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We really do have the technology!

Technologically speaking, there's a huge amount going on in astronomy right now. The space shuttle Atlantis is due to launch on May 11th on the fifth and final servicing mission to the Hubble Space Telescope, ESA will launch not one but two telescopes, Planck and Herchel, abord an Ariane 5 on Thursday 14 May, and the first fringes have been detected between two completed ALMA antennas high in the Atacama desert.

ALMA antennas
The two ALMA antennas used in the project's successful test observation of "first astronomical fringes", at the Operations Support Facility at an altitude of 2900 metres. CREDIT: ALMA (ESO/NAOJ/NRAO)
First up, ALMA. The Atacama Large Millimetre Array (ALMA) is going to be one impressive telescope when it is complete (not quite as good as the SKA of course, but I'm sure you've worked out that my opinion is slightly biased here!). The finished instrument will consist of more than 60 individual dishes spread out across the Atacama desert high in the Chilean Andes where the atmosphere is incredibly dry. ALMA is an interferometer like MERLIN, the VLA and ATCA, but it will operate in the millimetre and submillimetre regimes at much higher frequencies. So what? Well, this will be great for astrochemistry - there are huge numbers of spectral lines from all sorts of different molecules which are in this region of the spectrum, so ALMA will help our understanding of star formation and galaxy evolution by providing a detailed spatial and spectral view of the mm/sub-mm sky. Telescopes are under construction at the moment and some have recently been delivered to the site. First fringes (for an interferometer, this is the equivalent of first light) were obtained on 30th April between two of the 12-m antennas which have been constructed at the ALMA Operations Support Facility (OSF), high in Chile’s Atacama region, at an altitude of 2900 metres. This is an important milesone in the construction of the array - it is the first time that antennas and the other systems required to record data have been joined together to make an observation. "We're very proud and excited to have made this crucial observation, as it proves that the various hardware components work smoothly together. This brings us another step closer to full operations for ALMA as an astronomical observatory," says Wolfgang Wild, the European ALMA Project Manager. The two dishes were pointed at Mars for the test observation, an object in the sky which is bright in the sub-mm and is a useful calibrator. The final telescopes will be situated at an altitude of 5000 metres where the atmosphere is thinner and drier, so there is very little of the atmospheric water vapour which causes huge problems in this part of the spectrum. “We are on target to do the first interferometry tests at the 5000-metre high-altitude site by the end of this year, and by the end of 2011 we plan to have at least 16 antennas working together as a single giant telescope,” said Thijs de Graauw, ALMA Director.

The Hubble Space Telescope CREDIT: NASA
Next on the horizon is the launch of Atlantis on the fifth and final Hubble servicing mission. On 11th May, the shuttle will launch with a crew of seven to carry out the replacement and repair of several instruments which will (hopefully) see the telescope continue to function for several more years. Launched in 1990, the telescope has been used by many astronomers, helped make numerous ground-breaking discoveries and produced some of the most well-known astronomical images of the last two decades. Astronauts from both NASA and ESA have visited Hubble in 1993, 1997, 1999 and 2002 to carry out maintenance and repairs, most recently replacing the Faint Object Camera with the Advanced Camera for Surveys, fixing NICMOS, and replacing the solar panels. Following the loss of Columbia in 2003, plans for a fifth servicing mission were cancelled, but later reinstated. Originally scheduled to fly in September 2008, the mission was again postponed to allow the replacement of another critical system which had failed. The primary objective of the mission is to deliver two new instruments: the Cosmic Origins Spectrograph (COS) will sit in the slot currently occupied by the now redundant Corrective Optics Space Telescope Axial Replacement (COSTAR) package, and the enhanced Wide Field Camera 3 (WFC3) will replace the current Wide Field Planetary Camera 2 (WFPC2). After this mission, every major component on the spacecraft, apart from the mirrors, will have undergone at least one upgrade since Hubble's launch. With any luck, the upgrades will allow the telescope to continue functioning through to at least 2013.

Herschel and Planck
Artists impression of the Herschel and Planck satellites CREDIT: ESA
Last, but not least, is the upcoming launch of not one but two telescopes by ESA. Scheduled for 13:12 GMT on May 14th, Planck and Herschel will lift off together on an Ariane 5 from ESA's launch site in French Guiana. Herschel is a large far-infrared space telescope designed to study some of the coldest objects in space, in a part of the electromagnetic spectrum still mostly unexplored. Its mirror is almost 1.5 times larger than Hubble's and six times larger than that of its predecessor, ISO. Planck, on the other hand, is a microwave telescope that will map the fossil light of the Universe - light from the Big Bang - with unprecedented sensitivity and accuracy. It is designed to map the tiny fluctuations in the CMB previously mapped by COBE and WMAP in much greater detail. The two satellites will launch together and then separate once in space to travel independently out to a point known as L2, a gravitationally stable orbit 1.5 million kilometres on the opposite side of the Earth from the Sun.

All in all (despite the problems of the STFC), it's an exciting time for astronomy.

Posted by Megan on Thursday 07th May 2009 (14:02 UTC) | Add a comment | Permalink


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