Every 25 months the planet Mars moves into a position that favors launches of spacecraft from earth. Three weeks ago, the Russians took advantage of that opportunity by sending two unmanned ships toward the red planet. Last week, as the latest Mars "window" was about to close, the Soviets surprised the scientific world by launching two more Mars-bound robots. It is the first time either the U.S.S.R. or the U.S. has sent so many simultaneous probes to another planet.
As usual, Tass was guarded; it reported that the purpose of the latest probesMars 6 and 7was to investigate the neighboring world and...