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capability up to 4300 kg on Ariane-4 about 1986. Eventually a returnable manned 
vehicle, called Hermes, is anticipated for Ariane-6. Three of the first four 
test launches from the facility in Kourou, Guiana were successful, but the first 
operational launch in September 1982 also failed. Nevertheless the vehicle is 
expected to be fully operational in 1983, and its first remote sensing payload 
will be the SPOT-1 in October 1984. 
ESA is committed to the development and launch of a European remote sensing satel- 
lite, called ERS-1 (ESA Resources Satellite). The principal objective of ERS-1 is 
ice and ocean monitoring. Launch by Ariane-2 or -3 into a 675 km altitude, 9 89 
inclination sun-synchronous orbit is expected in late 1987 or early 1988. 
As shown in Figure 4, the basic spacecraft will be the SPOT vehicle. The sensors 
will be: 
o Synthetic aperture radar with 30 or 100m resolution, 239 incidence 
angle, and 80 km swath 
o Wind scatterometer with 50 km spatial resolution, and 400 km swath 
to determine wind speed to +/-2m/second and wind direction to +/-20° 
o Wave scatterometer to determine ocean wave length to +/-25% and wave 
direction to +/-200 
o Radar altimeter with a foot print of 1.6-20 km (depending on sea state) 
to determine ocean wave heights +/-10% 
o Along track scanning radiometer with three infrared channels to 
determine sea surface temperature and water vapor content for a 
1 km pixel and 500 km swath. 
AMI (SAR & WAVE MODE) 
ANTENNA 
POSSIBLE LOCATION 1 
FOR SCIENTIFIC PAYLOAD i I 
IN 
     
      
  
RADAR 
ALTIMETER 
GENERATOR 
AMI (WIND) 
SCATTEROMETER ANTENNAS 
Figure 4.--The European Space Agency Resource Satellite ERS-1 will 
carry synthetic aperture radar, wind and wave scatterometers, a 
radar altimeter, and an along-track scanning radiometer as a 
scientific payload 
The spacecraft will also carry laser retroreflectors for accurate tracking from 
the ground. On-board tape recorders will be provided for all instruments except 
the synthetic aperture radar. Data will be transmitted on X-band to the ESA 
Earthnet ground stations. A second identical spacecraft is contemplated for the 
1989-1990 time frame. 
349