Photo/Illutration A testing facility for the land-based Aegis Ashore missile defense system on Hawaii's Kauai island (Asahi Shimbun file photo)

A partial estimate for an alternative to the land-based Aegis Ashore missile defense system abruptly scrapped this summer came up with a minimum figure of 190 billion yen ($1.8 billion).

That would make it the most expensive maritime equipment ever purchased by the Self-Defense Forces as an Aegis destroyer comes in at about 170 billion yen.

There are three options for installing the envisaged new system at sea: a Maritime SDF destroyer, a commercial vessel or an oil-rig type of megafloat.

The cost of a maritime platform and retrofitting it to allow for installation was put at between 190 billion yen and 280 billion yen, including the cost of the equipment itself, sources said.

Defense Ministry officials were to present the cost estimates to ruling coalition lawmakers on Nov. 25.

Prime Minister Yoshihide Suga had instructed ministry officials to devise an alternative to the U.S.-developed Aegis Ashore system before year-end.

However, ministry officials balked at making a hasty decision when no estimate of the total costs, including those for maintenance and repairs, were available.

Two major shipbuilding companies were commissioned to make cost estimates for the three options.

Sources said the estimate for using an MSDF destroyer came to between 240 billion yen and 250 billion yen, while using a commercial ship would run between 190 billion yen and 200 billion yen. Using an oil-rig megafloat would cost between 210 billion yen and 280 billion yen.

“The figures are based on calculations made from the information that we have in hand now, but there is every chance the figures could further inflate,” said one source.

The commissioned companies had only about a month to make the cost estimates, so ministry officials said changes in the figures were likely.

Projected operating costs for the three options have yet to be made, which would hamper efforts to estimate the life cycle costs that the central government has increasingly emphasized when considering the acquisition of new defense equipment.

(This article was written by Yoshitaka Ito and Daizo Teramoto.)