Outlook – June 29, 2019

GIANT LEAP

16 OUTLOOK 1 July 2019

by Ajay Sukumaran in Bangalore

A

N Indian lunar mission that will

boldly go where no country has

ever gone before—the moon’s

south polar region. That’s how

the Indian Space Research

Organisation (ISRO) website touts

the country’s second moon mission,

Chandrayaan-2. On July 15, the orb-

iter-lander-rover combo will lift off

from Sriharikota and stick to the cir-

cuitous route that the mavens at

ISRO are familiar with to our clos-

est galactic neighbour. Two months

later, in early September, the lander

will separate from the spacecraft and

start its descent to the moon’s sur-

face—a countdown to ISRO’s real test.

More than a decade after the Chan­

drayaan­1 moon mission, its sequel pre­

sents the space agency with its most

complex challenge so far, according to

ISRO chief K. Sivan, who announced the

launch date last week. The D­Day, as he

put it, will be around September 6. By

then, the lander will be about 30 km away

from the moon and ISRO will have to

execute a 15­minute braking manoeuvre

to soft­land on the lunar surface.

“Those 15 minutes are going to be the

most terrifying for us,” said Sivan at a

press conference in Bangalore. “Every

second of the flight from the start of

the landing process till touchdown is

crucial. It’s a new thing for ISRO.” In

2008, the organisation had experi­

mented with a moon impact probe

which was meant to crash­land on the

lunar surface.

Chandrayaan­2 is headed to the moon’s

south pole, a region that is relatively less

explored. Part of the reason why the

south pole was chosen is convenience—it

is relatively flat, does not have too many

craters, offers visibility and solar light to

power the systems. It’s also attractive

from a scientific point of view—data from

ISRO’s first lunar mission had provided

evidence of the presence of sub­surface

ice in craters near the moon’s north pole.

The south pole, which is more under

shadow than the north, is expected to

CHANDRAYAAN-2,

a 3,84,000-km flight

into outer space to pry

on moon’s south pole

“The 15 minutes from

when the lander is 30

km away from the moon

to the soft-landing on the

surface are going to be

the most terrifying.”

K. Sivan

Chairman, ISRO

because radio contact is cut off and a

lander or rover can’t directly relay sig­

nals to the earth.

Meanwhile, NASA is charting out a

mission named Artemis to return astro­

nauts to the moon by 2024. “First, we

are focused on speed to land the next

man, and first woman, on the moon by

2024,” announced NASA administrator

Jim Bridenstine in April. “Second, we

will establish sustainable missions by

2028.” As NASA puts it, Artemis is the

first step to begin the next era of explo­

ration and send humans to Mars.

“There are two primary motivations

driving interest in the moon, explains S.

Chandrashekar of the National Institute

for Advanced Studies in Bangalore. “A

scientific understanding of the moon will

shed light on some fundamental ques­

tions associated with the origins of the

solar system. The other reason is that if

you want to initiate missions to explore

the outer planets, such as Mars, the obvi­

ous place to have a base is on the moon

and use it to go to Mars or further explore

the solar system.”

As for Chandrayaan­2, once the lander

touches down on the moon, a six­whe­

eled rover will inch its way out of the

craft onto the lunar surface, travelling at

the speed of one centimetre a second.

Both the lander and the rover will have a

lifespan of 14 earth days during which

they will collect data and carry out

experiments—all in a lunar day’s work,

as that’s the time the moon takes to

complete one rotation on its axis. O

provide opportunities to study signs of

water, ice and minerals. “We are going to

a place where nobody else has gone, so we

are expecting a huge amount of new sci­

ence,” said Sivan.

Incidentally, the fiftieth anniversary

of the 1969 Apollo 11 spaceflight is also

in July. Now, half a century since Neil

Armstrong and Buzz Aldrin landed on

the moon, there’s renewed interest in

earth’s natural satellite—a new race to

the moon, as the headlines go. This

January, China’s Chang ’e 4 mission

landed on the far side of the moon, the

first spacecraft to do so. The moon’s far

side poses a communication challenge

MOON TREK ISRO personnel work on the orbiter of Chandrayaan-

Photographs: PTI