Chandrayaan 2 LIVE Updates: New method of controlling thrusters will be used during soft-landing

Will ISRO try to operate the lander & rover after the long, lunar night? 

After the 14-day lunar day, during which time the lander and rover will carry out their missions, the lunar night could leave both instruments damaged due to the extreme, continuous exposure to frigid lunar temperatures. The spacecraft will likely NOT survive it, but if it does… the solar cells will charge up the instruments and we have left a battery backup for such an occasion. If we’re lucky, they will survive it, but it cannot be guaranteed, the chairman said.

Lander to brake gradually, land after multiple manoeuvers in orbit

After separation from the orbiter, the Vikram lander will be maneuvered multiple times as it is slowed in stages and its orbit lowered with each maneuver.

Check out Dr Sivan taking a model of Chandrayaan 2 for a spin!

When will get the first data from the Pragyan rover?

Even as the rover rolls out on to the surface, the rover’s external camera will be active, Dr K Sivan says. The scientific data, however, will only come through about 5.8 hours after the landing, he added.

How ISRO plans to get around the moon dust problem

To get around the sharp, jagged-edged dust blowing up from the surface of the moon during landing, all the engines except one (the main) engine will be switched off. The engine that will stay on will only push the dust horizontally, thereby keeping the spacecraft risk-free in this regard.

Soft-landing will use a new configuration & means of operating thrusters 

Separation from orbiter isn’t a crucial part of the mission.

For the Vikram lander to land softly in a controlled manner, and will use a new technique, with throttlable control over the engine’s thrusters. This is something ISRO is attempting for the first time, says the chairman.

Communication link doubles as 2-way health-check

The lander and orbiter both have independent communication links with the deep space network (DSN). Any action from the orbiter will be communicated to the lander and vice versa. Whether it’s health of an instrument or progress on the mission, we will be assured of the health of both components this way.

‘World is eager for data from Chandrayaan 2’

“The landing site in the South polar region is somewhere no mission has previously been, the world is eager to know what the mission will find here,” says the chairman. The water and mineral deposits in the region are particularly interesting, he added.

Only 37% of missions attempting a lunar soft-landing have succeeded — what is ISRO doing differently? 

We’re learning from past failures, and adding more and more valuable input. In the years since some of the earliest missions. From the Israel Beresheet landing, we learnt that the landing needs to be largely, if not completely, autonomous (i.e. controlled by the spacecraft without live input from ISRO engineers).

Stepping away briefly from Chandrayaan 2

Asked about the SSLV project, Dr Sivan shared that ISRO will attempt to launch the first SSLV mission in December this year.

“We’re confident that we’ve done our best”  

The soft-landing is the one aspect of the mission we have never attempted. It will be difficult, says Dr K Sivan. At the system levels, sensor level and sub-system level, we’ve done everything possible at our end to ensure the mission’s success.

First photos from the mission

The first images from the mission can be expected around 5.5 hours after the landing, says the Chairman.

Control over the soft-landing 

If the landing surface is sloped, the spacecraft could topple. The same for boulders. The decision on a good spot to land won’t be made by ISRO engineers, but by Chandrayaan 2’s autonomous landing systems.

What’s next?

From 2nd September, all eyes will be on the lander. Much like the bridegroom at a wedding, Dr Sivan says. On 3rd and 4th September, the first maps of the landing site will be created to ensure the landing site is as safe as previously thought to make a soft-landing. 

The soft-landing itself is expected to begin at 1.40am on 7 September. Touchdown is expected at 1.55am, the Chairman announces.

What’s next?

The next lunar burn will be tomorrow around 1pm, followed by 3 more manoeuvers on 30th, 31st August & 1st September to bring down the orbital altitude of Chandrayaan 2 in preperation for landing.

The Chairman reviewed the mission’s milestones so far, and points out the enormous accuracy required to make a soft-landing. “Out of 10.5cm/sec, if there’s a one-second blunder in the mission, the spacecraft will miss the landing site by 7 degrees,” he said. 

Yikes!

Here’s a look at what the mission is about, and why ISRO is specifically targeting a region near the South Pole for its landing site. 
(Clue: Treasure hunt!)

Now that ISRO has its own YouTube channel, you can watch the briefing live via the embedded video link here.

Today’s success is one of very few remaining critical milestones before the spacecraft attempts to soft-land in the moon’s South Polar region on 7 September. 

Here’s a **step-by-step look at the Chandrayaan 2 mission so far and what's still to come** .

ISRO confirmed as much in a tweet ~half an hour ago!

#ISRO
Lunar Orbit Insertion (LOI) of #Chandrayaan2 maneuver was completed successfully today (August 20, 2019). The duration of maneuver was 1738 seconds beginning from 0902 hrs IST

For more details visit https://t.co/FokCl5pDXg

— ISRO (@isro) August 20, 2019

Hello all, 

We’re eagerly waiting to hear from the Chairman of ISRO today after the great news we heard this morning!