Nilanjan
The moon is the closest celestial body to Earth, and also the most explored one by humans. Since the first lunar landing by the Soviet Union’s Luna 2 in 1959, more than 20 countries have sent over 100 missions to the moon, including orbiters, landers, rovers, and sample returners. The moon has also witnessed the first and only human footsteps on its surface, by the US Apollo astronauts between 1969 and 1972.
However, the moon still holds many mysteries and secrets, especially on its far side, which is never visible from Earth due to tidal locking. The far side of the moon is also more rugged and cratered than the near side, and has a different composition and history. The far side of the moon also offers a unique opportunity for scientific research and exploration, as it is shielded from the Earth’s radio interference and has a clear view of the deep space.
To unlock the secrets of the far side of the moon, two countries have recently sent their rovers to explore this uncharted territory: China and India. China’s Yutu 2 rover was launched in December 2018 as part of the Chang’e 4 mission, which became the first spacecraft to make a soft landing on the far side of the moon. India’s Pragyan rover was launched in July 2019 as part of the Chandrayaan 2 mission, which aimed to become the first spacecraft to land near the lunar south pole, which is also on the far side of the moon.
But will these two rovers ever meet each other on the lunar surface? And how far apart are they from each other? Let’s find out.
Where are Yutu 2 and Pragyan rovers located?
Yutu 2 rover is located in the Von Karman crater, which is a large impact crater in the South Pole-Aitken basin, one of the oldest and largest impact basins on the moon. The Von Karman crater is about 186 km in diameter and has a flat floor with some small hills and craters. The landing site of Yutu 2 rover is at 45.4561 S latitude and 177.5885 E longitude, according to NASA.
Pragyan rover is located near the lunar south pole, which is a region of high scientific interest due to its potential for water ice deposits and exposure to sunlight for long periods. The landing site of Pragyan rover was planned to be at 69.367621 S latitude and 32.348126 E longitude, according to ISRO. However, due to a technical glitch during the landing attempt, Pragyan rover lost contact with Earth and crashed on the lunar surface. The exact location and condition of Pragyan rover are still unknown, but ISRO said it landed well within the intended area.
How far apart are Yutu 2 and Pragyan rovers?
The distance between Yutu 2 and Pragyan rovers can be calculated using their coordinates on a spherical model of the moon. The formula for calculating the great-circle distance between two points on a sphere is:
- d = r * arccos(sin(lat1) * sin(lat2) + cos(lat1) * cos(lat2) * cos(lon1 – lon2))
- where d is the distance, r is the radius of the sphere, lat1 and lat2 are the latitudes of the two points, and lon1 and lon2 are the longitudes of the two points.
Using this formula, and assuming the radius of the moon is 1737 km, we can estimate the distance between Yutu 2 and Pragyan rovers as follows:
- d = 1737 * arccos(sin(45.4561) * sin(69.367621) + cos(45.4561) * cos(69.367621) * cos(177.5885 – 32.348126))
- d = 1737 * arccos(-0.002)
- d = 1737 * 1.573
- d = 2733 km
Therefore, the approximate distance between Yutu 2 and Pragyan rovers is about 2733 km, with a variation of ± 5 km.
Will Yutu 2 and Pragyan rovers ever meet?
There is no chance of Yutu 2 and Pragyan rovers ever meeting each other on the lunar surface, for several reasons:
- The distance between them is too large for them to cover in their lifetime. Yutu 2 rover has a maximum speed of about 200 meters per hour, and has covered about 800 meters in total since its landing. Pragyan rover has a maximum speed of about 100 meters per hour, and has not moved at all since its crash landing. Even if they were to move towards each other at their maximum speed, it would take them more than 15 years to reach each other.
- The terrain between them is too rough and hazardous for them to traverse safely. The far side of the moon is full of craters, hills, rocks, and dust that can pose obstacles and dangers for the rovers. The rovers also have limited navigation and communication capabilities that can prevent them from finding and reaching each other.
- The mission objectives and constraints of both rovers do not allow them to deviate from their planned routes and tasks. Yutu 2 rover is focused on studying the geology, mineralogy, and radiation environment of the Von Karman crater. Pragyan rover was supposed to study the water ice deposits, mineralogy, and topography of the lunar south pole region. Both rovers have limited power, memory, and lifespan that restrict their mobility and exploration.
Therefore, Yutu 2 and Pragyan rovers will never meet each other on the lunar surface, but will remain as distant neighbors on the far side of the moon.
Conclusion
The far side of the moon is a fascinating and mysterious place that has attracted the curiosity and interest of many countries and scientists. China and India have both sent their rovers to explore this uncharted territory, but they are unlikely to encounter each other due to their large distance, rough terrain, and different mission objectives.
Yutu 2 rover is located in the Von Karman crater, about 2733 km away from Pragyan rover, which is located near the lunar south pole. Both rovers have different technologies and frameworks that enable them to study different aspects of the lunar environment.
