So Precise, the Moon Affects its Construction

In “The £2.5 million fighter jet system that’s so precise it’s affected by the MOON’S gravity” (Daily Mail, 9 April 2015), Victoria Woollaston writes:

“Aside from making a fighter jet lightweight, agile and astonishingly fast, engineers of one the world’s most advanced aircraft have another, more surprising issue to contend with: the moon.

“BAE System’s Typhoon is so accurate that even the movements of the tide can disrupt the jet fighter’s positioning and accuracy.

“To counteract even the slightest shifts in gravitational pull, experts must build the jet on ‘floating’ concrete rafts that move in sync with the moon.

“These rafts measure 59ft (18 metres) long and 9.8ft (3 metres) thick and are used to house the measuring equipment.

“Two laser trackers and nine jacks are positioned on a single surface, to make sure all movement is relative, and they control the alignment of the barges by cancelling out the subtle effects of the moon and the tides it creates.

“This means the jet will be in ‘near perfect alignment whatever the moon may be doing,’ said Martin Topping, Head of Typhoon Maintenance and Upgrade.

” ‘Every time the moon pulls the tide in and out, the ground under our feet actually moves by between one and two millimetres, he continued.
‘This means the jet will be in ‘near perfect alignment whatever the moon may be doing,’ said Martin Topping, Head of Typhoon Maintenance and Upgrade.

” ‘Every time the moon pulls the tide in and out, the ground under our feet actually moves by between one and two millimetres, he continued.”