Setback HIFI

The HIFI spectrometer on board the European space telescope Herschel – launched on 14 May – is experiencing a setback. The space measuring instrument has been temporarily switched off due to a problem in the so-called Local Oscillator Control Unit. The exact cause of the problem on this ESA mission remains unclear. Extensive tests – now with the additional assistance of an ESA team – will now be performed to find the answer. When it is considered safe, the back-up system will be switched back on. Then a fully functional HIFI will resume the search for the presence of water in remote parts of the universe.


Herschel was launched on 14 May 2009 and since then HIFI has functioned perfectly. Moreover, a wealth of highly promising scientific data was obtained during the test phase. All was proceeding well until an error occurred in the control module (the Local Oscillator Control Unit) at the start of August. As the so-called housekeeping of the module has failed ("the black box"), quickly determining the exact cause of the problem is difficult. However for the time being, Frank Helmich, scientific leader of the HIFI project, is assuming an external cause. "We do not know for certain yet, but it is quite possible that the electronics in HIFI have been thrown into disarray due to a collision with an energetic cosmic particle, for example. That really would be a case of bad luck."

At SRON’s Groningen location there is an identical copy of HIFI on which as many scenarios as possible are currently being tested. That costs a lot of time, but Helmich has every confidence that the cause of the defect can still be traced in this manner: "Our current expectation is that we will need at least another two weeks. If the back-up copy of the control module is switched back on HIFI will be fully functional again." On Monday 7 September a meeting took place between the teams from SRON and ESA about the investigation strategy to be followed.

HIFI – Heterodyne Measuring instrument for the Far Infrared – is investigating the composition of interstellar gas clouds and measures, for example, how much carbon and water these contain. This is one way of finding out more about the birth and early development of stars and planets. HIFI shall also make measurements of the atmosphere of planets and comets in our Solar System.