The near Solid-state Data Recorders

ata recorders make it possible for the Near Earth Asteroid Rendezvous (NEAR) spacecraft to delay and slow the transmission of information to Earth, thereby accommodating the temporal and bandwidth limitations of the communications link. NEAR is the first spacecraft developed by the Applied Physics Laboratory to employ solid-state recorders, supplanting magnetic tape recorders used previously. Also, the 132 dynamic random-access memory devices, which are at the heart of the NEAR recorders, constitute the first large-scale use of plastic encapsulated microcircuits on a Laboratory spacecraft. Earlier spacecraft relied almost exclusively on hermetically packaged microcircuits. Several measures, including two layers of error detection and correction, were taken to mitigate the effects of single-event upsets that may be induced by charged particles in space. (