Archive for European Space Agency

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Cosmic Vision

Posted in Science Politics, The Universe and Stuff with tags , , , , , , , , , on February 20, 2010 by telescoper

It’s nice to have a bit of science stuff to blog about for a change. Just this week the European Space Agency (ESA) has  announced the results of its recent selection process for part of its Cosmic Visions programme, which represents ESA’s scientific activity for the period 2015-2025.

The selection process actually began in 2007, with over 50 proposals. This list was then whittled down so that there were six candidate missions under consideration for the so-called M-class launch slots (M meaning medium-sized), and three in the L-class list of larger missions. The latest exercise was to select three of the M-class missions for further study. They succeeded in selecting three, but have also kept another, much cheaper, mission in the frame.

As far as I understand it, only two M-class missions are actually envisaged so the race isn’t over yet, but the missions still in the running are:

PLATO.  The PLATO mission is planned to study planets around other stars. This would include terrestrial planets in a star’s habitable zone, so-called Earth-analogues. In addition, PLATO would probe stellar interiors by through stellar seismology. In some sense, this mission is the descendant of a previous proposal called Eddington. (PLATO stands for PLAnetary Transits and Oscillations of stars – I’ll give it 3/10 for quality of acronym).

EUCLID. Euclid would address key questions relevant to fundamental physics and cosmology, namely the nature of the mysterious dark energy and dark matter. Astronomers are now convinced that these substances dominate ordinary matter. Euclid would map the distribution of galaxies to reveal the underlying ‘dark’ architecture of the Universe. I don’t think this is meant to be an acronym, but I could be wrong. Perhaps it’s European Union Cosmologists Lost in Darkness?

SOLAR ORBITER. Disappointingly, this is neither an acronym nor a Greek person. It would take the closest look at our Sun yet possible, approaching to just 62 solar radii. It would deliver images and data that include views of the Sun’s polar regions and the solar far side when it is not visible from Earth.

These are the three main nominations, but the panel also decided to endorse another mission, SPICA, because it is much cheaper than the approximately 500 Million Euro price tag on the other contenders. SPICA would be an infrared space telescope led by the Japanese Space Agency JAXA. It would provide ‘missing-link’ infrared coverage in the region of the spectrum between that seen by the ESA-NASA Webb telescope and the ground-based ALMA telescope. SPICA would focus on the conditions for planet formation and distant young galaxies.

Many of Cardiff’s astronomers will be very happy if SPICA does end up being selected as it is the one most directly related to their interests and also their experience with Herschel which is, incidentally,  continuing to produce fantastic quality data. If SPICA is to happen, however, extra money will have to be found and that, in the current financial climate, is far from guaranteed.

Which of these missions will get selected in the end is impossible to say at this stage. There are dark mutterings going on about how realistic is the price tag that has been put on some of the contenders. Based on past experience, cost overruns on space missions are far from unlikely and when they happen they can cause a great deal of damage in budgets. Let’s hope the technical studies do their job and put realistic figures on them so the final selection will be fair.

Whatever missions fly in the end, I also hope that the Science and Technology Research Council (STFC) – or whatever replaces it – remembers that these are science missions, and its responsibility extends beyond the building of instruments to fly on them. Let’s to hope we can count on their support for research grants enabling us to answer the science questions they were designed to address.

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Astronomy Look-alikes, No. 12

Posted in Astronomy Lookalikes with tags , , on January 30, 2010 by telescoper

I’m struck by the remarkable similarity between the depiction below of WALL-E, an absurdly comical fantasy robot that exists only in the realm of  Science Fiction, and the European Space Agency’s Exomars Rover. I wonder if by any chance they might be related?

P.S. Thanks to Rigsby Matt Griffin for this one!

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First Light from Planck!

Posted in The Universe and Stuff with tags , , , on September 17, 2009 by telescoper

Credit to Andrew Jaffe for alerting me to the fact that ESA’s first press release concerning Planck has now been, well, released…

I last blogged about Planck when it had reached its orbit around L2 and cooled down to its working temperature of 100 milliKelvin. Over the ensuing weeks it has been tested and calibrated, prodded and poked (electronically of course) and generally tuned up. More recently it has completed a “mini-survey” to check that it’s all working as planned.

The way Planck scans means that it takes about six months to cover the whole sky, which is much longer than the two-week period allowed for the mini-survey. This explains the fact that a relatively narrow slice of the celestial sphere has been mapped. However, you can see the foreground emission from the Galactic plane quite clearly. Here is the region shown in the box split into the nine separate frequency channels that Planck observes:

The High Frequency Instrument (HFI) is more sensitive to dust, while the Low Frequency Instrument (LFI) detects more radio emission. It all seems to be working as expected!

And finally here’s a blow up of the smaller square above the Galactic plane shown as seen by  LFI and HFI:

This region is much less prone to foreground emission. The fact that similar structures are seen in the two completely independent receivers shows that the structure is not just instrument noise. In other words, Planck is seeing the cosmic microwave background!

Now Planck will carry out its full survey, scanning the sky for another year or so. There will then be an intense period of data analysis for about another year after which the key science results will be published. Exciting times.

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Atlantes

Posted in Science Politics, The Universe and Stuff with tags , , , , , , on September 10, 2009 by telescoper

I’ve just noticed a  post on another blog about the  meeting of the Herschel ATLAS consortium that’s  going on in Cardiff at the moment, so I thought I’d do a quickie here too. Actually I’ve only just been accepted into the Consortium so quite a lot of the goings-on are quite new to me.

The Herschel ATLAS (or H-ATLAS for short) is the largest open-time key project involving Herschel. It has been awarded 600 hours of observing time  to survey 550 square degrees of sky in 5 wavelenth bands: 110, 170, 250, 350, & 500 microns. It is hoped to detect approximately 250,000 galaxies,  most of them in the nearby Universe, but some will undoubtedly turn out to be very distant, with redshifts of 3 to 4; these are likely to be very interesting for  studies of galaxy evolution.

Herschel is currently in its performance verification (PV) phase, following which there will be a period of science validation (SV). During the latter the ATLAS team will have access to some observational data to have a quick look to see that it’s  behaving as anticipated. It is planned to publish a special issue of the journal Astronomy & Astrophysics next year that will contain key results from the SV phase, although in the case of ATLAS many of these will probably be quite preliminary because only a small part of the survey area will be sampled during the SV time.

Herschel seems to be doing fine, with the possible exception of the HIFI instrument which is currently switched off owing to a fault in its power supply. There is a backup, but the ESA boffins don’t want to switch it back on and risk further complications until they know why it failed in the first place. The problem with HIFI has led to some rejigging of the schedule for calibrating and testing the other two instruments (SPIRE and PACS) but both of these are otherwise doing well.

The data for H-ATLAS proper hasn’t started arriving yet so the meeting here in Cardiff was intended to sort out the preparations, plan who’s going to do what, and sort out some organisational issues. With well over a hundred members, this project has to think seriously about quite a lot of administrative and logistical matters.

One of the things that struck me as particular difficult is the issue of authorship of science papers. In observational astronomy and cosmology we’re now getting used to the situation that has prevailed in experimental particle physics for some time, namely that even short papers have author lists running into the hundreds. Theorists like me usually work in teams too, but our author lists are, generally speaking, much shorter. In fact I don’t have any publications  yet with more than six or seven authors; mine are often just by me and a PhD student or postdoc.

In a big consortium, the big issue is not so much who to include, but how to give appropriate credit to the different levels of contribution. Those senior scientists who organized and managed the survey are clearly key to its success, but so also are those who work at the coalface and are probably much more junior. In between there are individuals who supply bits and pieces of specialist software or extra comparison data. Nobody can pretend that everyone in a list of 100 authors has made an identical contribution, but how can you measure the differences and how can you indicate them on a publication? Or  shouldn’t you try?

Some suggest that author lists should always be alphabetical, which is fine if you’re “Aarseth” but not if you’re “Zel’dovich”. This policy would, however, benefit “al”, a prolific collaborator who never seems to make it as first author..

When astronomers write grant applications for STFC one of the pieces of information they have to include is a table summarising their publication statistics. The total number of papers written has  to be given, as well as the number in which the applicant  is  the first author on the list,  the implicit assumption being that first authors did more work than the others or that first authors were “leading” the work in some sense.

Since I have a permanent job and  students and postdocs don’t, I always make junior collaborators  first author by default and only vary that policy if there is a specific reason not to. In most cases they have done the lion’s share of the actual work anyway, but even if this is not the case it is  important for them to have first author papers given the widespread presumption that this is a good thing to have on a CV.

With more than 100 authors, and a large number of  collaborators vying for position, the chances are that junior people will just get buried somewhere down the author list unless there is an active policy to protect their interests.

Of course everyone making a significant contribution to a discovery has to be credited, and the metric that has been used for many years to measure scientific productivity is the numbered of authored publications, but it does seem to me that this system must have reached breaking point when author lists run to several pages!

It was all a lot easier in the good old days when there was no data…

PS. Atlas was a titan who was forced to hold the sky  on his shoulders for all eternity. I hope this isn’t expected of members of the ATLAS consortium, none of who are titans anyway (as far as I can tell). The plural of Atlas is Atlantes, by the way.

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Hubble Flash

Posted in The Universe and Stuff with tags , , , , , on September 9, 2009 by telescoper

Just a quick post to point out that brand new “Early Release” images have just appeared following the recent refurbishment of the Hubble Space Telescope.

You can read the accompanying press release here, so I’ll just post this brief description:

These four images are among the first observations made by the new Wide Field Camera 3 aboard the upgraded NASA Hubble Space Telescope.

The image at top left shows NGC 6302, a butterfly-shaped nebula surrounding a dying star. At top right is a picture of a clash among members of a galactic grouping called Stephan’s Quintet. The image at bottom left gives viewers a panoramic portrait of a colorful assortment of 100,000 stars residing in the crowded core of Omega Centauri, a giant globular cluster. At bottom right, an eerie pillar of star birth in the Carina Nebula rises from a sea of greenish-colored clouds.

My own favourite has to be Stephan’s Quintet, but they all look pretty fantastic.

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Everyone’s Gone to the Moon

Posted in Uncategorized with tags , , , , on July 16, 2009 by telescoper

Since the media have been banging on about it all week, as have various other bloggers, I suppose I should at least mention that today (16th July 2009) is the fortieth anniversary of the launch of NASA’s  Apollo 11 mission which put the first man on the Moon. I’m reliably informed that the picture on the left shows the second man on the Moon, Buzz Aldrin, although I don’t think the costume gives much clue to the identity of the wearer.

My response to the media furore  is muted because I’m decidedly ambivalent about the whole business of manned space exploration. I’m not going to be churlish and say that all the Apollo missions did was provide America with a much-needed propaganda victory during the Cold War. I think it’s true that putting a man on the Moon was a great achievement in terms of ingenuity and organization. It’s  probably also true that it inspired many people to go into science who otherwise wouldn’t have done so. I’d even say that the sight of Earth from the Moon marked the beginning of a new age of awareness of the fragility of our own existence on our home planet and, perhaps even a step towards our coming-of-age as a species.

The reason I am ambivalent, however, is that the scientific returns from the Apollo missions were entirely negligible, at least in terms of value for money,  partly because the Apollo missions weren’t really designed to do science in the first place and partly because the Moon just isn’t very interesting…

Mankind hasn’t returned to the Moon since the Apollo series came to an end. That’s not a matter for regret, just a reflection of the fact that there isn’t much to be found there. In those forty years  astronomy and space science have moved on immeasurably through spaceborne observatories and unmanned probes. We have learned far more about the Universe  those ways than could ever be achieved by sending a few people to collect rocks from a dull piece of rubble in our backyard. In the process, the Universe has grown in size relative to the scale possible to reach by human engineering projects. The last forty years has shown us that, in retrospect, going to the Moon wasn’t really all that impressive compared to what we can find out by remote means.

Unfortunately there appears to be an increasingly vocal lobby in favour of diverting funds from fundamental science into manned space exploration, much of it aimed at the goal of putting a person on Mars.  This has not yet resulted in a commitment by the United Kingdom government to join in manned space exploration, but it is worrying that the Chief Executive of the Science & Technology Facilities Council is a failed astronaut who I fear sees this as an attractive option. Even more worryingly, Science Minister Lord Drayson seems to be keen too. It’s up to  scientists to present the case to government for maintaining investment in fundamental science and against having the budget plundered to play Star Trek.

The European Space Agency‘s Aurora programme is intended to culminate with a manned trip to Mars, at an overall cost of over £30 billion. One of the arguments I hear over and over again in favour of this programme is that it will inspire young people to take up science, especially physics. Well, maybe. But people can’t become scientists unless they have the opportunity to learn science at School and there is a drastic shortage of physics teachers these days. What’s the point of being inspired if you can’t get the education anyway? You could train an awful  lot of school teachers for  a small fraction of the Aurora budget.  And what’s the point of inspiring people to take up astronomy and space science when you’re also busy slashing the budget for research and ending the careers of those excellent scientists we’ve already got?

So by all means let’s celebrate the marvellous achievements of 1969, but let’s move on and not pretend that there is any good scientific reason for repeating them.

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