After Indian Cricket team’s shock
exit from the semi-finals of World Cup Cricket, the nation has something to
cheer for-India’s pride and glory, ISRO (Indian Space Research Organisation) is
going to launch Chandrayaan-2 mission at 2:50 am on July 15th from
the Satish Dhawan Space Centre, Sriharikota. The present Mission is an advanced
version of Chandrayaan-1, India’s first mission to the moon launched on October
22nd, 2008.
Chandrayaan-1
Chandrayaan in Sanskrit means “Moon
Craft”. Moon orbiter of Chandrayaan-1 helped in determining presence of water
molecules on the surface of the Moon. Equipped with instruments needed for collecting
data on Moon’s geology, minerology and topography, the spacecraft orbited Moon
3400 times and transmitted data back to mission centre. From the mapping orbit
located at an altitude of 100 kilometres, space craft, deliberately crashed Moon
Impact Probe into Moon’s south pole to detect presence of water.
After 10 months of its launch, ISRO
lost contact with the orbiter. Though Chandrayaan-1 failed to complete is
mission life of two years, it had many achievements to its credit. It was
ISRO’s first interplanetary mission. The instruments aboard the mission
detected water in the thin lunar atmosphere, water ice near surface of the
poles and the over 70,000 images captured during its life span helped in
creating three-dimensional map of Moon and its past tectonic activity. This
highly successful scientific mission besides establishing ISRO’s technological prowess
motivated scientists to intensify Moon exploration.
Background
Encouraged by the new findings of
Chandrayaan-1, scientists finalised the payloads by 2013 and prepared ground
for Chandrayaan-2. Originally conceived as a joint mission between ISRO and
ROSCOSMOS (Russian Space Agency) the mission, Chandrayaan-2 was rescheduled to
2016 after Russia couldn’t develop lander for the mission. Subsequently after
failure of its Mars Mission, Russia withdrew from the Chandrayaan-2 mission.
India then decided to carry out the mission independently and scheduled the
launch for March 2018. But was delayed to April, then June and finally the team
made some comprehensive changes in the mission in October pushing the launch date
to 2019. In the meantime, India carried out its second interplanetary mission
to Mangalyaan in November 2013. ISRO took the World by storm by launching Mars
Orbiter Mission (MOM) successfully in its very first attempt incurring a cost
of mere $74 million (11% of NASA’s Mars Mission).
Chandrayaan-2
The Mission altogether contains
three parts- Chandrayaan Orbiter, Vikram Lander and Pragyaan Rover. Chandrayaan-2
Orbiter carrying the lander and rover module, weighing 3.8 tonnes will be
hoisted into Geosynchronous Transfer Orbit (GTO) by the indigenously developed
cryo-vehicle, Geosynchronous Launch Vehicle (GSLV Mk-III). GSLVs are specially
designed to inject satellites weighing more than 4 tonnes to geosynchronous
orbit. The three-stage rocket containing a pair of S-200 solid boosters, a core
liquid L-110 stage and upper cryogenic engine are perfectly suited for the new
parameters of the mission. Having conducted two successful launches earlier,
ISRO decided to use Mk-III launch vehicle for the lunar mission. Unlike
Chandrayaan-1 the current mission is technologically more challenging and
complex. Accuracy is the key. Even a slightest error of one kilometre can be
disastrous.
After 17 minutes of lift-off, the
upper cryogenic engine will inject the orbiter into earth’s parking orbit. In
the next 53 days, Orbiter will travel 3.84 lakh kilometers to reach the
designated lunar orbit. During the first 16 days of lift-off, the propulsion
system of orbiter will fire “earth-bound burns” to propel it into higher
orbits. Subsequently for the next five days, the orbiter will travel towards
the moon. With another firing, the orbiter sucked up by lunar gravity will be
hoisted to a peri-lunar orbit. The Orbiter will finally enter the 100km
circular orbit around moon after four lunar-burn manoeuvres. It will go around
the moon for 27 days. The orbiter with a mission life of one year besides
carrying the lander-rover composite module has the essential communication
equipment to relay message between lander, rover and mission centre on Earth.
On September 6th/7th
after travelling 3.84 lakh kilometres, the orbiter will prepare the module for
soft-landing. After going through the
numerous images captured by the Chandrayaan-1, scientists have pinned down on a
region for touchdown, which is a plain between two craters, Manzinus C and
Simpelius N, 70 degrees South of equator and 350 km north of South pole. It has
a slope of less than 12 degrees ideally suited for landing. A nerve-wrecking
time frame of 15 minutes will be challenging for soft-landing of the lander. As
per programmed set of events for the soft landing, four days before landing,
lander will separate from the orbiter and reach an orbit 30kmX100km. In the
scheduled 15-minute window, lander will decelerate its speed rapidly and lose
altitude. 100mt from the lunar surface, lander will hover for 25seconds to take
a call on final spot for touchdown. Firing all five engines for 13 seconds, it
will touch lunar surface. 15 minutes after landing it will send first
photograph and four hours after landing, rover will crawl out to conduct experiments
for 14 earth days or one lunar day.
India’s Chandrayaan-2 is immensely
significant for being the first mission attempting to soft-land on Moon’s South
pole. Poles with permanently shadowed craters termed as “lunar cold traps” with
water ice have fossilised records of the evolution of moon and solar system.
Exploring these regions can greatly enhance knowledge of our nearest space
neighbour, Moon. South pole is the region which is explored the least. Coming
shortly after Israel’s Beresheet crash while landing on lunar surface, on April
11th, space enthusiasts are closely observing India’s Moon Mission.
Lander, Vikram is named after the founder
of Indian Space Program, Dr. Vikram Sarabhai will act as communication link
between the rover, orbiter and Earth. It houses instruments for measuring lunar
seismic activity, ILSA; Thermal probe; Radio Anatomy of Moon Bound
Hypersensitive Ionosphere and Atmosphere; Imaging System; Radio Occultation
Experiment and instrument provided by NASA- retoreflector.
Rover, Pragyaan meaning Wisdom in Sanskrit
is an autonomous unit weighing 27 kilograms. It has six wheels, a radio antenna
to communicate, solar panels and carries Laser Induced Breakdown Spectroscope,
Alpha particle induced radio Spectroscope and Imaging System. It can travel up
to 500 meters. Of the 14 instruments on board, 13 are Indian. The cost of
entire mission is 630 crores ($87 million).
Barring China’s Chang’e, last year,
no mission has soft-landed on lunar surface. A successful soft-landing will put
India in an exclusive club of the US, Russia, China and Japan who have reached
Moon and elevate its status as an emerging space power. India’s moon mission
coincides with the 50 years of America’s conquest of Moon on July 16th
1969, when America’s Eagle landed on lunar surface and Neil Armstrong walked
over it. For all the trails and tribulations faced by Indian space program, a
successful Chandrayaan will be a giant leap forward. India’s unmanned mission
to Moon will be a fitting centenary tribute to Dr. Vikram Sarabhai who
envisioned potential of space exploration and its quintessential role in
powering telecommunication, weather forecasting, education and broadcasting.
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