The prognosis was not good last week when the Japanese space agency JAXA lost communication with its new Hitomi X-ray astronomy satellite. However, there was some hope a few days later when the space agency re-established intermittent contact with the spacecraft orbiting some 360 miles above Earth.
Since then, astronomers have been observing the satellite, originally known as Astro-H, as it orbits Earth. The photos accompanying this story, taken by astronomer William Keel of the University of Alabama on Sunday evening, appear to show various parts of the spacecraft catching the sun as they slowly rotate. The brightest moments are probably caused by solar panels rotating in view. The pattern of brighter and then dimmer light suggests that at least two large stretches, with different periods, are out of control.
An astronomer who has followed Hitomi closely, Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics, tweeted on Sunday night: “Unfortunately, I now believe the radio signals were the last gasps of a mortally wounded Astro-H.”
It was originally speculated that debris could have hit the satellite, but JAXA has since said there was an equipment malfunction. Possible causes of the spacecraft breakup include a rupture of the helium tank housing the x-ray instruments, a fuel leak, or battery failure.
Regardless of the cause, the loss of the spacecraft is a major blow to X-ray astronomers, who have few tools at their disposal to probe high-energy but very short-wavelength X-rays absorbed by Earth’s atmosphere. X-rays are useful for studying black holes, neutron star mergers, highly magnetized starquakes, and other unusual high-energy astrophysics. But scientists were most intrigued by the new kinds of high-energy cosmic interactions they might see with Hitomi that they can’t predict.