Cosmonaut Yuri Romanenko returned to earth yesterday after a record 326 days in space. The descent module of the TM-3 spacecraft carrying Mr. Romanenko and two other cosmonauts, Alexander Alexandrov and Anatoly Levchenko, landed 48 miles from the town of Arkarlyk in the Soviet republic of Kazakhstan just after noon Moscow time, the official news agency Tass reported.
Soviet officials said that the landing was right on target, and Tass announced that all three men ``feel well.''
If medical tests on Romanenko produce nothing unexpected, the new space endurance record will be a further step in the Soviet Union's aim of an eventual manned flight to Mars - an estimated 30 months' flight from Earth.
Soviet officials reported a few days ago that there was ``less than one year'' to go before the first unmanned space probe left for Mars.
Soviet scientists say that one of the key problems to solve before a manned probe becomes feasible is the human body's response to long periods of weightlessness.
The previous space endurance record was 237 days, set by three Soviet cosmonauts aboard a previous space station, Salyut-7, in 1984.
Tass says that Romanenko's health was continuously monitored during his mission. Recent Soviet reports have mentioned only one problem: a recent bout of homesickness.
Romanenko and Mr. Alexandrov handed over their Mir space station to another crew, which reached the station on Dec. 23. The new two-man team, led by space veteran Vladimir Titov, may end up breaking Romanenko's record: They are reportedly expected to spend a year in space.
The successful hand over - another first - further underlines the Soviet preeminence in space.
The Mir station, described as a small floating laboratory, has been in space since February 1986. Its first crew boarded it a month later, and spent 125 days aboard. It was then left empty until Romanenko and another colleague, Alexander Laveikin, docked with it last February.
Mr. Laveikin developed heart problems in July, was replaced by Alexandrov and brought back to earth. Soviet television recently showed him working at the space center in Baikonur.
One of the newly returned cosmonauts, test pilot Anatoly Levchenko, spent only a few days in space. Official reports say that he will immediately be put behind the controls of a plane in an experiment designed to test his ability to readjust to gravity after weightlessness.