Science: Project Stratoscope

Astronomers need air to breathe just like anybody else, but when thinking professionally they often wish that the atmosphere would quietly go away. Even when the air is clearest, it contains irregularities that smear out the sharpness of telescopic photographs. Since there is no way to chase the atmosphere away from an astronomical observatory, the next best thing would be to lift the observatory above the troublesome part of the atmosphere. This trick was done for the first time last week by Project Stratoscope of the Office of Naval Research.

On a quiet morning soon after sunup, a big polyethylene balloon took off from near Minneapolis with a weird apparatus dangling far below it. Suspended in a frame was a reflecting telescope of 12-in. aperture built by Perkin-Elmer Corp. of Norwalk, Conn. Its mirrors were made of quartz so that they would not be distorted by solar radiation, and it had an ingenious device to change the focus slightly during each sequence of 20 pictures. This would ensure that one of these pictures would be in good focus. Another device, assembled at the University of Colorado, had the duty of keeping the telescope pointing at the sun.

Automatic Observatory. The astronomer in charge of the balloon-borne observatory, Dr. Martin Schwarzschild of Princeton University, did not go aloft with his telescope. To keep him alive and functioning at extreme altitude would have been too difficult. And besides, as he explained, even the most careful motions of a human operator would destroy the serene stability of the balloon.

As soon as the balloon took off, it was out of human hands. When it reached 80,000 ft., automatic controls would ready the telescope and point it at the sun. They would take about 8,000 pictures (f/200, 1/1000 sec. exposure). Then, their duty done, they would separate the observatory from the balloon and drop it to earth on a giant parachute.

All these things happened just as planned. Seven hours after launching, the observatory parachuted down, apparently undamaged, near Athens, Wisconsin, 150 miles away. A Navy truck guided by radio tracking, pounced on it promptly and brought the 35-mm. film back for developing. When the first pictures came from the darkroom, Dr. Schwarzschild pronounced them the best ever taken of the sun.

Hot Bubbles. Dr. Schwarzschild realizes that only an astronomer can appreciate the full beauty of his photographs. They are covered with roundish bright spots, each of which is a bubble of hot gas 200-500 miles in diameter that has worked its way up from the sun’s interior like a thunderhead. The charm of the pictures, says Schwarzschild, is their unprecedented sharpness.

The balloon climbed above 95% of the atmosphere, and left nearly all of its turbulence far below. Even though the automatic observatory was not so elaborate as a ground observatory, it took much better pictures. When they have been carefully studied, they will give scientists new information about the seething turbulence of the sun’s surface, which affects the earth in many important ways.

The first flight of Project Stratoscope, thinks Dr. Schwarzschild, was so successful that the same method may be used to take pictures of the planets. A larger balloon-borne telescope floating far above atmospheric turbulence might decide once and for all the romantic debate about life on Mars.