Yes, one of the premises is it flips bits, a phenomena called Single Event Upset(SEU) - e.g. the open source LEON FT (http://www.gaisler.com/index.php/products/processors/leon3ft) processor, is designed to be able to correct and detect such errors - in addition to being manufactured with materials that block radiation. In spacecrafts such radiation hardened processors are often used in addition to having redundancy.

One issue with only using redundancy to overcome errors from radiation is you'll have a hard time determining which processor has an error - especially when several processors are affected at the same time.