Ship replacement requires a multi-decade horizon

Near-term requirements are inadequate for a class expected to serve for thirty years or more. A weapon system may take twenty or thirty years to develop and then remain in use for another thirty, pushing strategic thought sixty years ahead or farther. Planners cannot predict individual technologies with certainty, but they still have to consider the wars, missions, and strategic conditions a future fleet may face. Surface ships are especially exposed because they are likely to receive several new weapons and service-life upgrades during their careers. Designing in space, access, power, and adaptable combat-system capacity is part of replacement planning even when the eventual equipment does not yet exist.