Balloon to play a satellite role

Title

Identifier

Ballast away!

Language

English

Source

Panorama Volume XII (No. 2) February 1960

Year

1960

Rights

In Copyright - Educational Use Permitted

Fulltext

Ballast away! BALLOON TO PLAY A SATELLITE ROLE A12-foot spherical balloon has been built to be floated in space by a future Ex plorer satellite of the U.S. Army. The aluminum-clad balloon—or subsatellite as it is officially des cribed—would be much larger than scientific satellites now plan ned, and thus far more visible in space. Officials of the National Ad visory committee for Aeronautics, which designed and built the sub satellite. estimated that the sphere would be visible to the human eye at dawn and dusk at an alti tude of 800 miles, and under op timum conditions as high as 1,600 miles. The balloon, made of plastic film and aluminum foil, has been designed to provide accurate in formation on the density of space as it floats at high speeds around the world. February 1960 89 In a collapsed state, the bal loon would be carried to orbiting speed and altitude along with the satellite proper. Then it would de tach from its satellite and be in flated by a bottle of gas. I n the near vacuum of space, B the balloon would orbit around the world like the instrumented satellite. Because of its light weight, however, the balloon would be highly sensitive to the slight air drag of space, and gra dually fall behind the satellite. Studies of the distance between the satellite and sub-satelljte would permit accurate measure ments of the density of space. The balloon experiment will be conducted by one of the two—or perhaps three—additional Explorer satellite firings authorized by the Defense Department as a prelude to probes of the moon by space vehicles. The satellites will be part of the s International Geophysical Year, which ends in December. What scientific experiments will be conducted by the additional Explorer satellites is being kept a tight secret by the Unitea States National Committee for the Inter national Geophysical Year. Com mittee spokesmen have declined to discuss any future t satellite experi ments on the ground that release of such information would tend to “build up” public hopes, which would be dashed if a launching failed. The balloon experiment, it ■ was learned, is being prepared for an Explorer satellite scheduled to be launched several months hence. It is hoped that the satel lite and its balloon companion can be launched in a generally northto-south orbit, thus making them visible over much of the United States. The balloon and its bottle of inflating gas will weigh about 15. pounds. The instrumented pay load of the first Explorer satellites weighed 18 pounds. The Army believes, however, that this “pay load” can easily be increased by 50 per cent through improvements in the Jupiter-C launching missile. A similar but much smaller bal loon experiment has been pre pared bv the National Advisory Committee for Aeronautics for one of the satellites to be launched by the Navy’s Project Vanguard. The Vanguard subsatellite will be onlv thirty inches in diameter. The advisory committee is now studying the feasibility of launch ing 100-foot inflatable spheres to act as communications relay sta tions in space. Meanwhile, Project Vanguard is scheduled to trv to launch sev en scientific satellites in the re maining months of the Interna tional Geophysical Year, with the first expected in mid-April. There is a possibility of an eighth launching. Vanguard launched a test satel lite on March 17. * 90 Panorama

pages

89+

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