This text dates from 1992, and will be updated soon...
The Magellan spacecraft launched onboard the Space Shuttle in April of 1989 uses a radar-based high resolution imaging technique to carry out its mapping of the Venus surface. Many real aperture radar echos are computer processed to create a large synthetic aperture image through a Synthetic Aperture Radar (SAR) technique. Multiple swaths are combined to produce image mosaics. The creation of synthetic aperture images must account for the relative geometry and movement between the target and spacecraft radar and for multiple surface images of different amplitudes and phases. For Magellan an advanced SAR technique is responsible for the highly detailed, nearly seamless photographs of the surface of Venus - but it is computationally intensive.The Advanced Digital SAR Processor (ADSP) technology developed by OAST has been adapted and used for the ground processing of the radar data returned by Magellan. This processor integrates algorithm elements into a programmable pipeline architecture with great speed.
This ADSP provides a peak compute rate of 6 gigaflops, more than that of a Cray 2 computer. The significance is that this compute rate permits processing four times faster than real-time acquisition rates. It is the Input/Output computer system that limits the actual processing rate to approximately real time.
Work was initiated in 1980 to provide an engineering technology demonstration of (ADSP) to support late 1980's missions. In 1983 it was decided that the ADSP technology development would be focused on Magellan requirements. In 1985 the Magellan Project decided to modify and use the engineering model of ADSP as the prime mission operations processor for SAR data.
OAST completed work on this technology with the delivery of the ADSP engineering model to the Magellan Project in 1986. Magellan demonstrated the success of the ADSP technology which now provides a a flexible architecture that can serve many missions. For more information please contact: Gordon Johnston, NASA Headquarters, Code RSS, Washington, D.C. 20546. Phone: (202) 453-2851.