Trump orders future carriers to use steam catapults

US President Donald Trump has directed future aircraft carriers to use older steam catapult technology instead of advanced electromagnetic systems for launching warplanes.

Trump announced the order on Thursday in a national security presidential memorandum on Navy shipbuilding and ship repair. The order directs the Pentagon to draft a plan to replace the Electromagnetic Aircraft Launch System and Advanced Weapons Elevators with steam and hydraulic systems on forthcoming aircraft carriers.

The first ship affected will be the USS Doris Miller, the fourth Gerald R. Ford-class carrier, which has a projected delivery date of 2034.

The Wall Street Journal reported, citing Bryan Clark of the Hudson Institute, that changing the catapult systems will likely cost billions of dollars. Steam systems would also require more sailors to operate and maintain.

General Atomics, which won the contract to build electromagnetic catapults for the Doris Miller, said the decision to switch systems "warrants careful reconsideration." Senator Mark Kelly, a former astronaut and retired US Navy combat pilot, criticised the order as unnecessary interference in Navy engineering.

Trump said the United States had an "atrophied shipbuilding industrial base" that made building and repairing warships slower and more costly. The memorandum also authorised the Pentagon to award contracts allowing near-term purchases from foreign suppliers, with foreign firms allowed to build up to two ships in their parent shipyards and further vessels to be built in American yards.