Infrared astronomy is a relatively new field that has already contributed a lot of results. In less than 3 decades, astronomers working with infrared have discovered dozens of previously undetected galaxies, and made other discoveries as startling as the staggering amount of water vapour contained in our own Milky Way.
The submillimeter waveband of the electromagnetic spectrum remains less well known by astronomers due to our atmosphere’s dampening effect. This spectral band shows great promise in studying gas and dust clouds which give birth to new stars in our own galaxy or others.
Herschel’s primary objective is to carry out a comprehensive study of the entire sky and the sub-millimetre waves emitted by hundreds of celestial bodies to describe their chemical characteristics, determine their metallicity, evaluate their dust content, and deduce their history in terms of star formation. This leads to a broader objective of mapping molecules in interstellar space and to observe key molecules in these environments’ chemistry in a unique way. Herschel’s objectives also include observing chemical composition in planets’, comets’, and satellites’ atmospheres and surfaces.
In 1997, ESA’s Science Programme Committee confirmed the Herschel mission as the 4th angular stone of the agency’s Horizon 2000 programme. This sub-millimetre astronomy project was a collaboration with NASA.
The mission’s primary objectives were to answer essential questions: how were galaxies created in the early days of our universe? How did the stars form all along its history? And how are these two processes connected?
To find answers, Herschel was placed in orbit around the L2 Lagrange point of the Sun-Earth system (approximately 1.5 million kilometres from our planet, opposite from the Sun). The satellite was scheduled to operate for 3 years, but went beyond expectations and remained operational for almost 4 years.