01-06-2009 - Traces, n. 6

the planck adventure

How It Photographs
the Infant Universe

The Planck Observatory was launched along with Herschel (an infrared space telescope) on March 14, 2009, at 10:12 am local time, from the European Space Port in Kourou, French Guyana. It was launched using the Ariane 5 rocket, weighing 780 tonnes and standing 59 meters high. Beginning June 5th, ESA’s Planck satellite will perform a critical mid-course maneuver that will place the satellite on its final trajectory for arrival at L2, the second Lagrange point of the Sun–Earth system, early in July.

The mission. Planck is Europe’s first mission to study the Cosmic Microwave Background, the relic radiation from the Big Bang, which occurred about 14 thousand million years ago. It can do so with unprecedented precision. The observations are aimed at deciphering the “defects” in the intensity and polarization of the Cosmic Background, so as to throw new light on the first moments of the life of the universe, its geometry, its composition and evolution.

The satellite. Planck carries two scientific instruments on the focal plane of a telescope measuring 1.5 x 1.9 meters. The detectors are so sensitive that they can measure temperature variations in the sky of millionths of a degree. In order to achieve this, some of Planck’s detectors must be cooled to about one-tenth of a degree above absolute zero (-273.15 °C), so that their own heat does not swamp the signal from the sky.  The combination of the High Frequency Instrument, or HFI, and the Low Frequency Instrument, or LFI, covers 9 bands of wavelengths between 11 and 0.3 mm with unprecedented angular resolution and sensitivity. The satellite measures 4.2 meters in height and in width, and weighs 1,950 kg at launch.

Cooperation. The two instruments, LFI and HFI, were projected and built by two international consortiums led respectively by Italy and France. In particular, the Italian contribution to the Planck project is at a very high level (IASF of Bologna, University of Milan, SISSA, Osservatorio Astronomico, Trieste, University of Rome), and also involves the Italian Space Industry (Thales Alenia Space of Milan and Turin), with the support of the Italian Space Agency. The LFI consortium includes Finland, Great Britain, Spain, USA, Germany, Switzerland, Norway, and Denmark.