131 



To distinguish anthropogenic influences from natural cUmate 

 processes and to understand the mechanisms involved in global 

 change will require at least a decade, and probably much more, of 

 accurate global monitoring of atmospheric and sea temperature, 

 the concentration and distribution of radiatively active gases, vol- 

 canism, and aerosols, solar, and terrestrial radiation fluxes, ice 

 masses, and sea level. 



Existing global observing and monitoring programs must be sus- 

 tained and new commitments made. The Volkmer committee ex- 

 pressed strong support for the study of Sun-Earth interactions, and 

 recommended to NASA, DOD, NSF, and the USGS that they spon- 

 sor study within the National Research Council of the full scope of 

 science and solar-terrestrial relationships. 



I am pleased to report that the science agencies have responded 

 positively to the congressional recommendation and that progress 

 has been made both on the national scene and abroad during the 

 past year toward definition of a broad plan of study of the Sun- 

 Earth system. 



Finally, I wish to offer some remarks about one specific thrust in 

 astronomy. This is a trend toward interferometry to achieve the ul- 

 timate in high resolution. In radio interferometry, the state-of-the- 

 art is represented by the very long baseline array, an approved pro- 

 gram which calls for an array of 10 25-meter telescopes across the 

 continent and to Hawaii and Puerto Rico. It will have a resolving 

 power of a single telescope 8,000 kilometers in diameter. The cost 

 of construction will be $75 million, and the annual operating 

 budget, about $5 million. 



An equivalent array is planned by the Canadians, and their 

 design will digitize data in the same format as the VLBA so that 

 the power of both arrays can be combined. In Europe, a VLBA net- 

 work will link telescopes in all of Western Europe. Again, the 

 format will permit joint operation, and the combined United 

 States-Canadian-European array will be a truly giant instrument of 

 remarkable image-forming speed and fineness of detail. 



The next extension will carry such interferometry into space and 

 will undoubtedly require the staging capability of the Space Station. 

 With Japan and ESA assuming partnership in the Space Station de- 

 velopment, they will very likely seek partnership in the astronomy 

 goals as well. 



Lastly, I would like to take this occasion to inform the task force 

 that the National Research Council will examine a broad perspec- 

 tive on international cooperation in big science in September of 

 this year. A special committee on large international science and 

 technology facilities will convene under the cochairmanship of 

 Frederick Seitz, the former president of the Academy of Sciences, 

 and Ralph Gomory, vice president of IBM, to discuss the issues and 

 recommend the form of further study. 



Thank you, Mr. Chairman. 



[The prepared statement of Dr. Friedman follows:] 



