CLIMAX ON MOON
LAST MINUTES OF LANDING
Isro will attempt to land Vikram on
Moon at 6.04pm. The landing module will be at an altitude of 25km when the
power descent phase begins. This involves a set of complex tasks. If all goes
according to plan, here's how Chandrayaan-3 will touch down the lunar surface
Successful Chandrayaan 3 will Mark THE FIRST
SPACECRAFT LANDING ON LUNAR SOUTHPOLE WHERE UNKNOWNS LURK IN DARK
T Vikram soft lands on Moon on
Wednesday, India would be the only nation to mark its presence in the south
polar region of Earth's natural satellite Rusata's Lana 35, which was on its
way to the south pole, crash-landed on Sunday
INDIA WOULD BE THE ONLY NATION TO MARK ITS
PRESENCE IN THE SOUTH POLAR REGION OF EARTH’S NATURAL SATELLITE.
Since Russia hard landed its Lana 2 on Moon
on September 12, 1950, there have been scores of successful Junar missions
including six manned missions. Except two of them, all had landed on the
equatorial region of Moon. Chandrayaan will be attempting to touch down around
60 degrees south, 100km awayfrom Chandrayaan-2's landing site
Two missions had landed away from the lunar
equator Nasa's Surveyor 7 landed 41 degrees south latitude on Janu ary 10,
1968, and China's Chang'e 4 landed 45 degrees south on January 3, 2019, on the
far side of Moon.
The lunar south pole, which is hidden from
Earth's view, has remained unex plored. Filled with craters and trenches as
well, many parts of the region are in per petual darkness. Scientists believe
it holds reduce it water ice in regions that have not had sun light. Water ice
in significant quantities could be a stepping stone to future crewed missions
as the water ice could be used to extract oxygen and fuel.
Temperature in the shadowed regions of the
lunar south pole craters may be as low as-205 deg C, and hence they may con-
tain fossil records of hydrogen, water ice and other volatiles that may hold
clues to early life "At the lunar south pole, the sun hovers below or just
above the horizon, resulting in temperatures upwards of 54 deg C during sunlit
periods During these periods of illumination, soaring moun tains cast dark
shadows and deep craters protect perpetual darkness in their abyss" the US
Space Agency said on its website.
ROUGH BRAKING ALTITUDE HOLDING
Begins at 25m with Vikram's orientation being
horizontal. After the end of this phase, which will around 980 secs (around 115
mins), Vikram reaches an altitude of At 7.4km, the lander holds the altitude
for about 10 secs before going down to 5.5km.
FINE BRAKING
This phase begins at an altitude of 6.8km.
About 175 secs (around 29 mins)later, Vikram reaches an altitude of 800m
Now the lander hovers for 12 secs. In another
131 secs (around 2.2 mins), it reaches an altitude of around 150m
TERMINAL DESCENT
This is the most crucial part of the landing
whenVikram hovers for around 22 secs at 150m and checks for boulders, craters
or other obstacles Based on hazard verification, Vikram either continues
vertical descent or chooses an alternative site a few metres away. If it does
thelatter, there will be a delay of 52 secs
In the next 38 secs, Vikram reaches an
altitude of 60m and descends to 10m above the From 10m, Vikram takes 9 seconds
to soft-land on Moon
The most critical part of the
landing is the process of reducing the velocity the tander from 30km height to
the final landing site. At 25km to 30kn, the lander is horizontal. Transferring
it from horotal orientation to vertical is very challenging we had problems
bere with Chandrayaan-2 We have to ensure that not too much fuel is consumed,
the distance is calculated correctly, all algorithms work for this we've
changed the guidance design introduced newer algorithms and extensive
simulations havebeen done.
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