As the launch date for India’s second Moon mission nears, the journey of Chandrayaan 2 has already started as its journey from ISRO’s satellite centre in Bengaluru and will be moving towards India’s rocket port situated at Sriharikota. The lift-off is slated for 2:51 AM on July 15, 2019.
The Indian Space Research Organisation (ISRO) has already set the date for its next big mission which is called the Chandrayaan-2. The Chandrayaan-1 was the first Moon space probe and now the second mission Chandrayaan-2 will send an orbiter to the Moon. The Chandrayaan-2 will be the second mission to the Moon and they will be sending the orbiter, lander, and rover on the Moon’s surface.
The latest Chandrayaan-2 mission will be the second endeavour in terms of lunar exploration for India after Chandrayaan-1. The lunar exploration mission has been developed by the Indian Space Research Organisation (ISRO) and the mission includes launching using the Geosynchronous Satellite Launch Vehicle Mark III (GSLV Mk III). The payload includes a lunar, orbiter, lander, and a rover. All of the equipment has been designed and developed in India only.
The lunar exploration mission, as we know, is not an easy task. There are countless points to look into and a lot of calculations. The accuracy has to be on point otherwise there could be a catastrophic failure with losses running into millions of rupees.
Talking about challenges for Chandrayaan-2, here are some:
The distance to the Moon is around 3.844 lakh km. Ensuring trajectory accuracy while navigating such a large distance poses many challenges as the trajectory is influenced by the non-uniform gravity of the Earth and Moon, the gravitational pull of other astronomical bodies, solar radiation pressure, and the Moon’s true orbital motion.
Because of the large distance from Earth and limited onboard power, radio signals used for communication are weak with heavy background noise, which needs to be picked up by large antennas.
Trans Lunar Injection (TLI) and Lunar Capture
Chandrayaan 2 will perform a series of TLI burns for raising its apogee successively to reach the vicinity of Moon’s orbit. Because the Moon’s location is continually changing because of orbital motion, the intersection of Chandrayaan 2 and the Moon’s path has to predict sufficiently well before in advance with a high level of accuracy. As the Moon moves closer to the apogee of Chandrayaan 2, onboard thrusters fire precisely to reduce its velocity for lunar capture. The margin of error in these calculations and manoeuvres is very narrow.
Orbiting around the Moon
Lunar gravity is ‘lumpy’ because of uneven mass distribution under the surface. This also affects the orbit of the spacecraft. Additionally, precise knowledge of the thermal environment at orbital altitude is essential for keeping on-board electronics safe.
Soft landing on the Moon
This part is the most difficult move and has been divided into ‘rough braking’ and ‘fine braking’. Variation in local gravity has to be calculated into lunar descent trajectory. The onboard NGC and Propulsion System has to work in unison, autonomously, and automatically for a successful landing. Additionally, the landing site landscape features should not result in a communication shadow area.
The lunar surface is spotted with craters, rocks, and dust. The firing of onboard engines so close to the lunar surface results in the backwards flow of hot gases along with the dust. Lunar dust is minuscule and is hard, barbed, and jagged. Its negative charge makes it stick to most surfaces, thus causing a disruption in deployment mechanisms, solar panel performance, and NGC sensor performance.
A lunar day or night lasts 14 Earth days. This results in extreme surface temperature variations. Additionally, the ambient pressure of the lunar surface is a hard vacuum. This makes the lunar surface a dangerous environment for lander and rover operations.