Whipple Says Satellite to Be Visible Here

The experimental earth satellites will be visible in Cambridge, officials at the College Observatory and the Smithsonian Astrophysical Observatory said yesterday.

The metal sphere, 20 inches in diameter, will be visible only during twilight hours, and to the naked eye only if the viewer has exceptional vision.

Fred L. Whipple, professor of Astronomy and director of the Smithsonian Observatory, is supervising the entire project of tracking the satellite's path. He said yesterday that since the sphere will attain a maximum height of 800 miles, it will be visible in this area, although it will probably go no further north than Philadelphia.

Karl Henize, the Smithsonian astronomer in charge of the photographic tracking of the sphere, said that the satellite would be seen to the South, at an average elevation of 65 degrees from the horizon.

Whipple said that the satellite is likely to be set aloft toward the end of 1957, and it will circle the earth in about 100 minutes. Groups of visual observers will be forwarded to computing machines at the Smithsonian here.

The computing machines will determine the orbit, and tracking will then be carried out by a dozen or so photographic stations. When the satellite begins to lose altitude, it will be moving so unpredictably that visual observers must once more assume tracking operations.

From the satellite's behavior, scientists hope to learn important facts about the upper atmosphere, cosmic rays, the earth's shape, and certain data on which space travel must be predicated.