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 33.

    Even though Herschel's infra-red capability will end, I wonder if it has any future working with the visible spectrum. An instrument as powerful as this could be a very handy tool in the search for and cataloging of NEO nasties (that's not the same as neo-Nazis, by the way). I guess that has already been considered but it is still worth debating...

  • rate this

    Comment number 32.

    Just thinking about what comes next after Herschel. For me the money should go on developing a new generation of (?? optical frequency) telescope with the aim of being able to resolve nearby extra solar planets directly and in more detail.
    In particular imagine if we could resolve the Proxima and Alpha Centauri systems down to the smaller planets and their orbits in detail. An enormous leap!!

  • rate this

    Comment number 31.

    Presumably if we ever get that far out with humans, we could simply top it up with coolant and it would start working again - after all its not going to get damaged that far out .... the 'if' is the important part of this equation.

  • rate this

    Comment number 30.

    £240 million. Is that what our govt. deem to be enough for the future of the human race? Earth is merely a mote of dust, drifting along the vast entinity we know as the universe. If we do not invest in space exploration and travel, we will lag in the preservation of society and we will fall. They do not understand that we need to expand, to take our place in the universe

  • rate this

    Comment number 29.

    Tom Baker
    2 Hours ago

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

    How? Send it up by FedEx!

  • rate this

    Comment number 28.

    I wish they were able to refuel the helium tanks and prolong the life of Herschel. It would be cheaper and yield even better value.

  • rate this

    Comment number 27.

    @17 David Robinson - bumped it up 1 for you, Someone is a bit harsh. Mind you, I think they should ban Sheldon Cooper from rating comments.

  • rate this

    Comment number 26.

    I think the kit has performed over and above what it was designed to do. The important thing is that it has given us enough data to keep scientists busy for the foreseeable future. I billion euros sounds a lot but not if you think of the businesses and individuals that are making a living from it - aside from any scientific profit that is.

  • rate this

    Comment number 25.

    #6 Is partially correct. I use helium to fire gold particles containing potential anti-cancer therapies into tumour cells and the price of a cylinder has sky rocketed due to short supply.

    However its not 'irreplacable'. Helium is produced in natural gas due to Uranium decay. However demand is currently outstripping current manufacturing capabilities.

  • rate this

    Comment number 24.

    When you consider that in 2012 we paid our MPs a total of £164 million in salaries and expenses (and for what?), I reckon €240m a year for such fabulous scientific exploration as this is bloody good value! Long may it continue.

  • rate this

    Comment number 23.

    Pity its now going to stop sending pictures..

    Now we have to wait till 2018 for the launch of the James Webb telescope and with its 6.5M mirror it should give fantastic results, far beyond and superior to Herschel.

    By, and thanks for the pictures.

  • rate this

    Comment number 22.

    17 David Robinson - Both helium-4 & helium-3 are used in cryogenics, they have different boiling points and one is evaporated off to cool the other, just like how sweat cools your skin.
    Don't know why your comment got such a low rating though, helium-4 is also running low.

  • rate this

    Comment number 21.

    These telescopes are the most amazing technical achievements at a fraction of the cost of what we waste on uneaten food for example. Why do certain people have such a problem with the human race making discoveries that tell us about our place in the universe? Goodbye Herschel, job well done. Roll on James Webb telescope!

  • rate this

    Comment number 20.

    Congratulations ESA and ALL of the scientists and engineers who made this extraordinary piece of work happen.

    Herschel will still be revealing discoveries decades into the future I am sure.

    Such a tiny amount of money to produce such a wealth of discovery for ALL of humanity

    How many bankers can even begin to comprehend that?

    Herschel is money well spent.

  • rate this

    Comment number 19.

    #2 Tom Baker
    "Seems short sighted that it wasn't designed to have it's coolant recharged. Such a pity."

    Simply not technically possible. To liquefy helium requires a big powerful and very heavy machine - too much noise and vibration, too much weight, too much power needed.
    Active helium recycling was too difficult to be practical even on the ISS for the Alpha Magnetic Spectrometer.

  • rate this

    Comment number 18.

    It was money well spent. Herschel made many important discoveries during its mission. Some of these will no doubt bring economic benefits in a few decades time. Fundamental research is long term investment, only the short sighted will doubts its value.

    It's a shame they did not install warm instrument in Herschel that will function in the post coolant phase.

  • rate this

    Comment number 17.

    @ 11. Drunken Hobo
    Thanks for pointing out it's Helium 3. Not obvious from the article (or if you aren't a physicist). My comment #6 about helium stocks is still a valid one (although not so relevant), and not worthy of a down vote by anyone I would have thought :-(

  • rate this

    Comment number 16.

    #7:- Raziel, remember when the telescope was first suggested and later launched - the banks hadn't screwed us to the floor then. That was a lesson still to come, so don't say this wasn't a pragmatic use of funds.

  • rate this

    Comment number 15.

    How true. I can already hear their fingers typing frantically so I'll make it easy for them.

    1) That is not a lot of money when compared to other fields, i.e. medical, arts, army etc.
    2) The data retrieved is of great interest and use to mankind. So before you say it doesn't benefit you, it does!
    3) This article is not about God/religion. it is about science, please remember that. Thank you

  • rate this

    Comment number 14.

    I think it would be great if they opened the floor to ideas about what to do with the instrument once it goes blind. We spent a lot of money and effort putting it up there and perhaps someone could think of a use for it. Admittedly it's a long shot but you never know it's work asking.


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