The Sendai White Balloon

Wednesday, 17 June 2020. Early morning in northern Sendai. Accounts of the first sighting vary, from about 4:00 a.m. to about 5:00 a.m. High above Aoba Ward, something white was hanging in the sky.

It was a white sphere. Beneath it hung a cross-shaped frame. Along one arm ran panels that looked like solar panels. On the other arm, two white propellers were seen turning. Camera footage from the Sendai Astronomical Observatory, broadcast on television, showed it hovering above the cross.

Residents across northern Sendai reached for their phones. Photos appeared under the Japanese hashtag for "unidentified flying object", and it became the third most popular trending topic on Japanese Twitter. "This white thing isn't moving at all. What is it? Can anyone tell me?" one post asked. A string of calls reached the police, the Sendai weather office and the Kahoku Shimpo newspaper.

It was reported from Natori, Fukushima City, Higashine and Yamagata City. Passengers on airliners flying to Haneda photographed it from above. Altitude estimates ran from at least 1,500 m to above 10,000 m. Size estimates ran from about 2 m across to at least 10 m. For hours it lingered, largely motionless. In the afternoon it drifted east toward the Pacific. It had stayed up for about 13 hours or more. Strong north-westerly winds were blowing between 3,000 and 10,000 m.

The Sendai Regional Meteorological Observatory was blunt. "The object looks like a balloon for monitoring weather, but it's not ours." Miyagi Prefectural Police sent a helicopter during the morning commute. Several reports say it had to turn back in bad weather. By noon there were no significant leads. No flight notice had been filed under the Civil Aeronautics Act. Kyushu University said the balloon was not theirs.

Chief Cabinet Secretary Yoshihide Suga said the government knew nothing of its origin. Defense Minister Taro Kono said surveillance was continuing. Later, asked where it had gone and whether it might return, he gave the answer that stuck. "Ask the balloon."

The gap filled quickly. A weather balloon. A research balloon. A North Korean propaganda balloon. An alien craft. A Godzilla omen. Shinichiro Higashino, an associate professor of aeronautics at Kyushu University, was measured: "It's possible it could conduct scientific observations or monitor something." Later critics noted that checking with US forces in Japan had not occurred to Miyagi officials.

February 2023. A Chinese balloon crossed the United States and was shot down off South Carolina. Miyagi Governor Yoshihiro Murai said it resembled the 2020 object. On 14 February, the Ministry of Defense concluded that balloon-shaped objects seen in November 2019, June 2020 and September 2021 were "strongly presumed" to be unmanned reconnaissance balloons flown by China. Japan called airspace violations by such balloons "totally unacceptable". Wang Wenbin of China's Foreign Ministry pushed back: "Japan is making groundless accusations and smearing China without conclusive evidence."

The balloon was never recovered. No radar data was ever made public. Kono, by then Digital Minister, was questioned in the Diet over "Ask the balloon". The white object over Aoba Ward now has an official answer. It has never been physically confirmed.