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Chandrayaan 2: 100m above Moon, Vikram will pick final landing spot

Forty-seven days after it left Earth, Chandrayaan-2 lander Vikram... Read More
BENGALURU: Forty-seven days after it left Earth,

Chandrayaan-2 lander Vikram

will decide on the exact landing spot on

Moon

when it would be 100m above the lunar surface between 1.30am and 2.30am on Saturday. If all goes well, it'll touch down 78 seconds later.


Isro had chosen a primary landing site and a secondary one, now Vikram will approach the primary landing site, which in turn has two landing zones. "Vikram will be selecting one of these landing zones at the primary site after analysing data at that moment," said an Isro scientist.

Chandrayaan-2's preferred landing site is between two craters, Manzinus and Simpelius, about 350km north of Moon's south pole.


At a height of 100m, Vikram will hover for a few seconds before the final descent. "Within each landing site, two zones are identified of size 500m x 500m, separated by 1.6km. The prime target will be the first zone," says an Isro paper.



Isro considered that both the primary and backup site should have Sun's elevation at more than six degrees on the landing day to ensure enough illumination for the lunar craft to capture images. The lander has been taking pictures of the preferred landing sites since Tuesday.

"If it can land on the first zone, Vikram will, in 65 seconds, reach a height of 10m directly. In case it has to pick the second landing site, it will use 40 seconds to first descend to a height of 60m, then, drop to 10m in the next 25 seconds," the scientist explained. Once Vikram reaches 10m, it takes about 13 seconds for the touchdown.



Vikram's final descent from the lunar orbit would've started from an altitude of 35km. As per Isro's plan, about 10 minutes after the descent is initiated, Vikram would have dropped to a height of 7.4km from the lunar surface. In the next 38 seconds, it will reach a height of 5km and another 89 seconds later Vikram's altitude will be 400m. Here, Vikram will hover for a few seconds to collect data before plunging to 100m in 66 seconds.

A successful soft-landing would make India the fourth country after the US, Russia and China to do so. Only 37% of all Moon landing attempts have been successful.
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Chethan Kumar

As a young democracy grows out of adolescence, its rolling out re... Read More
Top Comment
D
Dileep Sathe
1895 days ago
Failures in science<br/>Failures in science are common because scientist(s) try to explore an unknown world. As a retired teacher of HSC physics / chemistry, I watched the live telecast of Chandrayan. Comparing events of last 100 seconds with a topic of HSC Chemistry, I could see a similarity between the two. Let me compare those two here to bring out the similarity, thereby encouraging HSC as well as 2 and -2 students.<br/>In HSC chemistry, students have to learn Gay-Lussc&rsquo;s (1778 to 1850) law of combining volumes of gases and its explanation on particle basis, first given by J.J. Berzelius (1779 to 1848). Apparently, it was very impressive but contained a violation of John Dalton&rsquo;s (1766 to 1844) atomic theory. Therefore the explanation of Berzelius remained hypothesis &ndash; due to the use of a term compound-atom, which was not in accordance to Dalton&rsquo;s atomic theory.<br/>On realizing this difficulty, Amedeo Avogadro replaced the compound-atom term by a new term that is molecule and argued that although atoms are indivisible &ndash; as per John Dalton &ndash; molecules are divisible. That raised the status of Avogadro&rsquo;s explanation to the law. In terms of cricket, Avogadro made the winning stroke.<br/>Yesterday, ISRO reached the status of Berzelius hypothesis and narrowly missed the status winning stroke. Our scientists took Vikram from Sri Harikotta to Chandra without any problem for more than a month. They will surely make the winning stroke next year.
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