On August 23, 2023, the Indian space agency Indian Space Research Organization (ISRO) successfully landed its lunar mission Chandrayaan-3 on the moon's south pole. This makes India the first nation to land a spacecraft on rough terrain near the lunar south pole in human history and the fourth to successfully land a spacecraft on the Moon. Until then, only three nations had achieved unmanned landings on the Moon – the Soviet Union, the United States and China. The United States is the only nation that has successfully landed a man on the Moon.
What is chandrayaan-3?
Chandrayaan-3 is Indian space agency ISRO's third lunar mission launched under the Chandrayaan program or Indian Lunar Exploration Programme. India's Chandrayaan program aims to send manned missions to the Moon and find ways to maintain a presence there for future missions further into space. The success of Chandrayaan-3 is a feat not just for India but for the entire humanity.
'Chandrayaan' is a Sanskrit word meaning lunar vehicle; 'Chandra' means moon and 'Yaan' means vehicle. In Sanskrit, the moon is also known by the names 'Tusharanshu' and 'Himanshu'. Both mean 'one that is partially covered with snow or ice'. One of Chandrayaan-3's main goals is to find ice on the lunar surface that could provide fuel, oxygen and drinking water for distant space exploration missions.
The mission
ISRO launched its first lunar mission Chandrayaan-1 in 2008. The spacecraft carried a lunar impact probe that was successful in detecting water on the lunar surface. Chandrayaan-1 also carried out mapping and profiling of the moon's atmosphere.
The second lunar mission 'Chandrayaan-2' was scheduled for 2013 but was postponed to 2016 when Russia failed to develop the lander for the space agency. As a result, India decided to develop its lunar mission independently and launched 'Chandrayaan-2' in 2019. Chandrayaan-2 was supposed to land a lander and a rover on the lunar surface. Although it successfully placed an orbiter into lunar orbit, the mission was unable to land safely on the moon. The orbiter continued to operate collecting scientific data on the Moon and is expected to remain operational for seven and a half years.
In the same year, ISRO approved a third mission to the Moon, 'Chandrayaan-3', to achieve the incomplete objective of 'Chandrayaan-2', i.e. safely landing a spacecraft on the Moon. The new spacecraft was intended to land on the same place where 'Chandrayaan-2' was supposed to land. India launched 'Chandrayaan-3' on July 14, 2023, at 2:35 pm IST, from the Satish Dhawan Space Center in Sriharikota, Andhra Pradesh, India. The mission took 40 days to reach the Moon and landed safely on the lunar surface on August 23.
India's Chandrayaan-3 and Russia's Luna-25 were in a race to land on the lunar south pole for the first time in human history. The Luna-25 mission, launched on August 10, entered lunar orbit on August 16, but its lander crashed on the Moon on August 19 after a failed orbital maneuver. After launch, Chandrayaan-3 entered lunar orbit on August 5 and its lander 'Vikram' successfully landed the lunar south pole on August 23, making India the first country to land a spacecraft on the lunar south pole. moon.
Chandrayaan-3 successfully demonstrated India's indigenous technology to safely and successfully land a spacecraft on the challenging terrains on the far side of the moon. The mission now aims to successfully demonstrate the movement of its rover 'Pragyan' in the difficult terrain of the South Pole. The rover will carry out several scientific experiments on the lunar surface.
ISRO's next lunar mission 'Chandrayaan-4' is expected to launch in 2026-28. It will be a collaborative mission with the Japanese space agency JAXA and will aim to sample the lunar surface in situ.
The launch vehicle
LVM3 is the launch vehicle used for both Chandrayaan-2 and Chandrayaan-3. LVM-3 is ISRO's operational heavy-lift launch vehicle. This is the fourth operational flight of LVM3 that launched Chandrayaan-3 to Geo-Transfer Orbit (GTO). The LVM3 is India's largest and heaviest launch vehicle, used to transport satellites for Indian and international customers. It is used by India to launch multi-satellite, multi-orbit satellites (LEO, MEO, GEO) and interplanetary missions.
The spacecraft
The Chandrayaan-3 spacecraft consists of three main components – a propulsion module, a 'Vikram' lander and a 'Pragyan' rover, all developed independently and indigenously.
The propulsion module transported the lander and rover from the injection orbit to the 100 km lunar orbit. The module also carried a Habitable Planetary Earth payload (SHAPE) spectropolarimeter, the only payload on the propulsion module, for spectral and polarimetric measurements of Earth from lunar orbit. It uses a bipropellant propulsion system (MMH+MON3) and has an S-band transponder for communication with the ground control station.
The 'Vikram' lander is named after the father of the Indian space program, Vikram Sarabhai. It is about 2 meters tall and has a mass of just 1,700 kg. It is powered by a solar panel and a battery. The lander is equipped with four legs and four landing thrusters for safe landing on the Moon. For communication with the Chandrayaan-3 orbiter and the ground control station, the module uses ISDN channels. It can communicate data directly to the ground control station or through the orbiter. The lander is responsible for soft landing on the lunar surface. After a successful soft landing at the lunar south pole, the lander will remain operational for 14 Earth days (1 lunar day) on the moon. The lander has three payloads on board.
The rover is called 'Pragyan', which means 'wisdom' in Sanskrit. It is about 1 meter long and has a mass of about 27 kg. It is equipped with six wheels that will help it move around the lunar surface. The rover is equipped with two payloads, a terrain camera and a panoramic camera.
4 hours after successfully landing on the Moon, the Pragyan rover descended from the lander to the lunar surface. You will explore the surrounding area over a period of 14 days. The rover will travel at a speed of about 1 cm per second and will be able to cover a distance of about 500 meters. The rear wheels of the rover will leave imprints of India's national emblem and the ISRO logo on the surface of the moon.
Check out the following video of the 'Pragyan' rover arriving on the lunar surface, taken by the Chandrayan-3 Vikram lander:
Pragyan aims to study the chemical composition and mineralogy of the lunar surface, map the surrounding area, take panoramic images of the surroundings and search for water on the moon. At the time of writing this article, Pragyan has already performed an 8 meter moonwalk. It will have communication via the lander during its 14-day lunar walk. The landing site of the Chandrayaan-3 lander and rover is exactly 625.64 km from the lunar south pole.
Payloads and equipment
Chandrayaan-3 carries a total of 6 payloads. The propulsion module will remain as an orbiter currently in a 153 x 163 km orbit inserted prior to separation from the lander. He carries a spectropolarimeter of the habitable planet Earth (SHAPE). This is the only payload of the Chandrayaan-3 propulsion module. It is an experimental payload to study the spectropolarimetric signatures of the habitable planet Earth in the near-infrared (NIR) wavelength range (1~1.7um).
The lander carries three payloads:
RAMBHA-LP Langmuir probe: It will measure the density of the plasma near the surface (ions and electrons) and its variation over time.
ChaSTE: The Chandra Surface Thermophysical Experiment (ChaSTE) will perform measurements of the thermal properties of the lunar surface near the polar region.
ILSA: The Lunar Seismic Activity (ILSA) instrument will measure seismicity around the landing site and outline the structure of the lunar crust and mantle.
The lander is also equipped with two cameras:
Vikram Lander Imager (LI)-1 Camera: This camera is located on the top of the lander and is used to take images of the lunar surface during descent and landing. It has a resolution of 1024×1024 pixels.
Lander Position Detection Cameras (LPDF): These cameras are located on the sides of the lander and are used to track the position of the lander during descent and landing. They have a resolution of 256x256 pixels.
There are several sensors on the lander, including an altimeter (to measure the height of the lander relative to the lunar surface), an IMU (to measure the orientation and angular velocity of the lander), and a positioning sensor (to determine its position in the lunar module). surface). In addition to all these payloads and sensors, the lander is equipped with a navigation system, communication system, power system and thermal control system.
The 'Pragyan' rover carries two payloads:
APXS: Alpha Particle X-ray Spectrometer (APXS) will measure chemical composition and infer mineralogical composition for understanding the lunar surface.
LIBS: Laser-induced decay spectroscope (LIBS) will determine the elemental composition of lunar soil and rocks around the lunar landing site.
In addition to these payloads, Pragyan is equipped with a terrain camera (to map the surrounding area), a panoramic camera (to capture panoramic images of the moon), a magnetometer (to measure the moon's magnetic field), dust detector (to measuring amount of dust in the lunar atmosphere), temperature sensor (to record the ambient temperature on the moon), communication system with the 'Vikram' lander and the Chandrayaan-3 orbiter, navigation system and power system.
The journey
Following is a brief timeline of the Chandrayaan-3 mission:
July 14, 2023: Chandrayaan-3 is launched from the Satish Dhawan Space Center.
July 15, 2023: Chandrayaan-3 enters Earth's orbit.
July 17, 2023: Chandrayaan-3 enters a translunar trajectory.
August 5, 2023: Chandrayaan-3 enters lunar orbit.
August 17, 2023: The lander separates from the orbital module.
August 18, 2023: The lander begins its descent to the lunar surface.
August 23, 2023: The lander lands on the lunar surface.
August 23, 2023: The rover deploys from the lander module.
Will Chandrayaan-3 return to Earth?
No, Chandrayaan-3 was not designed for a return trip to Earth. The Vikram' lander and the 'Pragyan' rover will explore the moon for 14 Earth days and will remain on the moon after completing the exploration. The Chandrayaan-3 orbiter will remain operational for 7.5 years and will continue collecting scientific data from the moon.
Why is Chandrayaan-3 important?
Chandrayaan-3 landed near the moon's south pole. This specific region of the Moon is of great scientific interest due to some unique characteristics. The lunar south pole is characterized by the presence of permanently shadowed craters where it is possible to find deposits of volatile substances such as ice water. These craters never receive direct sunlight and have extremely low temperatures. Before Chandrayaan-3, no other nation had landed a spacecraft on the Moon's south pole due to its extremely challenging terrain. If the presence of water ice is confirmed by Chandrayaan-3, it will be a valuable resource for future lunar explorations, using the Moon as a base for manned missions to deep space or even exploring possibilities of human settlement on the Moon. Chandrayaan-3 will also be useful in understanding the geological history of the Moon and the processes that shaped its surface.
Unlike China and Russia, India is a signatory to the Artemis Accord along with the United States and nearly 30 other countries. The United States is planning to return astronauts to the Moon by 2030, with the first human landing known as the Artemis III mission scheduled for 2025-26. The Artemis mission aims to send the first woman and first black person to the moon. The international space mission aims to establish a long-term presence on the Moon and use the Moon as a gateway to send the first astronauts to Mars. Chandrayaan-3 will be useful for the Artemis missions, as the lunar south pole is the only region where lasting presence on and around the Moon is possible.
Chandrayaan-3 also demonstrated India's capability for cost-effective space engineering and exploration. Chandrayaan-3 was released with a budget of just $74 million, half the budget of the Hollywood film Interstellar. The mission strengthened India's position for future space tourism.