correspondence Space: telescopes reveal the way forward Astronauts’ skills should be saved for major work in exploring the origins of the Universe.

Sir — Following the Columbia tragedy, vehicles that dock at the space station. scientists must re-evaluate the role of If astronauts again travel far from astronauts in scientific research (see Earth, a manned lunar station would Nature 421, 559; 2003). We should ask have great scientific potential and be a astronauts to participate only in frontline stepping-stone to a martian exploration. research that would otherwise be prohibi- In general, the Moon is not an attractive tively difficult. The continued exploration telescope location, given its huge monthly of the origins of the Universe and life itself thermal cycle. But the south lunar pole with astronomical telescopes is such an has attractive features for people and area. For example, primitive life on an telescopes. Hydrogen is present, probably

extrasolar planet could be detected as water ice, and because the Moon’s spin OBSERVATORY/NASA CONNORS/STEWARD T. as a chemical transformation of its axis is not much tilted there are peaks atmosphere, as happened on Earth experiencing uninterrupted sunshine. a billion or more years ago. But the A habitation on one of these could telescopes must be of unprecedented size have constant solar power and a room- and sophistication. To be realistic, they Potential: a 10-metre successor to Hubble. temperature environment. A telescope will need continuing development in here would maintain constant deflection space, with controls and instruments one housing the main mirrors and built under gravity as it rotated once a month upgraded as experience is developed. to survive radiation damage; the other to track the stars. It could be built and Such evolution has been crucial to the much smaller, lighter and containing the tested in the sunshine, and for cryogenic success of the Hubble Space Telescope. sensitive instruments and active optics operation would be cooled down simply Astronauts have carried out repairs and controls. After verification of performance by erecting a shallow bowl of multilayer upgrades, transforming it into a long-lived in orbit at room temperature, the two insulation to screen out radiation from the and exceptionally productive observatory. would be transferred independently to the Sun and Earth. For servicing or repairs, the Some advanced telescopes will build on remote operating point. The large structure bowl would be lowered to warm up the this experience. The 10-metre X-ray would use efficient but slow solar-electric telescope. A 20-metre telescope built in Evolving Universe Spectroscopy (XEUS) propulsion; the smaller instrument would this way would be of quite extraordinary telescope will be built at the International be moved quickly through the radiation sensitivity and flexibility, and would Space Station and operated nearby. A 10- belts by conventional means. Both would represent a huge accomplishment for metre successor to Hubble (see simulation carry enough fuel to allow a return to lunar-based astronauts. in figure) for the optical and ultraviolet low-Earth orbit for repairs and upgrades Roger Angel band could be similarly developed, by astronauts when necessary. Attachment Department of Astronomy and Steward eventually achieving the sensitivity to and detachment could be achieved Observatory, University of Arizona, 933 North study extrasolar terrestrial planets. robotically, as with the unmanned supply Cherry Avenue, Tucson, Arizona 85721, USA Large infrared telescopes can also be extremely powerful, but present a special problem, because they need to be would now have to say about the early cryogenically cooled to be sensitive to faint Space: next step is an history of the Solar System had Apollo heat sources. Thus they cannot be operated International Moon Base not taken place. Even today, one can conveniently in low orbit where they scarcely attend a scientific meeting on would be warmed by Earth’s radiated heat. Sir — Your far-sighted Editorial (Nature the subject without seeing geochemical The first large telescope of this type, the 421, 559, 2003) on the future of human and isotope analyses of Apollo samples James Webb Space Telescope, is planned space exploration in the wake of the presented in one context or another. for operation a million miles away. But Columbia accident is a welcome contrast Yet Apollo, quite literally, only scratched with a 6-metre aperture it will be much to some of your more sceptical comments the surface of the Moon, and there is so bigger than its cryogenic precursors, larger about this subject in the past. Your call for much more to learn. Moreover, while and more complex even than Hubble. If its vision, and clear endorsement of the Mars does indeed beckon, we should parts wear out or need upgrading, or if its exploratory value of human spaceflight, probably learn to operate successfully folded optics do not deploy correctly, it was a breath of fresh air. I would like to on the Moon before attempting this might be possible to bring the telescope make two points. much greater challenge. back to a rendezvous as close as the Moon First, you identify three possible future Second, your Editorial implied that (Nature 419, 666; 2002), but at consid- roles for humans in space: as geologists human space exploration is solely NASA’s erable risk to astronauts. Otherwise we exploring near-Earth asteroids; as responsibility. But if such exploration is must launch an entirely new telescope at servicing crews for telescopes at L2; and worthwhile, as I believe it is, we should all the same scale, or abandon the project. as explorers on Mars. There are indeed share in the costs and the risks as well as in For still larger and more complex good reasons for believing that all these the benefits. The pre-eminent value of the cryogenic telescopes and interferometers, activities, and more, would benefit from much-maligned International Space strategies to combine remote operation a human presence in space, but we must Station is not so much the science to be and more convenient astronaut access are not forget the Moon. performed on it, valuable though that is, clearly desirable. For example, a telescope The Apollo missions pioneered the use but the model it provides for international could be assembled in low-Earth orbit as of astronauts as field geologists, and I cooperation in space. We should aim to two linked spacecraft: a large but simple shudder to think what the textbooks build on this experience to develop a

NATURE | VOL 422 | 27 MARCH 2003 | www.nature.com/nature © 2003 Nature Publishing Group 373 correspondence global human spaceflight infrastructure recording the processes by which images Swift publication would from which science can only benefit — are created, so that these can be accurately an international Moon base being the replicated. Currently, such information reward good reviewers obvious next step. is usually held only in the laboratory Sir — I completely agree with T. Clausen Ian Crawford from which the image came, if it is and O. B. Nielsen, who say in Corres- School of Earth Sciences, Birkbeck College, recorded at all. pondence (Nature 421, 689; 2003) that Malet Street, London WC1E 7HX, UK The BioImage Database Project peer-reviewing needs to be adequately (http://www.bioimage.org), part of rewarded for the system to work efficiently. ORIEL (Online Research Information However, their proposed remedies, such as Environment for the Life Sciences; mandatory inclusion of reviews in CVs, do Illustration: database http://www.oriel.org), will be a searchable not seem promising, not least because this pictures tell a true story database of multidimensional images of is already routinely done and does not biological specimens. From its outset, we seem to change the general picture. Sir — Julio M. Ottino in his Commentary have felt it essential to acquire not just While toiling on my considerable “Is a picture worth 1,000 words?” (Nature high-quality source images, but also the backlog of manuscripts to review, I came 421, 474–476; 2003) divides images into various images derived from them, and up with a scheme that might stand a two categories: those that convey data detailed metadata documenting the better chance of improving the situation: and those that illustrate scientific ideas. process of their creation. We believe that diligent reviewing could be rewarded by He defends the practice of image this approach addresses many of the issues speeding up publication of the reviewer’s manipulation as sometimes being a raised by Ottino, and should be far more own research. necessary part of the process of discovery, widely adopted. Currently, most of the prominent yet expresses concern about the blurring Chris Catton, David Shotton journals impose a strict deadline (typically of the line between fantasy and reality in Image Bioinformatics Laboratory, between 7 and 14 days) on reviewers, yet scientific illustration. Department of Zoology, University of Oxford, the level of compliance is dismally low, as It may be that the two categories are not South Parks Road, Oxford OX1 3PS, UK any author waiting for longer than two that distinct. The European Space Agency’s months for reviews of a submitted programme Innovative Technologies from manuscript can testify. Science Fiction for Space Applications My suggestion is that a researcher who assumes that even the most fantastic Illustration: images fail meets the deadline for a particular journal illustrations may be a useful stimulus to to portray dynamic skies with satisfactory reviews on, say, six science. On the other hand, images that consecutive occasions within a two-year purport to convey factual data may Sir — An example of the visual deception period is guaranteed by the journal that convey something else entirely. Many practised by scientific illustrators seeking his or her next submission will be given observers, for example, were convinced greater impact — as described by Julio M. privileged status and reviewed within that they could see little human beings Ottino in his Commentary (Nature 421, that same deadline. If the journal’s editor in the sperm images produced by the 474; 2003) — is the increasingly prevalent cannot receive reviews of a privileged sixteenth-century microscopist Antoni practice of adding foreground stars and submission before the deadline, the van Leeuwenhoek, and they recorded background galaxies to images generated journal would have to make a decision this observation as fact, presumably from numerical simulations of galactic based on the other referees’ comments influenced by their beliefs. collisions. Examples appear in National or, if none had been received, accept the Today, we can and should capture Geographic 203, 2, 2003; and on the paper as it stands. not just an image but information Gadget website at www.mpa-garching. A possible variant is for journals that documenting the process of image creation mpg.de/gadget. Another is one of my reject many submissions without review itself, from the original unmodified data simulations, published unadulterated to guarantee to review a privileged to the final web-ready or journal-ready on the cover of Nature on 9 March 1989, submission (again, within the deadline). artwork. If questions arise about the which was later “improved” by the image- This is unlikely to burden these high- interpretation of an image, we need to be makers at NASA’s Space Telescope Science profile journals with piles of junk, because able to go back to the raw data or, if this is Institute (http://hubblesite.org/ an individual writing six or more useful impossible, at least to have a full record of newscenter/archive/2001/22/video/c) — reviews for one of them within a limited what was done to it, and why. For example, without my consent. time span is, by definition, a highly in performing video-enhanced contrast Although one may agree that competent researcher. microscopy, one always subtracts a digital superimposed stars and galaxies add a bit Of course, a crucial aspect is the notion background ‘mottle’ image from the live of visual interest to the blankness of of a ‘useful’ review: to earn a privileged video stream to obtain the mottle-free cyberspace, it is disturbing that these submission, reviews would have to be of video frames that are recorded, and additions are entirely static. In reality, high quality, as judged by the journal’s viewers need to be informed that foreground stars hurtle past like snowflakes editors, rather than one-liners. I believe background subtraction has been carried in a blizzard, and even background galaxies that such direct feedback between a out. Similar arguments relate to the point change noticeably over the hundreds of researcher’s own publications and spread functions used in preparing the millions of years that are represented in the reviewing activity could seriously improve deconvolved fluorescence images computer simulations. Static foreground the peer-review system. mentioned in the article. stars and background galaxies undermine Feedback loops do wonders in Of course, as in the days of pen-and-ink the basic idea of a dynamic Universe that biological systems; they just might work illustration, scientists should still consider these images and animations presumably for science, too. the purpose served by each image in their attempt to convey. Eugene V. Koonin publications, and should make these Joshua E. Barnes National Center for Biotechnology Information, objectives clear to their readers. Scientists Institute for Astronomy, University of Hawaii, National Library of Medicine, National Institutes of today have the additional responsibility of Honolulu, Hawaii 96822, USA Health, Bethesda, Maryland 20894, USA

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