2 Cosmonauts Return Safely After 2 Failures : Soviet and Afghan Land on Earth on Their Third Attempt; Oxygen Running Low on Spaceship

Two cosmonauts, stranded in space with life-support systems expected to last only two more days, successfully returned to Earth early today after failing twice on Tuesday, Radio Moscow and the official Tass news agency reported.

The cosmonauts, one from the Soviet Union and the other from Afghanistan, had only enough oxygen for 48 hours and only emergency food stocks left aboard their Soyuz TM-5 spaceship, according to specialists at the Soviet space center here.

Tass reported that “both cosmonauts feel fine after the landing.”

No other details on the descent and landing were immediately available.

The two cosmonauts, Soviet veteran Vladimir Lyakhov, 47, and Afghan pilot Abdul Ahad Mohmand, 29, were returning from the Soviet Union’s orbiting Mir space station when control system equipment aboard their spaceship malfunctioned, initially preventing them from landing in Soviet Central Asia. Mohmand is the first Afghan in space.

“Don’t worry, nothing terrible has happened,” Valery Ryumin, an official at the mission control center, earlier told Izvestia, the government newspaper.

But Ryumin said that, after two equipment failures, the Soyuz crew might be forced to descend using manual rather than automatic controls in order to end the flight as soon as possible.

“According to a report by specialists of the mission control center,” Tass said in a dispatch before the successful third attempt, “life-sustaining resources of the cosmonauts will suffice for 48 hours. However, they are in for difficult hours in orbit until the designated time of landing; the descent vehicle in which they are now is not provided with everyday living facilities.”

The Soyuz reentry module that carried the cosmonauts is designed for short flights only and did not have the capability to return to the Mir space station, which it left Monday after five days. The Soyuz orbital module was jettisoned just before the first reentry attempt.

The cosmonauts’ predicament brought an offer of assistance on Tuesday from the National Aeronautics and Space Administration, which said its global space tracking and communications system, more sophisticated than the Soviets’, could keep constant contact with the spacecraft.

Although the Soviet mission control center initially turned down the U.S. offer, saying the problems were “minor” and that no assistance was required, NASA renewed it Tuesday evening in a cable to Moscow.

“We saw reports that (the situation) may be more serious, and we stand by ready to help,” Jennifer Clapp, a NASA spokeswoman, said in Washington.

Although the United States and the Soviet Union do not have an agreement providing for cooperation on manned space flights, President Reagan and Mikhail S. Gorbachev, the Soviet leader, did agree last year on closer cooperation in space sciences.

“The news from Moscow was so striking that we wanted to help,” Clapp had said.

The first re-entry attempt failed, according to Soviet space officials, when rays from the sun, as the spacecraft orbited from night into day, prevented the operation of an infrared sensor that enables the Soyuz to orient itself based on the thermal radiation from Earth.

Turned On Too Late

As a result, the spacecraft’s engine turned on too late, cosmonaut Alexander Alexandrov told Soviet newsmen at the mission center. Re-entry then would have meant overshooting the planned landing area by 435 to 500 miles and perhaps coming down across the Soviet border in China.

The spacecraft’s motor was turned off, Alexandrov said, and preparations were made for a second reentry attempt three hours later on a subsequent orbit with the data needed for orientation taken from the Soyuz computer.

But that attempt failed, according to Alexandrov, because the spaceship’s automatic equipment had not been fully reset after the first try, and the engine fired for only six seconds rather than the nearly four minutes required.

The mission control center then decided to postpone the landing until today.

Sergei Zagorodny, a spokesman for Glavkosmos, said earlier that the mission control center had been in radio contact with the cosmonauts and was confident that they would be able to land today.

Possible Manual Descent “The cosmonauts must now choose another descent path,” he had said, adding that they would either have to reprogram the computer for an automatic landing or descend using manual controls to land in Kazakhstan in Soviet Central Asia.

The cosmonauts themselves were reported to have taken their predicament without concern.

“There is food, but we won’t touch it,” Izvestia quoted Lyakhov as saying as he joked about preferring to defer lunch rather than tax the spacecraft’s limited sewage disposal system. “There’s never been anything like this.”

Lyakhov and Mohmand, accompanied by Valery Polyakov, a Soviet cosmonaut-physician, blasted off from Baikonur, the Soviet launch center in Kazakhstan, on Aug. 29 in a mission that the Soviet Union and Afghanistan hailed as marking their cooperation in peace after the long Soviet involvement in the Afghan civil war.

The three docked with the orbiting Mir space station two days later, joining two other Soviet cosmonauts already on board. On Monday, they were shown on Soviet television announcing the completion of their week of research and their return to Earth.

Due to Set Record

Polyakov, 46, stayed on Mir to monitor the health of the other cosmonauts, Vladimir Titov and Musa Manarov, who were launched last Dec. 21 and are due to set a space endurance record by remaining in orbit a full year.

The research done by the Soviet-Afghan mission included space photography of remote regions of Afghanistan to search for mineral and water resources and to plan the country’s economic development.

The spacecraft they are using, the TM-5, had been left docked with the Mir space station in June by a joint Soviet-Bulgarian crew, and their original ship, the Soyuz TM-6, is now docked at Mir.