BEIJING, June 3 (Xinhua) -- After China's Chang'e-6 touched down on the far side of the moon Sunday morning to collect samples, foreign scientists participating in the mission expressed their excitement and thanks for taking their scientific instruments to the moon.

The Chang'e-6 mission carried four payloads developed through international cooperation, providing more opportunities for global scientists and merging human expertise in space exploration.

Scientific instruments from France, Italy and the European Space Agency (ESA)/Sweden are aboard the Chang'e-6 lander.

"Thank China so much for taking us to the moon," Sylvestre Maurice, a French astronomer from the University of Toulouse, said after he watched the landing process in a control room at the National Astronomical Observatories of the Chinese Academy of Sciences on Sunday.

"Today's landing is absolutely amazing. It's hard to land on a planet, and it's very hard especially on the moon. Don't think it's easy. Remember it's on the far side of the moon where we cannot see. And China had even to put another relay satellite to watch the landing. They landed right where they wanted to. So it's quite an achievement, something we've been looking for so many years," said Maurice.

Supported by the Queqiao-2 relay satellite, the lander-ascender combination of the Chang'e-6 probe successfully landed at the designated landing area at 6:23 a.m. (Beijing Time) in the South Pole-Aitken (SPA) Basin, according to the China National Space Administration.

"The far side of the moon is very unique. The South Pole-Aitken Basin is a huge basin. There was an impact long time ago to remove most of the crust, so we might have landed as close as possible to the mantle of the moon," Maurice said.

"As planetary scientists, the best thing we can dream of is to have samples in our lab. Nothing is better than having samples here, where we can study them and really go into the details of the story of the moon," said Maurice.

He mentioned that French scientists have got the lunar sample returned by the Chang'e-5 mission and would carry out research on it.

"We were very lucky to collaborate with China on different projects including the Chang'e lunar program and the Tianwen-1 Mars mission," he added.

Mathieu Grialou, a representative from the French space agency CNES, said Chang'e-6 will be the first mission to bring back samples from the far side of the moon. "We are very thrilled to be a small part of this very big mission."

"We are very happy to cooperate with China on this mission as China is now a big player in space," Grialou said. "It's great that we can contribute together to a better knowledge of the moon and our solar system."

A scientific instrument named Detection of Outgassing RadoN (DORN), developed by French scientists and onboard the lander of Chang'e-6, will detect radon isotopes and study the transmission and diffusion mechanisms of volatile compounds in the lunar environment.

Witnessing the landing of Chang'e-6, Pierre-Yves Meslin, principal investigator of DORN from France, said, "We have been thinking about this moment for years and even more intensely for the last few months and weeks and days. We were almost watching at the moon every night here in Beijing."

"We are very glad to be on the surface of the moon. Our instrument will start working. Now the pressure will be on us to succeed in our measurements," Meslin said.

He said the objective of the instrument is to study the origin and dynamics of the lunar exosphere. It will try to measure a radioactive gas called radon that is produced by lunar rocks in the lunar interior. "This gas might migrate from the warm regions of the moon to the cold regions of the moon, and we will try to understand its dynamics in the lunar environment. It will be the first time to measure it on the surface of the moon."

He mentioned that his team had a short time to develop the instrument, with only 3.5 years. "The schedule was very tight but we succeeded with the help of our Chinese partners."

"It's always good to share ideas with the different countries, which allows us to move forward to enrich our knowledge. As Europeans, we don't have the capacity to deploy our instruments on the surface of the moon yet. So we rely on international partners. China is now one of the most reliable partners that can safely land on the moon, as we have one more proof today," said Meslin.

Patrick Pinet, a scientist at the University of Toulouse, said Chang'e-6's landing seems smooth and easy, but it relies on a very heavy job and high skills. "And we're very impressed by what was achieved by China this time again."

"It's a very moving time for me," he said, noting that when he was 10 years old, he watched Neil Armstrong's landing on the moon on TV, and today it is his first experience of witnessing a landing on the far side of the moon in a control room in China. "It's 55 years later, and a lot of things have evolved through time."

"We really expect to have some success with this mission and with the next ones to come," he added.

The lander of the Chang'e-6 spacecraft also carried an instrument, called Negative Ions on the Lunar Surface (NILS), developed by the ESA/Sweden to the moon, which will be used to detect negative ions and study the interaction between plasma and the lunar surface.

Neil Melville-Kenney, NILS technical officer of the ESA, said the CNSA's initiative to invite international partners to participate in the Chang'e-6 mission is very much appreciated by the international community.

"It's a very impressive mission, a very ambitious mission. So we are very pleased to be a part of it. And the collaboration has gone very smoothly. Now we are waiting for the payload to be turned on so that we can get our first data," he said.

"It's very important to have international cooperation for space exploration. I think space exploration encourages us to consider our planet as one and our people as one. And it's important that we work together as we start to explore the solar system more and more. Together we can achieve greater things," he added.