With the complete depletion of its stored helium, which was used to cool the spacecraft's instruments, the Herschel space observatory is experiencing a rise in temperatures, rendering its sensitive equipment unusable, according to a report issued by NASA and the European Space Agency yesterday.

Launched in 2009, Herschel's detectors were designed to pick up the glow from celestial objects with infrared wavelengths as long as 625 micrometers -- 1,000 times longer than what we can see with our eyes.

Because heat interferes with the sensitive equipment, the instruments were chilled to temperatures as low as 2 Kelvins -- minus 271 degrees Celsius -- using liquid helium.

This map, superimposed over an image of Jupiter, shows the distribution of water in the stratosphere of Jupiter. The image was created using data collected by the Herschel space observatory's Photodetecting Array Camera and Spectrometer (PACS) instrument at around 66.4 microns, a wavelength that corresponds to one of water's many spectral signatures.

The image shows an asymmetric distribution of water across the planet, with the southern hemisphere showing the most water. The highest concentrations are depicted in white and cyan. Based on this and other data collected by Herschel, astronomers have established that at least 95 percent of the water present in Jupiter's stratosphere was supplied by the impact of comet Shoemaker-Levy 9 in 1994.