This is the second mission from ISRO to send a
spacecraft to the Moon.
The mission also involves a lander and a rover
ISRO has set July 9 to 16 as the window for
launching the mission.
September 6 is the date for a soft-landing on
ISRO has chosen the southern pole of the moon
for its lander. This region has not been explored by any space agency so far.
The mission involves an orbiter, a lander and a
The orbiter has eight science instruments:
Mapping Camera 2 (TMC-2): It provides a detailed 3D map.
Large Array Soft X-Ray Spectrometer (CLASS): Maps abundance of major rock
X-Ray Monitor (XSM): observes X-rays emitted from sun & supports CLASS
High Resolution Camera (OHRC): Provides high-resolution images of the landing
Infrared Spectrometer (IIRS): Identifies minerals and signatures of hydroxyl
and water molecules
Aperture Radar (SAR): Maps lunar craters and other features especially in polar
Atmospheric Composition Explorer (CHACE-2): Will carry out a detailed study of
the lunar exosphere
Anatomy of Moon Bound Hypersensitive Ionosphere and Atmosphere (RAMBHA):
Measures Total Electron Content (TEC)
The Lander has three science instruments:
(Langmuir probe): Measures TEC of the lunar ionosphere and its morphology.
Measures surface plasma density & changes.
Surface Thermophysical Experiment (ChaSTE): Measures thermal properties of
regolith and polar region
for Lunar Seismic Activity (ILSA): Measures seismicity of landing site and
structure of crust and mantle
The Rover contains:
Breakdown Spectrometer (LIBS): Derives chemical composition and infers
mineralogical composition on the surface
particle X-Ray Spectrometer
(APXS): Determines the elemental composition of rocks and soil.
Apart from these, a passive payload –
Retroreflector – from NASA is also a part of the mission.
As per ISRO, the following are the seven
challenges of landing a probe on the moon:
an accurate trajectory to the moon – the trajectory distance to the moon is
3.844 lakh kilometres. Maintaining the trajectory is dependent on the gravity
of the moon which varies in different parts of the moon. Also, there will be
the influence of the sun and other astronomical bodies on the spacecraft.
Communication – there will be a communication delay between the probe and
the ground station. This is due to the distance and limited on-board power of
the transmitter. A message sent will be received after a few minutes. Also, due
to the background noise, the signal becomes weals which must be picked by
Lunar Injection and Lunar Capture Mission – In this mission, a series of
engine burns will take place to get closer to the Moon whose location keeps
changing. The scientists must predict the intersection of the spacecraft and
the moon’s path in advance and the margin of error is narrow.
Around Moon – The lunar gravity varies due to the uneven distribution of
mass and the spacecraft’s orbit gets influenced. Also, exact knowledge of
temperature 100km from the moon is necessary.
Landing on Moon – ISRO stated that soft landing on the moon is the most challenging
part of the Chandrayaan-2 mission. The lander named Vikram must be
descended on the moon by adjusting to the local gravity variation. While
descending, all systems and units must work in unison. And the lander has to
touch down on the rugged terrain gently without any damage or falling into
communication shadow area.
Dust – the Lunar Dust is very fine, hard and negatively charges. While
firing on-board engines, the dust might flow back and stick to the probe
leading to disruption in deployment mechanism or functioning of the solar
Temperatures and Vacuum – A lunar day or night lasts for 14 Earth days.
This causes extreme temperature variations. Ambient pressure of surface is a
hard vacuum which makes it a hostile environment for lander and rover.
Chandrayaan-2 weighs 3,500 kg.
It will be launched by GSLV-Mk III rocket.
The mission if successful will create history
and ISRO will yet again prove its mettle in conducting deep space experiments.