on the lunar surface on 23 or 24 August, then for the next 15 days, many experiments will be done through the lander and the rover. After the night on the moon, the temperature there reaches minus 180 degrees. The lander and rover have been designed to survive even at such low temperatures. But, after 15 days, when it will be day on the moon again, it is difficult to say whether they will survive or not. Hence the operational period of the lander and rover has been kept at 15 days. After that this mission would be over,” he said.
ROVER WILL HIT LUNAR SURFACE WITH HIGH LASER RAYS
Somnath said that after landing on the lunar surface, there will be two experiments through the rover. The Pay-load Laser Induced Breakdown Spectroscope (LIBS) on the rover will bombard the lunar surface with high powered laser beams. Due to this, dust particles and gases will come out from the surface of the moon. By studying these dust particles and gas, we can find out about the chemical composition of the moon and the presence of minerals. Apart from this, it also has a payload named Alpha Practicing X-ray Spectrometer (APXS). This will determine the elemental composition of the lunar surface near the landing site. With this payload, we will try to find out what are the elements on the lunar surface like magnesium, aluminum, silica, calcium titanium, iron. The camera installed in the lander will monitor the movements of the rover. Rover has to walk around the lander. The effort is that he should always be in the sight of the lander’s camera. After the 14th day of the mission, we will know how much distance the rover has covered in these 14 days.
THREE EXPERIMENTS WILL BE DONE THROUGH ROVER
He said that the Lander Vikram has three payloads which will do three experiments. It has a Radio Autonomy of Moon Bound Hypersensitive Ionosphere and Atmosphere (RAMBHA). This will give information about the electron density and temperature in the lunar surface environment. Along with this, it will also give information about the development and density of temporary plasma on the Moon. The second is the Lunar Surface Thermo Physical Experiment (ChasTE). It will give information about the temperature at different depths of the lunar surface. In active mode operation it will give an indication of the thermal conductivity over a given period of time. Another payload is the Instrument for Lunar Seismic Activity. Its primary objective is to ascertain the seismicity around the landing site. It is a type of seismometer that can detect the displacement, velocity or acceleration of the ground due to an earthquake.
Excerpts from the interview on page 2.