Dragonquest McCaffrey Anne (1983)

Another Turn, and the deadly silver Threads begin falling again. The bold dragonriders take to the skies, while their magnificent dragons swirl and swoop through space, belching flames that destroy the shimmering strands before they reach the ground. But F’lar knows he must find a better way to protect the people and lands of Pern, and he must find it before the rebellious Oldtimers can breed any more dissent, before his brother F’nor is foolhardy enough to launch another suicide mission, and before the mercurial fire lizards cause even more trouble.