ASI - Agenzia Spaziale Italiana - Mission and Projects ASI - Agenzia Spaziale Italiana - Mission and Projects


Infrared Astronomy Observatory

Main Theme Infrared Astronomy
Mission Responsibility ESA
Launch Date 2009
End of Mission 2012
Current phase End of phase C/D


Herschel is a cornerstone mission of ESA's Science Programme. It will put into orbit a telescope 3.5 m in diameter which has been passively cooled at 80K and operates in the far infrared to sub-millimetre. Three instruments built by research institution consortiums will be mounted on the focal plane. It will be possible to obtain wide-band images at the line of diffraction limit between 60 and 500 µm and to carry out high-resolution spectroscopic measurements between 150 and 500 µm.


The three instruments are:
- PACS, an image spectrophotometer operating between 60-210 µm that uses bolometric matrices for wide-band observations and a grid spectrometer and matrices of photoconductors for the line images
- SPIRE, an image spectrophotometer operating between 200-620 µm that uses only bolometric matrices. The in-line images are obtained through a Fourier transform spectrometer
- HIFI, a multi-channel heterodyne detection system. The instrument continuously covers the spectral interval between 500 GHz and 1100 GHz beyond a window of 2500 GHz. The spectral resolution can reach 107.

The launch is planned for February 2009 in tandem with the Planck satellite. After the launch the two satellites will separate to reach Lagrange point L2, 1.5 million kilometres from Earth, where the respective observation programmes will be executed.

Scientific Objectives
Herschel will be ESA's first space astronomy observatory for astronomy observations in the sub-millimetre and in the far infrared. The main purpose is to investigate the formation and evolution of galaxies in the Universe and to observe the interior of stellar formation regions.

Italian Contribution
Italian participation to the mission includes the development of the Digital Processing Units (DPU) and the on-board software of the three instruments, the realization of the optic part of the Wide-Band Spectrometer of the HIFI, the in- laboratory calibration of the PACS spectrometer, participation in the three Instrument Control Centres (ICC) and the participation in the preparation of the observation programme and the data analysis procedures.
The activities are coordinated by INAF/IFSI of Rome. In particular, IFSI has the PI-ship of the approved key project "Hi-Gal--Survey of the galactic plane with Herschel".

International Agreements
The Herschel mission is in the framework of ESA's Science Programme to which Italy contributes about 13%.