BEIJING, China (AP) -- A Chinese astronaut celebrated his birthday in orbit on Thursday as the flight of the Shenzhou 6 capsule entered its second day, setting a new record for the length of a Chinese space mission.Astronauts Fei Junlong and Nie Haisheng blasted off Wednesday on China's second manned space mission, a costly prestige project meant to affirm Beijing's status as a rising world power.On Thursday, they were to carry out tasks such as opening and closing the door and removing their space suits that are meant to test the capsule's stability, the official Xinhua News Agency said."Although everything is smooth so far, all scientific and technological staff need to be cautious," Xinhua said, citing aerospace experts.Nie, a military officer and former fighter pilot, was celebrating his 41st birthday in orbit.State television showed his 11-year-old daughter, Nie Tianxiang, singing "Happy Birthday" to him by radio from the Jiuquan rocket base in China's northwest as technicians clapped. Xinhua said Nie clapped and told his daughter: "It's marvelous around here. The earth looks beautiful."Xinhua didn't say whether Nie would celebrate with a birthday cake, but listed the favorite foods the astronauts had on board, including beef with preserved orange peel and dried strawberries and peaches.Early Thursday, the mission exceeded the 21 1/2 hours that astronaut Yang Liwei spent in orbit on China's first space flight in 2003.That mission made China only the third nation that has sent a human into space on its own, after Russia and the United States.By noon Thursday, the Shenzhou 6 had circled Earth 18 times, Xinhua said, giving it a rate of one orbit about every 90 minutes. It said the capsule was traveling at 7.8 kilometers (4.9 miles) per second, or about 28,080 kph (17,528 mph).The government has not said how long Fei and Nie would stay aloft, but news reports said it could be three to five days. Xinhua reported that they had food and water for a week.A Shanghai newspaper said the capsule was to land Saturday in China's northern grasslands. The report by the Morning Post didn't cite any source, but Shanghai is a center for the government's space program, and reports by media there have often proven accurate.Another report said Shenzhou 7 would be launched in 2007 carrying at least two astronauts, and would include China's first space walk. Shenzhou 8 would follow, docking to an unmanned orbiter in preparation for building China's first space station, the Shanghai Daily reported, citing Han Hongyin, a designer of the propulsion system used on the Shenzhou spacecraft.Chinese space officials say they hope to land an unmanned probe on the Moon by 2010.The flight was front-page news in China's major newspapers, which carried photos of Fei and Nie in orbit and waving to technicians at the Jiuquan site before their liftoff.The manned space program is a key prestige project for the communist government. Chinese leaders hope that patriotic pride at its triumphs will shore up their standing amid wrenching economic change and public anger over corruption and a growing gap between rich and poor.State television showed live scenes of the astronauts -- known in Chinese as yuhangyuan, or "travelers of the universe" -- taking off their bulky, 10-kilogram (22-pound) space suits and moving around their cabin.Both Fei, also 41, and Nie are military officers, former fighter pilots and Communist Party members.Xinhua said both men talked to their families on Wednesday."May you carry out the task entrusted to you by the motherland and return smoothly," Fei's wife, Wang Jie, was quoted as saying. The report said Nie's wife wished him luck, and "at these words, Nie Haisheng was in tears."The Shenzhou -- or Divine Vessel -- capsule is based on Russia's workhorse Soyuz, though with extensive modifications. China also bought technology for space suits, life-support systems and other equipment from Moscow, though officials say all of the items launched into space are made in China.China has had a rocketry program since the 1950s and sent its first satellite into orbit in 1970. It regularly launches satellites for foreign clients aboard its giant Long March boosters.Copyright 2005 The Associated Press. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.