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Journalism of Courage
The Indian Space Research Organisation (ISRO) is once again attempting a soft landing on the Moon with the Chandrayaan-3 mission, which is scheduled to launch from Sriharikota at 2.30 PM on July 14. Despite the fact that humans first landed on the Moon more than 50 years ago, the task is still quite difficult.
The Chandrayaan-2 mission ended in failure in September 2019 when the Vikram lander crashed into the Moon’s surface. Earlier that year, the Israeli-led Beresheet mission also had a similar fate. Fast-forward many years later and the Japanese Hakuto-R mission also failed to complete a soft landing on the Moon in April this year.
And, these are just some of the many failed missions that hoped to touch the Moon. In the 1960s, during the space race, the United States and the Soviet Union crashed spacecraft after spacecraft till they finally succeeded landing one. China is the only other country that completed a soft landing on the Moon and it did that on its first try with the Chang’e-5 mission in 2013.
But what makes Luna such a difficult target even after all these years of space exploration? Let’s explore that.
Long before you can even think of landing on the Moon, you will have to figure out how to get there. On an average, the Moon is about 3,84,400 kilometres away from our planet and depending on the path taken by the spacecraft, that distance can be much higher. A failure can occur anywhere on this long, long journey.
And that is true even for missions that just want to travel the Moon without landing. NASA had to terminate the Lunar Flashlight mission because a failure in the spacecraft’s propulsion system meant that it could not enter the lunar orbit.
Spacecraft returning back to our planet, like NASA’s Orion after the Artemis 1 mission, can rely on the Earth’s thick atmosphere providing enough friction to slow down before touching down safely. But spacecraft entering the Moon do not have that luxury because of its extremely thin atmosphere.
In such a scenario, the only thing that can slow down a spacecraft is its propulsion system. This means that it will have to carry a lot of fuel just so that it has enough to slow itself down quickly enough to make a safe landing. But carrying more fuel means the spacecraft is heavier, requiring more fuel. This problem is a bit similar to what is known as the “Tyranny of the Rocket Equation.”
Needless to say, there is no GPS on the Moon. Spacecraft cannot rely on a network of satellites to precisely land at a particular location because that simply does not exist on the Moon. This means that onboard computers will have to make quick calculations and decisions to land itself precisely on the Moon.
This becomes especially complicated when a spacecraft gets within the crucial last few kilometres, according to a report in the journal, Nature . At that point, the computers on board will have to autonomously react quickly to last-minute issues. For example, sensors could become confused by the large amounts of dust kicked up by the propulsion systems.
This is made even more difficult by the fact that the Moon has an uneven surface littered with craters and boulders. Landing on either could prove catastrophic for the mission.
