Seventy-five years ago Pearl Harbor was still recovering from the surprise attack that had occurred four months earlier — the sunken hulks of the Arizona, Oklahoma and Utah still lying where they had been torn apart by torpedoes and bombs.

Imperial Japan was now ravaging Southeast Asia.

“Japanese forces defeated the United States in one battle after another. Blackout drills on both coasts unnerved many people. Their homeland had suffered a devastating attack,” wrote Jonna Doolittle Hoppes in “Calculated Risk.”

President Franklin D. Roo-sevelt wanted payback. It would come in the form of an audacious plan put forth by, of all people, a Navy anti-submarine warfare officer, Capt. Francis Low, to use Army bombers launched from an aircraft carrier.

On April 18, 1942, 80 men “achieved the unimaginable” when they took off from the deck of the aircraft carrier USS Hornet on a top-secret mission to bomb Japan, the National Museum of the Air Force said.

Sixteen lumbering B-25 Mitchell bombers were part of the group that came to be known as the Doolittle Tokyo Raiders because they were led by Lt. Col. James H. “Jimmy” Doolittle.

Although the strikes caused relatively little damage, “American morale zoomed from the depths to which it had plunged following Japan’s many early victories,” the Air Force said.

Hoppes, granddaughter of Jimmy Doolittle, will be at the Pacific Aviation Museum Pearl Harbor from 10 to 11 a.m. Monday for a free presentation for students and teachers.

For that, Hoppes said she plans to focus on the fact that her famous grandfather “came from sort of a lower-middle-class family and built himself up through education and through perseverance into not just a great pilot, but a scientist.”

At 2:30 p.m. Tuesday, Hoppes will conduct a “hangar talk” at the museum for the general public, followed by a book signing.

Additionally, the museum has on display a ship’s bell from the Hornet that is on loan from the Navy and is normally at a Pearl Harbor munitions depot that’s off-limits to the public.

Doolittle, also famous for setting endurance and speed records in the 1920s and 1930s, believed that his greatest contribution to aviation was in instrumented “blind flight” development, his granddaughter said.

On the 75th anniversary of the famous raid, what should be remembered is that “they were young kids stepping up, serving this country,” Hoppes said in a phone interview. “Most veterans will tell you they are just doing their job, but their (the Raiders) job was one where there was a really high probability that they wouldn’t come back.”

The challenges came even before takeoff. A Japanese picket boat spotted the task force 650 miles from Japan, forcing the pilots to start their mission more than 200 miles farther away than planned.

Tom Griffin, a navigator in the No. 9 plane in the sequence, recalled in 2008 that although the departure by previous planes technically gave followers more “runway” space, all the planes were moved up to the same spot for takeoff because there was just 6 feet of clearance on either side.

“The longer the run on a flight deck that’s weaving and bowing into the heavy seas, the more chance you had of running into the (aircraft carrier’s) island or to put the wheel over the left side,” Griffin said.

He remembered the crew discussing the likelihood they would run out of fuel at sea before reaching China after the bombing run.

“Everyone has to have a light at the end of the tunnel,” Griffin said. “We talked it over, and we thought, if we run out of gas down in the China Sea and we see a ship, we’ll ditch next to it and they’ll take us aboard. We all had .45s (pistols), and if it was a friendly ship, we sail off with them. Unfriendly, we were going to take it over.”

Griffin admits the plan “didn’t seem too promising.” The crew member on the “Whirling Dervish” died in 2013 at age 96.

Just one of the Raiders is left, Doolittle’s co-pilot, Dick Cole, who is 101.

With the planes low on fuel after the raid, one made it to Russia, and 15 crashed in China or ditched at sea. Three Raiders were killed in action, and four died in captivity.

The attack on their homeland stunned the Japanese — embarrassed leaders had promised it would never be attacked. Four fighter groups were transferred from the front lines to defend mainland Japan, the Air Force said.

And to prevent future American attacks on the mainland, Adm. Isoroku Yamamoto “ordered the disastrous attack on Midway Island, which became the turning point in the war in the Pacific,” the Air Force said.