Table:
text: Operation Hardtack II
Test Blasts
Hardtack II Tests
Name_ Location_ Elevation_Height Delivery Purpose Yield
Mars NTS Area 12f metres (ft) - metres (ft) underground tunnel safety test 13 tons
Mora NTS b Area 7 metres (ft) + metres (ft) balloon weapons development 2 kilotons
Hidalgo NTS Area 7b metres (ft) + metres (ft) balloon safety test 77 tons
Colfax NTS Area 3k metres (ft) - metres (ft) underground shaft one-point safety test 5.5 tons
Tamalpais NTS Area 12b metres (ft) - metres (ft) underground tunnel weapons development 72 tons
Quay NTS Area 7c metres (ft) + metres (ft) tower weapons development 79 tons
Lea NTS Area 7b metres (ft) + metres (ft) balloon weapons development 1.4 kilotons

Question: What was the purpose of the Quay test blast Operation Hardtack II?