Moonmen Gain Times; Ship to Land Friday

The three Apollo 13 astronauts gained a crucial 10-hour margin of oxygen, water, and electrical power with a short burst of rocket fire last night.

The three-James A. Lovell, Jr., Fred W. Haise, Jr., and Jack L. Swigert-fired the main engine of Aquarius, their moon lander, at 9:45 p. m.

Apollo Control in Houston expects the astronauts to splash down in the Pacific about 300 miles southeast of Samoa at 12:18 p. m. Friday afternoon.

Apollo Control expressed fears that 45-mile-an-hour winds from tropical storm Helen might hinder recovery, but the recovery team said it is confident that it can cope with heavy seas.

Earlier last night Apollo Control lost contact with the spacecraft when the moonship looped around the moon on its way back to earth. Radio contact resumed about 8 p. m. when the spaceship emerged from behind the moon.