NASA has just successfully launched an infrared space telescope. Another one? But what for?
06:09 California time, on 14 December, a Delta II rocket blasted off from the Vandenberg air force base in order to safely place NASA’s WISE observatory in Earth orbit at an altitude of 523 km (NASA TV video below).
Infrared in “panoramic” mode WISE (Wide-field Infrared Survey Explorer) is not the only space telescope to have infrared capacities, or even, to be exclusively dedicated to this wavelength range. The biggest, for example, would be Spitzer, but this one is coming to the end of is useful life, and obviously, there is the European Herschel which has only just begun its operational phase. We could then ask the question: “why another one?”
An illustration showing WISE (2.85 m long and weighing in at 750 kg) against an infrared sky background. Credit: NASA
The answer is, in fact, quite simple since, as its name indicates, WISE will be operating as a wide-field camera (“Wide-field” is its W) and carrying out a genuine survey (“Survey” is the S of its acronym) of the sky. Herschel is a state-of-the-art instrument that works as a high-performance telephoto lens, but which only sees a small portion of the canopy of heaven. WISE, however, will provide astronomers with an essential overview, a global “panorama” of the sky in infrared light. In a month’s time, following a test and start-up phase, its main 40 cm mirror will begin sweeping the canopy of heaven with a field of view of 43 minutes of arc (basically one and a half times the full Moon). At the end of 7 months, WISE will have covered 99% of the sky 8 times (several sweeps makes it possible to increase the accuracy of the data gathered).
The Orion constellation — one of the great “classics” of the winter sky in the northern hemisphere — in visible light (left) and in infrared light (right). This comparison demonstrates the advantages of infrared astronomy. The Earth’s atmosphere blocks a large part of the infrared spectrum which explains why orbital observatories such as WISE are used. Credit: NASA
From asteroids to galaxies With its sensitivity in the infrared range and by going from close up to further away, this new space telescope will be able to detect asteroids and comets within the solar system, stars which are near to us but difficult to detect in the visible range such as brown dwarfs (“aborted suns”), dust discs from which planets are formed around stars and even the most luminous of far off galaxies in the infrared range. WISE will carry out a genuine survey for each of these fields as it is to cover the entire sky. Thus, as far as asteroids and comets are concerned, the data gathered should result in a better estimation of the number of objects likely to pass close to our planet as well as their size, in other words a more accurate assessment of any potential threats of collision with the Earth. At the end of the day WISE, will provide an infrared map of the canopy of heaven which will be used for selecting future observations for the James Webb Space Telescope, a giant infrared observatory equipped with a 6.5 m diameter mirror (a record!) which associates NASA, the ESA, European Space Agency, and the CSA, Canadian Space Agency. Its launch with an Ariane 5 is scheduled for 2014. Published on 14 December 2009
This is the mythical rocket par excellence, the one that launched Sputnik, the first satellite and Gagarin, the first man in space. The CSG, Guiana Space Centre, is now one of its launch bases: a historic achievement.
The first episode of this famous science-fiction series was broadcast in September 1966. NASA has often made references to these programmes, as in the case of the space shuttle Enterprise, which had the same name as the spaceship in the series.
50 years ago on 5 May 1961, a few weeks after Gagarin, American Alan Shepard reached space. Several years later, he was to walk on the Moon, summarising as it were the race in which the Soviet Union and the United States were competing.
