The sad news was announced on Monday, August 8th, to the shocked team members.

The XRS has lost all of its liquid helium. Since the XRS has to be super cold, and the liquid helium was an essential part of the cooling system, we can no longer use the XRS.

Things were going smoothly for the first 3 weeks of the mission. It was successfully cooled to 60 miliKelvin. The team saw, from the early data of the internal X-ray sources, that the detector was working as expected. They expected great scientific return for their years of hard work, over the next 3 years or so.

The first sign of trouble was seen on July 29. Temperature spikes were seen, indicating that helium gas (almost certainly vented from the tank) got to parts of the XRS that it shouldn't have gotten into. If this was a one-time event, then we could have continued using the XRS as planned. All the team needed to do was to devise a special procedure to get the extra helium off the detector surface.

But similar events happened a few more times, including twice on August 8th. There was too much helium gas for the cooling system to keep up, and we ended up losing all liquid helium.

Both JAXA and NASA plan to look into this problem to make sure we understand what happened in detail. It's too late to save the XRS on Suzaku, but we need to know what went wrong so we can do it right the next time. Yes, there will be a next time, because an instrument like the XRS can do so much for astronomy, and we saw from the limited data that it would have worked really well, if only we could have kept it cold.

In the meantime, Suzaku still has two types of instruments, the XIS and the HXD. Both are working well. Both are very capable instruments, and together, they are sure to help astronomers answer some key questions about the X-ray universe.

We hope to report happier news on the Suzaku Learning Center in the near future.

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