On Monday 22nd of July 2019, the Indian Space Agency ISRO has successfully launched the moon probe Chandrayaan-2 into Earth orbit. Where Apollo 11 took a few days to reach the moon, Chandrayaan-2 will take at least 7 weeks and is scheduled for landing on September 6. Why does it take them so long to get to the moon this time and what will Chandrayaan-2 be doing on the moon anyway?
The Apollo program was designed to transport humans and Chandrayaan-2 is a robotic mission. This means it doesn’t need the quickest route to the moon. Apollo was using the heaviest rockets ever built to get to the moon to do just that, ISRO used considerably lighter rockets, also a more cost efficient way. Chandrayaan-2 will first spent 23 days in Earth’s orbit before jettison to the moon. While in orbit, it will gain speed to make the long journey to the moon.
Landing close to the aspired landing date is crucial. Chandrayaan-2 will have to make up for lost time as the launch has been postponed by a week, caused by a suspected helium leak. ISRO is however confident that this shouldn’t be a problem and has anticipated a delay in their plans. This means it will spend less time orbiting the moon than originally planned. Then, if all goes well, in the first week of September, the orbiter will release the lander called Vikram to the surface. One of the prime objectives is the demonstration of a soft landing on the moon and operate a robot rover from there.
The lander Vikram
Vikram is named after Vikram Sarabhai who is regarded to be the father of the Indian space program. This mission is of great importance for the Indian Space Program so this is significant. It has a camera attached but will also measure seismologic activities in the landing area. It will also measure temperatures and the variation and density on the lunar surface plasma. Also, it carries NASA’s Laser Retroreflector Array (LRA). This device can measure precisely the distance between the reflector and any orbiter around the moon. The LRA will remain operative after Vikram’s scientific operations end, they will last about 14 days.
Vikram also carries the moon rover Pragyan, which means wisdom in Sanskrit. The rover is expected to last one lunar day, or 14 earth days, and operates on solar power. However, the rover is able to store power and has a sleep / wake mechanism so it is possible that the rover will be operative after 14 days, when the night ends on their place on the moon. Both Pragryan and Vikram weren’t designed to survive these cold conditions at night. Hence the importance of the landing date. How later the lander reaches the moon surface, the less time there is for the planned experiments. Pragyan will send its data to Vikram who then sends this data back to earth.
On the moon surface
The rover is expected to drive 500 meters. It has a speed of 1 cm per second. The rover will map the lunar surface near the landing site, which is close to the south pole of the moon. A place relatively unexplored. Together with the orbiter its goal is to give a more detailed impression of that region of the moon. Apart from a camera it will use lasers and xray to do this.
It’s not the first time India landed on the moon, however their earlier attempt in 2008 with Chandrayaan-1 crash landed. The soft landing attempt is therefore one of the important parts of this mission, also as it serves as a test for future missions to Mars. This doesn’t mean Chandrayaan-1 failed. It remained operative for 10 months and has detected signs of water on the moon. Hard to say it failed indeed. Chandrayaan-2 will undoubtedly secure India and ISRO their place in deep space exploration. Chandrayaan-2 has a relatively short lifespan but considering the results of their previous moon mission, the prospects are incredibly good.
It may take Chandrayaan-2 a long time to reach the moon, but it will do so in an efficient way. It will hopefully demonstrate a soft landing on the moon around 6 or 7 September (2019). The lander will function as a transmission center between earth and the rover which will map the south pole region of the moon. It has 14 days to do so before the cold night kicks in. We can only hope they’ll exceed life expectancy and will make amazing discoveries. Just like their older sibling 11 years ago.