The Master Plan, part II

In the previous section, we introduced the strategy put forward by the NAS through the so called decadal survey reports and reviewed for some items how the previous 1991 one, known also as the Bahcall report, fared in the meantime. We pick here with the top major project as per the last 2000 decadal report, the new space telescope, and continue with other projects.

Not present in the Bahcall report and topping the list for 2000, is the proposed 8 m. at first, scaled down to 6.2 m. afterwards, Next Generation Space Telescope (NGST). This is the successor for Hubble at a projected cost of about U$ 1,000 million. The NGST has already been renamed the James Webb telescope - breaking a tradition of naming new facilities once commissioned - after former NASA head, responsible for the Apollo project. For many scientists, it is the current flagship of space observatory projects, launch planned for 2011.

Webb will be far different from Hubble in several aspects. First, it will be an exposed mirror design instead of a closed tube like Hubble. It will sport an advanced segmented mirror instead of the infamous rigid 2m. flawed mirror of its predecessor, and will be optimized for infrared astronomy. Following international cooperation trends, it will include major subsystems developed by the European Space Agency and Canada.

There are a couple of good reasons why U$ 1,000 million should be expended in yet another space based infrared telescope. First, it will be a more advanced design than Spitzer, with a light gathering capability and resolution in line with its much larger main mirror diameter or aperture (6.2 m. against 0.89 m).
Second, it will specifically target an as yet unobserved quarry: the first generation of galaxies lying so far its light - normally in the visible region - has been shifted all the way to the infrared. Webb will hopefully glimpse the first luminous structures after the Big Bang, aiming squarely at the first and second ladders of the outstanding questions, origin of the Universe, origin of galaxies and galactic structure, thus filling an up to now dark gap.

Late breaking news from the Hubble telescope report sightings of galaxies as far back in time as 700 million years after the Big Bang. This feat was accomplished with an extremelly long exposure (400 Earth orbits from Sept/2003 to Jan/2004), which points to the need for a much more efficient instrument to perform a reasonable survey.