Good news! If you heard about the possible ammonia leak on the ISS that drove the crew into the Russian segment, well, rest easy — it turned out to be a false alarm. A system on the exterior of the station detected a reduction in pressure in the coolant system, and then a sensor on the interior detected a rise in cabin pressure; those two things together would tend to suggest that coolant was leaking into the cabin atmosphere. Fortunately, it was a false alarm, and no ammonia was leaked at all. NASA engineers and the astronauts are still working together to figure out what caused the false indication, but the important thing is that everybody is fine and back to work studying the affect of microgravity on the immune systems of fruit flies and studying the behavior of infectious organisms in space.