Japan, China, India, the U.S. and even Google ? everyone wants to go to the moon - By Thomas Bührke

In the past, interest in the moon tended to be scientific. These days, it is also commercial.

The inter-continental timing was perfect. In the early hours of one Friday morning (Central European Time), Japanese space agency Jaxa punctually launched its lunar probe Selene. Meanwhile, just as the countdown was beginning in the Tanegashima rocket center in southern Japan, Internet company Google announced it had earmarked $30 million (?21 million) for any private company, which can land a robotic rover on the moon.

Clearly, there is a new race to the moon. Inspired by 2003's European probe Smart-1, China, India and the U.S. are now planning their own missions to the nearest celestial body. The Americans are hoping to get a man on the moon by 2019, the first time in 47 years. In the meantime, Japan, India and China are playing technical catch-up, and scientists are confident there are many more lunar secrets waiting to be uncovered.

Weighing in at 3 tons, the 16-foot-long Japanese spaceship Selene is the most sophisticated lunar probe since the Apollo era. Named after the Greek moon goddess, it is set to approach the moon in about 20 days. Once there, it will divide. At 2,400 km, the mother ship will release a small relay satellite, as well as a radio satellite at 800 km. Selene itself will be put into an orbit at an altitude of 100 km. A stereo camera will supply spatial images of the moon's surface, while a number of instruments will explore its substructure. A laser ray will probe the lunar surface in order to compile detailed maps.

The purpose of the relay satellite is to transfer data from the main probe to ground control. Its chosen path allows for permanent contact between Selene and Earth, with small fluctuations in its orbit enabling scientists to identify irregularities in the gravitational field and investigate the moon's inner structure, including, for the first time, the far side of the moon. The radio satellite will broadcast signals, which allow its path to be tracked precisely.

But the Japanese are not solely concerned with hard science. The high-resolution television images supplied by Selene will fuel Japan's fascination with space, with one highlight expected to be the sight of the earth rising on the moon's horizon, as dramatically as it did back in the Apollo era.

The next scheduled rocket launch to the moon is expected to take place in India. In spring, the country will launch its first lunar probe. The primary task of the 525-kg Chandrayaan 1 will be to explore the moon's mineral and chemical structure. To this end, it will be equipped with six Indian instruments and five from Europe and the U.S, including an infrared spectrometer from the Max Planck Institute for Solar System Research in Katlenburg-Lindau.

NASA will then mark its own return to lunar research in October 2008, when it launches its Lunar Reconnaissance Orbiter. The LRO will travel at a height of 30 to 50 km, with its cameras recording large-to-very-large, high-resolution images.

At the same time, it will launch a second probe known as LCROSS (Lunar Crater Observation and Sensing Satellite). Its mission is a spectacular one. As the spacecraft approaches the moon's south pole, the two-ton upper stage will separate, and impact a crater in the south pole area. A plume from the upper stage crash will develop as the Shepherding Spacecraft heads in toward the moon. The Shepherding Spacecraft will fly through the plume, and instruments on the spacecraft will analyze the cloud to look for signs of ice believed to be in the permanently dark craters of the moon's south pole.

Chinese plans for space are less publicized. By the end of next year, a spaceship known as Chang'e 1 will have set off for the moon, its stereo camera recording a spatial relief of the lunar surface from its 100 km in orbit.

There are several reasons for this new race to the moon. While the Americans have mid-term plans to set up a station on the moon, India and China see the moon as the first stop in inter-planetary space travel.

"Keeping up with space travel is a way of staying in the vanguard of general technological developments," said planet researcher Gerhard Neukum of the Free University in Berlin.

"Competition between India and China has gathered momentum," explained Urs Mall from the Max Planck Institute for Solar System Research. While China has already sent astronauts into the Earth's orbit, observers expect India to win the race to the moon - on the grounds that Indian researchers have more specific scientific plans than their Chinese counterparts, whose space program is run by the military.

Despite Apollo, much of the moon is still uncharted territory.

"We are hoping that increased investigation of the moon will provide fundamental insights into the early history of the solar system," said Jürgen Oberest of the German Aerospace Center in Berlin, one of the scientific partners of the Selene project.

American and Soviet moon missions of past decades might have boosted knowledge of the moon but Harald Hiesinger from the Institute for Planetology at Münster University says they were just the beginning.

"Nine rock samples from random locations on Earth would not be enough to reveal the structure and history of our planet," he stressed.

Scientists are especially excited about the Aitken Crater. With a diameter of 2,240 km, it is larger than India. This impact basin created by a meteorite is located on the far side, between the South Pole and equator, and is about 2,240 km in diameter and 13 km in depth.

Google, meanwhile, is not interested in any scientific exploration of the moon, despite investing $30 million in research, $20 million earmarked for the first private company that manages to land a rover on the moon by 2012. To be eligible, the winning craft will have to land on the moon, roam for a minimum of 500 meters and beam photographs, videos and measurements back to Earth. The second landing will be awarded $5 million, while the first to supply images of Apollo instruments or locate ice will receive a $5 million bonus.

"Returning to the moon to explore it as a commercial business is the start of a great adventure," said Google founder Sergey Brin.

The competition is running under the aegis of the X Prize Foundation, which two years ago awarded $10 million to Burt Ratan and Microsoft founder Paul Allen when their airplane SpaceShipOne reached a height of 100 km twice in a row.

But this time, the stakes are higher. Peter Diamandis, director of the X Prize Foundation, has talked effusively of his hopes for the future. Companies these days have the creativity to "dramatically reduce the costs of space research," he said.

And that will be necessary. Generally, the expense of constructing a lunar probe is 10 to 20 times as high as the prize money. Moreover, the proposed development period of five years is very short. All things said, it seems likely that Google will never have to pay the prize money.

- Thomas Bührke writes about science for the Süddeutsche Zeitung, which published this article on Sept. 15.