Herschel space telescope to go blind

Betelgeuse Herschel has built a huge catalogue of far-infrared and sub-mm images of the sky. This recently released image shows the layers of gas shed by Betelgeuse, one of the most familiar stars in the night sky
Cygnus-X Herschel will be remembered as the telescope that produced great vistas of gas and dust, as here in the constellation of Cygnus. Invisible to optical telescopes like Hubble, these billowing clouds and threading filaments trace the locations where future stars will form
Eagle With its far-infrared detectors, Herschel has been able to re-visit familiar objects to provide new data. This picture shows the classic “Pillars of Creation” in the Eagle Nebula, in the constellation Serpens. At long wavelengths, the clouds of gas and dust in the pillars glow, revealing processes at play in star formation
Goods survey Herschel has sought to study the evolution of galaxies. In this image taken of a small patch of sky in the constellation of Ursa Major, countless galaxies are recorded. Some of these fuzzy blobs are many billions of light-years distant
Comet One of Herschel's instruments is called HIFI. The spectrograph's job is to untangle the chemistry of space. Its study of Comet Hartley 2 showed the object to have water-ice with a similar composition to Earth's oceans
Andromeda At a relatively close distance of 2.5 million light-years, Andromeda is very similar in size to our own Milky Way Galaxy. Here, Herschel's observations (orange) are combined with the Newton XMM telescope's (blue)
RCW 120 Herschel's view of RCW 120, a bubble of gas and dust in space around a massive star. Another huge star, 8-10 times the mass of our Sun, is forming on the bubble's boundary - seen as a bright white object
Twisted ring Herschel has revealed new things about our own galaxy. Here, looking towards the centre of the Milky Way, it spies a ribbon of cold gas and dust that is more than 600 light-years across and which appears to be twisted. Scientists have yet to explain it

The European Space Agency (Esa) is about to lose the use of one of its flagship satellites.

Since 2009, the billion-euro Herschel telescope has been unravelling the complexities of star birth and galaxy evolution.

But its instruments employ special detectors that need to be chilled to fantastically low temperatures.

The helium refrigerant that does this job will run out in a few weeks and when it does, Herschel will go blind.

The coming demise of the telescope is no surprise. It is occurring just as was forecast at the start of the mission, almost to the month.

Researchers are now busy running through a final list of observations, acquiring as many images as they can in the time left available.

Already, thousands of pictures have been deposited in the Herschel archive, which is set to become a key reference source for decades into the future.

"I think there is a consensus in the community that Herschel has been a tremendous success and that we have made beautiful observations," Esa project scientist Dr Göran Pilbratt told BBC News.

The telescope was launched almost four years ago and sent to an observing position 1.5 million km from Earth.

It was equipped with a 3.5m mirror - the largest monolithic mirror ever flown - and three state-of-the-art instruments sensitive to long wavelengths of light, in the far-infrared and sub-millimetre range (55 to 672 microns).

Herschel diagram (BBC) The Herschel telescope has to be kept extremely cold to study its frigid targets

This technology has allowed Herschel to study the processes at play as large clouds of gas and dust collapse to form new stars. Its deep vision has also enabled scientists to trace the story of how galaxies have changed through cosmic time.

But the design of the instruments, and in particular of their detectors, has required Herschel be operated close to absolute zero (-273.15C).

Herschel Space Telescope

 Herschel mirror
  • Herschel is one of the largest space telescopes ever launched; its 3.5m diameter mirror perfectly captures infrared light
  • Infrared shines through gas and dust clouds that can block visible light - Herschel can see deep into dusty star-forming regions
  • The telescope is named after the astronomer William Herschel who discovered infrared radiation while studying the Sun in 1800
  • The Earth's atmosphere absorbs infrared, so Herschel was launched into space in 2009 to get a clear view of the infrared Universe

This has been achieved with the aid of a cooling system run on superfluid helium, more than 2,000 litres of which were loaded into the telescope at launch.

The cryogen has gradually boiled off during the course of the mission, and the latest calculation from engineers is that it will be gone entirely sometime in the final two weeks of this month.

Once the detectors start to warm from their ultra-frigid state, they will stop working. The end, when it happens, will be quite sudden.

Those astronomers in the queue to use Herschel at that moment will no doubt be disappointed, but also philosophical: observing time was allocated on the basis that the opportunity could not be guaranteed as the mission moved into its end phase.

Some engineering tests will be conducted on the telescope in April. The Esa operations team will then put the satellite into a slow drift around the Sun before ceasing all communications.

Prof Matt Griffin, from Cardiff University, is team leader on the Spire instrument, which is sensitive to some of the longest wavelengths. He said the telescope had exceeded all expectations.

"It will be a sad day when it makes its last observation, but the data that it has collected during its lifetime will keep astronomers busy for years," he told BBC News.

"For the next three years, the Spire team will work hard to put all Spire data into the best possible condition to be as easy as possible to access and to use in the future.

"Amongst Herschel's most exciting results have been the detection of many thousands of distant star-forming galaxies that are helping us understand how galaxies formed and evolved over cosmic time, and the mapping out in our own galaxy of the filaments and cores that are the sites of new suns being formed today."

Jonathan Amos Article written by Jonathan Amos Jonathan Amos Science correspondent

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  • rate this

    Comment number 13.

    @ 8. david williams

    Actually, the UK's contribution to the ESA is €240m, which covers the cost of all the European space missions. It's actually only 1/3 of what France and Germany contribute so you really have nothing to rant about.

  • rate this

    Comment number 12.

    The ~Euro 1 billion cost of Herschel has to be amortised over the 20 year lifetime from conception to end of post-operations. That's less than 1 pound a year per UK citizen - or 3 pounds a year just looking at the 4 year operational lifetime.
    The UK has recently increased its commitment to space funding because the return for UK industry on investment has been found to be several times the outlay.

  • rate this

    Comment number 11.

    6. David Robinson - The shortage of helium-3 is a big problem - that was produced as a by-product of H-bomb production. Since that has ceased, stocks have been dwindling.
    Astonishes me in a time that we're talking about asteroid mining that we let a satellite full of precious metals just drift off into empty space. Though a shame it had to come to an end at all; wonderful pictures & great science.

  • rate this

    Comment number 10.

    How would you imagine we would "Recharge this coolant"?.... I suppose we could fuse hydrogen nuclei together. EASY!

  • rate this

    Comment number 9.

    A great mission whose data will be productive for many years. Shame it couldn't be extended for the reasons already mentioned.

    Stand by for the tedious rabble of ignorati that don't have the intelligence to appreciate what this is all about and the religious ones who have all the answers because God told them.

  • rate this

    Comment number 8.

    £250,000,000 PER YEAR from us???
    What a bloody waste!

  • rate this

    Comment number 7.

    £240million a year from the U.K. !! Great scientific discoveries.. No doubt very exciting to those in that arena

    But to the layman, I for one am not convined that the outlay on a system with such a finite lifespan is pragmatic to say the least, considering the current economic climate.

  • rate this

    Comment number 6.

    Another 2000 litres of irreplaceable helium lost forever. Great science, and I hope there will be enough helium left in a few decades time to continue to do such things, and of course to build medical scanners which for most people are of more use. Definitely mustn't be wasted on party balloons.

  • rate this

    Comment number 5.

    @2. Herschel is orbiting the L2 Sun-Earth Lagrange point, which is way out beyond the moon's orbit. Not even the Apollo spacecraft went that far. And these days human space flight is restricted to low-earth orbit, so sadly we're further than ever from being able to reach Herschel to refuel or repair it. (Or the Planck, James-Webb, or Gaia space observatories, for that matter.)

  • rate this

    Comment number 4.

    I remember it launching with Planck. Both telescopes have been fabulous successes. I cant wait for Planck's results to be published on the cosmic microwave background radiation. We are living in a golden age of cosmological discoveries on the history of the universe, inflation, dark energy, dark matter and how it relates to particle physics. Well worth the £240 million a year from the UK.

  • rate this

    Comment number 3.

    shame a lot of science will be missed in the future . no real space programe to repair and reuse .. ie shuttle and anyway too far away to retrive maybe time for a space elevator instead

  • rate this

    Comment number 2.

    Seems short sighted that it wasn't designed to have it's coolant recharged. Such a pity.

  • rate this

    Comment number 1.

    Fantastic Pics and science have been "beamed" back.

    Job well done.


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