Chandrayaan-3 vs. Luna-25: Are India and Russia racing to the moon's south pole?

These missions are more like a marathon than a sprint around the moon.

Although the race to the lunar south pole has been made the focus of India and Russia's moon landing attempts, there is much more involved.

On July 14, India's Chandrayaan-3 lunar lander lifted off, and on August 5, it reached lunar orbit. In preparation for a landing attempt that is anticipated to take place on August 23, it is now reducing its orbit.

Russia is now undertaking its first lunar landing since the Luna-24 Soviet-era sample return mission in 1976. After taking a more direct path to the moon than previous missions, Luna-25 launched on August 10 and might try a landing as early as August 21.

The so-called race is fascinating, but it is a bit of a non-starter because there is no clear winner and no clear reward at stake. On the other hand, there are also significant prestige issues, consequences for prospective follow-up missions, and chances for international collaboration to take into account.

There is obviously a lot of science at stake as well.

Who will touch down first?

Timing of the sun's course is a significant element in determining when these spacecraft will land. Because sunlight will power the spacecraft on the surface, the sun must be rising over each of these probes' landing sites. When the probes' orbits will cross the locations of their landings is another consideration. The moon will rotate below as Luna-25 and Chandrayaan-3 circle above in polar lunar orbits.

The landing point for Chandrayaan-3 is located at 69.37S 32.35E. The solar-powered Vikram lander and Pragyan rover will touchdown on Aug. 23 at roughly 17:47 IST (12:17 GMT, 8:17 a.m. EDT) since the sun will rise over this region early on Aug. 21 GMT.

At 72.9 S 43.2 E, the Boguslawsky crater is the objective of Luna-25. The sun will rise earlier on August 20 over this location because to its farther east location, which might allow the Luna-25, which is powered in part by solar power, to touch down sooner. However, it will rely on the lunar orbit that Luna-25 will be in and the strategy of Roscosmos.

Due to their solar-powered propulsion and limited mission period of one lunar day (about 14 days on Earth), Vikram and Pragyan will need to land as soon as possible in order to maximize their efficiency. A landing time early in the local lunar day may not be as important with Luna-25 because it is equipped with a radioisotope thermoelectric generator (RTG) that will provide the heat and electricity needed to keep the lander operating for at least a year.

Will they successfully land?

A fleet of spacecraft from several nations are now visiting the moon, which has sparked a resurgence in interest worldwide. Even though the moon has frequently welcomed robotic landers, only China (with the Chang'e 3, 4, and 5 missions) has made a successful landing thus far this century. And in contrast to those Chinese missions, those made by India and Russia are aiming for the area around the lunar south pole.

Though it is exciting to see which ship lands first, the important question is whether they manage a smooth, safe landing or make a harsh, mission-ending impact.

Since the Soviet era, Russia has not made a lunar landing. Luna 24 was the final Soviet mission, and it was launched 47 years ago. Fobos-Grunt, Russia's most recent interplanetary mission, which was designed to gather samples from the moon Phobos of Mars, was unable to leave low Earth orbit in 2011. Since more than ten years ago, Luna-25 has been postponed. In the later stages of the spacecraft's construction, engineers also had to make adjustments to the landing guidance system.

India wants to become the fourth country after China, the former Soviet Union, and the United States to make a gentle lunar landing. Along with the Mangalyaan mission, which entered Mars' orbit in 2014 and concluded its tenure in 2022 when its battery ran out, it would also be a huge accomplishment for the nation. The Chandrayaan-2 spacecraft's unsuccessful landing attempt in 2019 resulted to lessons being learnt, according to the Indian Space Research Organization (ISRO).

Israeli and Japanese firms' recent unsuccessful moon landing efforts emphasize the difficulties that still lie ahead.

Therefore, it cannot be assumed that either mission will land successfully, and both India's and Russia's efforts will be closely scrutinized across the world.

The south pole will they actually reach?

Concerning the potential existence of trapped water-ice that may be utilized as fuel or to provide lunar homes with life-sustaining elements, landing near the south pole is the center of worldwide curiosity.

India and Russia plan to touch down on the moon at 69 and 72 degrees south of the equator, respectively, which is farther south than any previous lunar touchdown. Although the locations are not thought to be genuinely polar, we will nonetheless discover new things. It is also well known that landing close to the equator is advantageous for a variety of technical factors, such as illumination, communications, and more straightforward terrain.

"Neither is a polar location, but rather high latitude locations," Clive Neal, a lunar exploration specialist at the University of Notre Dame in Indiana, told These landers will provide information from new regions on the moon because we haven't actually explored such southern high latitude locations previously, which is interesting from a scientific perspective.

Both missions primarily intended to test and show off technologies for upcoming soft moon landings.

How well do the spacecraft correspond?

The weight of the landers is comparable, with Luna-25 weighing around 3,860 lbs (1,750 kg) upon launch, of which slightly more than half is anticipated to be propellant. In contrast, the Chandrayaan-3 Vikram lander weighed 3,862 lbs (1,752 kg), which included a 57 pounds (26 kgs) rover called Pragyan. A large portion of Vikram's bulk serves as landing propellant.

Eight scientific instruments are carried on Luna 25, including the lunar manipulator complex (LMK), which can dig up lunar regolith, and the Neutron and gamma detector (ADRON-LR), which is designed to look for water ice.

In the meantime, Vikram will try to make the most of its (one and only) day in the sun. One of its four research payloads, a thermal probe, will be inserted into the lunar surface at a depth of around four inches (10 centimeters) and measure the temperature of the lunar regolith during the lunar day.

For research on lunar regolith, Pragyan will be equipped with the Laser-Induced Breakdown Spectroscope (LIBS) and the Alpha Particle X-ray Spectrometer (APXS). However, the retroreflector on Vikram will be helpful even after the lander stops functioning. The enhanced retroreflector, which is similar to those placed on the moon during the Apollo missions and is made to reflect light directly back to its source, will be used to precisely measure the separation between the Earth and the moon.

International collaboration, which is typically a key component of space missions, is one noteworthy facet of these missions. However, following its invasion of Ukraine in February 2022 and the country's continued occupation of Ukrainian land, Russia has been mostly isolated worldwide. The European Space Agency was prompted to stop participating in the Luna-25, -26, and -27 missions as a result. The Rosalind Franklin rover from the ExoMars mission, which will now launch no early than 2028 and hunt out signs of past or current life, was also delayed.

As a result, Luna-25's landing attempt no longer had access to ESA's PILOT-D guidance camera.

On the other side, the ESA's "Estrack" network of deep space stations is assisting India's mission by tracking, controlling, and receiving data from Chandrayaan-3. The retroreflector for lunar laser ranging is provided by NASA.

effect on next missions?

Additional Luna probes are being planned for launch by Russia, including Luna-26 in 2027, Luna-27 the following year, and Luna-28 no sooner than 2030. Instead of the US-led Artemis program, it seeks to play a significant role in the China-led International Lunar Research Station (ILRS).

Later in the decade, India and Japan want to undertake the Lunar Polar Exploration Project (LUPEX), a collaborative effort. Additionally, the nation has ratified the Artemis Accords.

The results of Luna-25 and Chandrayaan-3's landing efforts might have an impact on their involvement in future missions or even larger programs. We shall learn who the winners are in a few days.