177 



ENVIROSMtNTAL RESLARCH AND DEVTaX)PME.Vr 



Box 5. International Approaches to Space-Based 

 Remote Sensing 



Difficulties with remote sensing arrangements abound. A large gap In the 

 satellite monitoring of stratospheric ozone depletion is likely to open in 1995, 

 when the U.S. -led Upper Air Research Satellite (UARS) stops functioning. 

 This leaves a three-year gap until the earliest possible launch of a similar 

 satellite as part of the U.S. -led Earth Observing System (EOS). But the latest 

 plan for EOS from the U.S. National Aeronautics and Space Administration 

 would further delay the first launch of instruments to monitor changes in 

 stratospheric ozone. NASA Is preparing plans that call for the launch of EOS 

 atmospheric chemistry experiments in 2000 or 2002. rather than, as origi- 

 nally planned, in 1998. During this period, other satellites will carry total 

 ozone mapping spectrometers, which measure the total amount of c jne in 

 the column of atmosphere beneath a satellite. But it Is also impc lant to 

 record in detail the chemical changes occurring In the stratosphere. 



The situation with respect to climate monitoring is in many ways worse, 

 largely due to the complexity of the systems that must be monitored. Again, 

 EOS will provide valuable data, but there will be gaps in the monitoring of 

 important parameters. Problems have also plagued the gathering and dis- 

 semination of surface data, which is of substantial commercial interest. The 

 U.S. I^ndsat program includes as one of the principal requirements in 

 granting licenses to operators a provision that data be made available on 

 a public nondiscriminatory basis. 



Fifteen nations have built ground stations to receive and process 

 Landsat data, which is transmitted by a radio link from a polar-orbiting 

 spacecraft. These stations cost about S20 million to build, emd about $3 mil- 

 lion each year to operate. Two spacecraft now in orbit are coming to the end 

 of their service life. A sixth replacement spacecraft has been much delayed, 

 and it is inevitable that there will be an interruption in service for several 

 years. As a consequence, users around the world are modifying their ground 

 stations to operate with the French Spot system, which provides similar 

 Information. 



In 1987, the Soviet Union began to offer high-resolution photographs ob- 

 tained from its KFA-1000 and other satellites to customers outside the Soviet 

 bloc at a competitive price. The European Space Agency also intends to pro- 

 vide Landsat-type data. A number of other countries, including Japan, India. 

 Indonesia, and Brazil, are developing or have recently launched remote 

 sensing satellites. 



In view of the gaps in data coverage and overlaps in land sensing data, 

 several suggestions have been put fonward to attempt to correct the situa- 

 tion. Prime Minister John Major of the United Kingdom has suggested that 

 the problem could be addressed by the Committee on Earth Observing 

 Satellites (CEOS), comprised of members of most of the countries with an 

 interest in remote sensing satellites. The committee's objectives are to op- 

 timize the benefits of space-borne earth observation through cooperation of 

 Its memt>ers in mission planning and to develop compatible data products, 

 formats, services, applications, and policies. 



