Chandrayaan-3 vs Russia Luna-25 mission

 

Chandrayaan-3 vs Russia Luna-25 mission | How close are they to Moon's south pole

It was on July 14 when India's Chandrayaan-3 lunar lander lifted off, and on August 5, it arrived in lunar orbit. It is now reducing its orbit in anticipation of an August 23 landing attempt.

Russia, meanwhile, is returning to the Moon for the first time since the Luna-24 sample return mission in 1976 (during the Soviet era). With a more direct route to the Moon, Luna-25, which launched on August 10, could try a landing as soon as August 21.

The so-called race is intriguing, but it's hard to get excited about it because there's no clear reward and the location of the finish line is up for debate. However, there are also consequential concerns of reputation, ramifications for prospective follow-up missions, and prospects for international cooperation. Here is a lot of science on the line, of course.

Which will land first?

 The position of the sun in the sky plays a major role in determining when these spacecraft will touch down. The sun must be rising over the landing sites of these probes so that solar panels may charge their batteries. Another consideration is when the probes' orbits will pass over the landing sites. Luna-25 and Chandrayaan-3 will be in polar lunar orbits as the Moon rotates beneath them.

The coordinates 69°37′S 32°35′E have been chosen as a landing spot for Chandrayaan-3. By the time the solar-powered Vikram lander and Pragyan rover touch down on the surface on August 23 at roughly 17:47 IST (1217 GMT, 08:17 a.m. EDT), the sun will have risen over the area, providing adequate lighting.

Additionally, Luna-25 is aiming for the Boguslawsky crater at 72.9°S 43.2°E. Since this area is more to the east, the sun will rise over it sooner on August 20; this could also allow the largely solar-powered Luna-25 to land earlier. Luna-25's lunar orbit and Roscosmos's intentions will determine this, nevertheless.

With only one lunar daytime (about 14 Earth days) to complete their mission, it is crucial that Vikram and Pragyan land as soon as possible after taking off. However, Luna-25 is equipped with a radioisotope thermoelectric generator (RTG) that can provide heat and electricity for at least a year; thus, landing early on the local lunar day may not be as important.

Will they land successfully?

There is increasing international curiosity about the Moon, so many spacecraft from different nations are currently going there. There have been many robotic lander trips to the Moon, but only China's Chang'e 3, 4, and 5 missions have been successful this century. India and Russia are trying to reach the Moon, but their sights are set on the Moon's south pole instead of China's.

The real question is not whether the vessel will arrive first but whether it will accomplish a safe, gentle landing or make a hard collision to end its mission. Since the Soviet era, Russia has not returned to the Moon. The Soviet Union sent its last spacecraft, Luna 24, into orbit 47 years ago. In 2011, Russia's final attempt to send a spacecraft beyond Earth's orbit, Fobos-Grunt, failed. The mission's goal was to collect samples from Mars' Moon Phobos. More than ten years have passed with no sign of Luna-25. The landing navigation system also required modifications when engineers got to work on the spacecraft.

India hopes to become the fourth country after the United States (USA), the former Soviet Union (USSR), and China to accomplish a soft landing on the Moon. Along with the Mangalyaan mission, which entered Mars' orbit in 2014 but ended its tenure in 2022 due to battery failure, this would be a remarkable milestone for the country. The Indian Space Research Organisation (ISRO) claims it has matured due to the failure of the 2019 Chandrayaan-2 landing attempt.

Will they land at the south pole?

Interest worldwide is focused on a hypothetical landing at the south pole, where trapped water ice may be exploited as fuel or to supply lunar colonies with life-sustaining ingredients. India and Russia hope to be the first to touch down on the Moon at latitudes 69 and 72 degrees south of the lunar equator. The locations aren't technically polar, but that doesn't mean we won't get useful information from them. Landing around the equator is recommended because of the improved lighting, communications, and navigable terrain.

"Neither is a polar location, but rather high latitude locations," Clive Neal, an expert on lunar exploration from the University of Notre Dame's Department of civil and environmental engineering in Indiana, told Space.com. "From a curiosity and science standpoint, these landers will give data from new locations on the Moon." "We have not visited such southern high-latitude locations before."Demonstrating and test technology for future soft landings on the Moon is the primary goal of both missions.

How do the spacecraft match up?

The landers are comparably heavy; Luna-25 weighs around 3,860 lb (1,750 kg) before launch, with more than half of it projected to be propellant. Meanwhile, the Chandrayaan-3 Vikram lander's total mass and accompanying rover, Pragyan, was 3,862 pounds (1,752 kilogrammes). Most of Vikram's weight consists of landing rocket fuel.

With its eight scientific instruments, Luna 25 can do everything from excavating lunar regolith with its lunar manipulator complex (LMK) to hunting for water ice using its neutron and gamma detector (ADRON-LR).

During this time, Vikram will attempt to capitalise on its moment in the spotlight. With its four science packages, one of which is a thermal probe that will be inserted into the lunar soil to a depth of about four inches (10 centimetres) to measure the temperature of the lunar regolith during a lunar day, the rover is a major step forward in exploring the Moon.

Meanwhile, Pragyan will bring the Alpha Particle X-ray Spectrometer (APXS) and the Laser-Induced Breakdown Spectroscope (LIBS) to study the lunar regolith. However, Vikram's retroreflector will continue to serve its purpose even after the lander has stopped functioning. The retroreflector, which measures the exact distance between the Earth and the Moon and any changes to that distance, is an improved version of the ones left on the Moon by the Apollo missions.