SRON Netherlands Institute for Space Research

Our mission is to bring about breakthroughs in international space research


Our mission is to bring about breakthroughs in international space research


SRON Netherlands Institute for Space Research



HIFI, one of the three scientific instruments on ESA's Herschel Space Observatory, has taken a hit by a cosmic ray particle in a critical area again. On Monday 28 February a particle presumably hit the electronics of the instrument, which brought HIFI observations to a full stop. However, after switching HIFI off and then on again the instrument came back online. HIFI will now be able to continue its highly successful quest for carbon and water in gas clouds, which sheds new light on the birth and early development of stars and planets.

Because HIFI was offline the specialists from ESA and SRON can't be sure that the cause of the malfunction is a hit by a cosmic particle, but this is by far the most probable scenario. In the extreme conditions of space every instrument runs the risk of being damaged by hits of cosmic ray particles. This is the reality of space research. A few months after the successful launch in May 2009 HIFI (the Heterodyne Instrument for the Far-Infrared) was probably hit by a cosmic ray particle in its electronics.

The HIFI instrument
This led to a series of events that eventually caused a malfunction of the prime electronics. It became clear that HIFI had to fall back on its back-up electronics. In the joint HIFI-ESA investigation that followed new procedures were devised that successfully minimized the risks of operating HIFI on its backup electronics. HIFI was switched on again and continued to observe its main targets in the first year with great success, showing a wealth of spectral detail that no other instrument could beat.

Computer memory

'Water lines'detected by HIFI in deep space
Since then HIFI has been hit tens of times by cosmic rays without any further damage, showing the new procedures to be resilient against particle impacts. However, the investigation of 2009 also indicated that there was one area in the electronics that remained vulnerable: the computer memory of the auxiliary computer in one of the electronic units (the LCU microprocessor). It is this computer memory which has most probably been hit by a particle again on Monday 28 February 2011, which put a full stop to HIFI. The only possible solution was powercycling (turning off and then on again) of the instrument from the Control Centre on Earth. This is what has been done after carefully choosing the right conditions to do so, like the temperature of the electronics.

Back online

ESA's space telescope Herschel
As expected, HIFI came back online, showing that careful operation in space research is the key to success. The HIFI specialists from ESA and SRON expect to have to switch HIFI off and on at least one more time during the lifetime of Herschel, but this incident has given them the confidence that it can be done without affecting the health of the instrument. HIFI will now continue its observations alongside the two other Herschel instruments PACS and SPIRE.

Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. HIFI has been designed and built by a consortium of institutes and university departments from across Europe, Canada and the United States under the leadership of SRON Netherlands Institute for Space Research and with major contributions from Germany, France and the US.


SRON has four programme lines, Astrophysics, ExoplanetsEarth, and Technology, with science groups attached, and two expertise groups, Instrument science and Engineering.


The Astrophysics programme at SRON is dedicated to unraveling the history of the universe, from the first stars and black holes to large-scale structure.

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The Exoplanets programme is dedicated to atmospheres of planets beyond our solar system and is an in-between of SRON's Astrophysics and Earth programmes.

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The Earth programme is aimed at the climate and air quality of planet Earth, with focus on the global carbon cycle and aerosols.

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The Engineering group covers SRON's skills and know-how with regard to product assurance, quality assurance, configuration control, design engineering – electronic & mechanical – and parts procurement. It is an expertise group that provides resources for all SRON instrument projects.

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The Instrument science group covers SRON's skills and know-how with regard to instrument physics, system engineering (up to full-instrument level) and project management. It is an expertise group that provides resources for all SRON instrument projects.

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The Technology programme is SRON's backbone for the development of enabling technology.

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SRON’s mission is to bring about breakthroughs in international space research 

Therefore the institute develops pioneering technology and advanced space instruments, and uses them to pursue fundamental astrophysical research, Earth science and exoplanetary research. As national expertise institute SRON gives counsel to the Dutch government and coordinates - from a science standpoint - national contributions to international space missions. SRON stimulates the implementation of space science in our society.