WASHINGTON (Reuters) - The Pentagon is evaluating whether potential cyber missions could drive demand for additional Boeing Co (>> Boeing Co) EA-18G electronic attack jets, or Growlers, the top U.S. Navy officer told Reuters on Thursday.

Chief of Naval Operations Admiral Jonathan Greenert said any decisions about additional orders of Growlers should be included in the Pentagon's budget request for fiscal 2017, since Boeing will shut the production line after all orders have been fulfilled.

Greenert said it was imperative to map out any additional orders now, given the high cost of restarting production once the line closed.

"This is kind of a no-fail deal," he said in an interview. Boeing was pursuing several other foreign orders, but he did not believe they were large enough to sustain production of the jets.

Boeing's combined St. Louis production line for F/A-18E/F fighter jets and the EA-18G Growlers was slated to shut in 2017, until Congress added funding for 12 more F/A-18E/F Super Hornets to the fiscal 2016 budget plan, and Boeing signed a deal to sell 28 of the jets to Kuwait.

If those orders are confirmed, the line should remain open well into 2019, Boeing has said.

Greenert, who will retire and be replaced by Admiral John Richardson on Sept. 18, said the Navy still believed its planned purchase of 153 Growlers was sufficient, but more work was underway to assess the needs of other military services, as well as the possible use for cyber missions.

He said the Navy had asked the Pentagon's Cost Analysis and Program Evaluation (CAPE) office to evaluate the electronic warfare needs of the U.S. Air Force and Marine Corps.

Navy officials had estimated that the two services might need about 30 more Growlers to meet their needs, according to sources familiar with the study, although both services had told Navy officials they planned to satisfy their requirements using the Lockheed Martin Corp (>> Lockheed Martin Corporation) F-35 fighter jet. The sources requested anonymity because the study was incomplete.

Greenert said a department-wide review of electronic warfare needs had also revealed a possible need to outfit Growlers or other aircraft with special cyber "pods" or "nodes" that could be used for jamming or infiltrating enemy computer networks, and removing information.

That issue was still being evaluated by the military services, and would also include U.S. Cyber Command and the staff of the Joint Chiefs, he said, adding that he expected the fiscal 2017 budget proposal to provide clear answers about the number of jets needed.

Greenert said the Navy was watching for possible shortfalls of F/A-18E/F fighter jets on its aircraft carriers, given delays in the F-35 program and lengthy repair times for existing jets.

He said the Navy had made progress in speeding up repairs of older jets, which could limit the need for more Super Hornets. "I think we'll manage our way through that," Greenert said.

Boeing had no immediate comment.

Greenert said the Navy remained focused on improving cybersecurity after a major breach of the unclassified Navy-Marine Corp network last year, and would dedicate "hundreds of millions of dollars" to the effort, beginning in October.

(Reporting by Andrea Shalal; Editing by Richard Chang)

By Andrea Shalal