This is the 9264th most frequent Russian word.
спасательный
Rescue or saving.
Here, 'спасательный' is used as an adjective to describe the type of ring, indicating its purpose for rescue.
Спасательный круг лежал на берегу.
The life ring was lying on the shore.
In this sentence, 'спасательная' describes 'операция', referring to an operation intended for rescue.
Спасательная операция началась в пять утра.
The rescue operation started at five in the morning.
'Спасательные' modifies 'вышки' (towers), specifying their function as part of safety and rescue infrastructure.