JAXA declares Hitomi a loss

The Hitomi x-ray observatory, aka Astro-H, aka NeXT, that Japan launched just a couple of months ago was in its commissioning period when it abruptly lost contact with Earth on March 26.  JAXA has been struggling to regain control of the spacecraft, but sadly have now resigned themselves to its fate.  It is a total loss.  Furthermore, the intermittent garbled signals they thought they’d detected from it seem actually to have been radio interference in other signals unrelated to Hitomi, and not a true signal after all.

Ground observations in by visual and radio telescopes show that both of the spacecraft’s solar arrays have separated, and it has been tumbling since March 26.  It is very difficult to determine what went wrong, since most of the evidence is silently orbiting the Earth, but JAXA will be poring over manufacturing data, flight spares, and configuration data stored on Earth to try to figure it out.  Tentatively, it appears to have been a problem with the attitude control system, possibly in the software that controlled its orientation while passing through a magnetic anomaly which temporarily crippled the star tracker, which may have allowed the reaction control wheels to become oversaturated, further compromising its ability to control its orientation.  They believe tentatively that it got itself into a spin so violent that the solar arrays were literally ripped from the spacecraft.

This of course a very disappointing result.  Hitomi was to be a flagship x-ray observatory, carrying an instrument originally intended for Chandra, observing in frequencies that no other x-ray observatories currently cover.  It would cost tens of millions just to replace one of the instruments aboard the spacecraft; there’s no telling when, if ever, this mission could be reflown.

Goodbye, Hitomi.



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