GOES-7: rebuilding the weather watch.

GOES-7: Rebuilding the weather watch

Weather satellites used to be viewed asperhaps the classic example of the routine side of the Space Age, but few U.S. space activities are described as "routine' these days. Thus the Feb. 24 liftoff and promising initial checkout of a satellite called GOES-7 have elated officials both at NASA, thanks to the second success in a row of its Delta rocket following a failure 10 months ago, and at the National Oceanic and Atmospheric Administration (NOAA), where hopes are high at last of filling a key gap in its weather coverage.

The usually reliable Delta that failedlast May 3 (SN: 5/10/86, p. 292) was carrying what would have become GOES-7, sent aloft early to make up for malfunctions that had crippled another GOES and forced NOAA to rely on a single satellite instead of a pair capable of monitoring the entire country. The new GOES-7 is to be positioned in its geostationary orbit above the equator at 75|W longitude, roughly on a line with Philadelphia, while GOES-6 is moved from its present central location at 108|W to 135|W, between the West Coast and the Hawaiian Islands. Restoring the system to its two-satellite spread, says a NOAA official quoted by the Associated Press, is "something to keep everyone jumping for joy from Hawaii to Maine.'

GOES-7 also carries an experiment thatNOAA hopes will lead to faster alerts via the SARSAT (Search And Rescue Satellite) system, which for more than four years has been monitoring emergency signals from distressed ships and aircraft. The system, which now includes two satellites from the United States and three from the Soviet Union, can relay the signals from suitably equipped vessels to Coast Guard and other facilities that can dispatch rescue forces. Since it went into operation, says James Bailey, chief of NOAA's Search and Rescue Program Management Staff in Suitland, Md., the system has helped in more than 300 separate emergency situations.

The satellites involved so far, however,have been not in geosynchronous orbits, fixed over particular locations on the earth, but in paths that carry them over the planet's poles, so that the entire surface passes beneath them. A limitation has been that in some cases the signals received by the satellite cannot be relayed to their intended recipients until the satellite has come into radio "sight' of a ground station. GOES-7 will enable scientists to test whether the system can be used from the high vantage point of geosynchronous locations, more than 22,000 miles up, both relaying signals from other satellites and sending its own alerts.