Great tidbit -- found this in the NYT archive (likely paywall): https://www.nytimes.com/1990/07/18/us/hubble-has-backup-mirror-unused.html https://www.nytimes.c

Great tidbit -- found this in the NYT archive (likely paywall): https://www.nytimes.com/1990/07/18/us/hubble-has-backup-mirror-unused.html https://www.nytimes.com/1990/07/18/us/hubble-has-backup-mirr...