Chandrayaan-3 (transl. Moon-craft, pronunciation (help·info))[8] is the third and most recent Indian lunar exploration mission under the Chandrayaan programme of ISRO.[8] It consists of a lander named Vikram and a rover named Pragyan similar to Chandrayaan-2. Its propulsion module would act like an orbiter. The propulsion module carries the lander and rover configuration until the spacecraft is in a 100-kilometre (62 mi) lunar orbit.[9][10] Following Chandrayaan-2, where a last-minute glitch in the landing guidance software led to the lander crashing after entering lunar orbit, another lunar mission was proposed.[11] The launch of Chandrayaan-3 took place on 14 July 2023, at 2:35 pm IST.[12] The lander and rover are expected to land near the lunar south pole region on 23 August 2023. The powered descent is scheduled for 23 August 2023, around 05:45 pm IST and touchdown is expected on the same day around 06:05 pm IST.

1. Chandrayaan-3 (transl. Moon-craft, pronunciation (help·info))[8]
is the third and most recent
Indian lunar exploration mission under the Chandrayaan programme of ISRO.[8]
It consists of a
lander named Vikram and a rover named Pragyan similar to Chandrayaan-2. Its propulsion
module would act like an orbiter. The propulsion module carries the lander and rover
configuration until the spacecraft is in a 100-kilometre (62 mi) lunar orbit.[9][10]
Following Chandrayaan-2, where a last-minute glitch in the landing guidance software led to the
lander crashing after entering lunar orbit, another lunar mission was proposed.[11]
The launch of Chandrayaan-3 took place on 14 July 2023, at 2:35 pm IST.[12]
The lander and
rover are expected to land near the lunar south pole region on 23 August 2023. The powered
descent is scheduled for 23 August 2023, around 05:45 pm IST and touchdown is expected on
the same day around 06:05 pm IST.[13][14]
Background[edit]
As part of the Chandrayaan programme to demonstrate soft landing on the Moon, ISRO
launched Chandrayaan-2 on board a Launch Vehicle Mark-3 (LVM3) launch vehicle consisting of
an orbiter, a lander and a rover.[15]
The lander was scheduled to touchdown on the lunar surface
in September 2019 to deploy the Pragyan rover.[16][17]
The European Space Tracking (ESTRACK) operated by European Space Agency (ESA) will
support the mission according to a contract. Under the new cross-support arrangement, ESA
tracking support could be provided for upcoming ISRO missions such as those of India’s first
human spaceflight programme, Gaganyaan and the Aditya-L1 solar research mission. In return,
future ESA missions will receive similar support from ISRO’s own tracking stations.[18]
Mission objectives[edit]
ISRO has set the following mission objectives for the Chandrayaan-3 mission:
1. Getting a lander to land safely and softly on the surface of the Moon.
2. Observing and demonstrating the rover’s loitering capabilities on the Moon.
3. In-site observation and conducting experiments on the materials available on the lunar
surface to better understand composition of the Moon.[19]
Spacecraft design and instrumentation[edit]
Design[edit]
Chandrayaan-3 comprises three main components:
Propulsion module: The propulsion module will carry the lander and rover configuration till
100 km lunar orbit. It is a box-like structure with one large solar panel mounted on one side and a
large cylinder on top (the Intermodular Adapter Cone) that acts as a mounting structure for the
lander.[10][9]
Lander: The lander is responsible for the soft landing on the Moon. It is also box-shaped, with
four landing legs and four landing thrusters of 800 newtons each. It will be carrying the rover and
various scientific instruments to perform in-site analysis.
The lander for Chandrayaan-3 will have only four throttle-able engines with thrust valve slew
rate changing capabilities, unlike Vikram on Chandrayaan-2 which had five 800 Newtons engines
with a fifth one being centrally mounted with a fixed thrust. One of the main reasons of
Chandrayaan-2 failure, i.e., attitude increase during camera coasting phase was removed by
allowing the lander to control attitude and thrust in all phases of descent. Attitude correction
range is increased from 10°/s in Chandrayaan-2 to 25°/s in Chandrayaan-3. Additionally, the
Chandrayaan-3 lander will be equipped with a Laser Doppler Velocimeter (LDV) to allow
measuring attitude in 3 directions.[20][21]
The impact legs have been made stronger compared to

2. Chandrayaan-2 and instrumentation redundancy has been increased. It will target a more precise
4 km (2.5 mi) by 4 km (2.5 mi) landing region based on images previously provided by OHRC on
Chandrayaan-2. ISRO improved the structural rigidity, increased polling in instruments, increased
data frequency and transmission and added other multiple software and contingency systems, as
the lander is designed to withstand failed landing attempt via multiple complicated software
simulations.[22][21]
Rover:
 Six-wheeled design
 Mass of 26 kilograms (57 pounds)
 Range of 500 metres (1,600 ft)
 Dimensions : 917 millimetres (3.009 ft) x 750 millimetres (2.46 ft) x 397 millimetres (1.302 ft)
The Chandrayaan-3 rover is expected to make a number of important scientific discoveries,
including:
 The composition of the lunar surface
 The presence of water ice in the lunar soil
 The history of lunar impacts
 The evolution of the Moon’s atmosphere

Integrated module

3. 
Propulsion module

Lander

4. 
Rover
Payloads[edit]
Lander
 Chandra's Surface Thermophysical Experiment (ChaSTE) will measure the thermal
conductivity and temperature of the lunar surface.
 Instrument for Lunar Seismic Activity (ILSA) will measure the seismicity around the landing
site.
 Langmuir Probe (LP) will estimate the plasma density and its variations.[23]
Rover
 Alpha Particle X-Ray Spectrometer (APXS) will derive the chemical composition and infer
mineralogical composition of the lunar surface.
 Laser Induced Breakdown Spectroscope (LIBS) will determine the elemental composition
(Mg, Al, Si, K, Ca, Ti, Fe) of lunar soil and rocks around the lunar landing site.[23]
Propulsion module
 Spectro-polarimetry of Habitable Planet Earth (SHAPE) to study the spectral and polarimetric
measurements of Earth from the lunar orbit in the near-infrared (NIR) wavelength range (1-
1.7 μm).[10][9]

Alpha Particle X-Ray Spectrometer (APSX) payload on the rover

5. 
Chandra’s Surface Thermophysical Experiment (ChaSTE) payload on the lander

Instrument for Lunar Seismic Activity (ILSA) payload on the lander

Laser Induced Breakdown Spectroscope (LIBS) payload on the rover

Langmuir Probe (RAMBHA-LP) payload on the lander

Spectro-polarimetry of Habitable Planet Earth (SHAPE) payload on the propulsion module

6. Mission Timeline[edit]
Mission profile[edit]
Animation of Chandrayaan-3
Around the Earth – Orbit raising phase
Around the Earth
Around the Moon
Chandrayaan-3's Path · Earth · Moon
Launch[edit]
LVM3 M4, Chandrayaan-3 – Launch vehicle lifting off from the Second Launch Pad (SLP)
of SDSC-SHAR, Sriharikota
Chandrayaan-3 was launched on 14 July 2023, at 2:35 pm IST as scheduled, from Satish
Dhawan Space Centre Second Launch Pad in Sriharikota, Andhra Pradesh, India. The
spacecraft entered lunar orbit on 5 August 2023.[24]
It is anticipated that the Chandrayaan-3
mission will achieve a soft landing on the lunar South Pole region on 23 August.[25]
Choosing the month of July for the launch of Chandrayaan 3 was a special move because of a
calculation made by ISRO regarding the closeness of Earth and Moon.[26]
On August 5, the Indian Space Research Organisation achieved a Lunar-Orbit Insertion (LOI),
successfully placing the Chandrayaan-3 spacecraft into orbit around the Moon. The LOI

7. operation was carried out from the ISRO Telemetry, Tracking, and Command Network (ISTRAC)
located in Bengaluru.[27][28]
After a series of Lunar Bound Maneuvers, on August 17, the Vikram lander separated from the
propulsion module, to begin its solo journey to the lunar surface.
Orbit raising and station keeping[edit]
Chandrayaan-3 orbital maneuver
The satellite was launched aboard the LVM3-M4 rocket in the afternoon of 14 July 2023, at 2:35
pm IST to a EPO perigee of 170 km (106 mi) and an apogee of 36,500 km (22,680 mi). This was
followed by a series of orbit raising operations (using an on-board LAM and chemical thrusters)
that placed the satellite in the Trans-lunar injection orbit.