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Orbital optical interferometry?
Many years ago, I would read pieces in both professional and popular
science journals that predicted that we would eventually have two or more optical telescopes in orbit (presumably in Lagrange points?). Though these telescopes would be separated by great distances (at the very least by kilometers, if not tens or hundreds of kilometers), they would be some- how slaved together and their optical signals combined as a huge optical interferometer. The core idea was that their baseline (the great separation) would give them a stupendous and unheard of resolution of distant objects. Some astronomers said they could even resolve the spectra of very complex biological molecules in the atmospheres of earth-like planets... definitive molecules like chlorophyll. I assume that other equally extraordinary results would be possible. But I never see such think pieces anymore. I understand that there has been massive defunding going on all across most pure science. Very sad and infuriating. But is there more to it than this? Has optical interferometry itself proved to be too intractable? Cheers. [[Mod. note -- Yes, this sort of optical interferometry is very hard, i.e., requires a lot of engineering development & hence costs a lot. A somewhat-less-hard step would be optical interferometry within a single spacecraft, and even this has proven hard (expensive) to develop. See http://en.wikipedia.org/wiki/Space_I...ometry_Mission for a space mission of this sort which was proposed in the US, and eventually cancelled (essentially due to lack of funding). However, in a different arena, constellations of free-flying spacecraft with laser links have been proposed for gravitational-wave detection. LISA, http://en.wikipedia.org/wiki/Laser_I..._Space_Antenna was and is the "classic" proposal of this sort. It was to have been a joint ESA/NASA mission. NASA pulled out of the project in 2011 due to funding limitationsr. ESA continues to explore/plan for a scaled-down version of LISA, now known as eLISA or NGO (most researchers strongly prefer the former name!). Under current plans eLISA will launch around 2034. If ESA is able to obtain funding or hardware contributions from other countries such as China or the USA, eLISA may grow back into something close to the original LISA proposal, and/or launch sooner. A technology development mission to test LISA/eLISA technology, "LISA Pathfinder", should launch this coming fall (2015). -- jt]] |
#2
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Orbital optical interferometry?
In article ,
stargene wrote: But I never see such think pieces anymore. I understand that there has been massive defunding going on all across most pure science. Very sad and infuriating. But is there more to it than this? Has optical interferometry itself proved to be too intractable? Ground-based optical interferometry is alive and well, of course, e.g. https://www.eso.org/sci/facilities/p...opes/vlti.html but the requirement to compensate for the atmosphere restricts it to comparatively bright sources and in general there are not enough baselines to make images (models are fitted to the interferometric data instead). Going to space would help with the first of these problems but make the second harder. Martin -- Martin Hardcastle School of Physics, Astronomy and Mathematics, University of Hertfordshire, UK Please replace the xxx.xxx.xxx in the header with herts.ac.uk to mail me |
#3
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Orbital optical interferometry?
In article ,
stargene writes: Many years ago, ... we would eventually have two or more optical telescopes in orbit (presumably in Lagrange points?). Though these telescopes would be separated by great distances (at the very least by kilometers, if not tens or hundreds of kilometers), they would be some- how slaved together and their optical signals combined as a huge optical interferometer. As Jonathan wrote, this turns out to be difficult and expensive, though not necessarily impossible. A further disadvantage is that it doesn't generate an image unless there are many telescopes. Nevertheless, direct imaging of extrasolar planets (and zodiacal dust) remains a high priority. Two approaches under active study are a coronagraph and a starshade. Recent reports on both are at http://exep.jpl.nasa.gov/newsletters.../probereports/ -- Help keep our newsgroup healthy; please don't feed the trolls. Steve Willner Phone 617-495-7123 Cambridge, MA 02138 USA |
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