Chandrayaan 3 is an ISRO (Indian Space Research Organization) mission with the main objective of placing a lander and rover in the highlands close to the south pole of the Moon in the June/July timeframe in 2023 and demonstrating end-to-end touchdown and roving capabilities.
It will additionally make a range of scientific measurements on the floor and from orbit. It includes a lander/rover and a propulsion module.
The lander/rover will be comparable to the Vikram rover on Chandrayaan 2, with upgrades to assist make sure a protected landing.
It will be carried to lunar orbit through the propulsion module which will stay in orbit round the Moon and act as a communications relay satellite.
The rover will elevate a seismometer, warmness drift experiment, and spectrometers.
Spacecraft and Subsystems
The propulsion module is a box-like shape with one giant photo voltaic panel hooked up on one facet and a massive cylinder on pinnacle (the Intermodule Adapter Cone) that acts as a mounting shape for the lander.
The essential thruster nozzle is on the bottom. It has a mass of 2148 kg and can generate 758 W power.
The lander is additionally commonly box-shaped, with 4 touchdown legs and 4 touchdown thrusters. It has a mass of 1752 kg, inclusive of 26 kg for the rover, and can generate 738 W the usage of side-mounted photo voltaic panels.
The lander has a variety of sensors to make certain a secure touchdown, inclusive of an accelerometer, altimeters (Ka-band and laser), Doppler velocimeter, celebrity sensors, inclinometer, landing sensor, and a suite of cameras for hazard avoindance and positional knowledge.
Reaction wheels are used for mindset control, and propulsion is furnished by way of a MMH and MON3 bipropellant machine with 4 800 N throttleable engines and eight fifty eight N throttleable engines.
An X-band antenna is used for communications. The lander includes the rover in a compartment with a ramp for deployment onto the surface.
The rover is a rectangular chassis set up on a six-wheel rocker-bogie wheel power assembly.
It has navigation cameras and a photo voltaic panel that can generate 50 W. It communicates without delay with the lander by way of Rx/Tx antennas.
The lander will raise an instrument referred to as Chandra’s Surface Thermophysical Experiment (ChaSTE) to measure floor thermal properties, the Instrument for Lunar Seismic Activity (ILSA) to measure seismicity round the landing site, the Radio Anatomy of Moon Bound Hypersensitive ionosphere and Atmosphere (RAMBHA) to find out about the gasoline and plasma environment, and a passive laser retroreflector array supplied via NASA for lunar ranging studies.
The rover will lift two gadgets to find out about the neighborhood floor elemental composition, an Alpha Particle X-ray Spectrometer (APXS) and Laser Induced Breakdown Spectroscope (LIBS).
The Propulsion Module / Orbiter will elevate one test known as the Spectropolarimetry of HAbitable Planet Earth (SHAPE) to find out about Earth from lunar orbit.
Mission Profile
The mission is scheduled to launch in 2023 on a GSLV Mark three heavy carry launch automobile from Satish Dhawan Space Center in Sriharikota, India.
It will vicinity Chandrayaan three into an about a hundred and seventy x 36,500 km elliptic parking orbit. The propulsion module will deliver the lander/rover will into a a hundred km round polar lunar orbit and separate.
The lander will then contact down with the rover in the south polar place of the Moon, close to 69.37 S, 32.35 E. Touchdown speed is deliberate to be less than two m/s vertical and 0.5 m/s horizontal. The propulsion module / communications relay satellite tv for pc will stay in lunar orbit to allow communications with Earth.
Chandrayaan two will additionally be used as a backup relay.
The lander and rover are designed to operate for one lunar daylight hours length (about 14 Earth days).
What we know about India’s Chandrayaan 3 Moon landing mission
After India’s Chandrayaan 2 lander unfortunately failed to land on the Moon in 2019 during its final mission phase, the Indian Space Research Organization (ISRO) undertook building a repeat mission with Chandrayaan 3.
It is currently undergoing final tests and is slated for launch late 2023. Originally slated for launch in the first half of 2023, Chandrayaan 3 was robbed of its ride to space as ISRO prioritized two GSLV Mk IIIs for commercial OneWeb launches.
To increase the chances of sticking the landing this time around, ISRO has made several upgrades to the Chandrayaan-2-like lander such as software improvements, strengthened legs, a couple of new sensors, and better power and communication systems.
The host of sensors on the lander, its engine configuration and the gentle touchdown specifications are listed on ISRO’s official Chandrayaan 3 page.
The mission will also have a 2148-kilogram orbiter that will propel the 1752-kilogram lander to the Moon post-launch and put it into a 100-kilometer circular polar orbit. During and after landing, the orbiter will relay communications between the lander and Earth. It will also host the SHAPE Earth-observing experiment, which is a near-infrared spectro-polarimeter made to observe the full Earth disc from the Moon to get a sense of what signatures of habitable Earth-like exoplanets would look like.
The Chandrayaan 2 orbiter will serve as a backup (and secondary) relay provider. Being a repeat of the Chandrayaan 2 landing attempt, the mission will last a maximum of one lunar day i.e. 14 Earth days.
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The landing site
Like other lunar highlands, the Chandrayaan 3 landing region is expected to contain material from the ancient lunar crust as well as materials ejected when nearby craters formed during the period of heavy bombardment by asteroids and comets roughly 3.8 to 4.1 billion years ago. Both of these types of materials are great targets for the two spectrometers onboard Chandrayaan 3’s rover.
The lander
The lander will carry payloads similar to Chandrayaan 2. It will insert a thermal probe about 10 centimeters into the lunar soil to measure its thermal properties and learn about the Moon’s interior. A seismometer onboard will detect moonquakes, like NASA’s Apollo missions did. If a strong enough moonquake occurs during the mission, it could provide additional clues about the Moon’s interior, particularly its core.
Vikram will also carry a Langmuir probe to determine the amount, distribution and properties of hot, ionized particles on the lunar surface created by the solar wind, and a radio occultation experiment that will measure electron density in the Moon’s thin but persistent atmosphere. NASA is contributing a retroreflector, an upgraded version of the ones left on the Moon by Apollo missions, which scientists will bounce laser pulses off to better understand the gravitational dynamics of the Earth-Moon system.
The rover
The six-wheeled, 26-kilogram Chandrayaan 3 rover, essentially the same design as the one on Chandrayaan 2 but with enhanced software, will study the geology of the landing region. An X-ray spectrometer will study what the region’s rocks and lunar soil are made of. A high-power laser will shoot and vaporize target material and analyze radiation emitted from it to determine the material’s composition using a (different) spectrometer. Both spectrometers are expected to find pristine materials from the ancient lunar crust.
Aside: Reddit user u/ravi_ram has compiled a nice list of research papers related to the Chandrayaan 2 rover.
ISRO’s lunar soil simulant
Communications support
ISRO uses its own Indian Deep Space Network as a primary means for communicating with its planetary spacecraft but partners with other space agencies for backup and secondary options. India’s Chandrayaan 1 orbiter had DSN support too.
ISRO’s lack of mission information
All of this information has been put together by following minor developments and tracking multiple sources consistently for over a year. For such a critical mission, it’s frustrating as an Indian to see ISRO not even have a one-pager on their website about Chandrayaan 3, and no official mechanism to provide major updates.
If anything, ISRO has continued to withhold any substantial information on the mission. When Twitter user @frustratedpluto submitted several questions to ISRO under the Indian Right to Information Act in September 2021, nearly all the responses read as follows.
The information sought is exempted from disclosure under Section-8(1)(a) of RTI Act as it would prejudicially affect the scientific, technical and strategic interest of the state/country.
ISRO, a tax-payer-funded civilian space agency, has been outright refusing to provide the public any asked-for substantial information on Chandrayaan 3’s configuration, tests, and more. Even the purely scientific question of “Provide me with the location of the NASA’s LRA payload onboard the Vikram lander on Chandrayaan 2” was given the same response. Indians who have submitted questions to ISRO before are unfortunately familiar with this dreaded statement. It almost makes one think of Chandrayaan 3 as a cold-war-era lunar defense mission rather than a robotic explorer.
For an organization that’s supposed to help inculcate scientific thinking and aspiration in hundreds of millions of Indians, this is a dreadful state of affairs.
