The Japanese astronomy satellite known as Hitomi started to malfunction on March 26, sparking speculation that it had been hit by space debris.
However the U.S. Air Force has found no evidence to support the hypothesis, meaning that a technical problem is more likely to blame. The Japan Aerospace Exploration Agency (JAXA) said that it lost communications with the Hitomi satellite at 3:40 am Eastern time on March 26, writes Mike Gruss for Space News.
U.S. Air Force investigation points to technical fault
“We have seen nothing that says it was struck by debris,” said Capt. Nicholas Mercurio, a spokesman for the 14th Air Force and Joint Functional Component Command for space. This is despite the fact that the Air Force’s Joint Space Operations Center at Vandenberg Air Force base spotted 5 pieces of space debris near the satellite around 4:20 am.
However further analysis showed that breakup occurred around 9:42 pm, six hours before JAXA lost contact with x-ray satellite Hitomi. According to reports there is still a vague hope of recovering the satellite as the Uchinoura Ground Station in Japan received short signals on March 28. The Santiago Tracking Station in Chile also made brief contact.
JAXA is still not sure what state the satellite is in. It continues to observe objects near Hitomi using radar at Kamisaibara Space Guard Center and telescopes at the Bisei Space Guard Center. An investigation is ongoing and JAXA has not released a statement on the malfunction.
Data from other sources used to paint a picture of Hitomi incident
After a potential orbital debris event, scientists attempt to “rewind the tape,” according to Mercurio. This means gathering data from industry partners and international allies, trying to paint a picture of what went on.
Mercurio says that Air Force officials had pulled in data and studied it by March 29, finding “nothing” that would suggest a debris strike on Hitomi.
The Hitomi satellite was launched on an H-2A rocket on February 17. The 2,700-kilogram satellite was originally known as Astro-H, and carries instruments to perform x-ray astronomy observations.
Various instruments on board were provided by NASA, the European Space Agency and the Canadian Space Agency. Hitomi was halfway through a checkout and calibration phase when contact was lost.
Investigations ongoing into cause of satellite anomaly
It seems likely that a fuel or gas leak, a faulty battery or another kind of explosive event caused the problems. According to Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics who expertly tracks satellite activity, the event drove the satellite off course.
McDowell says that Hitomi is now in orbit around 5 kilometers lower than expected. The incident also apparently affected the rotation of the satellite, meaning that its antenna is not pointing in the direction it should be.
This explains the short bursts of contact with ground stations. “JAXA has not been able to figure out the state of its health, as the time frames for receiving the signals were very short,” the space agency said.
“JAXA continues to investigate the relationship between the information from JSpOC and the communication anomaly,” the space agency said. “JAXA will do its best to recover communications with Hitomi and investigate the cause of the anomaly.”
Hitomi is the sixth x-ray astronomy satellite that Japan has sent into orbit. Since 1979 the country has been studying the hottest parts of the universe using similar observatories. The ambitious Hitomi project was supposed to last 3 years, but looks to have run into significant problems early on.
