September 17, 2010 A return to the lunar surface N. Gopal Raj The two Asian giants, China and India, are gearing up for the next phase of lunar exploration. Each of them has successfully sent a scientific probe that photographed and studied Earth's natural satellite while circling it. China now plans to send the Chang'e-2 to the moon at the end of this year. An orbiter like its predecessor, this spacecraft will be equipped with a high-resolution camera that will help identify possible landing areas on the moon. According to a recent report from the Xinhua news agency, it will also “test key soft-landing technologies.” The country then intends to set a rover down on the lunar surface with the Chang'e-3 mission in 2013. A subsequent mission will attempt to bring lunar samples back to earth four years later. Meanwhile, the Indian Space Research Organisation (ISRO) is pursuing the Chandrayaan-2 project. This mission, which is currently scheduled for 2013, envisages having both an orbiter circling the moon as well as a lander taking a rover down to the lunar surface. The rover will then trundle about and study the composition of lunar rocks and soil. ISRO recently announced details of seven instruments that would be carried on the orbiter and rover. India and Russian help India has chosen to take Russian help for this ambitious project. The space agencies of the two countries signed an agreement to work together on the Chandrayaan-2 mission when Prime Minister Manmohan Singh visited Russia in 2007. The original idea was that India would be responsible for the orbiter while Russia would provide the lander and the rover. But as things have worked out, Russia will be making only the lander while ISRO will develop both the orbiter and the rover. The tie-up is intended to take advantage of the wealth of experience that the Russians have with automated missions to the moon. The epic space race between the U.S. and the [former] U.S.S.R. is best remembered for America's triumph in putting a dozen of its astronauts on the moon. What is often forgotten is the latter's belated successes with automated missions involving two rovers and three sample-return missions. The Soviet Union's programme for manned exploration of the moon never received the sort of wholehearted government backing that the U.S. once did. It was also undermined by feuds between key design bureaus in the Soviet space programme. As a result, a rocket powerful enough to carry humans to the moon could not be developed in time. (See “Soviet Union in the race to the Moon”, The Hindu, July 30, 2009.) Unmanned exploration Watching the steady progress of the U.S. effort which they could not match, the Soviet leaders and space community turned to unmanned exploration. If their cosmonauts could not go to the moon, perhaps some of their tasks could be carried out by automated rovers and sample-return spacecraft. Their Luna 9 spacecraft had, after all, been the first to achieve a soft-landing on the moon in January 1966. But even automated exploration proved problematic. In 1969, when Apollo 11 landed the first astronauts on the moon, Soviet space scientists and engineers were struggling with one failure after another. The new Proton rocket, which was used to launch the automated lunar spacecraft, had a troubled start. (It went on to become a reliable launch vehicle that is still in use today.) A Proton rocket carrying the first lunar rover blew up less than a minute after launch in February 1969. In June the same year, a spacecraft to bring back a sample of lunar soil was launched, as space historian Asif A. Siddiqi puts it, to “reclaim some glory for the Soviet space programme.” But an upper stage of the rocket failed and the spacecraft wound up in the Pacific Ocean. Another sample-return mission was launched in mid-July that year, just three days before the Apollo 11 astronauts left the earth. After successfully entering lunar orbit, Luna 15, however, crashed into the side of a mountain as it was descending to the surface. Three subsequent Soviet sample-return missions were also unsuccessful. Finally Luna 16 landed safely on the moon's Sea of Fertility in September 1970. Less than an hour after landing, an automatic drill took a sample of lunar soil, which was then deposited in a return capsule. After successfully lifting off from the moon, the capsule brought some 105 grams of lunar soil back to the Soviet Union. The rovers Another impressive achievement soon followed. Luna 17 took a rover, known as Lunokhod 1, to the moon in November 1970. The Lavochkin Design Bureau, which built both the sample-return and rover spacecraft, used a lander that was essentially common to the both. The sample-return mission had an ascent stage fixed on top of the lander. Likewise, the rover too was strapped to the lander, which was equipped with ramps so that the wheeled vehicle could roll off on to the lunar surface. “The mobile Lunokhod 1 was an extremely sophisticated, self-contained explorer, although its appearance prompted observers to describe it as a bathtub on wheels with two large protruding eyes,” remarked Nicholas Johnson in his book on Soviet lunar and planetary exploration. Lunokhod 1 was an outstanding success, Dr. Siddiqi has pointed out in his book on the Soviet efforts during the space race. It operated for 10 months, during which time it travelled over 10 km, taking 20,000 photographs and over 200 panoramas of the lunar surface. During that period, it withstood the intense cold of the lunar night and the searing heat of the lunar day. Subsequently, Luna 21 took another rover, the Lunokhod 2, to the moon in 1973. The Soviets also successfully carried out two further sample-return missions, in 1972 and again in 1976. Since then, no more rovers have roamed around on the moon. Nor have there been any more sample-return missions. Now, China and India are seeking to return once again with automated spacecraft to explore the lunar landscape.
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