Science: Rehearsal for 1975

When Soyuz 16 landed safely on the snow-covered steppes of Kazakhstan last week after six days in orbit, Soviet space officials were exultant. The successful flight, they said, showed that their cosmonauts and spacecraft were capable of carrying out their assigned role in next July's historic orbital linkup of an American Apollo and Soviet Soyuz.

U.S. space officials could only hope that the Russians were right. Although the U.S. Apollo spacecraft has more than demonstrated its incredible capabilities on eight missions to the moon, the Soviets are still ironing the kinks out of...