The U.S. Air Force said a malfunctioning Japanese astronomy satellite known as ASTRO-H was not hit by debris. Credit: JAXA.

WASHINGTON – The U.S. Air Force has found no evidence that a Japanese astronomy satellite that malfunctioned March 26 was struck by debris, making a technical problem the more likely culprit.

“We have seen nothing that says it was struck by debris,” Capt. Nicholas Mercurio, a spokesman for the 14th Air Force and Joint Functional Component Command for space, said in an interview with SpaceNews.

In a March 27 statement, the Japan Aerospace Exploration Agency said it lost communications with the Hitomi satellite at 3:40 a.m. Eastern March 26. About 40 minutes later, at 4:20 a.m. Eastern, the Air Force’s Joint Space Operations Center at Vandenberg Air Force base detected five pieces of debris in the vicinity of the satellite. Subsequent analysis by the JSpOC concluded the breakup event occurred about 9:42 p.m. Eastern March 25, or about six hours before JAXA lost communications with Hitomi.

JAXA is still holding out hope of recovering Hitomi, having received “very short” signals from the satellite March 28 at the Uchinoura Ground Station in Japan and from the Santiago Tracking Station in Chile. JAXA said March 29 it had not determined the health of the satellite and is observing the objects near the satellite using a radar at Kamisaibara Space Guard Center and telescopes at the Bisei Space Guard Center, both owned by the Japan Space Forum.

JAXA continues to investigate the anomaly but has not speculated on the cause of the malfunction. However, the Air Force said it had found no evidence of an orbital debris strike.

After each orbital debris event, such as what happened with the Hitomi satellite, a team at JSpOC essentially tries to “rewind the tape,” Mercurio said, and learn exactly what happened. This effort includes immediately asking industry partners and international allies for data from their sensors and radars that may have been cued in the direction of the event and reviewing any relevant information.

By the morning of March 29, Air Force officials had studied the data and said they saw “nothing” that indicates Hitomi was struck by debris, Mercurio said.

JAXA launched Hitomi, originally known as Astro-H, on an H-2A rocket Feb. 17. The 2,700-kilogram satellite carries several instruments to perform x-ray astronomy observations. Some of the spacecraft’s instruments were provided by NASA, the European Space Agency and the Canadian Space Agency. The spacecraft was in the middle of a three-month checkout and instrument calibration phase when the malfunction took place.

Mike Gruss covers military space issues, including the U.S. Air Force and Missile Defense Agency, for SpaceNews. He is a graduate of Miami University in Oxford, Ohio.