A Nice, Precise Operation

It blasted off from a secret U.S.S.R. test base--a huge rocket that hurled into orbit a huge satellite. The satellite separated into three parts, and one of them moved outward, leaving the earth's environs forever. Then Moscow announced triumphantly that "an automatic interplanetary station'' weighing 1,419 lbs., emblazoned with the Soviet coat of arms, was on its way to Venus--or thereabouts.

All well and, from the Russian viewpoint, better than good. Even if the Soviet probe never comes anywhere near Venus, the U.S.S.R. can still claim another successful space first: launching an interplanetary vehicle from a circling earth-satellite. Although never before tried, the trick has long been discussed by satellite scientists, who agree that it has important advantages. If an interplanetary vehicle is carried piggyback on a satellite, its speed and direction can be measured accurately and unhurriedly while it is still on a "parking'' orbit. Then, far in advance, a point can be selected that will be best for the probe's interplanetary takeoff.

Slower but Surer. Such a take-off can be accomplished in various ways. To judge from their scanty description, the Russians separated a "guided space rocket" from the main body of their sputnik, and pointed it in the correct direction, presumably by discharging small rockets or gas-jets. When it reached the preselected point on its orbit, the main rocket fired, contributing additional push that made the station spiral away from the earth and curve inward toward the sun and the orbit of Venus (see diagram).

Soon after the Venus probe left its parking orbit, Russia announced that it was on the correct course and would keep its date with Venus in late May. The U.S.S.R. probably planned to have the station reach its goal on May 15, when the orbits of Venus and the earth are in the same plane. This would have simplified the aiming problem. But two days later, Moscow announced that the station was moving somewhat slower than expected--so that Venus, doing its solar rounds, would catch up with it in late April, or a month earlier than planned.

As is their normal practice, the Russians did not say whether they intended their station to hit Venus, circle it or indeed to pass within a million miles of it. The unscheduled change of travel time may mean that the aim was not perfect and that the station will miss Venus by an astronomical margin. But the station presumably carries in-course guidance rockets, so it may be able to correct its trajectory.

Mystery Planet. Again, the U.S.S.R. did not disclose what observations, if any, the station will make when and if it gets to Venus. Since Venus is practically unknown inside its eternal layer of opaque clouds, very simple instruments should be able to gather important information about it. No one knows whether it has a magnetic field, or even whether it rotates on its axis. Its surface may be hot, dusty and stirred by terrific winds; it may be covered by a single deep ocean, perhaps made of petroleum instead of water. Any shred of information about the mystery planet will be treasured as a jewel by astronomers.

The Venus station presumably left its earth-orbit while over Soviet territory, where Russian tracking and guidance stations are concentrated. No non-Soviet scientist saw it depart, and none so far has picked up its radio transmissions. The Russians told their frequency (922.8 megacycles), but did not tell Western radio telescopes where to point. Since the transmitter operates only when triggered from the earth, would-be trackers not in the know have little chance of receiving its signals by blind scanning.

U.S. and other non-Russian scientists were impressed, but hardly astonished, by the Soviet success. Said Dr. William H. Pickering, director of Caltech's Jet Propulsion Laboratory at Pasadena: "This was not an engineering breakthrough, but it was a demonstration of a very nice, precise operation."

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